Pharyngeal pumping inhibition and avoidance by acute exposure to high CO2 levels are both regulated by the BAG neurons via different molecular pathways

PubMed Central

Sharabi, Kfir; Charar, Chayki; Gruenbaum, Yosef

2015-01-01

Carbon dioxide (CO2) is a key molecule in many biological processes. Studies in humans, mice, D. melanogaster, C. elegans, unicellular organisms and plants have shed light on the molecular pathways activated by elevated levels of CO2. However, the mechanisms that organisms use to sense and respond to high CO2 levels remain largely unknown. Previous work has shown that C. elegans quickly avoid elevated CO2 levels using mechanisms that involve the BAG, ASE and AFD neurons via cGMP- and calcium- signaling pathways. Here, we discuss our recent finding that exposure of C. elegans to high CO2 levels leads to a very rapid cessation in the contraction of the pharynx muscles. Surprisingly, none of the tested CO2 avoidance mutants affected the rapid pumping inhibition response to elevated CO2 levels. A forward genetic screen identified that the hid-1-mediated pathway of dense core vesicle maturation regulates the pumping inhibition, probably through affecting neuropeptide secretion. Genetic studies and laser ablation experiments showed that the CO2 response of the pharyngeal muscle pumping is regulated by the BAG neurons, the same neurons that mediate CO2 avoidance. PMID:26430557

Recent development on high-power tandem-pumped fiber laser

NASA Astrophysics Data System (ADS)

Zhou, Pu; Xiao, Hu; Leng, Jinyong; Zhang, Hanwei; Xu, Jiangmin; Wu, Jian

2016-11-01

High power fiber laser is attracting more and more attention due to its advantage in excellent beam quality, high electricto- optical conversion efficiency and compact system configuration. Power scaling of fiber laser is challenged by the brightness of pump source, nonlinear effect, modal instability and so on. Pumping active fiber by using high-brightness fiber laser instead of common laser diode may be the solution for the brightness limitation. In this paper, we will present the recent development of various kinds of high power fiber laser based on tandem pumping scheme. According to the absorption property of Ytterbium-doped fiber, Thulium-doped fiber and Holmium-doped fiber, we have theoretically studied the fiber lasers that operate at 1018 nm, 1178 nm and 1150 nm, respectively in detail. Consequently, according to the numerical results we have optimized the fiber laser system design, and we have achieved (1) 500 watt level 1018nm Ytterbium-doped fiber laser (2) 100 watt level 1150 nm fiber laser and 100 watt level random fiber laser (3) 30 watt 1178 nm Ytterbium-doped fiber laser, 200 watt-level random fiber laser. All of the above-mentioned are the record power for the corresponded type of fiber laser to the best of our knowledge. By using the high-brightness fiber laser operate at 1018 nm, 1178 nm and 1150 nm that we have developed, we have achieved the following high power fiber laser (1) 3.5 kW 1090 nm Ytterbium-doped fiber amplifier (2) 100 watt level Thulium-doped fiber laser and (3) 50 watt level Holmium -doped fiber laser.

Compact high-efficiency 100-W-level diode-side-pumped Nd:YAG laser with linearly polarized TEM00 mode output.

PubMed

Xu, Yi-Ting; Xu, Jia-Lin; Guo, Ya-Ding; Yang, Feng-Tu; Chen, Yan-Zhong; Xu, Jian; Xie, Shi-Yong; Bo, Yong; Peng, Qin-Jun; Cui, Dafu; Xu, Zu-Yan

2010-08-20

We present a compact high-efficiency and high-average-power diode-side-pumped Nd:YAG rod laser oscillator operated with a linearly polarized fundamental mode. The oscillator resonator is based on an L-shaped convex-convex cavity with an improved module and a dual-rod configuration for birefringence compensation. Under a pump power of 344 W, a linearly polarized average output power of 101.4 W at 1064 nm is obtained, which corresponds to an optical-to-optical conversion efficiency of 29.4%. The laser is operated at a repetition rate of 400 Hz with a beam quality factor of M(2)=1.14. To the best of our knowledge, this is the highest optical-to-optical efficiency for a side-pumped TEM(00) Nd:YAG rod laser oscillator with a 100-W-level output ever reported.

Sodium pump molecular activity and membrane lipid composition in two disparate ectotherms, and comparison with endotherms.

PubMed

Turner, Nigel; Hulbert, A J; Else, Paul L

2005-02-01

Previous research has shown that the lower sodium pump molecular activity observed in tissues of ectotherms compared to endotherms, is largely related to the lower levels of polyunsaturates and higher levels of monounsaturates found in the cell membranes of ectotherms. Marine-based ectotherms, however, have very polyunsaturated membranes, and in the current study, we measured molecular activity and membrane lipid composition in tissues of two disparate ectothermic species, the octopus (Octopus vulgaris) and the bearded dragon lizard (Pogona vitticeps), to determine whether the high level of membrane polyunsaturation generally observed in marine-based ectotherms is associated with an increased sodium pump molecular activity relative to other ectotherms. Phospholipids from all tissues of the octopus were highly polyunsaturated and contained high concentrations of the omega-3 polyunsaturate, docosahexaenoic acid (22:6 (n-3)). In contrast, phospholipids from bearded dragon tissues contained higher proportions of monounsaturates and lower proportions of polyunsaturates. Sodium pump molecular activity was only moderately elevated in tissues of the octopus compared to the bearded dragon, despite the much greater level of polyunsaturation in octopus membranes. When the current data were combined with data for the ectothermic cane toad, a significant (P = 0.003) correlation was observed between sodium pump molecular activity and the content of 22:6 (n-3) in the surrounding membrane. These results are discussed in relation to recent work which shows a similar relationship in endotherms.

Portable insulin infusion pumps as an alternative means of insulin delivery in type I diabetes. Report on 11 patients.

PubMed

Distiller, L A

1983-03-26

In many cases of type I diabetes it is extremely difficult to maintain adequate long-term diabetic control. Over the last decade a better understanding has been gained of the relationship between hyperglycaemia and the onset of diabetic microvascular disease. Because of this new techniques are being developed to improve diabetic control; one of these is the use of portable 'open loop' insulin infusion pumps. The results achieved in the first 11 patients to use the Auto-Syringe AS-6C insulin infusion pump on an outpatient basis for longer than 4 months are described. A highly significant improvement in fasting blood glucose levels, 2-hour postprandial blood glucose levels, mean blood glucose levels, glycosylated haemoglobin levels and mean glycaemic excursions was noted in all patients. No cutaneous complications developed despite the use of indwelling subcutaneous needles for up to 4 days at a time. Patient acceptability was excellent and none of the patients had any problems in adapting to 24-hour pump use. The importance of correct patient selection and continuous home blood glucose monitoring is stressed. Insulin infusion pumps can provide an alternative and highly efficacious means of maintaining excellent diabetic control in a select group of type 1 diabetics. However, it is essential that the physician be trained in the use of these pumps and that adequate back-up services are available.

High-energy, high-repetition-rate picosecond pulses from a quasi-CW diode-pumped Nd:YAG system.

PubMed

Noom, Daniel W E; Witte, Stefan; Morgenweg, Jonas; Altmann, Robert K; Eikema, Kjeld S E

2013-08-15

We report on a high-power quasi-CW pumped Nd:YAG laser system, producing 130 mJ, 64 ps pulses at 1064 nm wavelength with a repetition rate of 300 Hz. Pulses from a Nd:YVO(4) oscillator are first amplified by a regenerative amplifier to the millijoule level and then further amplified in quasi-CW diode-pumped Nd:YAG modules. Pulsed diode pumping enables a high gain at repetition rates of several hundred hertz, while keeping thermal effects manageable. Birefringence compensation and multiple thermal-lensing-compensated relay-imaging stages are used to maintain a top-hat beam profile. After frequency doubling, 75 mJ pulses are obtained at 532 nm. The intensity stability is better than 1.1%, which makes this laser an attractive pump source for a high-repetition-rate optical parametric amplification system.

Simulation of the shallow groundwater-flow system near Mole Lake, Forest County, Wisconsin

USGS Publications Warehouse

Fienen, Michael N.; Juckem, Paul F.; Hunt, Randall J.

2011-01-01

The shallow groundwater system near Mole Lake, Forest County, Wis. was simulated using a previously calibrated regional model. The previous model was updated using newly collected water-level measurements and refinements to surface-water features. The updated model was then used to calculate the area contributing recharge for one existing and two proposed pumping locations on lands of the Sokaogon Chippewa Community. Delineated 1-, 5-, and 10-year areas contributing recharge for existing and proposed wells extend from the areas of pumping to the northeast of the pumping locations. Steady-state pumping was simulated for two scenarios: a base pumping scenario using pumping rates that reflect what the Tribe expects to pump and a high pumping scenario, in which the rate was set to the maximum expected from wells installed in this area. In the base pumping scenario, pumping rates of 32 gallons per minute (gal/min; 46,000 gallons per day (gal/d)) from the existing well and 30 gal/min (43,000 gal/d) at each of the two proposed wells were simulated. The high pumping scenario simulated a rate of 70 gal/min (101,000 gal/d) from each of the three pumping wells to estimate of the largest areas contributing recharge that might be expected given what is currently known about the shallow groundwater system. The areas contributing recharge for both the base and high pumping scenarios did not intersect any modeled surface-water bodies; however, the high pumping scenario had a larger areal extent than the base pumping scenario and intersected a septic separator.

Gigahertz single-electron pumping in silicon with an accuracy better than 9.2 parts in 10{sup 7}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamahata, Gento, E-mail: yamahata.gento@lab.ntt.co.jp; Karasawa, Takeshi; Fujiwara, Akira

2016-07-04

High-speed and high-accuracy pumping of a single electron is crucial for realizing an accurate current source, which is a promising candidate for a quantum current standard. Here, using a high-accuracy measurement system traceable to primary standards, we evaluate the accuracy of a Si tunable-barrier single-electron pump driven by a single sinusoidal signal. The pump operates at frequencies up to 6.5 GHz, producing a current of more than 1 nA. At 1 GHz, the current plateau with a level of about 160 pA is found to be accurate to better than 0.92 ppm (parts per million), which is a record value for 1-GHz operation. At 2 GHz,more » the current plateau offset from 1ef (∼320 pA) by 20 ppm is observed. The current quantization accuracy is improved by applying a magnetic field of 14 T, and we observe a current level of 1ef with an accuracy of a few ppm. The presented gigahertz single-electron pumping with a high accuracy is an important step towards a metrological current standard.« less

Advanced performance of small diaphragm vacuum pumps through the use of mechatronics

NASA Astrophysics Data System (ADS)

Lachenmann, R.; Dirscherl, J.

Oil-free diaphragm vacuum pumps have proven to be the best way in vacuum generation for the chemical laboratory and they also find increasing use as backing pumps for modern wide-range turbo molecular pumps. The majority of vacuum pumps in practical use pump only a rather small percentage of their lifetime at full gas load. A pump backing a turbo molecular pump does not have to pump a significant gas load when the high-vacuum pump is running at ultimate vacuum pressure. Also, for a vacuum distillation the vacuum pump has to operate at full speed only at the beginning to lower the pressure inside the system to a vacuum level where evaporation starts. In a rather leak-tight system the distillation process continues by evaporating from the hot liquid and condensing at the cold condenser without the need of a mechanical vacuum pump. Rotational speed controlled diaphragm pumps are now available through progress in mechatronics and offer high pumping speed capability for fast pump-down cycles and precise pressure control for distillations. At low gas load the rotational speed can be reduced, improving maintenance intervals, power consumption, noise, vibration and - surprisingly - also ultimate pressure. The different behaviour in pumping speed and ultimate pressure of rotational speed controlled diaphragm pumps in comparison to constant-speed pumps is related to the mechanical properties of the valves and gas dynamics .

Phosphate-core silica-clad Er/Yb-doped optical fiber and cladding pumped laser.

PubMed

Egorova, O N; Semjonov, S L; Velmiskin, V V; Yatsenko, Yu P; Sverchkov, S E; Galagan, B I; Denker, B I; Dianov, E M

2014-04-07

We present a composite optical fiber with a Er/Yb co-doped phosphate-glass core in a silica glass cladding as well as cladding pumped laser. The fabrication process, optical properties, and lasing parameters are described. The slope efficiency under 980 nm cladding pumping reached 39% with respect to the absorbed pump power and 28% with respect to the coupled pump power. Due to high doping level of the phosphate core optimal length was several times shorter than that of silica core fibers.

An ultra-high gain and efficient amplifier based on Raman amplification in plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vieux, G.; Cipiccia, S.; Grant, D. W.

Raman amplification arising from the excitation of a density echelon in plasma could lead to amplifiers that significantly exceed current power limits of conventional laser media. Here we show that 1–100 J pump pulses can amplify picojoule seed pulses to nearly joule level. The extremely high gain also leads to significant amplification of backscattered radiation from “noise”, arising from stochastic plasma fluctuations that competes with externally injected seed pulses, which are amplified to similar levels at the highest pump energies. The pump energy is scattered into the seed at an oblique angle with 14 J sr -1, and net gainsmore » of more than eight orders of magnitude. The maximum gain coefficient, of 180 cm -1, exceeds high-power solid-state amplifying media by orders of magnitude. The observation of a minimum of 640 J sr -1 directly backscattered from noise, corresponding to ≈10% of the pump energy in the observation solid angle, implies potential overall efficiencies greater than 10%.« less

An ultra-high gain and efficient amplifier based on Raman amplification in plasma

DOE PAGES

Vieux, G.; Cipiccia, S.; Grant, D. W.; ...

2017-05-25

Raman amplification arising from the excitation of a density echelon in plasma could lead to amplifiers that significantly exceed current power limits of conventional laser media. Here we show that 1–100 J pump pulses can amplify picojoule seed pulses to nearly joule level. The extremely high gain also leads to significant amplification of backscattered radiation from “noise”, arising from stochastic plasma fluctuations that competes with externally injected seed pulses, which are amplified to similar levels at the highest pump energies. The pump energy is scattered into the seed at an oblique angle with 14 J sr -1, and net gainsmore » of more than eight orders of magnitude. The maximum gain coefficient, of 180 cm -1, exceeds high-power solid-state amplifying media by orders of magnitude. The observation of a minimum of 640 J sr -1 directly backscattered from noise, corresponding to ≈10% of the pump energy in the observation solid angle, implies potential overall efficiencies greater than 10%.« less

Surface deformation induced by water pumping for construction of Mass Rapid Transportation in Taipei basin

NASA Astrophysics Data System (ADS)

Hu, J. C.; Wu, P. C.; Tung, H.; Tsai, M. C.

2017-12-01

In 1968, there were 2,200 wells in the Taipei Basin used for water supply to meet the requirement of high population density. The overuse of ground water lead to the land subsidence rate up to 5 cm/yr. Although the government had already begun to limit groundwater pumping since 1968, the groundwater in the Taipei Basin demonstrated temporary fluctuation induced by pumping water for large deep excavation site or engineering usage. The previous study based on precise leveling suggested that the surface deformation was highly associated with the recovery of water level. In 1989, widespread uplift dominated in Taipei basin due to the recovery of ground water Table. In this study, we use 37 high-resolution X-band COSMO-SkyMed radar images from May 2011 to April 2015 to characterize deformation pattern in the period of construction of Mass Rapid Transportation (MRT). We also use 30 wells and 380 benchmarks of precise leveling in Taipei basin to study the correlation of surface deformation and change of ground water table. The storability is roughly constant across most of the aquifer with values between 0.8 x 10-4 and 1.3 x 10-3. Moreover, the high water pumping in two major aquifers, Jignme and Wuku Foramtions, before the underground construction for MRT led to inflict surface deformation and no time delay observed for surface deformation during the water pumping. It implies that the poro-elastic effect dominates in major aquifers in Taipei basin.

High-Power Nd:GdVO4 Innoslab Continuous-Wave Laser under Direct 880 nm Pumping

NASA Astrophysics Data System (ADS)

Deng, Bo; Zhang, Heng-Li; Xu, Liu; Mao, Ye-Fei; He, Jing-Liang; Xin, Jian-Guo

2014-11-01

A high-power cw end-pumped laser device is demonstrated with a slab crystal of Nd:GdVO4 operating at 1063 nm. Diode laser stacks at 880 nm are used to pump Nd:GdVO4 into emitting level 4F3/2. The 149 W output power is presented when the absorbed pump power is 390 W and the optical-to-optical conversion efficiency is 38.2%. When the output power is 120 W, the M2 factors are 2.3 in both directions. Additionally, mode overlap inside the resonator is analyzed to explain the beam quality deterioration.

Theoretical model and simulations for a cw exciplex pumped alkali laser.

PubMed

Huang, Wei; Tan, Rongqing; Li, Zhiyong; Lu, Xiaochuan

2015-12-14

The Exciplex Pumped Alkali Laser (XPAL) system, which is similar to DPAL (Diode Pumped Alkali vapor Laser), has been demonstrated in mixtures of Cs vapor, Ar, with and without ethane. Unlike DPAL, it uses the broadband absorption blue satellite of the alkali D₂ line, created by naturally occuring collision pairs. For example, Cs-Ar collision pairs have an absorption width which is as wide as the one of commercial semiconductor diode lasers. A continuous wave XPAL four-level theoretical model is presented in this paper. More factors are considered, such as the spectral dependence of pumped laser absorption for broadband pumping and the longitudinal population variation. Some intra-cavity details, such as longitudinal distributions of pumped laser and alkali laser, can also be solved well. The predictions of optical-to-optical efficiency as a function of temperature and pumped laser intensity are presented. The model predicts that there is an optimum value of temperature or pumped laser intensity. The analysis of the influence of cell length on optical-to-optical efficiency shows that a better performance can be achieved when using longer cell. The prediction of influence of Ar concentration and reflectivity of output coupler shows that higher optical-to-optical efficiency could be achieved if lower reflectivity of output coupler and higher Ar concentration are used. The optical-to-optical efficiency as high as 84% achieved by optimizing configuration with the pumped intensity of 5 × 10⁷ W/cm² presented shows that broadband pumped four-level XPAL system has a potential of high optical-to-optical efficiency.

High-power and highly efficient diode-cladding-pumped holmium-doped fluoride fiber laser operating at 2.94 microm.

PubMed

Jackson, Stuart D

2009-08-01

A high-power diode-cladding-pumped Ho(3+), Pr(3+)-doped fluoride glass fiber laser is demonstrated. The laser produced a maximum output power of 2.5 W at a slope efficiency of 32% using diode lasers emitting at 1,150 nm. The long-emission wavelength of 2.94 microm measured at maximum pump power, which is particularly suited to medical applications, indicates that tailoring of the proportion of Pr(3+) ions can provide specific emission wavelengths while providing sufficient de-excitation of the lower laser level.

Pump Hydro Energy Storage systems (PHES) in groundwater flooded quarries

NASA Astrophysics Data System (ADS)

Poulain, Angélique; de Dreuzy, Jean-Raynald; Goderniaux, Pascal

2018-04-01

Pump storage hydroelectricity is an efficient way to temporarily store energy. This technique requires to store temporarily a large volume of water in an upper reservoir, and to release it through turbines to the lower reservoir, to produce electricity. Recently, the idea of using old flooded quarries as a lower reservoir has been evoked. However, these flooded quarries are generally connected to unconfined aquifers. Consequently, pumping or injecting large volumes of water, within short time intervals, will have an impact on the adjacent aquifers. Conversely, water exchanges between the quarry and the aquifer may also influence the water level fluctuations in the lower reservoir. Using numerical modelling, this study investigates the interactions between generic flooded open pit quarries and adjacent unconfined aquifers, during various pump-storage cyclic stresses. The propagation of sinusoidal stresses in the adjacent porous media and the amplitude of water level fluctuations in the quarry are studied. Homogeneous rock media and the presence of fractures in the vicinity of the quarry are considered. Results show that hydrological quarry - rock interactions must be considered with caution, when implementing pump - storage systems. For rock media characterized by high hydraulic conductivity and porosity values, water volumes exchanges during cycles may affect significantly the amplitude of the water level fluctuations in the quarry, and as a consequence, the instantaneous electricity production. Regarding the impact of the pump - storage cyclic stresses on the surrounding environment, the distance of influence is potentially high under specific conditions, and is enhanced with the occurrence of rock heterogeneities, such as fractures. The impact around the quarry used as a lower reservoir thus appears as an important constraining factor regarding the feasibility of pump - storage systems, to be assessed carefully if groundwater level fluctuations around the quarry are expected to bring up adverse effects. Results highlight opportunities and challenges to be faced, to implement pump - storage hydroelectricity systems in old flooded open pit quarries.

DEVELOPMENT OF COLD CLIMATE HEAT PUMP USING TWO-STAGE COMPRESSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Bo; Rice, C Keith; Abdelaziz, Omar

2015-01-01

This paper uses a well-regarded, hardware based heat pump system model to investigate a two-stage economizing cycle for cold climate heat pump applications. The two-stage compression cycle has two variable-speed compressors. The high stage compressor was modelled using a compressor map, and the low stage compressor was experimentally studied using calorimeter testing. A single-stage heat pump system was modelled as the baseline. The system performance predictions are compared between the two-stage and single-stage systems. Special considerations for designing a cold climate heat pump are addressed at both the system and component levels.

Development of a new control device for stabilizing blood level in reservoir during extracorporeal circulation.

PubMed

Momose, Naoki; Yamakoshi, Rie; Kokubo, Ryo; Yasuda, Toru; Iwamoto, Norio; Umeda, Chinori; Nakajima, Itsuro; Yanagisawa, Mitsunobu; Tomizawa, Yasuko

2010-03-01

We developed a simple device that stabilizes the blood level in the reservoir of the extracorporeal circulation open circuit system by measuring the hydrostatic pressure of the reservoir to control the flow rate of the arterial pump. When the flow rate of the venous return decreases, the rotation speed of the arterial pump is automatically slowed down. Consequently, the blood level in the reservoir is stabilized quickly between two arbitrarily set levels and never falls below the pre-set low level. We conducted a basic experiment to verify the operation of the device, using a mock circuit with water. Commercially available pumps and reservoir were used without modification. The results confirmed that the control method effectively regulates the reservoir liquid level and is highly reliable. The device possibly also functions as a safety device.

Manipulating the wavelength-drift of a Tm laser for resonance enhancement in an intra-cavity pumped Ho laser.

PubMed

Huang, Haizhou; Huang, Jianhong; Liu, Huagang; Li, Jinhui; Lin, Zixiong; Ge, Yan; Dai, Shutao; Deng, Jing; Lin, Wenxiong

2018-03-05

We demonstrate an enhancement mechanism and thermal model for intra-cavity pumped lasers, where resonance enhancement in intra-cavity pumped Ho laser was achieved by manipulating the wavelength-drift nature of the Tm laser for the first time. Optical conversion efficiency of 37.5% from an absorbed 785 nm diode laser to a Ho laser was obtained with a maximum output power of 7.51 W at 2122 nm, which is comparable to the conversion efficiency in 1.9 μm LD pumped Ho lasers. Meanwhile, more severe thermal effects in the Ho-doped gain medium than the Tm-doped one at high power operation were verified based on the built thermal model. This work benefits the design or evaluation of intra-cavity pumped lasers, and the resonance enhancement originated from the difference in reabsorption loss between stark levels at the lasing manifolds of quasi-three-level rare-earth ions has great interest to improve the existing intra-cavity pumped lasers or explore novel lasers.

Genetic characterisation of tigecycline-resistant Enterobacter spp. in blood isolates causing bacteraemia.

PubMed

Cha, Min Kyeong; Kang, Cheol-In; Park, Ga Eun; Kim, So Hyun; Chung, Doo Ryeon; Peck, Kyong Ran; Song, Jae-Hoon

2018-01-05

Tigecycline (TIG) is one of the most important antimicrobial agents used to treat infections by multidrug-resistant bacteria. However, rates of TIG-resistant pathogens have increased recently. This study was conducted to identify the antimicrobial susceptibility profiles and to investigate the role of efflux pumps in high-level TIG-resistant Enterobacter spp. isolates causing bacteraemia. A total of 323 Enterobacter spp. causing bacteraemia were collected from eight hospitals in various regions of South Korea. Minimum inhibitory concentrations (MICs) were determined by the broth microdilution method and Etest. Expression levels of the efflux pump gene acrA and its regulators (ramA and rarA) were examined by quantitative real-time PCR. Isolate relatedness was determined by multilocus sequence typing (MLST). Among the 323 clinical isolates included in this study, 37 (11.5%) were TIG-non-susceptible, of which 8 isolates were highly resistant to TIG with MICs of 8mg/L (4 isolates) or 16mg/L (4 isolates). All high-level TIG-resistant isolates showed increased expression of acrA (0.93-13.3-fold) and ramA (1.4-8.2-fold). Isolates with a tigecycline MIC of 16mg/L also showed overexpression of rarA compared with TIG-susceptible isolates. In this study, overexpression of acrA, ramA and rarA was observed in high-level TIG-resistant Enterobacter spp. isolates. We suggest that rarA might be involved in the regulation of acrA overexpression in high-level TIG-resistant Enterobacter spp. isolates. Efflux pump-mediated resistance should be closely monitored because it could be indirectly attributed to the use of other antibiotics transported by the same efflux pump. Copyright © 2017. Published by Elsevier Ltd.

SSME structural dynamic model development

NASA Technical Reports Server (NTRS)

Foley, Michael J.

1989-01-01

The high pressure fuel turbopump (HPFTP) is a major component of the Space Shuttle Main Engine (SSME) powerhead. The device is a three stage centrifugal pump that is directly driven by a two stage hot gas turbine. The purpose of the pump is to deliver fuel (liquid hydrogen) from the low pressure fuel turbopump (LPFTP) through the main fuel valve (MFV) to the thrust chamber coolant circuits. In doing so, the pump pressurizes the fuel from an inlet pressure of approximately 178 psi to a discharge pressure of over 6000 psi. At full power level (FPL), the pump rotates at a speed of over 37,000 rpm while generating approximately 77,000 horsepower. Obviously, a pump failure at these speeds and power levels could jeopardize the mission. Results are summarized for work in which the solutions obtained from analytical models of the fuel turbopump impellers are compared with the results obtained from dynamic tests.

NO Metabolites Levels in Human Red Blood Cells are Affected by Palytoxin, an Inhibitor of Na(+)/K(+)-ATPase Pump.

PubMed

Carelli-Alinovi, Cristiana; Tellone, Ester; Russo, Anna Maria; Ficarra, Silvana; Pirolli, Davide; Galtieri, Antonio; Giardina, Bruno; Misiti, Francesco

2014-01-01

Palytoxin (PTX), a marine toxin, represents an increasing hazard for human health. Despite its high toxicity for biological systems, the mechanisms triggered by PTX, are not well understood. The high affinity of PTX for erythrocyte Na(+)/K(+)-ATPase pump is largely known, and it indicates PTX as a sensitive tool to characterize the signal transducer role for Na(+)/K(+)-ATPase pump. Previously, it has been reported that in red blood cells (RBC), probably via a signal transduction generated by the formation of a PTX-Na(+)/K(+)-ATPase complex, PTX alters band 3 functions and glucose metabolism. The present study addresses the question of which other signaling pathways are regulated by Na(+)/K(+)-ATPase in RBC. Here it has been evidenced that PTX following its interaction with Na(+)/K(+)-ATPase pump, alters RBC morphology and this event is correlated to decreases by 30% in nitrites and nitrates levels, known as markers of plasma membrane eNOS activity. Orthovanadate (OV), an antagonist of PTX binding to Na(+)/K(+)-ATPase pump, was able to reverse the effects elicited by PTX. Finally, current investigation firstly suggests that Na(+)/K(+)-ATPase pump, following its interaction with PTX, triggers a signal transduction involved in NO metabolism regulation.

High power diode lasers for solid-state laser pumps

NASA Technical Reports Server (NTRS)

Linden, Kurt J.; Mcdonnell, Patrick N.

1994-01-01

The development and commercial application of high power diode laser arrays for use as solid-state laser pumps is described. Such solid-state laser pumps are significantly more efficient and reliable than conventional flash-lamps. This paper describes the design and fabrication of diode lasers emitting in the 780 - 900 nm spectral region, and discusses their performance and reliability. Typical measured performance parameters include electrical-to-optical power conversion efficiencies of 50 percent, narrow-band spectral emission of 2 to 3 nm FWHM, pulsed output power levels of 50 watts/bar with reliability values of over 2 billion shots to date (tests to be terminated after 10 billion shots), and reliable operation to pulse lengths of 1 ms. Pulse lengths up to 5 ms have been demonstrated at derated power levels, and CW performance at various power levels has been evaluated in a 'bar-in-groove' laser package. These high-power 1-cm stacked-bar arrays are now being manufactured for OEM use. Individual diode laser bars, ready for package-mounting by OEM customers, are being sold as commodity items. Commercial and medical applications of these laser arrays include solid-state laser pumping for metal-working, cutting, industrial measurement and control, ranging, wind-shear/atmospheric turbulence detection, X-ray generation, materials surface cleaning, microsurgery, ophthalmology, dermatology, and dental procedures.

Simulation of groundwater flow in the Edwards-Trinity and related aquifers in the Pecos County region, Texas

USGS Publications Warehouse

Clark, Brian R.; Bumgarner, Johnathan R.; Houston, Natalie A.; Foster, Adam L.

2014-01-01

The model was used to simulate groundwater-level altitudes resulting from prolonged pumping to evaluate sustainability of current and projected water-use demands. Each of three scenarios utilized a continuation of the calibrated model. Scenario 1 extended recent (2008) irrigation and nonirrigation pumping values for a 30-year period from 2010 to 2040. Projected groundwater-level changes in and around the Fort Stockton area under scenario 1 change little from current conditions, indicating that the groundwater system is near equilibrium with respect to recent (2008) pumping stress. Projected groundwater-level declines in the eastern part of the model area ranging from 5.0 to 15.0 feet are likely the result of nonequilibrium conditions associated with recent increases in pumping after a prolonged water-level recovery period of little or no pumping. Projected groundwater-level declines (from 15.0 to 31.0 feet) occurred in localized areas by the end of scenario 1 in the Leon-Belding area. Scenario 2 evaluated the effects of extended recent (2008) pumping rates as assigned in scenario 1 with year-round maximum permitted pumping rates in the Belding area. Results of scenario 2 are similar in water-level decline and extent as those of scenario 1. The extent of the projected groundwater-level decline in the range from 5.0 to 15.0 feet in the Leon-Belding irrigation area expanded slightly (about a 2-percent increase) from that of scenario 1. Maximum projected groundwater-level declines in the Leon-Belding irrigation area were approximately 31.3 feet in small isolated areas. Scenario 3 evaluated the effects of periodic increases in pumping rates over the 30-year extended period. Results of scenario 3 are similar to those of scenario 2 in terms of the areas of groundwater-level decline; however, the maximum projected groundwater-level decline increased to approximately 34.5 feet in the Leon-Belding area, and the extent of the decline was larger in area (about a 17-percent increase) than that of scenario 2. Additionally, the area of projected groundwater-level declines in the eastern part of the model area increased from that of scenario 2—two individual areas of decline coalesced into one larger area. The localized nature of the projected groundwater-level declines is a reflection of the high degree of fractured control on storage and hydraulic conductivity in the Edwards-Trinity aquifer. Additionally, the finding that simulated spring flow is highly dependent on the transient nature of hydraulic heads in the underlying aquifer indicates the importance of adequately understanding and characterizing the entire groundwater system.

The effects of residual pump blood on patient plasma free haemoglobin levels post cardiac surgery.

PubMed

Schotola, H; Wetz, A J; Popov, A F; Bergmann, I; Danner, B C; Schöndube, F A; Bauer, M; Bräuer, A

2016-09-01

At the end of cardiopulmonary bypass, there are invariably several hundred millilitres of residual pump blood in the reservoir, which can either be re-transfused or discarded. The objective of this prospective observational study was to investigate the quality of the residual pump blood, focusing on plasma free haemoglobin (pfHb) and blood cell counts. Fifty-one consecutive patients were included in the study. Forty-nine units of residual pump blood and 58 units of transfused red blood cell (RBC) concentrates were analysed. The mean preoperative pfHb of the patients was 0.057 ± 0.062 g/l, which increased gradually to 0.55 ± 0.36 g/l on arrival in the intensive care unit postoperatively. On the first postoperative day, the mean pfHb had returned to within the normal range. Our data showed that haemoglobin, haematocrit, and erythrocyte counts of residual pump blood were approximately 40% of the values in standardised RBC concentrates. Plasma free haemoglobin was significantly higher in residual pump blood compared to RBC concentrates, and nearly twice as high as the pfHb in patient blood samples taken contemporaneously. Our findings indicate that residual pump blood pfHb levels are markedly higher compared to patients' blood and RBC concentrates, but that its administration does not significantly increase patients' pfHb levels.

Simulation of Ground-Water Flow in the Irwin Basin Aquifer System, Fort Irwin National Training Center, California

USGS Publications Warehouse

Densmore, Jill N.

2003-01-01

Ground-water pumping in the Irwin Basin at Fort Irwin National Training Center, California resulted in water-level declines of about 30 feet from 1941 to 1996. Since 1992, artificial recharge from wastewater-effluent infiltration and irrigation-return flow has stabilized water levels, but there is concern that future water demands associated with expansion of the base may cause a resumption of water-level declines. To address these concerns, a ground-water flow model of the Irwin Basin was developed to help better understand the aquifer system, assess the long-term availability and quality of ground water, and evaluate ground-water conditions owing to current pumping and to plan for future water needs at the base. Historical data show that ground-water-level declines in the Irwin Basin between 1941 and 1996, caused the formation of a pumping depression near the pumped wells, and that recharge from the wastewater-treatment facility and disposal area caused the formation of a recharge mound. There have been two periods of water-level recovery in the Irwin Basin since the development of ground water in this basin; these periods coincide with a period of decreased pumpage from the basin and a period of increased recharge of water imported from the Bicycle Basin beginning in 1967 and from the Langford Basin beginning in 1992. Since 1992, artificial recharge has exceeded pumpage in the Irwin Basin and has stabilized water-level declines. A two-layer ground-water flow model was developed to help better understand the aquifer system, assess the long-term availability and quality of ground water, and evaluate ground-water conditions owing to current pumping and to plan for future water needs at the base. Boundary conditions, hydraulic conductivity, altitude of the bottom of the layers, vertical conductance, storage coefficient, recharge, and discharge were determined using existing geohydrologic data. Rates and distribution of recharge and discharge were determined from existing data and estimated when unavailable. Results of predictive simulations indicate that in 50 years, if artificial recharge continues to exceed pumpage in Irwin Basin, water levels could rise as much as 65 feet beneath the pumping depression, and as much as 10 feet in the wastewater-treatment facility and disposal area. Particle-tracking simulations were used to determine the pathlines and the traveltimes of water high in dissolved solids into the main pumping area. The pathlines of particles from two areas with high dissolved-solids concentrations show that in 50 years water from these areas almost reaches the nearest pumped well.

Hotfire testing of a SSME HPOTP with an annular hydrostatic bearing

NASA Technical Reports Server (NTRS)

Nolan, Steven A.; Hibbs, Robert I.; Genge, Gary G.

1993-01-01

A new fluid film bearing package has been tested in the SSME High Pressure Oxygen Turbopump (HPOTP). This fluid film element functions as both the pump end bearing and the preburner pump rear wear ring seal. Most important, it replaces a duplex ball bearing package which has been the primary life limiting component in the turbopump. The design and predicted performance of the turbopump are reviewed. Results are presented for measured pump and bearing performance. The most significant results were obtained from proximity probes located in the bearing bore which revealed large subsynchronous precession at 10 percent of shaft speed during engine start which subsided prior to mainstage power levels and reappeared during engine shutdown at equivalent power levels below 65 percent of nominal. This phenomenon has been attributed to rotating stall in the diffuser. The proximity probes also revealed the location of the bearing in the bore for different operating speeds. Pump vibration characteristics were improved as compared to pumps tested with ball bearings. After seven starts and more than 700 seconds of testing, the pump showed no signs of performance degradation.

Theoretical modeling of diode-laser-pumped 3-μm Er3+ crystal lasers

NASA Astrophysics Data System (ADS)

Tikerpae, Mark; Jackson, Stuart D.; King, Terence A.

1997-05-01

We present results from a theoretical model that has been developed to simulate the 3-micrometer laser transition in Er3+ doped Y3Al5O12 (YAG), Y2Sc2Ga3O12 (YSGG), LiYF4 (YLF) and BaY2F8 (BaYF) host crystals. The rate equations for the lowest seven energy levels of Er3+ were solved numerically and laser action was simulated under cw, gain-switched (pulse pumped) and Q-switched operation with optical pumping at wavelengths of 975 nm and 795 nm. The relative performance of each laser crystal was compared under identical pumping and cavity conditions to establish the optimum crystal host, doping concentration and pump wavelength for each mode of operation. Some unexpected saturation effects were investigated that could limit the maximum practical pump fluence used for high energy Q-switched systems. We investigate possible additional multi-ion energy transfer processes that may cause the decrease in efficiency that is observed experimentally at high Er3+ ion concentrations. In addition, lower laser level deactivation by co-doping with Pr3+ in BaYF was simulated and compared with singly doped Er:BaYF for a range of Er3+ and Pr3+ concentrations. It was found that co-doping was not as effective as the cooperative upconversion process present in singly doped Er3+ crystals for efficient laser operation.

Self-mode-locking operation of a diode-end-pumped Tm:YAP laser with watt-level output power

NASA Astrophysics Data System (ADS)

Zhang, Su; Zhang, Xinlu; Huang, Jinjer; Wang, Tianhan; Dai, Junfeng; Dong, Guangzong

2018-03-01

We report on a high power continuous wave (CW) self-mode-locked Tm:YAP laser pumped by a 792 nm laser diode. Without any additional mode-locking elements in the cavity, stable and self-starting mode-locking operation has been realized. The threshold pump power of the CW self-mode-locked Tm:YAP laser is only 5.4 W. The maximum average output power is as high as 1.65 W at the pump power of 12 W, with the repetition frequency of 468 MHz and the center wavelength of 1943 nm. To the best of our knowledge, this is the first CW self-mode-locked Tm:YAP laser. The experiment results show that the Tm:YAP crystal is a promising gain medium for realizing the high power self-mode-locking operation at 2 µm.

West Closure Complex Pump Intake Model, New Orleans, Louisiana

DTIC Science & Technology

2013-02-01

72  Figure 71. Velocities in Pump 12 intake, intake level = 2.0, only Pump 12 operating. Cross section looking downstream...intake level = 2.0, Pumps 11-13 operating. Cross -section looking downstream. Discharge = 1,740 cfs...73  Figure 73. Velocities in Pump 12 intake, intake level = 2.0, all 11 pumps operating. Cross - section looking downstream. Discharge

MEMS tandem ion-sorption micropump

NASA Astrophysics Data System (ADS)

Grzebyk, T.

2017-12-01

This paper presents a two-stage MEMS ion-sorption micropump, which works in a wide range of pressures—it allows efficient evacuation of gases from the internal volume of any microsystem starting from atmospheric pressure down to 10-6 hPa. The miniature pre-vacuum pump is realized as a two-electrode silicon-glass structure with a very close inter-electrode distance. The use of the silicon substrate as a getter material instead of a metallic layer significantly increases the pumping capacity and as a result, the initial pressure can be reduced to a level of 1 hPa. From this point the pumping is continued with the second glow-discharge high vacuum micropump. This pump is a multilayer structure, in which ions are trapped in crossed electric and magnetic fields. It allows further reduction of pressure down to 10-6 hPa. Both pumps are technologically compatible and together they enable the on-chip generation of avacuum at the desired level in a variety of miniaturized devices.

Separation and purification of enzymes by continuous pH-parametric pumping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, S.Y.; Lin, C.K.; Juang, L.Y.

1985-10-01

Trypsin and chymotrypsin were separated from porcine pancreas extract by continuous pH-parametric pumping. CHOM (chicken ovomucoid) was convalently bound to laboratory-prepared crab chitin with glutaraldehyde to form an affinity adsorbent of trypsin. The pH levels of top and bottom feeds were 8.0 and 2.5, respectively. Similar inhibitor, DKOM (duck ovomucoid), and pH levels 8.0 and 2.0 for top and bottom feeds, respectively, were used for separation and purification of chymotrypsin. e-Amino caproyl-D-tryptophan methyl ester was coupled to chitosan to form an affinity adsorbent for stem bromelain. The pH levels were 8.7 and 3.0. Separation continued fairly well with high yield,more » e.g., 95% recovery of trypsin after continuous pumping of 10 cycles. Optimum operational conditions for concentration and purification of these enzymes were investigated. The results showed that the continuous pH-parametric pumping coupled with affinity chromatography is effective for concentration and purification of enzymes. 19 references.« less

Institutional Diversity in Collective Action: Investigating Successful Village Level Maintenance of Hand Pumps in Malawi

NASA Astrophysics Data System (ADS)

Joubert, Brian Anthony

Providing clean water to rural communities in sub-Saharan Africa remains a challenge. Unsanitary and distant water sources cause a host of health and humanitarian problems. A common means of remedying this situation has been the donation of improved water sources, fitted with low-cost hand pumps. Due donor capacity and/ or policy most hand pumps are donated under the guise of Village Level Operation and Maintenance (VLOM). This premises the notion that recipient communities will take ownership of the new pump and as such will ensure its maintenance. To assist with this many donors carry out programs of technical repair training and the structuring of in-village leadership and management groups. The reality is that a high proportion of these pumps break down after donation and cease to work thereafter. Measures to redress technical elements of these failures through increased training or adequate distribution of spares has seen some success but failure rates remains high. This has led to a call for more attention to demand side issues, focusing on the communal aspects that may influence a village to act collectively in the maintenance of its hand pump. This thesis researched five Malawian villages where the community had maintained their hand pumps for a period of 10 or more years. These hand pumps were treated as shared resources and the literature on common-pool resources and social institutions was used as a theoretical framework. Applying these theories proved to be appropriate for analyzing the norms, conventions and forms of cooperative conduct. This allowed the research to gain insights into institutional diversity and the relationship between 'formal institutions', most often exogenous in nature, and informal' or customary collective action institutions embedded within the communities. Findings showed the emergence of three predominant themes within these successful case studies: 1) the role of leadership at varying levels and how it is embodied institutionally as a vehicle to drive collective action; 2) the contextual norms around rules, monitoring and punishment and; 3) how it should not be assumed that cases of successful pump maintenance necessarily guarantee gender 'empowerment', as is often touted by water development proposals.

Wavelength-tunable Q-switched Raman fiber laser

NASA Astrophysics Data System (ADS)

Ye, Jun; Xu, Jiangming; Zhang, Hanwei; Wu, Jian; Zhou, Pu

2018-03-01

In this presentation, a wavelength-tunable Q-switched Raman fiber laser is presented for the first time, which has a backward pumped configuration, including a section of 3 km passive fiber, a homemade tunable pump source and a highly reflective fiber loop mirror. The output wavelength of the Raman fiber laser can be tuned continuously with ~44 nm range via adjusting the pump wavelength. By inserting an acoustic-optical modulator, the Q-value of the cavity can be switched between high and low level. As a result, pulsed output with a repetition rate of 500 kHz and duration time of 60-80 ns is achieved.

Experimental investigation of a diode-pumped powerful continuous-wave dual-wavelength Nd:YAG laser at 946 and 938.6 nm

NASA Astrophysics Data System (ADS)

Chen, F.; Yu, X.; Yan, R. P.; Li, X. D.; Li, D. J.; Yang, G. L.; Xie, J. J.; Guo, J.

2013-05-01

In this paper, a diode-pumped high-power continuous-wave (cw) dual-wavelength Nd:YAG laser at 946 and 938.6 nm is reported. By using an end-pumped structure, comparative experiments indicate that a 5 mm-length Nd:YAG crystal with a Nd3+-doping concentration of 0.3 at.% is favorable for high-power laser operation, and the optimal transmissivity of the output coupler is 9%. As a result, a maximum output power of 17.2 W for a dual-wavelength laser at 946 and 938.6 nm is obtained at an incident pump power of 75.9 W, corresponding to a slope efficiency of 26.5%. To the best of our knowledge, this is the highest output power of a quasi-three-level dual-wavelength laser using a conventional Nd:YAG crystal achieved to date. By using a traveling knife-edge method, the beam quality factor and far-field divergence angle at 17 W power level are estimated to be 4.0 and 6.13 mrad, respectively.

Analyses of absorption distribution of a rubidium cell side-pumped by a Laser-Diode-Array (LDA)

NASA Astrophysics Data System (ADS)

Yu, Hang; Han, Juhong; Rong, Kepeng; Wang, Shunyan; Cai, He; An, Guofei; Zhang, Wei; Yu, Qiang; Wu, Peng; Wang, Hongyuan; Wang, You

2018-01-01

A diode-pumped alkali laser (DPAL) has been regarded as one of the most potential candidates to achieve high power performances of next generation. In this paper, we investigate the physical properties of a rubidium cell side-pumped by a Laser-Diode-Array (LDA) in this study. As the saturated concentration of a gain medium inside a vapor cell is extremely sensitive to the temperature, the populations of every energy-level of the atomic alkali are strongly relying on the vapor temperature. Thus, the absorption characteristics of a DPAL are mainly dominated by the temperature distribution. In this paper, the temperature, absorption, and lasing distributions in the cross-section of a rubidium cell side-pumped by a LDA are obtained by means of a complicated mathematic procedure. Based on the original end-pumped mode we constructed before, a novel one-direction side-pumped theoretical mode has been established to explore the distribution properties in the transverse section of a rubidium vapor cell by combining the procedures of heat transfer and laser kinetics together. It has been thought the results might be helpful for design of a side-pumped configuration in a high-powered DPAL.

Exploring high power, extreme wavelength operating potential of rare-earth-doped silica fiber

NASA Astrophysics Data System (ADS)

Zhou, Pu; Li, Ruixian; Xiao, Hu; Huang, Long; Zhang, Hanwei; Leng, Jinyong; Chen, Zilun; Xu, Jiangmin; Wu, Jian; Wang, Xiong

2017-08-01

Ytterbium-doped fiber laser (YDFL) and Thulium doped fiber laser (TDFL) have been two kinds of the most widely studied fiber laser in recent years. Although both silica-based Ytterbium-doped fiber and Thulium doped fiber have wide emission spectrum band (more than 200 nm and 400 nm, respectively), the operation spectrum region of previously demonstrated high power YDFL and TDFL fall into 1060-1100 nm and 1900-2050nm. Power scaling of YDFL and TDFL operates at short-wavelength or long-wavelength band, especially for extreme wavelength operation, although is highly required in a large variety of application fields, is quite challenging due to small net gain and strong amplified spontaneous emission (ASE). In this paper, we will present study on extreme wavelength operation of high power YDFL and TDFL in our group. Comprehensive mathematical models are built to investigate the feasibility of high power operation and propose effective technical methods to achieve high power operation. We have achieved (1) Diodepumped 1150nm long wavelength YDFL with 120-watt level output power (2) Diode-pumped 1178nm long wavelength YDFL operates at high temperature with 30-watt level output power (3) Random laser pumped 2153nm long wavelength TDFL with 20-watt level output power (4) Diode-pumped 1018nm short wavelength YDFL with a record 2 kilowatt output power is achieved by using home-made fiber combiner.

Spectra- and temperature-dependent dynamics of directly end-pumped holmium lasers

NASA Astrophysics Data System (ADS)

Ji, Encai; Shen, Yijie; Nie, Mingming; Fu, Xing; Liu, Qiang

2017-04-01

We develop a theoretical model with high accuracy for directly end-pumped Ho3+ laser system considering the influences of ground-state depletion, energy transfer up-conversion, temperature-dependent cross sections, and pump spectra shift. The heat generation in our model is precisely evaluated by calculating the transition rates of non-radiation relaxation processes among manifolds and in-band relaxation processes based on a detailed analysis of energy levels structure of holmium ions. A spatial dynamic thermal iteration method, just developed by our group, is applied to describe the coupled influences between spatial thermal effects and pump spectra. This model is verified to both adapt to the narrow-band good beam-quality pumped case and the broad-band bad beam-quality pumped case, which is in accordance with our previous reported experimental results.

A Pseudomonas putida efflux pump acts on short-chain alcohols.

PubMed

Basler, Georg; Thompson, Mitchell; Tullman-Ercek, Danielle; Keasling, Jay

2018-01-01

The microbial production of biofuels is complicated by a tradeoff between yield and toxicity of many fuels. Efflux pumps enable bacteria to tolerate toxic substances by their removal from the cells while bypassing the periplasm. Their use for the microbial production of biofuels can help to improve cell survival, product recovery, and productivity. However, no native efflux pump is known to act on the class of short-chain alcohols, important next-generation biofuels, and it was considered unlikely that such an efflux pump exists. We report that controlled expression of the RND-type efflux pump TtgABC from Pseudomonas putida DOT-T1E strongly improved cell survival in highly toxic levels of the next-generation biofuels n -butanol, isobutanol, isoprenol, and isopentanol. GC-FID measurements indicated active efflux of n -butanol when the pump is expressed. Conversely, pump expression did not lead to faster growth in media supplemented with low concentrations of n -butanol and isopentanol. TtgABC is the first native efflux pump shown to act on multiple short-chain alcohols. Its controlled expression can be used to improve cell survival and increase production of biofuels as an orthogonal approach to metabolic engineering. Together with the increased interest in P. putida for metabolic engineering due to its flexible metabolism, high native tolerance to toxic substances, and various applications of engineering its metabolism, our findings endorse the strain as an excellent biocatalyst for the high-yield production of next-generation biofuels.

Estimating formation properties from early-time oscillatory water levels in a pumped well

USGS Publications Warehouse

Shapiro, A.M.; Oki, D.S.

2000-01-01

Hydrologists often attempt to estimate formation properties from aquifer tests for which only the hydraulic responses in a pumped well are available. Borehole storage, turbulent head losses, and borehole skin, however, can mask the hydraulic behavior of the formation inferred from the water level in the pumped well. Also, in highly permeable formations or in formations at significant depth below land surface, where there is a long column of water in the well casing, oscillatory water levels may arise during the onset of pumping to further mask formation responses in the pumped well. Usually borehole phenomena are confined to the early stages of pumping or recovery, and late-time hydraulic data can be used to estimate formation properties. In many instances, however, early-time hydraulic data provide valuable information about the formation, especially if there are interferences in the late-time data. A mathematical model and its Laplace transform solution that account for inertial influences and turbulent head losses during pumping is developed for the coupled response between the pumped borehole and the formation. The formation is assumed to be homogeneous, isotropic, of infinite areal extent, and uniform thickness, with leakage from an overlying aquifer, and the screened or open interval of the pumped well is assumed to fully penetrate the pumped aquifer. Other mathematical models of aquifer flow can also be coupled with the equations describing turbulent head losses and the inertial effects on the water column in the pumped well. The mathematical model developed in this paper is sufficiently general to consider both underdamped conditions for which oscillations arise, and overdamped conditions for which there are no oscillations. Through numerical inversion of the Laplace transform solution, type curves from the mathematical model are developed to estimate formation properties through comparison with the measured hydraulic response in the pumped well. The mathematical model is applied to estimate formation properties from a singlewell test conducted near Waialua, Oahu, Hawaii. At this site, both the drawdown and recovery showed oscillatory water levels in the pumped well, and a step-drawdown test showed that approximately 86% of the drawdown is attributed to turbulent head losses. Analyses at this site using late-time drawdown data were confounded by the noise present in the measured water levels due primarily to nearby irrigation wells and ocean tides. By analyzing the early-time oscillatory recovery data at the Waialua site, upper and lower bounds were placed on the transmissivity, T, storage coefficient, S, and the leakance of the confining unit, K′/B′. The upper and lower bounds on T differ by a factor of 2. Upper and lower bounds on S and K′/B′ are much larger, because drawdown stabilized relatively quickly after the onset of pumping.

Hotfire testing of a SSME HPOTP with an annular hydrostatic bearing

NASA Technical Reports Server (NTRS)

Nolan, Steven A.; Hibbs, Robert I.; Genge, Gary G.

1994-01-01

A new fluid film bearing package has been tested in the Space Shuttle Main Engine (SSME) High Pressure Oxygen Turbopump (HPOTP). This fluid film element functions as both the pump end bearing and the preburner pump rear wear ring seal. Most importantly, it replaces a duplex ball bearing package which has been the primary life limiting component in the turbopump. The design and predicted performance of the turbopump are reviewed. Results are presented for measured pump and bearing performance during testing on the NASA Technology Test Bed (TTB) Engine located at MSFC. The most significant results were obtained from proximity probes located in the bearing bore which revealed large subsynchronous precession at ten percent of shaft speed during engine start which subsided prior to mainstage power levels and reappeared during engine shutdown at equivalent power levels below 65% of nominal. This phenomenon has been attributed to rotating stall in the diffuser. The proximity probes also revealed the location of the bearing in the bore for different operating speeds. Pump vibration characteristics were improved as compared to pumps tested with ball bearings. After seven starts and more than 700 seconds of testing, the pump showed no signs of performance degradation.

Contribution of putative efflux pump genes to isoniazid resistance in clinical isolates of Mycobacterium tuberculosis.

PubMed

Narang, Anshika; Giri, Astha; Gupta, Shraddha; Garima, Kushal; Bose, Mridula; Varma-Basil, Mandira

2017-01-01

Isoniazid (INH) resistance in Mycobacterium tuberculosis has been mainly attributed to mutations in katG (64%) and inhA (19%). However, 20%-30% resistance to INH cannot be explained by mutations alone. Hence, other mechanisms besides mutations may play a significant role in providing drug resistance. Here, we explored the role of 24 putative efflux pump genes conferring INH-resistance in M. tuberculosis. Real-time expression profiling of the efflux pump genes was performed in five INH-susceptible and six high-level INH-resistant clinical isolates of M. tuberculosis exposed to the drug. Isolates were also analyzed for mutations in katG and inhA. Four high-level INH-resistant isolates (minimum inhibitory concentration [MIC] ≥2.5 mg/L) with mutations at codon 315 (AGC-ACC) of katG showed upregulation of one of the efflux genes Rv1634, Rv0849, efpA, or p55. Another high-level INH-resistant isolate (MIC 1.5 mg/L), with no mutations at katG or inhA overexpressed 8/24 efflux genes, namely, Rv1273c, Rv0194, Rv1634, Rv1250, Rv3823c, Rv0507, jefA, and p55. Five of these, namely, Rv0194, Rv1634, Rv1250, Rv0507, and p55 were induced only in resistant isolates. The high number of efflux genes overexpressed in an INH-resistant isolate with no known INH resistance associated mutations, suggests a role for efflux pumps in resistance to this antituberculous agent, with the role of Rv0194 and Rv0507 in INH resistance being reported for the first time.

Laser demonstration and performance characterization of optically pumped Alkali Laser systems

NASA Astrophysics Data System (ADS)

Sulham, Clifford V.

Diode Pumped Alkali Lasers (DPALs) offer a promising approach for high power lasers in military applications that will not suffer from the long logistical trails of chemical lasers or the thermal management issues of diode pumped solid state lasers. This research focuses on characterizing a DPAL-type system to gain a better understanding of using this type of laser as a directed energy weapon. A rubidium laser operating at 795 nm is optically pumped by a pulsed titanium sapphire laser to investigate the dynamics of DPALs at pump intensities between 1.3 and 45 kW/cm2. Linear scaling as high as 32 times threshold is observed, with no evidence of second order kinetics. Comparison of laser characteristics with a quasi-two level analytic model suggests performance near the ideal steady-state limit, disregarding the mode mis-match. Additionally, the peak power scales linearly as high as 1 kW, suggesting aperture scaling to a few cm2 is sufficient to achieve tactical level laser powers. The temporal dynamics of the 100 ns pump and rubidium laser pulses are presented, and the continually evolving laser efficiency provides insight into the bottlenecking of the rubidium atoms in the 2P3/2 state. Lastly, multiple excited states of rubidium and cesium were accessed through two photon absorption in the red, yielding a blue and an IR photon through amplified stimulated emission. Threshold is modest at 0.3 mJ/pulse, and slope efficiencies increase dramatically with alkali concentrations and peak at 0.4%, with considerable opportunity for improvement. This versatile system might find applications for IR countermeasures or underwater communications.

High energy efficient solid state laser sources

NASA Technical Reports Server (NTRS)

Byer, Robert L.

1987-01-01

Diode-laser-pumped solid-state laser oscillators and nonlinear processes were investigated. A new generation on nonplanar oscillator was fabricated, and it is anticipated that passive linewidths will be pushed to the kilohertz regime. A number of diode-pumped laser transitions were demonstrated in the rod configuration. Second-harmonic conversion efficiencies as high as 15% are routinely obtained in a servo-locked external resonant doubling crystal at 15 mW cw input power levels at 1064 nm.

Water reuse and cost-benefit of pumping at different spatial levels in a rice irrigation system in UPRIIS, Philippines

NASA Astrophysics Data System (ADS)

Hafeez, M. M.; Bouman, B. A. M.; Van de Giesen, N.; Mushtaq, S.; Vlek, P.; Khan, S.

As agricultural water resources in Asia become increasingly scarce, the irrigation efficiency of rice must be improved. However, in this region there is very limited information available about water use efficiency across spatial levels in irrigation systems. This study quantifies the volume of water reuse and its related cost-benefits at five different spatial levels, ranging from 1500 ha to 18,000 ha, under gravity-fed irrigation system in Upper Pumpanga River Integrated Irrigation System (UPRIIS), Philippines. The major sources of water reuse are considered, namely groundwater pumping, pumping from creeks, combined use and irrigation supplies from check dams. The volume of water available from all four sources of water reuse was quantified through extensive measurements. Production functions were developed to quantify water-yield relationships and to measure the economic value of water reuse. This study was conducted during the dry season of 2001, which existed from 19 November 2000 until 18 May 2001. The water reuse by pumping and check dams was 7% and 22% of the applied surface water at District 1 level. The reuse of surface water through check dams increased linearly with 4.6 Mm 3 per added 1000 ha. Similarly, the total amount of reused water from pumping is equivalent to 30% of the water lost through rice evapotranspiration during the dry season 2001. The results showed that water reuse plays a dominant role in growing a rice crop during the dry season. The result showed no difference in pumping costs between the creek (US0.011/m 3) and shallow pumps (US0.012/m 3). The marginal value of productivity (MVP) of water reuse from creek (US0.044/m 3) was slightly higher than the water reuse through the pumping ground water (US0.039/m 3). Results also indicated that the total volume pumped per ha (m 3/ha) was ranging from 0.39 to 6.93 m 3/ha during the dry season. The results clearly indicate that the quantification of amount of water reuse is very crucial for understanding and finding of water use efficiency at the irrigation system level. The results also revealed that rice production systems are still profitable despite high pumping costs and other associated expenses at all spatial levels in District 1. More than 1500 farmers, from a total of 10,000, use 1154 pumps to draw water from shallow tube wells (or from drains and creeks) for supplementary irrigation at a District level. Reuse of water plays a vital role in growing a profitable rice crop during the dry season.

Kilohertz Pulse Repetition Frequency Slab Ti:sapphire Lasers with High Average Power (10 W)

NASA Astrophysics Data System (ADS)

Wadsworth, William J.; Coutts, David W.; Webb, Colin E.

1999-11-01

High-average-power broadband 780-nm slab Ti:sapphire lasers, pumped by a kilohertz pulse repetition frequency copper vapor laser (CVL), were demonstrated. These lasers are designed for damage-free power scaling when pumped by CVL s configured for maximum output power (of order 100 W) but with poor beam quality ( M 2 300 ). A simple Brewster-angled slab laser side pumped by a CVL produced 10-W average power (1.25-mJ pulses at 8 kHz) with 4.2-ns FWHM pulse duration at an absolute efficiency of 15% (68-W pump power). Thermal lensing in the Brewster slab laser resulted in multitransverse mode output, and pump absorption was limited to 72% by the maximum doping level for commercially available Ti:sapphire (0.25%). A slab laser with a multiply folded zigzag path was therefore designed and implemented that produced high-beam-quality (TEM 00 -mode) output when operated with cryogenic cooling and provided a longer absorption path for the pump. Excessive scattering of the Ti:sapphire beam at the crystal surfaces limited the efficiency of operation for the zigzag laser, but fluorescence diagnostic techniques, gain measurement, and modeling suggest that efficient power extraction ( 15 W TEM 00 , 23% efficiency) from this laser would be possible for crystals with an optical quality surface polish.

High-power diode laser bars as pump sources for fiber lasers and amplifiers (Invited Paper)

NASA Astrophysics Data System (ADS)

Bonati, G.; Hennig, P.; Wolff, D.; Voelckel, H.; Gabler, T.; Krause, U.; T'nnermann, A.; Reich, M.; Limpert, J.; Werner, E.; Liem, A.

2005-04-01

Fiber lasers are pumped by fibercoupled, multimode single chip devices at 915nm. That"s what everybody assumes when asked for the type of fiber laser pumps and it was like this for many years. Coming up as an amplifier for telecom applications, the amount of pump power needed was in the range of several watts. Highest pump powers for a limited market entered the ten watts range. This is a range of power that can be covered by highly reliable multimode chips, that have to survive up to 25 years, e.g. in submarine applications. With fiber lasers entering the power range and the application fields of rod and thin disc lasers, the amount of pump power needed raised into the area of several hundred watts. In this area of pump power, usually bar based pumps are used. This is due to the much higher cost pressure of the industrial customers compared to telecom customers. We expect more then 70% of all industrial systems to be pumped by diode laser bars. Predictions that bar based pumps survive for just a thousand hours in cw-operation and fractions of this if pulsed are wrong. Bar based pumps have to perform on full power for 10.000h on Micro channel heat sinks and 20.000h on passive heatsinks in industrial applications, and they do. We will show a variety of data, "real" long time tests and statistics from the JENOPTIK Laserdiode as well as data of thousands of bars in the field, showing that bar based pumps are not just well suitable for industrial applications on high power levels, but even showing benefits compared to chip based pumps. And it"s reasonable, that the same objectives of cost effectiveness, power and lifetime apply as well to thin disc, rod and slab lasers as to fiber lasers. Due to the pumping of fiber lasers, examples will be shown, how to utilize bars for high brightness fiber coupling. In this area, the automation is on its way to reduce the costs on the fibercoupling, similar to what had been done in the single chip business. All these efforts are part of the JENOPTIK Laserdiode"s LongLifeTechnologie.

A solar simulator-pumped gas laser for the direct conversion of solar energy

NASA Technical Reports Server (NTRS)

Weaver, W. R.; Lee, J. H.

1981-01-01

Most proposed space power systems are comprised of three general stages, including the collection of the solar radiation, the conversion to a useful form, and the transmission to a receiver. The solar-pumped laser, however, effectively eliminates the middle stage and offers direct photon-to-photon conversion. The laser is especially suited for space-to-space power transmission and communication because of minimal beam spread, low power loss over large distances, and extreme energy densities. A description is presented of the first gas laser pumped by a solar simulator that is scalable to high power levels. The lasant is an iodide C3F7I that as a laser-fusion driver has produced terawatt peak power levels.

High-power Femtosecond Optical Parametric Amplification at 1 kHz in BiB(3)O(6) pumped at 800 nm.

PubMed

Petrov, Valentin; Noack, Frank; Tzankov, Pancho; Ghotbi, Masood; Ebrahim-Zadeh, Majid; Nikolov, Ivailo; Buchvarov, Ivan

2007-01-22

Substantial power scaling of a travelling-wave femtosecond optical parametric amplifier, pumped near 800 nm by a 1 kHz Ti:sapphire laser amplifier, is demonstrated using monoclinic BiB(3)O(6) in a two stage scheme with continuum seeding. Total energy output (signal plus idler) exceeding 1 mJ is achieved, corresponding to an intrinsic conversion efficiency of approximately 32% for the second stage. The tunability extends from 1.1 to 2.9 microm. The high parametric gain and broad amplification bandwidth of this crystal allowed the maintenance of the pump pulse duration, leading to pulse lengths less than 140 fs, both for the signal and idler pulses, even at such high output levels.

A 100J-level nanosecond pulsed DPSSL for pumping high-efficiency, high-repetition rate PW-class lasers

NASA Astrophysics Data System (ADS)

De Vido, M.; Ertel, K.; Mason, P. D.; Banerjee, S.; Phillips, P. J.; Smith, J. M.; Butcher, T. J.; Chekhlov, O.; Divoky, M.; Pilar, J.; Hooker, C.; Shaikh, W.; Lucianetti, A.; Hernandez-Gomez, C.; Mocek, T.; Edwards, C.; Collier, J. L.

2017-02-01

In this paper, we review the development, at the STFC's Central Laser Facility (CLF), of high energy, high repetition rate diode-pumped solid-state laser (DPSSL) systems based on cryogenically-cooled multi-slab ceramic Yb:YAG. Up to date, two systems have been completed, namely the DiPOLE prototype and the DiPOLE100 system. The DiPOLE prototype has demonstrated amplification of nanosecond pulses in excess of 10 J at 10 Hz repetition rate with an opticalto- optical efficiency of 22%. The larger scale DiPOLE100 system, designed to deliver 100J temporally-shaped nanosecond pulses at 10 Hz repetition rate, has been developed at the CLF for the HiLASE project in the Czech Republic. Recent experiments conducted on the DiPOLE100 system demonstrated the energy scalability of the DiPOLE concept to the 100 J pulse energy level. Furthermore, second harmonic generation experiments carried out on the DiPOLE prototype confirmed the suitability of DiPOLE-based systems for pumping high repetition rate PW-class laser systems based on Ti:sapphire or optical parametric chirped pulse amplification (OPCPA) technology.

24. Pump Room interiordewatering pump motor on upper level. Note ...

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

24. Pump Room interior-dewatering pump motor on upper level. Note the removable roof hatch (steel frame) directly above motor. Dewatering pumps motor control center at left - Hunters Point Naval Shipyard, Drydock No. 4, East terminus of Palou Avenue, San Francisco, San Francisco County, CA

Relevant role of efflux pumps in high levels of rifaximin resistance in Escherichia coli clinical isolates.

PubMed

Gomes, C; Ruiz, L; Pons, M J; Ochoa, T J; Ruiz, J

2013-09-01

Enteropathogens have shown a high level of resistance against commonly used antibacterial drugs in Peru and it is necessary to explore alternative treatments. The aim of this study was to analyse the in vitro activity of rifaximin against diarrhoeagenic and commensal Escherichia coli in children less than 2 years of age. The minimal inhibitory concentration (MIC) to rifampicin and rifaximin was determined for 210 strains in the presence and absence of phenyl-arginine-β-naphthylamide (PAβN) and the mechanisms of resistance were investigated. The MIC levels ranged between 8 and >256 mg/litre and the predominant mechanism of resistance to rifaximin was the efflux pumps inhibited by PAβN in 95.2% of the isolates. The present MIC values are higher than those observed in other studies. Efflux pumps inhibited by PAβN were the cause of the rifaximin resistance in the majority of cases and suggest the presence of an environmental selective pressure. Consequently, rifaximin should be used with caution in the treatment of diarrhoea in Peru.

Superluminescence from an optically pumped molecular tunneling junction by injection of plasmon induced hot electrons

PubMed Central

Braun, Kai; Wang, Xiao; Kern, Andreas M; Adler, Hilmar; Peisert, Heiko; Chassé, Thomas; Zhang, Dai

2015-01-01

Summary Here, we demonstrate a bias-driven superluminescent point light-source based on an optically pumped molecular junction (gold substrate/self-assembled molecular monolayer/gold tip) of a scanning tunneling microscope, operating at ambient conditions and providing almost three orders of magnitude higher electron-to-photon conversion efficiency than electroluminescence induced by inelastic tunneling without optical pumping. A positive, steadily increasing bias voltage induces a step-like rise of the Stokes shifted optical signal emitted from the junction. This emission is strongly attenuated by reversing the applied bias voltage. At high bias voltage, the emission intensity depends non-linearly on the optical pump power. The enhanced emission can be modelled by rate equations taking into account hole injection from the tip (anode) into the highest occupied orbital of the closest substrate-bound molecule (lower level) and radiative recombination with an electron from above the Fermi level (upper level), hence feeding photons back by stimulated emission resonant with the gap mode. The system reflects many essential features of a superluminescent light emitting diode. PMID:26171286

Do Arthroscopic Fluid Pumps Display True Surgical Site Pressure During Hip Arthroscopy?

PubMed

Ross, Jeremy A; Marland, Jennifer D; Payne, Brayden; Whiting, Daniel R; West, Hugh S

2018-01-01

To report on the accuracy of 5 commercially available arthroscopic fluid pumps to measure fluid pressure at the surgical site during hip arthroscopy. Patients undergoing hip arthroscopy for femoroacetabular impingement were block randomized to the use of 1 of 5 arthroscopic fluid pumps. A spinal needle inserted into the operative field was used to measure surgical site pressure. Displayed pump pressures and surgical site pressures were recorded at 30-second intervals for the duration of the case. Mean differences between displayed pump pressures and surgical site pressures were obtained for each pump group. Of the 5 pumps studied, 3 (Crossflow, 24K, and Continuous Wave III) reflected the operative field fluid pressure within 11 mm Hg of the pressure readout. In contrast, 2 of the 5 pumps (Double Pump RF and FMS/DUO+) showed a difference of greater than 59 mm Hg between the operative field fluid pressure and the pressure readout. Joint-calibrated pumps more closely reflect true surgical site pressure than gravity-equivalent pumps. With a basic understanding of pump design, either type of pump can be used safely and efficiently. The risk of unfamiliarity with these differences is, on one end, the possibility of pump underperformance and, on the other, potentially dangerously high operating pressures. Level II, prospective block-randomized study. Copyright © 2017. Published by Elsevier Inc.

Vitamin K3 Induces the Expression of the Stenotrophomonas maltophilia SmeVWX Multidrug Efflux Pump.

PubMed

Blanco, P; Corona, F; Sánchez, M B; Martínez, J L

2017-05-01

Stenotrophomonas maltophilia is an opportunistic pathogen with increasing prevalence, which is able to cause infections in immunocompromised patients or in those with a previous pathology. The treatment of the infections caused by this bacterium is often complicated due to the several intrinsic antibiotic resistance mechanisms that it presents. Multidrug efflux pumps are among the best-studied mechanisms of S. maltophilia antibiotic resistance. Some of these efflux pumps have a basal expression level but, in general, their expression is often low and only reaches high levels when the local regulator is mutated or bacteria are in the presence of an effector. In the current work, we have developed a yellow fluorescent protein (YFP)-based sensor with the aim to identify effectors able to trigger the expression of SmeVWX, an efflux pump that confers resistance to quinolones, chloramphenicol, and tetracycline when it is expressed at high levels. With this purpose in mind, we tested a variety of different compounds and analyzed the fluorescence signal given by the expression of YFP under the control of the smeVWX promoter. Among the tested compounds, vitamin K 3 , which is a compound belonging to the 2-methyl-1,4-naphthoquinone family, is produced by plants in defense against infection, and has increasing importance in human therapy, was able to induce the expression of the SmeVWX efflux pump. In addition, a decrease in the susceptibility of S. maltophilia to ofloxacin and chloramphenicol was observed in the presence of vitamin K 3 , in both wild-type and smeW -deficient strains. Copyright © 2017 American Society for Microbiology.

2.097μ Cth:YAG flashlamp pumped high energy high efficiency laser operation (patent pending)

NASA Astrophysics Data System (ADS)

Bar-Joseph, Dan

2018-02-01

Flashlamp pumped Cth:YAG lasers are mainly used in medical applications (urology). The main laser transition is at 2.13μ and is called a quasi-three level having an emission cross-section of 7x10-21 cm2 and a ground state absorption of approximately 5%/cm. Because of the relatively low absorption, combined with a modest emission cross-section, the laser requires high reflectivity output coupling, and therefore high intra-cavity energy density which limits the output to approximately 4J/pulse for reliable operation. This paper will describe a method of efficiently generating high output energy at low intra-cavity energy density by using an alternative 2.097μ transition having an emission cross-section of 5x10-21 cm2 and a ground level absorption of approximately 14%/cm.

High-power dual-wavelength Ho-doped fiber laser at >2 μm tandem pumped by a 1.15 μm fiber laser

PubMed Central

Jin, Xiaoxi; Lou, Zhaokai; Chen, Yizhu; Zhou, Pu; Zhang, Hanwei; Xiao, Hu; Liu, Zejin

2017-01-01

We demonstrated a high-power continuous-wave (CW) dual-wavelength Ho-doped fiber laser (HDFL) at 2049 nm and 2153 nm with a simple coupled-cavity configuration. A ~100 W laser diode-pumped fiber laser at 1150 nm served as the pump source. The maximum output power reached ~22.3 W and the slope efficiency was 23%. By altering the incident pump power, the power ratio of two signal wavelengths could be tuned in a large range due to gain competition. As far as we know, this is the first CW dual-wavelength HDFL with the power exceeding ten-watt-level, and the first dual-wavelength HDFL with the central wavelengths exceeding 2.0 μm and 2.15 μm respectively. PMID:28181571

Highly stable self-pulsed operation of an Er:Lu2O3 ceramic laser at 2.7 µm

NASA Astrophysics Data System (ADS)

Wang, Li; Huang, Haitao; Shen, Deyuan; Zhang, Jian; Chen, Hao; Tang, Dingyuan

2017-04-01

We report on the highly stable self-pulsed operation of a 2.74 µm Er:Lu2O3 ceramic laser pumped by a wavelength locked narrow bandwidth 976 nm laser diode. The operating pulse repetition rate is continuously tunable from 126 kHz to 270 kHz depending on the pump power level. For 12.3 W of absorbed diode pump power, the Er:Lu2O3 ceramic laser generates 820 mW of average output power at a 270 kHz repetition rate and with a pulse duration of 183 ns. The corresponding pulse-to-pulse amplitude fluctuation is estimated to be less than 0.7%. In the continues-wave (CW) mode of operation, the laser yields over 1.3 W of output power with a slope efficiency of 11.9% with respect to the 976 nm pump power.

High-power dual-wavelength Ho-doped fiber laser at >2 μm tandem pumped by a 1.15 μm fiber laser

NASA Astrophysics Data System (ADS)

Jin, Xiaoxi; Lou, Zhaokai; Chen, Yizhu; Zhou, Pu; Zhang, Hanwei; Xiao, Hu; Liu, Zejin

2017-02-01

We demonstrated a high-power continuous-wave (CW) dual-wavelength Ho-doped fiber laser (HDFL) at 2049 nm and 2153 nm with a simple coupled-cavity configuration. A ~100 W laser diode-pumped fiber laser at 1150 nm served as the pump source. The maximum output power reached ~22.3 W and the slope efficiency was 23%. By altering the incident pump power, the power ratio of two signal wavelengths could be tuned in a large range due to gain competition. As far as we know, this is the first CW dual-wavelength HDFL with the power exceeding ten-watt-level, and the first dual-wavelength HDFL with the central wavelengths exceeding 2.0 μm and 2.15 μm respectively.

Lunar base heat pump

NASA Technical Reports Server (NTRS)

Goldman, Jeffrey H.; Tetreault, R.; Fischbach, D.; Walker, D.

1994-01-01

A heat pump is a device which elevates the temperature of a heat flow by a means of an energy input. By doing this, the heat pump can cause heat to transfer faster from a warm region to a cool region, or it can cause heat to flow from a cool region to a warmer region. The second case is the one which finds vast commercial applications such as air conditioning, heating, and refrigeration. Aerospace applications of heat pumps include both cases. The NASA Johnson Space Center is currently developing a Life Support Systems Integration Facility (LSSIF, previously SIRF) to provide system-level integration, operational test experience, and performance data that will enable NASA to develop flight-certified hardware for future planetary missions. A high lift heat pump is a significant part of the TCS hardware development associated with the LSSIF. The high lift heat pump program discussed here is being performed in three phases. In Phase 1, the objective is to develop heat pump concepts for a lunar base, a lunar lander, and for a ground development unit for the SIRF. In Phase 2, the design of the SIRF ground test unit is being performed, including identification and evaluation of safety and reliability issues. In Phase 3, the SIRF unit will be manufactured, tested, and delivered to the NASA Johnson Space Center.

Pancreatic bicarbonate secretion involves two proton pumps.

PubMed

Novak, Ivana; Wang, Jing; Henriksen, Katrine L; Haanes, Kristian A; Krabbe, Simon; Nitschke, Roland; Hede, Susanne E

2011-01-07

Pancreas secretes fluid rich in digestive enzymes and bicarbonate. The alkaline secretion is important in buffering of acid chyme entering duodenum and for activation of enzymes. This secretion is formed in pancreatic ducts, and studies to date show that plasma membranes of duct epithelium express H(+)/HCO(3)(-) transporters, which depend on gradients created by the Na(+)/K(+)-ATPase. However, the model cannot fully account for high-bicarbonate concentrations, and other active transporters, i.e. pumps, have not been explored. Here we show that pancreatic ducts express functional gastric and non-gastric H(+)-K(+)-ATPases. We measured intracellular pH and secretion in small ducts isolated from rat pancreas and showed their sensitivity to H(+)-K(+) pump inhibitors and ion substitutions. Gastric and non-gastric H(+)-K(+) pumps were demonstrated on RNA and protein levels, and pumps were localized to the plasma membranes of pancreatic ducts. Quantitative analysis of H(+)/HCO(3)(-) and fluid transport shows that the H(+)-K(+) pumps can contribute to pancreatic secretion in several species. Our results call for revision of the bicarbonate transport physiology in pancreas, and most likely other epithelia. Furthermore, because pancreatic ducts play a central role in several pancreatic diseases, it is of high relevance to understand the role of H(+)-K(+) pumps in pathophysiology.

Pump-induced phase aberrations in Yb3+-doped materials(Conference Presentation)

NASA Astrophysics Data System (ADS)

Keppler, Sebastian; Tamer, Issa; Hornung, Marco; Körner, Jörg; Liebetrau, Hartmut; Hein, Joachim; Kaluza, Malte C.

2017-05-01

Optical pumping of laser materials is an effective way to create a population inversion necessary for laser operation. However, a fraction of the pump energy is always transfered as heat into the laser material, which is mainly caused by the quantum defect. For Yb3+-doped materials, the small energy difference between the pump level and the laser level and the pumping with narrowband high-power laser diodes result in a quantum defect of approx. 9%, which is significantly lower compared to other dopants e.g. Ti3+ (33%) or Nd3+ (24%). Due to the low heat introduction, high optical-to-optical efficiency and high repetition rate laser systems based on diode-pumping are well-suited for a number of applications. Here, however, laser beam quality is of crucial importance. Phase distortions and beam profile modulations can lead to optical damages as well as a significant reduction of the focal spot intensity. Pump-induced phase aberrations are the main cause for phase distortions of the amplified laser beam. The heat transferred to the material causes a change of the refractive index (dn/dT), thermal expansion and stress within the laser material, eventually leading to spatial phase aberrations (also called `thermal lens'). However, the spatially dependent distribution of the population inversion itself also leads to spatial phase aberrations. Since electron excitation directly leads to a change in the charge distribution of the laser active ions, the dynamic response of the material to external fields changes. These electronic phase aberrations (also called `population lens') are described by a change in the polarizability of the material. Due to the low quantum defect of Yb3+-doped materials, this effect becomes more important. We show the first comprehensive spatio-temporal characterization of the pump-induced phase aberration including both effects. A high-resolution interference measurement was carried out with time steps of 50µs for times during the pump period and the cooling period between subsequent pump pulses. We found that both phase effects significantly contribute to the overall phase distortions. Since the temporal characteristic of the electronic phase depends on the fluorescence lifetime and the thermal phase on the thermal diffusivity, both phase effects could be distinguished by their different lifetimes. The measurements were carried out for Yb:YAG, Yb:CaF2 and Yb:glass, and are in excellent agreement to our detailed, COMSOL-based, spatio-temporal phase simulations. Since Yb:CaF2 and Yb:glass provide a negative dn/dT, the electronic phase change becomes even more important and, in case of Yb:CaF2, almost completely compensates the thermal phase imprint of a pump pulse during the time frame of laser pulse amplification.

The impact of baseline hemoglobin A1c levels prior to initiation of pump therapy on long-term metabolic control.

PubMed

Pinhas-Hamiel, Orit; Tzadok, Michal; Hirsh, Galit; Boyko, Valentina; Graph-Barel, Chana; Lerner-Geva, Liat; Reichman, Brian

2010-07-01

This study was done to identify factors influencing long-term metabolic control in youth with type 1 diabetes mellitus (T1DM) treated with an insulin pump. Data were obtained from retrospective chart review of 113 patients (52 males) with T1DM treated with an insulin pump for up to 7 years. Their mean +/- SD age at diagnosis of T1DM was 9.7 +/- 5.1 years, and that at pump therapy initiation was 13.8 +/- 6.1 years. Linear trends and changes in hemoglobin A1c (HbA1c) levels following pump insertion were evaluated according to gender, metabolic control prior to initiation of pump therapy, time from diagnosis of diabetes until pump therapy, age at initiation, and the duration of pump treatment. Mean HbA1c levels of patients with good baseline metabolic control (HbA1c level 9%) control groups (8.1 +/- 0.9% and 8.2 +/- 1.1%, respectively; P < 0.001). However, with time a significant trend for increasing HbA1c level was demonstrated in the group with good metabolic control (P value for trend = 0.004). HbA1c levels of patients with poor baseline metabolic control decreased significantly immediately after pump initiation (9.4 +/- 1.6% vs. 8.0 +/- 1.2%, P = 0.0001) and thereafter remained stable (P value for trend = 0.54). In the multivariable analyses, baseline HbA1c level

Progress report on the ground-water resources of the Louisville area, Kentucky, 1949-55

USGS Publications Warehouse

Bell, Edwin A.; Kellogg, Robert W.; Kulp, Willis K.

1963-01-01

In the Louisville area, the principal water-bearing formations are the glacial-outwash sand and gravel and, in places, the underlying limestone. During the period 1949 through 1955 pumpage from the two aquifers averaged about 30 mgd (million gallons per day). The pumpage was approximately in balance with the normal net recharge to the area but was only about 8 percent of the estimated potential supply of ground water, including induced infiltration from the river. In the Louisville area, ground water is used chiefly for air conditioning and for industrial cooling. In the part of the area southwest of the city, ground water is used also for public supply. High ground-water levels in 1937 resulted from the greatest flood of record. Subsequently, water levels generally declined in the entire Louisville area. In downtown Louisville, where ground water is used for air conditioning, the water level fluctuates seasonally in response to variations in the rate of pumping. In the heavily pumped industrial areas, where ground water is used for cooling, water-level fluctuations correlate with changes in rates of pumping caused by variations in production schedules. Levels were lowest during the years of World War II. During the period 1952-55, relatively low levels throughout the area reflected the effects of less than normal rainfall, summer drought, and sustained pumping. Ground water in the Louisville area is very hard and generally of the calcium bicarbonate or calcium sulfate type. It is high in iron and sulfate content but is moderately low in chloride content. In water of the sand and gravel aquifer, the concentration of sulfate has increased gradually during the period 1949-54.

Hydraulic and Thermal Response to Intermittent Pumping in Unconfined Alluvial Aquifers along a Regulated Stream

NASA Astrophysics Data System (ADS)

Maharjan, Madan

Groundwater response to stream stage fluctuations was studied using a year-long time series of stream stage and well heads in Glen Dale and New Martinsville, WV. Stream stage fluctuations exerted primary control over groundwater levels, especially during high flows. The location and operation of river pools created by dams alter groundwater flow paths and velocities. Aquifers are more prone to surface water infiltration in the upper reaches of pools than in lower reaches. Aquifer diffusivity is heterogeneous within and between the two sites. Temperature fluctuations were observed for 2.5 years in 14 wells in three alluvial aquifers. Temperature signals have 2 components corresponding to pump-on and pump-off periods. Both components vary seasonality at different magnitudes. While pump-off temperatures fluctuated up to 3.8o C seasonally, short-term temperature shifts induced by turning the pump on were 0.2 to 2.5o C. Pumping-induced temperature shifts were highest in magnitude in summer and winter. Groundwater temperature lagged behind that of surface water by approximately six months. Pumping induced and seasonal temperature shifts were spatially and temporally complex but indicate stream exfiltration is a major driver for a number of these wells. Numerical simulation of aquifer response to pumping show different conditions before and after well-field development. During pre-development, the stream was losing at high flow and gaining at low flow. During post-development, however, the stream was losing at high flow and spatially variable at low flow. While bank storage gained only during high stage, stream exfiltration occurred year-round. Pumping induced stream exfiltration by creating an extensive cone of depression beneath the stream in both upstream and downstream directions. Spatially and temporally variable groundwater-surface water interaction next to a regulated stream were studied using analytical and numerical models, based on field observations. Seasonality plays an important role in these interactions, but human activity may also alter its intensity.

Diode lasers optimized in brightness for fiber laser pumping

NASA Astrophysics Data System (ADS)

Kelemen, M.; Gilly, J.; Friedmann, P.; Hilzensauer, S.; Ogrodowski, L.; Kissel, H.; Biesenbach, J.

2018-02-01

In diode laser applications for fiber laser pumping and fiber-coupled direct diode laser systems high brightness becomes essential in the last years. Fiber coupled modules benefit from continuous improvements of high-power diode lasers on chip level regarding output power, efficiency and beam characteristics resulting in record highbrightness values and increased pump power. To gain high brightness not only output power must be increased, but also near field widths and far field angles have to be below a certain value for higher power levels because brightness is proportional to output power divided by beam quality. While fast axis far fields typically show a current independent behaviour, for broadarea lasers far-fields in the slow axis suffer from a strong current and temperature dependence, limiting the brightness and therefore their use in fibre coupled modules. These limitations can be overcome by carefully optimizing chip temperature, thermal lensing and lateral mode structure by epitaxial and lateral resonator designs and processing. We present our latest results for InGaAs/AlGaAs broad-area single emitters with resonator lengths of 4mm emitting at 976nm and illustrate the improvements in beam quality over the last years. By optimizing the diode laser design a record value of the brightness for broad-area lasers with 4mm resonator length of 126 MW/cm2sr has been demonstrated with a maximum wall-plug efficiency of more than 70%. From these design also pump modules based on 9 mini-bars consisting of 5 emitters each have been realized with 360W pump power.

Generation of high powers from diode pumped chromium-3+ doped colquiriites

NASA Astrophysics Data System (ADS)

Eichenholz, Jason Matthew

1998-12-01

There is considerable interest in the area of laser diode pumped solid-state lasers. Diode pumped solid-state lasers (DPSSL) operating at high average power levels are attractive light sources for various applications such as materials processing, laser radar, and fundamental physics experiments. These laser systems have become more commonplace because of their efficiency, reliability, compactness, low relative cost, and long operational lifetimes. Induced thermal effects in the solid-state laser medium hinder the scaling of DPSSL's to higher average power levels. Therefore a deep insight into the thermo-mechanical properties of the solid state laser is crucial in order to ensure a laser design which is optimized for high average power operation. A comprehensive study of the factors that contribute to thermal loading of the colquiriites was performed. A three-dimensional thermal model has been created to determine the temperature rise inside the laser crystal. This new model calculates the temperature distribution by considering quantum defect, upconversion, and upper-state lifetime quenching as heating sources. The thermally induced lensing in end pumped Cr3+ doped LiSrAlF6, LiSrGaF6, LiSrCaAlF6, and LiCaAlF6 were experimentally measured. Several diode pumped colquiriite laser systems were assembled to quantitatively observe and identify thermally induced effects. Significant differences in each of the colquiriite materials were observed. These differences are explained by the differences in the thermo-mechanical and thermo-optical properties of the material and are explained by the theoretical thermal model.

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

NASA Astrophysics Data System (ADS)

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.

Ho:YAG Single Crystal Fiber: Fabrication and Optical Characterization

DTIC Science & Technology

2014-06-16

between the 5I8 and 5I7 energy levels. The results verified the absorption peaks suitable for in- band direct pumping at 1908 nm and 1932 nm with the...Efficient high-power Ho:YAG laser directly in- band pumped by a GaSb -based laser diode stack at 1.9 μm,” Appl. Phys. B 106(2), 315–319 (2012). 21. M...characterized for its optical absorption and emission properties involving transitions between the 5I8 and 5I7 energy levels. The results verified

Optimization of a miniature Maglev ventricular assist device for pediatric circulatory support.

PubMed

Zhang, Juntao; Koert, Andrew; Gellman, Barry; Gempp, Thomas M; Dasse, Kurt A; Gilbert, Richard J; Griffith, Bartley P; Wu, Zhongjun J

2007-01-01

A miniature Maglev blood pump based on magnetically levitated bearingless technology is being developed and optimized for pediatric patients. We performed impeller optimization by characterizing the hemodynamic and hemocompatibility performances using a combined computational and experimental approach. Both three-dimensional flow features and hemolytic characteristics were analyzed using computational fluid dynamics (CFD) modeling. Hydraulic pump performances and hemolysis levels of three different impeller designs were quantified and compared numerically. Two pump prototypes were constructed from the two impeller designs and experimentally tested. Comparison of CFD predictions with experimental results showed good agreement. The optimized impeller remarkably increased overall pump hydraulic output by more than 50% over the initial design. The CFD simulation demonstrated a clean and streamlined flow field in the main flow path. The numerical results by hemolysis model indicated no significant high shear stress regions. Through the use of CFD analysis and bench-top testing, the small pediatric pump was optimized to achieve a low level of blood damage and improved hydraulic performance and efficiency. The Maglev pediatric blood pump is innovative due to its small size, very low priming volume, excellent hemodynamic and hematologic performance, and elimination of seal-related and bearing-related failures due to adoption of magnetically levitated bearingless motor technology, making it ideal for pediatric applications.

Continuous-wave Nd:YVO4/KTiOPO4 green laser at 542 nm under diode pumping into the emitting level

NASA Astrophysics Data System (ADS)

Liu, J. H.

2012-10-01

We report a green laser at 542 nm generation by intracavity frequency doubling of a continuous wave (CW) laser operation of a 1086 nm Nd:YVO4 laser under 880 nm diode pumping into the emitting level 4 F 3/2. A KTiOPO4 (KTP) crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an incident pump power of 14.5 W, as high as 1.33 W of CW output power at 542 nm is achieved. The optical-to-optical conversion efficiency is up to 9.2%, and the fluctuation of the green output power was better than 3.8% in the given 30 min.

Isothermal pumping analysis for high-altitude tethered balloons

PubMed Central

Kuo, Kirsty A.; Hunt, Hugh E. M.

2015-01-01

High-altitude tethered balloons have potential applications in communications, surveillance, meteorological observations and climate engineering. To maintain balloon buoyancy, power fuel cells and perturb atmospheric conditions, fluids could be pumped from ground level to altitude using the tether as a hose. This paper examines the pumping requirements of such a delivery system. Cases considered include delivery of hydrogen, sulfur dioxide (SO2) and powders as fluid-based slurries. Isothermal analysis is used to determine the variation of pressures and velocities along the pipe length. Results show that transport of small quantities of hydrogen to power fuel cells and maintain balloon buoyancy can be achieved at pressures and temperatures that are tolerable in terms of both the pipe strength and the current state of pumping technologies. To avoid solidification, transport of SO2 would require elevated temperatures that cannot be tolerated by the strength fibres in the pipe. While the use of particle-based slurries rather than SO2 for climate engineering can reduce the pipe size significantly, the pumping pressures are close to the maximum bursting pressure of the pipe. PMID:26543573

Isothermal pumping analysis for high-altitude tethered balloons.

PubMed

Kuo, Kirsty A; Hunt, Hugh E M

2015-06-01

High-altitude tethered balloons have potential applications in communications, surveillance, meteorological observations and climate engineering. To maintain balloon buoyancy, power fuel cells and perturb atmospheric conditions, fluids could be pumped from ground level to altitude using the tether as a hose. This paper examines the pumping requirements of such a delivery system. Cases considered include delivery of hydrogen, sulfur dioxide (SO2) and powders as fluid-based slurries. Isothermal analysis is used to determine the variation of pressures and velocities along the pipe length. Results show that transport of small quantities of hydrogen to power fuel cells and maintain balloon buoyancy can be achieved at pressures and temperatures that are tolerable in terms of both the pipe strength and the current state of pumping technologies. To avoid solidification, transport of SO2 would require elevated temperatures that cannot be tolerated by the strength fibres in the pipe. While the use of particle-based slurries rather than SO2 for climate engineering can reduce the pipe size significantly, the pumping pressures are close to the maximum bursting pressure of the pipe.

Advanced Pumped Storage Hydropower and Ancillary Services Provision

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muljadi, Eduard; Gevorgian, Vahan; Mohanpurkar, Manish

This paper presents a high-level overview of the capability of advanced pumped storage hydropower to provide ancillary services including frequency regulation and oscillation damping. Type 3 and Type 4 generators are discussed. The examples given are for a small power system that uses a diesel generator as the main generator and a very large system that uses a gas turbine as the main generator.

Ring-Down Spectroscopy for Characterizing a CW Raman Laser

NASA Technical Reports Server (NTRS)

Matsko, Andrey; Savchenkov, Anatoliy; Maleki, Lute

2007-01-01

.A relatively simple technique for characterizing an all-resonant intracavity continuous-wave (CW) solid-state Raman laser involves the use of ring-down spectroscopy. As used here, characterizing signifies determining such parameters as threshold pump power, Raman gain, conversion efficiency, and quality factors (Q values) of the pump and Stokes cavity modes. Heretofore, in order to characterize resonant-cavity-based Raman lasers, it has usually been necessary to manipulate the frequencies and power levels of pump lasers and, in each case, to take several sets of measurements. In cases involving ultra-high-Q resonators, it also has been desirable to lock pump lasers to resonator modes to ensure the quality of measurement data. Simpler techniques could be useful. In the present ring-down spectroscopic technique, one infers the parameters of interest from the decay of the laser out of its steady state. This technique does not require changing the power or frequency of the pump laser or locking the pump laser to the resonator mode. The technique is based on a theoretical analysis of what happens when the pump laser is abruptly switched off after the Raman generation reaches the steady state. The analysis starts with differential equations for the evolution of the amplitudes of the pump and Stokes electric fields, leading to solutions for the power levels of the pump and Stokes fields as functions of time and of the aforementioned parameters. Among other things, these solutions show how the ring-down time depends, to some extent, on the electromagnetic energy accumulated in the cavity. The solutions are readily converted to relatively simple equations for the parameters as functions of quantities that can be determined from measurements of the time-dependent power levels. For example, the steady-state intracavity conversion efficiency is given by G1/G2 1 and the threshold power is given by Pin(G2/G1)2, where Pin is the steady-state input pump power immediately prior to abrupt switch-off, G1 is the initial rate of decay of the pump field, and G2 is the final rate of decay of the pump field. Hence, it is possible to determine all the parameters from a single ring-down scan, provided that the measurements taken in that scan are sufficiently accurate and complete.

Power amplification for petawatt Ti: Sapphire lasers: New strategies for high fluence pumping

NASA Astrophysics Data System (ADS)

Canova, F.; Chambaret, J.-P.

2006-06-01

One of the major bottlenecks when we pump large Ti:Sapphire crystals, to reach Petawatt level laser amplification, is the careful control of the spatial energy distribution of Nd:Glass pump lasers. Commercially available nanosecond Nd:Glass and Nd:YAG lasers exhibit poor spatial profile quality especially in the near and in the intermediate field, which can lead to local hot spots, responsible of damages in crystals, and parasitic transverse lasing enhancement, strongly dependent on the profile of the pump beam . For these reasons, it is mandatory to keep the pump beam intensity profile as flat as possible on the pumped crystal. To guarantee the best pumping conditions we are investigating the combined use of DOE (diffractive optical elements) and optical smoothing techniques. In parallel we are starting a study on laser induced damages mechanisms in crystal. With DOE and microlens arrays we plan to guarantee to the beam a supergaussian shape. Simulation and first experiments with both optical systems show that a flat top spatial profile with less than 10% fluctuations and a 8th order supergaussian is possible with the present technology.Optical smoothing will keep the beam free of hot spots. We especially focused on the smoothing techniques involving optical fibers. This is the first time to our knowledge that this technique is applied to the pumping beams for Ti:Sapphire systems. A deep study of laser-crystal interaction will allow us to fully understand the damages created by hot spots. The knowledge of the phenomena involved in laser damages on Ti:Sapphire is mandatory to control the pumping processes and thresholds. In conclusion, mixing the advantages of these different approaches to overcome this bottleneck will allow us to amplify in a safety way femtosecond laser beams to the Petawatt level using Ti:Sapphire crystals.

Sounding experiments of high pressure gas discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biele, Joachim K.

A high pressure discharge experiment (200 MPa, 5{center_dot}10{sup 21} molecules/cm{sup 3}, 3000 K) has been set up to study electrically induced shock waves. The apparatus consists of the combustion chamber (4.2 cm{sup 3}) to produce high pressure gas by burning solid propellant grains to fill the electrical pump chamber (2.5 cm{sup 3}) containing an insulated coaxial electrode. Electrical pump energy up to 7.8 kJ at 10 kV, which is roughly three times of the gas energy in the pump chamber, was delivered by a capacitor bank. From the current-voltage relationship the discharge develops at rapidly decreasing voltage. Pressure at themore » combustion chamber indicating significant underpressure as well as overpressure peaks is followed by an increase of static pressure level. These data are not yet completely understood. However, Lorentz forces are believed to generate pinching with subsequent pinch heating, resulting in fast pressure variations to be propagated as rarefaction and shock waves, respectively. Utilizing pure axisymmetric electrode initiation rather than often used exploding wire technology in the pump chamber, repeatable experiments were achieved.« less

All-solid-state cw frequency-doubling Nd:YLiF4/LBO blue laser with 4.33 W output power at 454 nm under in-band diode pumping at 880 nm.

PubMed

Lü, Yanfei; Zhang, Xihe; Cheng, Weibo; Xia, Jing

2010-07-20

We generated efficient blue laser output at 454 nm by intracavity frequency doubling of a continuous-wave (cw) diode-pumped Nd:YLiF(4) (Nd:YLF) laser at 908 nm based on the (4)F(3/2)-(4)I(9/2) transition. With 32.8 W of incident pump power at 880 nm and the frequency-doubling crystal LiB(3)O(5), a level as high as 4.33 W of cw output power at 454 nm is achieved, corresponding to an optical conversion efficiency of 13.2% with respect to the incident pump power. To the best of our knowledge, this is the first blue laser at 454 nm generated by intracavity frequency doubling of a diode-pumped Nd:YLF.

Push pull microfluidics on a multi-level 3D CD.

PubMed

Thio, Tzer Hwai Gilbert; Ibrahim, Fatimah; Al-Faqheri, Wisam; Moebius, Jacob; Khalid, Noor Sakinah; Soin, Norhayati; Kahar, Maria Kahar Bador Abdul; Madou, Marc

2013-08-21

A technique known as thermo-pneumatic (TP) pumping is used to pump fluids on a microfluidic compact disc (CD) back towards the CD center against the centrifugal force that pushes liquids from the center to the perimeter of the disc. Trapped air expands in a TP air chamber during heating, and this creates positive pressure on liquids located in chambers connected to that chamber. While the TP air chamber and connecting channels are easy to fabricate in a one-level CD manufacturing technique, this approach provides only one way pumping between two chambers, is real-estate hungry and leads to unnecessary heating of liquids in close proximity to the TP chamber. In this paper, we present a novel TP push and pull pumping method which allows for pumping of liquid in any direction between two connected liquid chambers. To ensure that implementation of TP push and pull pumping also addresses the issue of space and heating challenges, a multi-level 3D CD design is developed, and localized forced convection heating, rather than infra-red (IR) is applied. On a multi-level 3D CD, the TP features are placed on a top level separate from the rest of the microfluidic processes that are implemented on a lower separate level. This approach allows for heat shielding of the microfluidic process level, and efficient usage of space on the CD for centrifugal handling of liquids. The use of localized forced convection heating, rather than infra-red (IR) or laser heating in earlier implementations allows not only for TP pumping of liquids while the CD is spinning but also makes heat insulation for TP pumping and other fluidic functions easier. To aid in future implementations of TP push and pull pumping on a multi-level 3D CD, study on CD surface heating is also presented. In this contribution, we also demonstrate an advanced application of pull pumping through the implementation of valve-less switch pumping.

Push pull microfluidics on a multi-level 3D CD

PubMed Central

Thio, Tzer Hwai Gilbert; Ibrahim, Fatimah; Al-Faqheri, Wisam; Moebius, Jacob; Khalid, Noor Sakinah; Soin, Norhayati; Kahar, Maria Kahar Bador Abdul; Madou, Marc

2013-01-01

A technique known as thermo-pneumatic (TP) pumping is used to pump fluids on a microfluidic compact disc (CD) back towards the CD center against the centrifugal force that pushes liquids from the center to the perimeter of the disc. Trapped air expands in a TP air chamber during heating, and this creates positive pressure on liquids located in chambers connected to that chamber. While the TP air chamber and connecting channels are easy to fabricate in a one-level CD manufacturing technique, this approach provides only one way pumping between two chambers, is real-estate hungry and leads to unnecessary heating of liquids in close proximity to the TP chamber. In this paper, we present a novel TP push and pull pumping method which allows for pumping of liquid in any direction between two connected liquid chambers. To ensure that implementation of TP push and pull pumping also addresses the issue of space and heating challenges, a multi-level 3D CD design is developed, and localized forced convection heating, rather than infra-red (IR) is applied. On a multi-level 3D CD, the TP features are placed on a top level separate from the rest of the microfluidic processes that are implemented on a lower separate level. This approach allows for heat shielding of the microfluidic process levels, and efficient usage of space on the CD for centrifugal handling of liquids. The use of localized forced convection heating, rather than infra-red (IR) or laser heating in earlier implementations allows not only for TP pumping of liquids while the CD is spinning but also makes heat insulation for TP pumping and other fluidic functions easier. To aid in future implementations of TP push and pull pumping on a multi-level 3D CD, study on CD surface heating is also presented. In this contribution, we also demonstrate an advanced application of pull pumping through the implementation of valve-less switch pumping. PMID:23774994

Pump tank divider plate for sump suction sodium pumps

DOEpatents

George, John A.; Nixon, Donald R.

1977-01-01

A circular plate extends across the diameter of "sump suction" pump, with a close clearance between the edge of the plate and the wall of the pump tank. The plate is located above the pump impeller, inlet and outlet flow nozzles but below the sodium free surface and effectively divides the pump tank into two separate chambers. On change of pump speed, the close fitting flow restriction plate limits the rate of flow into or out of the upper chamber, thereby minimizing the rate of level change in the tank and permitting time for the pump cover gas pressure to be varied to maintain an essentially constant level.

Early outcomes of on-pump versus off-pump coronary artery bypass grafting.

PubMed

Hussain, Ghulam; Azam, Hammad; Baig, Mirza Ahmad Raza; Ahmad, Naseem

2016-01-01

To see the early post-operative outcomes of off-pump versus on-pump coronary artery bypass graft surgery. This retrospective analytical study was conducted at Ch. Pervaiz Elahi Institute of Cardiology Multan, Pakistan. Our Primary outcome variables were; necessity of inotropic support, nonfatal myocardial infarction, ICU stay, nonfatal stroke, new renal failure requiring dialysis and death within 30 days after operation. There were two groups of patients; Group-I (On-pump group) and Group-II (Off-pump Group). SPSS V17 was used for data analysis. Independent sample t-test and Mann Whitney U test were used to compare quantitative Variables. Chi-square test and Fisher's exact test were used to analyze qualitative variables. P-value ≤ 0.05 was considered significant. Three hundred patients were included in this study. There were no significant difference regarding risk factors except hyper-cholestrolemia which was high in off pump group (p-value 0.05). Angiographic and Echocardiographic characteristics e.g. preoperative ejection fraction, LV function grade and severity of CAD was same between the groups. Mortality risk scores and Priority status for surgery were also same. Regarding post-operative outcomes; Post-op CKMB Levels, need and duration of inotropic support, mechanical ventilation time and ICU stay was significantly less in Off-Pump group (p-value 0.001, <0.0001, 0.006, 0.025 and 0.001 resp.). Peri-operative chest drainage was significantly high in On-pump CABG group (p-value 0.027). Incidence of post-op complications was not statistically different between the groups. At 30 days follow-up, Incidence of myocardial infarction, necessity and duration of inotropic support, ICU stay period and peri-operative bleeding were significantly less in off-pump group. The incidence of neurologic, pulmonary and renal complications was same between the off-pump and on-pump groups.

Early outcomes of on-pump versus off-pump coronary artery bypass grafting

PubMed Central

Hussain, Ghulam; Azam, Hammad; Baig, Mirza Ahmad Raza; Ahmad, Naseem

2016-01-01

Objectives: To see the early post-operative outcomes of off-pump versus on-pump coronary artery bypass graft surgery. Methods: This retrospective analytical study was conducted at Ch. Pervaiz Elahi Institute of Cardiology Multan, Pakistan. Our Primary outcome variables were; necessity of inotropic support, nonfatal myocardial infarction, ICU stay, nonfatal stroke, new renal failure requiring dialysis and death within 30 days after operation. There were two groups of patients; Group-I (On-pump group) and Group-II (Off-pump Group). SPSS V17 was used for data analysis. Independent sample t-test and Mann Whitney U test were used to compare quantitative Variables. Chi-square test and Fisher’s exact test were used to analyze qualitative variables. P-value ≤ 0.05 was considered significant. Results: Three hundred patients were included in this study. There were no significant difference regarding risk factors except hyper-cholestrolemia which was high in off pump group (p-value 0.05). Angiographic and Echocardiographic characteristics e.g. preoperative ejection fraction, LV function grade and severity of CAD was same between the groups. Mortality risk scores and Priority status for surgery were also same. Regarding post-operative outcomes; Post-op CKMB Levels, need and duration of inotropic support, mechanical ventilation time and ICU stay was significantly less in Off-Pump group (p-value 0.001, <0.0001, 0.006, 0.025 and 0.001 resp.). Peri-operative chest drainage was significantly high in On-pump CABG group (p-value 0.027). Incidence of post-op complications was not statistically different between the groups. Conclusions: At 30 days follow-up, Incidence of myocardial infarction, necessity and duration of inotropic support, ICU stay period and peri-operative bleeding were significantly less in off-pump group. The incidence of neurologic, pulmonary and renal complications was same between the off-pump and on-pump groups. PMID:27648039

Centaur liquid oxygen boost pump vibration test

NASA Technical Reports Server (NTRS)

Tang, H. M.

1975-01-01

The Centaur LOX boost pump was subjected to both the simulated Titan Centaur proof flight and confidence demonstration vibration test levels. For each test level, both sinusoidal and random vibration tests were conducted along each of the three orthogonal axes of the pump and turbine assembly. In addition to these tests, low frequency longitudinal vibration tests for both levels were conducted. All tests were successfully completed without damage to the boost pump.

Noise optimization of a regenerative automotive fuel pump

NASA Astrophysics Data System (ADS)

Wang, J. F.; Feng, H. H.; Mou, X. L.; Huang, Y. X.

2017-03-01

The regenerative pump used in automotive is facing a noise problem. To understand the mechanism in detail, Computational Fluid Dynamics (CFD) and Computational Acoustic Analysis (CAA) together were used to understand the fluid and acoustic characteristics of the fuel pump using ANSYS-CFX 15.0 and LMS Virtual. Lab Rev12, respectively. The CFD model and acoustical model were validated by mass flow rate test and sound pressure test, respectively. Comparing the computational and experimental results shows that sound pressure levels at the observer position are consistent at high frequencies, especially at blade passing frequency. After validating the models, several numerical models were analyzed in the study for noise improvement. It is observed that for configuration having greater number of impeller blades, noise level was significantly improved at blade passing frequency, when compared to that of the original model.

Geometric Optimization for Non-Thrombogenicity of a Centrifugal Blood Pump through Flow Visualization

NASA Astrophysics Data System (ADS)

Toyoda, Masahiro; Nishida, Masahiro; Maruyama, Osamu; Yamane, Takashi; Tsutsui, Tatsuo; Sankai, Yoshiyuki

A monopivot centrifugal blood pump, whose impeller is supported with a pivot bearing and a passive magnetic bearing, is under development for implantable artificial heart. The hemolysis level is less than that of commercial centrifugal pumps and the pump size is as small as 160 mL in volume. To solve a problem of thrombus caused by fluid dynamics, flow visualization experiments and animal experiments have been undertaken. For flow visualization a three-fold scale-up model, high-speed video system, and particle tracking velocimetry software were used. To verify non-thrombogenicity one-week animal experiments were conducted with sheep. The initially observed thrombus around the pivot was removed through unifying the separate washout holes to a small centered hole to induce high shear around the pivot. It was found that the thrombus contours corresponded to the shear rate of 300s-1 for red thrombus and 1300-1700s-1 for white thrombus, respectively. Thus flow visualization technique was found to be a useful tool to predict thrombus location.

All-fiber linearly polarized high power 2-μm single mode Tm-fiber laser for plastic processing and Ho-laser pumping applications

NASA Astrophysics Data System (ADS)

Scholle, K.; Schäfer, M.; Lamrini, S.; Wysmolek, M.; Steinke, M.; Neumann, J.; Fuhrberg, P.

2018-02-01

In this paper we present a high power, polarized 2 μm Thulium-doped fiber laser with high beam quality. Such laser systems are ideally suited for the processing of plastic materials which are highly transparent in the visible and 1 μm wavelength range and for the pumping of laser sources for the mid-IR wavelength region. For most applications polarized lasers are beneficial, as they can be easily protected from back reflections and combined with other laser sources or power scaled by polarization combining. The Tm-doped fiber laser is pumped in an all-fiber configuration by using a fiber coupled pump diode emitting around 790 nm. This pumping scheme allows the exploitation of the crossrelaxation process to populate the upper laser level. A compact and robust laser configuration was achieved by using an all-fiber configuration with single mode fibers and fiber Bragg gratings (FBG). Different FBG pairs with wavelength around 2 μm were tested. To achieve stable polarized output power the fibers with the FBG were 90° twisted at the splices. Stable linearly polarized output power up to 38 W with an extinction ratio of up to 50:1 was observed. With respect to the diode output power an optical-to-optical efficiency of 51 % was reached with a correspondent slope efficiency of 52 %. The emission linewidth at maximum power was measured to be < 0.3 nm which is well suitable for Ho-laser pumping. First tests of the precise processing of highly transparent plastic materials demonstrate the potentials of these laser systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galambos, Paul C.

This is the latest in a series of LDRD's that we have been conducting with Florida State University/Florida A&M University (FSU/FAMU) under the campus executive program. This research builds on the earlier projects; ''Development of Highly Integrated Magnetically and Electrostatically Actuated Micropumps'' (SAND2003-4674) and ''Development of Magnetically and Electrostatically Driven Surface Micromachined Pumps'' (SAND2002-0704P). In this year's LDRD we designed 2nd generation of surface micromachined (SMM) gear and viscous pumps. Two SUMMiT{trademark} modules full of design variations of these pumps were fabricated and one SwIFT{trademark} module is still in fabrication. The SwIFT{trademark} fabrication process results in a transparent pump housingmore » cover that will enable visualization inside the pumps. Since the SwIFT{trademark} pumps have not been tested as they are still in fabrication, this report will focus on the 2nd generation SUMMiT{trademark} designs. Pump testing (pressure vs. flow) was conducted on several of the SUMMiT{trademark} designs resulting in the first pump curve for this class of SMM pumps. A pump curve was generated for the higher torque 2nd generation gear pump designed by Jason Hendrix of FSU. The pump maximum flow rate at zero head was 6.5 nl/s for a 30V, 30 Hz square wave signal. This level of flow rate would be more than adequate for our typical SMM SUMMiT{trademark} or SwIFT{trademark} channels which have typical volumes on the order of 50 pl.« less

Sources of high-chloride water and managed aquifer recharge in an alluvial aquifer in California, USA

USGS Publications Warehouse

O'Leary, David; Izbicki, John A.; Metzger, Loren F.

2015-01-01

As a result of pumping in excess of recharge, water levels in alluvial aquifers within the Eastern San Joaquin Groundwater Subbasin, 130 km east of San Francisco (California, USA), declined below sea level in the early 1950s and have remained so to the present. Chloride concentrations in some wells increased during that time and exceeded the US Environmental Protection Agency’s secondary maximum contaminant level of 250 mg/L, resulting in removal of some wells from service. Sources of high-chloride water include irrigation return in 16 % of sampled wells and water from delta sediments and deeper groundwater in 50 % of sampled wells. Chloride concentrations resulting from irrigation return commonly did not exceed 100 mg/L, although nitrate concentrations were as high as 25 mg/L as nitrogen. Chloride concentrations ranged from less than 100–2,050 mg/L in wells affected by water from delta sediments and deeper groundwater. Sequential electromagnetic logs show movement of high-chloride water from delta sediments to pumping wells through permeable interconnected aquifer layers. δD and δ18O data show most groundwater originated as recharge along the front of the Sierra Nevada, but tritium and carbon-14 data suggest recharge rates in this area are low and have decreased over recent geologic time. Managed aquifer recharge at two sites show differences in water-level responses to recharge and in the physical movement of recharged water with depth related to subsurface geology. Well-bore flow logs also show rapid movement of water from recharge sites through permeable interconnected aquifer layers to pumping wells.

Hepatobiliary transporter expression and post-operative jaundice in patients undergoing partial hepatectomy.

PubMed

Bernhardt, Gerwin A; Zollner, Gernot; Cerwenka, Herwig; Kornprat, Peter; Fickert, Peter; Bacher, Heinz; Werkgartner, Georg; Müller, Gabriele; Zatloukal, Kurt; Mischinger, Hans-Jörg; Trauner, Michael

2012-01-01

Post-operative hyperbilirubinaemia in patients undergoing liver resections is associated with high morbidity and mortality. Apart from different known factors responsible for the development of post-operative jaundice, little is known about the role of hepatobiliary transport systems in the pathogenesis of post-operative jaundice in humans after liver resection. Two liver tissue samples were taken from 14 patients undergoing liver resection before and after Pringle manoeuvre. Patients were retrospectively divided into two groups according to post-operative bilirubin serum levels. The two groups were analysed comparing the results of hepatobiliary transporter [Na-taurocholate cotransporter (NTCP); multidrug resistance gene/phospholipid export pump(MDR3); bile salt export pump (BSEP); canalicular bile salt export pump (MRP2)], heat shock protein 70 (HSP70) expression as well as the results of routinely taken post-operative liver chemistry tests. Patients with low post-operative bilirubin had lower levels of NTCP, MDR3 and BSEP mRNA compared to those with high bilirubin after Pringle manoeuvre. HSP70 levels were significantly higher after ischaemia-reperfusion (IR) injury in both groups resulting in 4.5-fold median increase. Baseline median mRNA expression of all four transporters prior to Pringle manoeuvre tended to be lower in the low bilirubin group whereas expression of HSP70 was higher in the low bilirubin group compared to the high bilirubin group. Higher mRNA levels of HSP70 in the low bilirubin group could indicate a possible protective effect of high HSP70 levels against IR injury. Although the exact role of hepatobiliary transport systems in the development of post-operative hyper bilirubinemia is not yet completely understood, this study provides new insights into the molecular aspects of post-operative jaundice after liver surgery. © 2011 John Wiley & Sons A/S.

TANK48 CFD MODELING ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S.

2011-05-17

The process of recovering the waste in storage tanks at the Savannah River Site (SRS) typically requires mixing the contents of the tank to ensure uniformity of the discharge stream. Mixing is accomplished with one to four dual-nozzle slurry pumps located within the tank liquid. For the work, a Tank 48 simulation model with a maximum of four slurry pumps in operation has been developed to estimate flow patterns for efficient solid mixing. The modeling calculations were performed by using two modeling approaches. One approach is a single-phase Computational Fluid Dynamics (CFD) model to evaluate the flow patterns and qualitativemore » mixing behaviors for a range of different modeling conditions since the model was previously benchmarked against the test results. The other is a two-phase CFD model to estimate solid concentrations in a quantitative way by solving the Eulerian governing equations for the continuous fluid and discrete solid phases over the entire fluid domain of Tank 48. The two-phase results should be considered as the preliminary scoping calculations since the model was not validated against the test results yet. A series of sensitivity calculations for different numbers of pumps and operating conditions has been performed to provide operational guidance for solids suspension and mixing in the tank. In the analysis, the pump was assumed to be stationary. Major solid obstructions including the pump housing, the pump columns, and the 82 inch central support column were included. The steady state and three-dimensional analyses with a two-equation turbulence model were performed with FLUENT{trademark} for the single-phase approach and CFX for the two-phase approach. Recommended operational guidance was developed assuming that local fluid velocity can be used as a measure of sludge suspension and spatial mixing under single-phase tank model. For quantitative analysis, a two-phase fluid-solid model was developed for the same modeling conditions as the single-phase model. The modeling results show that the flow patterns driven by four pump operation satisfy the solid suspension requirement, and the average solid concentration at the plane of the transfer pump inlet is about 12% higher than the tank average concentrations for the 70 inch tank level and about the same as the tank average value for the 29 inch liquid level. When one of the four pumps is not operated, the flow patterns are satisfied with the minimum suspension velocity criterion. However, the solid concentration near the tank bottom is increased by about 30%, although the average solid concentrations near the transfer pump inlet have about the same value as the four-pump baseline results. The flow pattern results show that although the two-pump case satisfies the minimum velocity requirement to suspend the sludge particles, it provides the marginal mixing results for the heavier or larger insoluble materials such as MST and KTPB particles. The results demonstrated that when more than one jet are aiming at the same position of the mixing tank domain, inefficient flow patterns are provided due to the highly localized momentum dissipation, resulting in inactive suspension zone. Thus, after completion of the indexed solids suspension, pump rotations are recommended to avoid producing the nonuniform flow patterns. It is noted that when tank liquid level is reduced from the highest level of 70 inches to the minimum level of 29 inches for a given number of operating pumps, the solid mixing efficiency becomes better since the ratio of the pump power to the mixing volume becomes larger. These results are consistent with the literature results.« less

A Modular Control Platform for a Diode Pumped Alkali Laser

NASA Astrophysics Data System (ADS)

Shapiro, J.; Teare, S.

Many of the difficulties of creating compact, high power laser systems can be overcome if the heat dissipating properties of chemical lasers can be combined with the efficiency of diode lasers. Recently, the novel idea of using solid state diode lasers to pump gaseous gain media, such as is done in diode pumped alkali lasers (DPALs), has been proposed and early experiments have shown promising results. However, a number of technical issues need to be overcome to realize high output power from these lasers. In order to achieve higher power, the efficiency of coupling between pump laser energy and the chemical cell must be increased, and eventually multiple high power diode pumps must be combined and synchronized so that their energy can pump the chemical cell. Additionally, an inter-cavity adaptive optics system may be a requirement to be able to propagate these lasers with high efficiency. DPAL systems are complex and require a significant amount of data fusion and active feedback to control and optimize their performance. There are a wide range of components including pump lasers, gain cells and monitoring points needed to study and refine the overall laser system. In support of this dynamic development environment, we have developed a hardware framework using commercial off the shelf (COTS) components which supports the rapid assembly of functional system blocks into a cohesive integrated system. Critical to this system are a simple communication protocol, industry standard communication pipes (USB, Bluetooth, etc), and flexible high level scripting. Simplifying the integration process has the benefit of allowing flexible "on the fly" modifications to adapt the system as needed and enhance available functionality. The modular nature of the architecture allows scalability and adaptability as more pieces are added to the system. Key components of this system are demonstrated for selected portions of a DPAL system using a USB backbone.

The Effects of Altered Membrane Cholesterol Levels on Sodium Pump Activity in Subclinical Hypothyroidism.

PubMed

Roy, Suparna; Dasgupta, Anindya

2017-03-01

Metabolic dysfunctions characteristic of overt hypothyroidism (OH) start at the early stage of subclinical hypothyroidism (SCH). Na⁺/K⁺-ATPase (the sodium pump) is a transmembrane enzyme that plays a vital role in cellular activities in combination with membrane lipids. We evaluated the effects of early changes in thyroid hormone and membrane cholesterol on sodium pump activity in SCH and OH patients. In 32 SCH patients, 35 OH patients, and 34 euthyroid patients, sodium pump activity and cholesterol levels in red blood cell membranes were measured. Serum thyroxine (T₄) and thyroid stimulating hormone (TSH) levels were measured using enzyme-linked immunosorbent assays. Differences in their mean values were analysed using post hoc analysis of variance. We assessed the dependence of the sodium pump on other metabolites by multiple regression analysis. Sodium pump activity and membrane cholesterol were lower in both hypothyroid groups than in control group, OH group exhibiting lower values than SCH group. In SCH group, sodium pump activity showed a significant direct dependence on membrane cholesterol with an inverse relationship with serum TSH levels. In OH group, sodium pump activity depended directly on membrane cholesterol and serum T₄ levels. No dependence on serum cholesterol was observed in either case. Despite the presence of elevated serum cholesterol in hypothyroidism, membrane cholesterol contributed significantly to maintain sodium pump activity in the cells. A critical reduction in membrane cholesterol levels heralds compromised enzyme activity, even in the early stage of hypothyroidism, and this can be predicted by elevated TSH levels alone, without any evident clinical manifestations. Copyright © 2017 Korean Endocrine Society

The importance of intraoperative selenium blood levels on organ dysfunction in patients undergoing off-pump cardiac surgery: a randomised controlled trial.

PubMed

Stevanovic, Ana; Coburn, Mark; Menon, Ares; Rossaint, Rolf; Heyland, Daren; Schälte, Gereon; Werker, Thilo; Wonisch, Willibald; Kiehntopf, Michael; Goetzenich, Andreas; Rex, Steffen; Stoppe, Christian

2014-01-01

Cardiac surgery is accompanied by an increase of oxidative stress, a significantly reduced antioxidant (AOX) capacity, postoperative inflammation, all of which may promote the development of organ dysfunction and an increase in mortality. Selenium is an essential co-factor of various antioxidant enzymes. We hypothesized a less pronounced decrease of circulating selenium levels in patients undergoing off-pump coronary artery bypass (OPCAB) surgery due to less intraoperative oxidative stress. In this prospective randomised, interventional trial, 40 patients scheduled for elective coronary artery bypass grafting were randomly assigned to undergo either on-pump or OPCAB-surgery, if both techniques were feasible for the single patient. Clinical data, myocardial damage assessed by myocard specific creatine kinase isoenzyme (CK-MB), circulating whole blood levels of selenium, oxidative stress assessed by asymmetric dimethylarginine (ADMA) levels, antioxidant capacity determined by glutathionperoxidase (GPx) levels and perioperative inflammation represented by interleukin-6 (IL-6) levels were measured at predefined perioperative time points. At end of surgery, both groups showed a comparable decrease of circulating selenium concentrations. Likewise, levels of oxidative stress and IL-6 were comparable in both groups. Selenium levels correlated with antioxidant capacity (GPx: r = 0.720; p<0.001) and showed a negative correlation to myocardial damage (CK-MB: r =  -0.571, p<0.001). Low postoperative selenium levels had a high predictive value for the occurrence of any postoperative complication. OPCAB surgery is not associated with less oxidative stress and a better preservation of the circulating selenium pool than on-pump surgery. Low postoperative selenium levels are predictive for the development of complications. ClinicalTrials.gov NCT01409057.

Combination free electron and gaseous laser

DOEpatents

Brau, Charles A.; Rockwood, Stephen D.; Stein, William E.

1980-01-01

A multiple laser having one or more gaseous laser stages and one or more free electron stages. Each of the free electron laser stages is sequentially pumped by a microwave linear accelerator. Subsequently, the electron beam is directed through a gaseous laser, in the preferred embodiment, and in an alternative embodiment, through a microwave accelerator to lower the energy level of the electron beam to pump one or more gaseous lasers. The combination laser provides high pulse repetition frequencies, on the order of 1 kHz or greater, high power capability, high efficiency, and tunability in the synchronous production of multiple beams of coherent optical radiation.

Real-time Control of sewer pumps by using ControlNEXT to smooth inflow at Waste Water Treatment Plant Garmerwolde

NASA Astrophysics Data System (ADS)

van Heeringen, Klaas-Jan; van Nooijen, Ronald; Kooij, Kees; Postma, Bokke

2016-04-01

The Garmerwolde waste water treatment plant (WWTP) in the Groningen area of the Netherlands, receives waste water from a large area. That waste water is collected from many sewer systems and transported to the WWTP through pressurized pipes. The supply of waste water to the WWTP is relatively low and very irregular during dry-weather conditions, resulting in a random pattern of flows. This irregularity is the effect of the local control of the pumps, where the pumps are individually operated as an on/off control based on the water levels in the connected sewer system. The influent may change from zero to high values in a few minutes. The treatment processes at the WWTP are negatively influenced by this irregularity, which ends in high costs for energy and use of chemicals. The ControlNEXT central control system is used to control the 5 largest pump stations, such that the total inflow at the WWTP becomes much smoother. This results in a reduction of operational costs of about 10%. The control algorithm determines whether the actual condition is dry or wet, based on real-time radar precipitation images and the rainfall forecast product HiRLAM. All actual data is also collected and validated, like water levels, pump operations and pump availability. This data management is done using Delft-FEWS. If the situation is identified as "wet", the sewer systems are emptied as far as possible to create maximum storage. If the situation is "dry" (and of course there is a dead band between dry and wet), the pumps are operated such that the total inflow into the WWTP is smoothed. This is done with a Greedy algorithm, developed by Delft University of Technology. The algorithm makes a plan for the next 24 hours (as the daily inflow has a typical daily pattern) and generally stores some water volume in the sewer systems during the day to be able to continue operations during the night. The pumps are controlled with a time step of 5 minutes, where ControlNEXT manages the communication of pump operation setpoints to the SCADA system. In case of failing communication, backup procedures are programmed in the PLC of the pump stations. In that case the old on/off operation based on local water levels will be used. The system has been operational since January 2016 and has been monitored since then. In addition to monitoring the positive effect on the inflow at the WWTP, an important issue is the possible sedimentation in the sewer systems. This will be monitored too.

Safe intravenous administration in pediatrics: A 5-year Pediatric Intensive Care Unit experience with smart pumps.

PubMed

Manrique-Rodríguez, S; Sánchez-Galindo, A C; Fernández-Llamazares, C M; Calvo-Calvo, M M; Carrillo-Álvarez, Á; Sanjurjo-Sáez, M

2016-10-01

To estimate the impact of smart pump implementation in a pediatric intensive care unit in terms of number and type of administration errors intercepted. Observational, prospective study carried out from January 2010 to March 2015 with syringe and great volumen infusion pumps available in the hospital. A tertiary level hospital pediatric intensive care unit. Infusions delivered with infusion pumps in all pediatric intensive care unit patients. Design of a drug library with safety limits for all intravenous drugs prescribed. Users' compliance with drug library as well as number and type of errors prevented were analyzed. Two hundred and eighty-three errors were intercepted during 62 months of study. A high risk drug was involved in 58% of prevented errors, such as adrenergic agonists and antagonists, sedatives, analgesics, neuromuscular blockers, opioids, potassium and insulin. Users' average compliance with the safety software was 84%. Smart pumps implementation has proven effective in intercepting high risk drugs programming errors. These results might be exportable to other critical care units, involving pediatric or adult patients. Interdisciplinary colaboration is key to succeed in this process. Copyright © 2016 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

Low threshold and high efficiency solar-pumped laser with Fresnel lens and a grooved Nd:YAG rod

NASA Astrophysics Data System (ADS)

Guan, Zhe; Zhao, Changming; Yang, Suhui; Wang, Yu; Ke, Jieyao; Gao, Fengbin; Zhang, Haiyang

2016-11-01

Sunlight is considered as a new efficient source for direct optical-pumped solid state lasers. High-efficiency solar pumped lasers with low threshold power would be more promising than semiconductor lasers with large solar panel in space laser communication. Here we report a significant advance in solar-pumped laser threshold by pumping Nd:YAG rod with a grooved sidewall. Two-solar pumped laser setups are devised. In both cases, a Fresnel lens is used as the primary sunlight concentrator. Gold-plated conical cavity with a liquid light-guide lens is used as the secondary concentrator to further increase the solar energy concentration. In the first setup, solar pumping a 6mm diameter Nd:YAG rod, maximum laser power of 31.0W/m2 cw at 1064nm is produced, which is higher than the reported record, and the slope efficiency is 4.98% with the threshold power on the surface of Fresnel lens is 200 W. In the second setup, a 5 mm diameter laser rod output power is 29.8W/m2 with a slope efficiency of 4.3%. The threshold power of 102W is obtained, which is 49% lower than the former. Meanwhile, the theoretical calculating of the threshold power and slope efficiency of the solar-pumped laser has been established based on the rate-equation of a four-level system. The results of the finite element analysis by simulation software are verified in experiment. The optimization of the conical cavity by TraceProsoftware and the optimization of the laser resonator by LASCADare useful for the design of a miniaturization solar- pumped laser.

Thermal analysis of heat and power plant with high temperature reactor and intermediate steam cycle

NASA Astrophysics Data System (ADS)

Fic, Adam; Składzień, Jan; Gabriel, Michał

2015-03-01

Thermal analysis of a heat and power plant with a high temperature gas cooled nuclear reactor is presented. The main aim of the considered system is to supply a technological process with the heat at suitably high temperature level. The considered unit is also used to produce electricity. The high temperature helium cooled nuclear reactor is the primary heat source in the system, which consists of: the reactor cooling cycle, the steam cycle and the gas heat pump cycle. Helium used as a carrier in the first cycle (classic Brayton cycle), which includes the reactor, delivers heat in a steam generator to produce superheated steam with required parameters of the intermediate cycle. The intermediate cycle is provided to transport energy from the reactor installation to the process installation requiring a high temperature heat. The distance between reactor and the process installation is assumed short and negligable, or alternatively equal to 1 km in the analysis. The system is also equipped with a high temperature argon heat pump to obtain the temperature level of a heat carrier required by a high temperature process. Thus, the steam of the intermediate cycle supplies a lower heat exchanger of the heat pump, a process heat exchanger at the medium temperature level and a classical steam turbine system (Rankine cycle). The main purpose of the research was to evaluate the effectiveness of the system considered and to assess whether such a three cycle cogeneration system is reasonable. Multivariant calculations have been carried out employing the developed mathematical model. The results have been presented in a form of the energy efficiency and exergy efficiency of the system as a function of the temperature drop in the high temperature process heat exchanger and the reactor pressure.

Production of a beam of highly vibrationally excited CO using perturbations.

PubMed

Bartels, Nils; Schäfer, Tim; Hühnert, Jens; Field, Robert W; Wodtke, Alec M

2012-06-07

An intense molecular beam of CO (X(1)Σ(+)) in high vibrational states (v = 17, 18) was produced by a new approach that we call PUMP - PUMP - PERTURB and DUMP. The basic idea is to access high vibrational states of CO e(3)Σ(-) via a two-photon doubly resonant transition that is perturbed by the A(1)Π state. DUMP -ing from this mixed (predominantly triplet) state allows access to high vibrational levels of CO (X(1)Σ(+)). The success of the approach, which avoids the use of vacuum UV radiation in any of the excitation steps, is proven by laser induced fluorescence and resonance enhanced multi-photon ionization spectroscopy.

Production of a beam of highly vibrationally excited CO using perturbations

NASA Astrophysics Data System (ADS)

Bartels, Nils; Schäfer, Tim; Hühnert, Jens; Field, Robert W.; Wodtke, Alec M.

2012-06-01

An intense molecular beam of CO (X1Σ+) in high vibrational states (v = 17, 18) was produced by a new approach that we call PUMP - PUMP - PERTURB and DUMP. The basic idea is to access high vibrational states of CO e3Σ- via a two-photon doubly resonant transition that is perturbed by the A1Π state. DUMP -ing from this mixed (predominantly triplet) state allows access to high vibrational levels of CO (X1Σ+). The success of the approach, which avoids the use of vacuum UV radiation in any of the excitation steps, is proven by laser induced fluorescence and resonance enhanced multi-photon ionization spectroscopy.

Highly efficient dual-wavelength mid-infrared CW Laser in diode end-pumped Er:SrF2 single crystals

PubMed Central

Ma, Weiwei; Qian, Xiaobo; Wang, Jingya; Liu, Jingjing; Fan, Xiuwei; Liu, Jie; Su, Liangbi; Xu, Jun

2016-01-01

The spectral properties and laser performance of Er:SrF2 single crystals were investigated and compared with Er:CaF2. Er:SrF2 crystals have larger absorption cross-sections at the pumping wavelength, larger mid-infrared stimulated emission cross-sections and much longer fluorescence lifetimes of the upper laser level (Er3+:4I11/2 level) than those of Er:CaF2 crystals. Dual-wavelength continuous-wave (CW) lasers around 2.8 μm were demonstrated in both 4at.% and 10at.% Er:SrF2 single crystals under 972 nm laser diode (LD) end pumping. The laser wavelengths are 2789.3 nm and 2791.8 nm in the former, and 2786.4 nm and 2790.7 nm in the latter, respectively. The best laser performance has been demonstrated in lightly doped 4at.% Er:SrF2 with a low threshold of 0.100 W, a high slope efficiency of 22.0%, an maximum output power of 0.483 W. PMID:27811994

Highly efficient dual-wavelength mid-infrared CW Laser in diode end-pumped Er:SrF2 single crystals.

PubMed

Ma, Weiwei; Qian, Xiaobo; Wang, Jingya; Liu, Jingjing; Fan, Xiuwei; Liu, Jie; Su, Liangbi; Xu, Jun

2016-11-04

The spectral properties and laser performance of Er:SrF 2 single crystals were investigated and compared with Er:CaF 2 . Er:SrF 2 crystals have larger absorption cross-sections at the pumping wavelength, larger mid-infrared stimulated emission cross-sections and much longer fluorescence lifetimes of the upper laser level (Er 3+ : 4 I 11/2 level) than those of Er:CaF 2 crystals. Dual-wavelength continuous-wave (CW) lasers around 2.8 μm were demonstrated in both 4at.% and 10at.% Er:SrF 2 single crystals under 972 nm laser diode (LD) end pumping. The laser wavelengths are 2789.3 nm and 2791.8 nm in the former, and 2786.4 nm and 2790.7 nm in the latter, respectively. The best laser performance has been demonstrated in lightly doped 4at.% Er:SrF 2 with a low threshold of 0.100 W, a high slope efficiency of 22.0%, an maximum output power of 0.483 W.

Highly efficient dual-wavelength mid-infrared CW Laser in diode end-pumped Er:SrF2 single crystals

NASA Astrophysics Data System (ADS)

Ma, Weiwei; Qian, Xiaobo; Wang, Jingya; Liu, Jingjing; Fan, Xiuwei; Liu, Jie; Su, Liangbi; Xu, Jun

2016-11-01

The spectral properties and laser performance of Er:SrF2 single crystals were investigated and compared with Er:CaF2. Er:SrF2 crystals have larger absorption cross-sections at the pumping wavelength, larger mid-infrared stimulated emission cross-sections and much longer fluorescence lifetimes of the upper laser level (Er3+:4I11/2 level) than those of Er:CaF2 crystals. Dual-wavelength continuous-wave (CW) lasers around 2.8 μm were demonstrated in both 4at.% and 10at.% Er:SrF2 single crystals under 972 nm laser diode (LD) end pumping. The laser wavelengths are 2789.3 nm and 2791.8 nm in the former, and 2786.4 nm and 2790.7 nm in the latter, respectively. The best laser performance has been demonstrated in lightly doped 4at.% Er:SrF2 with a low threshold of 0.100 W, a high slope efficiency of 22.0%, an maximum output power of 0.483 W.

Assessment of implantable infusion pumps for continuous infusion of human insulin in rats: potential for group housing.

PubMed

Jensen, Vivi Flou Hjorth; Mølck, Anne-Marie; Mårtensson, Martin; Strid, Mette Aagaard; Chapman, Melissa; Lykkesfeldt, Jens; Bøgh, Ingrid Brück

2017-06-01

Group housing is considered to be important for rats, which are highly sociable animals. Single housing may impact behaviour and levels of circulating stress hormones. Rats are typically used in the toxicological evaluation of insulin analogues. Human insulin (HI) is frequently used as a reference compound in these studies, and a comparator model of persistent exposure by HI infusion from external pumps has recently been developed to support toxicological evaluation of long-acting insulin analogues. However, this model requires single housing of the animals. Developing an insulin-infusion model which allows group housing would therefore greatly improve animal welfare. The aim of the present study was to investigate the suitability of implantable infusion pumps for HI infusion in group-housed rats. Group housing of rats implanted with a battery-driven pump proved to be possible. Intravenous infusion of HI lowered blood glucose levels persistently for two weeks, providing a comparator model for use in two-week repeated-dose toxicity studies with new long-acting insulin analogues, which allows group housing, and thereby increasing animal welfare compared with an external infusion model.

Development of lasers optimized for pumping Ti:Al2O3 lasers

NASA Technical Reports Server (NTRS)

Rines, Glen A.; Schwarz, Richard A.

1994-01-01

Laboratory demonstrations that were completed included: (1) an all-solid-state, broadly tunable, single-frequency, Ti:Al2O3 master oscillator, and (2) a technique for obtaining 'long' (nominally 100- to 200-ns FWHM) laser pulses from a Q-switched, Nd oscillator at energy levels commensurate with straightforward amplification to the joule level. A diode-laser-pumped, Nd:YLF laser with intracavity SHG was designed, constructed, and evaluated. With this laser greater than 0.9 W of CW, output power at 523.5 nm with 10 W of diode-laser pump power delivered to the Nd:YLF crystal was obtained. With this laser as a pump source, for the first time, to our knowledge, an all solid-state, single frequency, Ti:Al203 laser with sufficient output power to injection seed a high-energy oscillator over a 20-nm bandwidth was demonstrated. The pulsed laser work succeeded in demonstrating pulse-stretching in a Q-switched Nd:YAG oscillator. Pulse energies greater than 50-mJ were obtained in pulses with 100- to 200-ns pulsewidths (FWHM).

New, efficient, room temperature mid-infrared laser at 3.9 mu m in holmium:barium yttrium fluoride and visible praseodymium:lithium yttrium fluoride laser for holography

NASA Astrophysics Data System (ADS)

Tabirian, Anna Murazian

This dissertation describes a series of experiments and theoretical studies, which led to the development of two new solid state laser systems: efficient, room temperature mid-infrared solid state laser at 3.9 μm in Ho 3+ doped BaY2F8 and visible Pr:LiYF4 laser at 640 mn for holography. The 3.9 μm laser wavelength matches the peak of mid-IR atmospheric transmission window, which makes it very important for multiple applications such as remote sensing, imaging, IR countermeasures, eye-safe lidars and environmental agent detection. We present the results of spectroscopic evaluations and numerical modeling of energy transfer processes between rare earth ions of Ho3+ doped in two host laser materials: BaY2F8 and LiYF 4. The 3.9 μm laser is based on transition with upper laser lifetime considerably shorter than lower level lifetime, which in general leads to self-terminating laser action in the cw mode or at high repetition rates. Therefore, three different pumping and lasing schemes, that could allow overcoming these limitations have been suggested and studied. First, cascade laser action at 1.4 μm and 3.9 μm was achieved with low thresholds and near-theoretical quantum efficiency in Ho3+ doped BaY2F8 pumped at 532 nm by a Q- switched frequency doubled Nd:YAG laser. Next, the feasibility of achieving 3.9 μm laser with cw resonant cascade pumping at 750 mn by a Ti:Sapphire laser was studied. New energy transfer process, such as upconversion from terminal level of the 3.9 μm laser was observed in high concentration Ho3+ doped BaY2F 8. Finally, we proposed to use high-energy flashlamp pumped tunable Cr:LiSAF laser operating in long pulse regime for the direct pumping of the upper level of the 3.9 μm laser. Pulsed laser oscillation at 3.9 μm is demonstrated in Ho3+ doped BaY2F8 with low threshold of 3 mJ and a slope efficiency of 14.5% with maximal energy of 30 mJ. The second part of the thesis describes the design and the development of the visible Pr:LiYF4 laser for holography at 640 nm resonantly pumped by the frequency-doubled flashlamp pumped tunable Cr:LiSAF laser at 444 nm.

Quantitative assessment of haemolysis secondary to modern infusion pumps.

PubMed

Poder, T G; Boileau, J-C; Lafrenière, R; Thibault, L; Carrier, N; de Grandmont, M-J; Beauregard, P

2017-04-01

Although most studies have shown that little haemolysis is induced by infusion pumps, there are some notable exceptions. Only limited data are available on the actual infusion pumps that are most used in hospitals in Quebec and elsewhere, namely, the Infusomat ® Space (peristaltic), Plum A+™ (piston) and Colleague ® CXE (shuttle) pumps. Haemolysis and potassium levels were compared before and after the use of the three different infusion pumps. Using 135 units of packed red blood cells (RBCs) aged from 10 to 28 days, 27 measurements were taken for each pump at various flow rates (30, 60, 150, 300 and 450 ml/h) and were compared with measurements taken before using the pumps. The range of flow rates was chosen to cover those of paediatric and adult transfusions. The shuttle- and piston-type pumps resulted in low haemolysis levels. The peristaltic-type pump produced significantly more haemolysis, which worsened at low flow rates, but the absolute value of haemolysis remained within the range recommended by the regulatory agencies in North America and Europe. Approximately two-thirds of the haemolysis produced by the peristaltic-type pump seemed to be secondary to the use of an antisiphon valve (ASV) on the transfusion line recommended by the manufacturer. Potassium levels did not increase with the use of the pumps. Modern infusion pumps widely used in hospitals in Quebec and elsewhere produce non-threatening levels of haemolysis during the transfusion of packed RBCs aged from 10 to 28 days. ASVs appear to induce additional haemolysis, and we do not recommend using them for blood transfusion. © 2017 International Society of Blood Transfusion.

Regulating Intracellular Calcium in Plants: From Molecular Genetics to Physiology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heven Sze

To grow, develop, adapt, and reproduce, plants have evolved mechanisms to regulate the uptake, translocation and sorting of calcium ions into different cells and subcellular compartments. Yet how plants accomplish this remarkable feat is still poorly understood. The spatial and temporal changes in intracellular [Ca2+] during growth and during responses to hormonal and environmental stimuli indicate that Ca2+ influx and efflux transporters are diverse and tightly regulated in plants. The specific goals were to determine the biological roles of multiple Ca pumps (ECAs) in the model plant Arabidopsis thaliana. We had pioneered the use of K616 yeast strain to functionallymore » express plant Ca pumps, and demonstrated two distinct types of Ca pumps in plants (Sze et al., 2000. Annu Rev Plant Biol. 51,433). ACA2 represented one type that was auto-inhibited by the N-terminal region and stimulated by calmodulin. ECA1 represented another type that was not sensitive to calmodulin and phylogenetically distinct from ACAs. The goal to determine the biological roles of multiple ECA-type Ca pumps in Arabidopsis has been accomplished. Although we demonstrated ECA1 was a Ca pump by functional expression in yeast, the in vivo roles of ECAs was unclear. A few highlights are described. ECA1 and/or ECA4 are Ca/Mn pumps localized to the ER and are highly expressed in all cell types. Using homozygous T-DNA insertional mutants of eca1, we demonstrated that the ER-bound ECA1 supports growth and confers tolerance of plants growing on medium low in Ca or containing toxic levels of Mn. This is the first genetic study to determine the in vivo function of a Ca pump in plants. A phylogenetically distinct ECA3 is also a Ca/Mn pump that is localized to endosome, such as post-Golgi compartments. Although it is expressed at lower levels than ECA1, eca3 mutants are impaired in Ca-dependent root growth and in pollen tube elongation. Increased secretion of wall proteins in mutants suggests that Ca and Mn homeostasis in post-Golgi compartments are critical for secretory activities. Moreover, perturbation of the secretory machinery limits growth possibly by upsetting the synthesis, processing and assembly of cell wall components. Analyses of whole genome transcriptome of pollen shows that a subset of Ca pump genes are developmentally regulated. Each ECA Ca pump is localized to distinct endomembrane compartments and regulate Ca and Mn homeostasis required for optimal growth and for tolerance to high Mn stress. Ca and Mn levels within endomembrane lumen appear to be critical for activities of the secretory machinery including post-Golgi compartments that coordinate membrane traffic and sorting of materials to the vacuole and the cell wall. Significance: Thus sorting of Ca/Mn by ECA pumps in endomembranes is critical for membrane trafficking pattern which serves as a central coordinator of plant growth, development and adaptation to abiotic and biotic stress.« less

Japanese power electronics inverter technology and its impact on the American air conditioning industry

NASA Astrophysics Data System (ADS)

Ushimaru, Kenji

1990-08-01

Since 1983, technological advances and market growth of inverter-driven variable-speed heat pumps in Japan have been dramatic. The high level of market penetration was promoted by a combination of political, economic, and trade policies in Japan. A unique environment was created in which the leading domestic industries, microprocessor manufacturing, compressors for air conditioning and refrigerators, and power electronic devices, were able to direct the development and market success of inverter-driven heat pumps. As a result, leading U.S. variable-speed heat pump manufacturers should expect a challenge from the Japanese producers of power devices and microprocessors. Because of the vertically-integrated production structure in Japan, in contrast to the out-sourcing culture of the United States, price competition at the component level (such as inverters, sensors, and controls) may impact the structure of the industry more severely than final product sales.

Proton pump inhibitor-induced tumour cell death by inhibition of a detoxification mechanism.

PubMed

Fais, S

2010-05-01

This review presents a possible new approach against cancer, as represented by inhibition of proton pumps, a mechanism used by tumour cells to avoid intracellular accumulation of toxic substances. Proton pump inhibitors (PPIs) belong to a family of pro-drugs that are currently used in the treatment of peptic diseases needing acidity to be activated. PPIs target the acidic tumour mass, where they are metabolized, thus blocking proton traffic. Proton pump inhibition triggers a rapid cell death as a result of intracellular acidification, caspase activation and early accumulation of reactive oxygen species into tumour cells. As a whole, the devastating effect of PPIs on tumour cells suggest the triggering of a fatal cell toxification. Many human tumours, including melanoma, osteosarcoma, lymphomas and various adenocarcinomas are responsive to PPIs. This appears highly conceivable, in as much as almost all human tumours are acidic and express high levels of proton pumps. Paradoxically, metastatic tumours appear to be more responsive to PPIs being more acidic than the majority of primary tumours. However, two clinical trials test the effectiveness of PPIs in chemosensitizing melanoma and osteosarcoma patients. Indeed, tumour acidity represents a very potent mechanism of chemoresistance. A majority of cytotoxic agents, being weak bases, are quickly protonated outside and do not enter the cells, thus preventing drugs to reach specific cellular targets. Clinical data will provide the proof of concept on the use of PPIs as a new class of antitumour agent with a very low level of systemic toxicity as compared with standard chemotherapeutic agents.

High-energy D/sub 2/O submillimeter laser for plasma diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Semet, A.; Johnson, L.C.; Mansfield, D.K.

1983-01-01

A narrow line optically pumped D/sub 2/O laser operating at 385 ..mu..m has delivered more than 5 J in pulses longer than 3 ..mu..sec using a large aperture unstable resonator cavity design. Pulse levels which are > 1 J and 1 ..mu..sec are necessary for a single shot ion temperature measurement by Thomson scattering in large tokamaks. Experiments have, for the most part, been conducted at a 360 J, 5 ..mu..sec CO/sub 2/ laser pump level where high efficiency (approx. 2.5 J at 385 ..mu..m) has been obtained. These are the highest energies reported to date in the far infrared.more » In addition, the pulse length has been extended beyond the vibrational relaxation time.« less

On-the-Fly Control of High-Harmonic Generation Using a Structured Pump Beam

NASA Astrophysics Data System (ADS)

Hareli, Liran; Lobachinsky, Lilya; Shoulga, Georgiy; Eliezer, Yaniv; Michaeli, Linor; Bahabad, Alon

2018-05-01

We demonstrate experimentally a relatively simple yet powerful all-optical enhancement and control technique for high harmonic generation. This is achieved by using as a pump beam two different spatial optical modes interfering together to realize tunable periodic quasi-phase matching of the interaction. With this technique, we demonstrate on-the-fly quasi-phase matching of harmonic orders 29-41 at ambient gas pressure levels of 50 and 100 Torr, where an up to 100-fold enhancement of the emission is observed. The technique is scalable to different harmonic orders and ambient pressure conditions.

Power scaling of supercontinuum seeded megahertz-repetition rate optical parametric chirped pulse amplifiers.

PubMed

Riedel, R; Stephanides, A; Prandolini, M J; Gronloh, B; Jungbluth, B; Mans, T; Tavella, F

2014-03-15

Optical parametric chirped-pulse amplifiers with high average power are possible with novel high-power Yb:YAG amplifiers with kW-level output powers. We demonstrate a compact wavelength-tunable sub-30-fs amplifier with 11.4 W average power with 20.7% pump-to-signal conversion efficiency. For parametric amplification, a beta-barium borate crystal is pumped by a 140 W, 1 ps Yb:YAG InnoSlab amplifier at 3.25 MHz repetition rate. The broadband seed is generated via supercontinuum generation in a YAG crystal.

On-the-Fly Control of High-Harmonic Generation Using a Structured Pump Beam.

PubMed

Hareli, Liran; Lobachinsky, Lilya; Shoulga, Georgiy; Eliezer, Yaniv; Michaeli, Linor; Bahabad, Alon

2018-05-04

We demonstrate experimentally a relatively simple yet powerful all-optical enhancement and control technique for high harmonic generation. This is achieved by using as a pump beam two different spatial optical modes interfering together to realize tunable periodic quasi-phase matching of the interaction. With this technique, we demonstrate on-the-fly quasi-phase matching of harmonic orders 29-41 at ambient gas pressure levels of 50 and 100 Torr, where an up to 100-fold enhancement of the emission is observed. The technique is scalable to different harmonic orders and ambient pressure conditions.

Development of high-power dye laser chain

NASA Astrophysics Data System (ADS)

Konagai, Chikara; Kimura, Hironobu; Fukasawa, Teruichiro; Seki, Eiji; Abe, Motohisa; Mori, Hideo

2000-01-01

Copper vapor laser (CVL) pumped dye laser (DL) system, both in a master oscillator power amplifier (MOPA) configuration, has been developed for Atomic Vapor Isotope Separation program in Japan. Dye laser output power of about 500 W has been proved in long-term operations over 200 hours. High power fiber optic delivery system is utilized in order to efficiently transport kilowatt level CVL beams to the DL MOPA. Single model CVL pumped DL oscillator has been developed and worked for 200 hours within +/- 0.1 pm wavelength stability. Phase modulator for spreading spectrum to the linewidth of hyperfine structure has been developed and demonstrated.

Two-photon absorption induced stimulated Rayleigh-Bragg scattering

NASA Astrophysics Data System (ADS)

He, Guang S.; Prasad, Paras N.

2005-01-01

A frequency-unshifted and backward stimulated scattering can be efficiently generated in one-photon-absorption free but two-photon absorbing materials. Using a number of novel two-photon absorbing dye solutions as the scattering media and nanosecond pulsed laser as the pump beams, a highly directional backward stimulated scattering at the exact pump wavelength can be readily observed once the pump intensity is higher than a certain threshold level. The spectral and spatial structures as well as the temporal behavior and optical phase-conjugation property of this new type of backward stimulated scattering have been experimentally studied. This stimulated scattering phenomenon can be explained by using a model of two-photon-excitation enhanced standing-wave Bragg grating initially formed by the strong forward pump beam and much weaker backward Rayleigh scattering beam; the partial reflection of the pump beam from this grating provides an positive feedback to the initial backward Rayleigh scattering beam without suffering linear attenuation influence. Comparing to other known stimulated (Raman, Brillouin, Rayleigh-wing, and Kerr) scattering effects, the stimulated Rayleigh-Bragg scattering exhibits the advantages of no frequency-shift, low pump threshold, and low spectral linewidth requirement.

The sodium pump α1 sub-unit: a disease progression–related target for metastatic melanoma treatment

PubMed Central

Mathieu, Véronique; Pirker, Christine; Martin de Lassalle, Elisabeth; Vernier, Mathieu; Mijatovic, Tatjana; DeNeve, Nancy; Gaussin, Jean-François; Dehoux, Mischael; Lefranc, Florence; Berger, Walter; Kiss, Robert

2009-01-01

Melanomas remain associated with dismal prognosis because they are naturally resistant to apoptosis and they markedly metastasize. Up-regulated expression of sodium pump α sub-units has previously been demonstrated when comparing metastatic to non-metastatic melanomas. Our previous data revealed that impairing sodium pump α1 activity by means of selective ligands, that are cardiotonic steroids, markedly impairs cell migration and kills apoptosis-resistant cancer cells. The objective of this study was to determine the expression levels of sodium pump α sub-units in melanoma clinical samples and cell lines and also to characterize the role of α1 sub-units in melanoma cell biology. Quantitative RT-PCR, Western blotting and immunohistochemistry were used to determine the expression levels of sodium pump α sub-units. In vitro cytotoxicity of various cardenolides and of an anti-α1 siRNA was evaluated by means of MTT assay, quantitative videomicroscopy and through apoptosis assays. The in vivo activity of a novel cardenolide UNBS1450 was evaluated in a melanoma brain metastasis model. Our data show that all investigated human melanoma cell lines expressed high levels of the α1 sub-unit, and 33% of human melanomas displayed significant α1 sub-unit expression in correlation with the Breslow index. Furthermore, cardenolides (notably UNBS1450; currently in Phase I clinical trials) displayed marked anti-tumour effects against melanomas in vitro. This activity was closely paralleled by decreases in cMyc expression and by increases in apoptotic features. UNBS1450 also displayed marked anti-tumour activity in the aggressive human metastatic brain melanoma model in vivo. The α1 sodium pump sub-unit could represent a potential novel target for combating melanoma. PMID:19243476

Advanced methods for modeling water-levels and estimating drawdowns with SeriesSEE, an Excel add-in

USGS Publications Warehouse

Halford, Keith; Garcia, C. Amanda; Fenelon, Joe; Mirus, Benjamin B.

2012-12-21

Water-level modeling is used for multiple-well aquifer tests to reliably differentiate pumping responses from natural water-level changes in wells, or “environmental fluctuations.” Synthetic water levels are created during water-level modeling and represent the summation of multiple component fluctuations, including those caused by environmental forcing and pumping. Pumping signals are modeled by transforming step-wise pumping records into water-level changes by using superimposed Theis functions. Water-levels can be modeled robustly with this Theis-transform approach because environmental fluctuations and pumping signals are simulated simultaneously. Water-level modeling with Theis transforms has been implemented in the program SeriesSEE, which is a Microsoft® Excel add-in. Moving average, Theis, pneumatic-lag, and gamma functions transform time series of measured values into water-level model components in SeriesSEE. Earth tides and step transforms are additional computed water-level model components. Water-level models are calibrated by minimizing a sum-of-squares objective function where singular value decomposition and Tikhonov regularization stabilize results. Drawdown estimates from a water-level model are the summation of all Theis transforms minus residual differences between synthetic and measured water levels. The accuracy of drawdown estimates is limited primarily by noise in the data sets, not the Theis-transform approach. Drawdowns much smaller than environmental fluctuations have been detected across major fault structures, at distances of more than 1 mile from the pumping well, and with limited pre-pumping and recovery data at sites across the United States. In addition to water-level modeling, utilities exist in SeriesSEE for viewing, cleaning, manipulating, and analyzing time-series data.

Diode-pumped continuous-wave eye-safe Nd:YAG laser at 1415 nm.

PubMed

Lee, Hee Chul; Byeon, Sung Ug; Lukashev, Alexei

2012-04-01

We describe the output performance of the 1415 nm emission in Nd:YAG in a plane-concave cavity under traditional pumping into the 4F5/2 level (808 nm) and direct in-band pumping into the 4F3/2 level (885 nm). An end-pumped Nd:YAG laser yielded maximum cw output power of 6.3 W and 4.2 W at 885 nm and 808 nm laser diode (LD) pumping, respectively. To the best of our knowledge, this is the highest output power of a LD-pumped 1415 nm laser.

Off-pump CABG surgery reduces systemic inflammation compared with on-pump surgery but does not change systemic endothelial responses: a prospective randomized study.

PubMed

Jongman, Rianne M; Zijlstra, Jan G; Kok, Wendelinde F; van Harten, Annemarie E; Mariani, Massimo A; Moser, Jill; Struys, Michel M R F; Absalom, Anthony R; Molema, Grietje; Scheeren, Thomas W L; van Meurs, Matijs

2014-08-01

Coronary artery bypass graft (CABG) surgery can result in severe postoperative organ failure. During CABG surgery, cardiopulmonary bypass (CPB) with cardiac arrest is often used (on-pump CABG), which often results in a systemic inflammatory response. To reduce this inflammatory response, off-pump CABG was reintroduced, thereby avoiding CPB. There is increasing evidence that the endothelium plays an important role in the pathophysiology of organ failure after CABG surgery. In this study, 60 patients who were scheduled for elective CABG surgery were randomized to have surgery for on-pump or off-pump CABG. Blood was collected at four time points: start, end, 6 h, and 24 h postoperatively. Levels of inflammatory cytokines, soluble adhesion molecules, and angiogenic factors and their receptors were measured in the plasma. No differences were found in preoperative characteristics between the patient groups. The levels of tumor necrosis factor-α, interleukin 10, and myeloperoxidase, but not interleukin 6, were increased to a greater extent in the on-pump CABG compared with off-pump CABG after sternum closure. The soluble endothelial adhesion molecules E-selectin, vascular cell adhesion molecule 1, and intracellular adhesion molecule 1 were not elevated in the plasma during and after CABG surgery in both on-pump and off-pump CABG. Angiopoietin 2 was only increased 24 h after surgery in both on-pump and off-pump CABG. Higher levels of sFlt-1 were found after sternum closure in off-pump CABG compared with on-pump CABG. Avoiding CPB and aortic cross clamping in CABG surgery reduces the systemic inflammatory response. On-pump CABG does not lead to an increased release of soluble endothelial adhesion molecules in the circulation compared with off-pump CABG.

Modeling of flowing gas diode pumped alkali lasers: dependence of the operation on the gas velocity and on the nature of the buffer gas.

PubMed

Barmashenko, B D; Rosenwaks, S

2012-09-01

A simple, semi-analytical model of flowing gas diode pumped alkali lasers (DPALs) is presented. The model takes into account the rise of temperature in the lasing medium with increasing pump power, resulting in decreasing pump absorption and slope efficiency. The model predicts the dependence of power on the flow velocity in flowing gas DPALs and checks the effect of using a buffer gas with high molar heat capacity and large relaxation rate constant between the 2P3/2 and 2P1/2 fine-structure levels of the alkali atom. It is found that the power strongly increases with flow velocity and that by replacing, e.g., ethane by propane as a buffer gas the power may be further increased by up to 30%. Eight kilowatt is achievable for 20 kW pump at flow velocity of 20  m/s.

Many-body physics in two-component Bose–Einstein condensates in a cavity: fragmented superradiance and polarization

NASA Astrophysics Data System (ADS)

Lode, Axel U. J.; Diorico, Fritz S.; Wu, RuGway; Molignini, Paolo; Papariello, Luca; Lin, Rui; Lévêque, Camille; Exl, Lukas; Tsatsos, Marios C.; Chitra, R.; Mauser, Norbert J.

2018-05-01

We consider laser-pumped one-dimensional two-component bosons in a parabolic trap embedded in a high-finesse optical cavity. Above a threshold pump power, the photons that populate the cavity modify the effective atom trap and mediate a coupling between the two components of the Bose–Einstein condensate. We calculate the ground state of the laser-pumped system and find different stages of self-organization depending on the power of the laser. The modified potential and the laser-mediated coupling between the atomic components give rise to rich many-body physics: an increase of the pump power triggers a self-organization of the atoms while an even larger pump power causes correlations between the self-organized atoms—the BEC becomes fragmented and the reduced density matrix acquires multiple macroscopic eigenvalues. In this fragmented superradiant state, the atoms can no longer be described as two-level systems and the mapping of the system to the Dicke model breaks down.

A study of water pump efficiency for household water demand at Lubuklinggau

NASA Astrophysics Data System (ADS)

Emiliawati, Anna

2017-11-01

Water pump is a device to transport liquid from one place to another. This device is used in most of household in Indonesia. Small-scale water pump which is effective to lift more discharge is generally used. The ones that are most preferred are centrifugal types which having low absorbability. Pump performance is limited by pressure level in real electrical power whereas pump efficiency is influenced by head and discharge. The research aims to find out the efficiency of five distinct brands of home water pumps which are broadly distributed in market. Efficiency analysis take by laboratorium and financial analysis using NPV and BCR are done in order to obtained dicharge and pressure from each pump. At the end of the research, one out of 5 home water pump brands will be selected as the optimal working home water pump with low operational expense based on the utilizing age. The result of the research shows that the maximum efficiency value among various brands of water pump is diverse. Each value is arranged as follow from water pump A to E orderly: 12,9%, 13,5%, 12,8%, 14,8%, and 3,4%. From the calculation, water demand of South Lubuklinggau at stage 1 is 1117,7 l/s and stage 2 is 3495,2 l/s.. Moreover, the researcher conducts of investment, operation and maintenance cost with 25 years pump utilizing age towards 2 conditions (1) of maximum efficiency, i.e. pump A Rp16.563.971; pump B Rp12.163.798; pump C Rp11.809.513,2; pump D Rp11.473.928,3; pump E Rp12.648.708,3; (2) of max discharge, i.e. pump A Rp111.993.822,8; pump B Rp26.128.845,1; pump C Rp51.697.208,8; pump D Rp51.098.687,4; pump E Rp22.915.952,7;Financial analysis with interest rate 13% show a positive NPV(+) for all pump except pump A in max efficiency and a negative NPV (-) for all except pump B in max discharge. BCR value for max efficiency are pump A 0,8; pump B 1,6; pump C 1,7; pump D 1,7 and pump E 1,3. And for max discharge are pump A 0,2; pump B 1,1; pump C 0,7; pump D 0,7 and pump E 0,9. Result from that analysis obtained pump B are feasible with low cost and high benefit.

Field Investigation of an Air-Source Cold Climate Heat Pump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Bo; Abdelaziz, Omar; Rice, C Keith

In the U.S., there are approximately 2.6 million dwellings that use electricity for heating in cold and very cold regions with an annual energy consumption of 0.16 quads (0.17 EJ). A high performance cold climate heat pump (CCHP) would result in significant savings over current technologies (greater than 60% compared to electric resistance heating). We developed an air-source cold climate heat pump, which uses tandem compressors, with a single compressor rated for the building design cooling load, and running two compressors to provide, at -13 F (-25 C), 75% of rated heating capacity. The tandem compressors were optimized for heatingmore » operation and are able to tolerate discharge temperatures up to 280 F (138 C). A field investigation was conducted in the winter of 2015, in an occupied home in Ohio, USA. During the heating season, the seasonal COP was measured at 3.16, and the heat pump was able to operate down to -13 F (-25 C) and eliminate resistance heat use. The heat pump maintained an acceptable comfort level throughout the heating season. In comparison to a previous single-speed heat pump in the home, the CCHP demonstrated more than 40% energy savings in the peak heating load month. This paper illustrates the measured field performance, including compressor run time, frost/defrosting operations, distributions of building heating load and capacity delivery, comfort level, field measured COPs, etc.« less

Performance and Economic Modeling of Horizontally Drilled Ground-Source Heat Pumps in Select California Climates

NASA Astrophysics Data System (ADS)

Wiryadinata, Steven

Service life modeling was performed to gage the viability of unitary 3.5 kWt, ground-source terminal heat pumps (GTHP) employing horizontal directionally drilled geothermal heat exchangers (GHX) over air-source terminal heat pumps (PTHP) in hotels and motels and residential apartment building sectors in California's coastal and inland climates. Results suggest the GTHP can reduce hourly peak demand for the utility by 7%-25% compared to PTHP, depending on the climate and building type. The annual energy savings, which range from -1% to 5%, are highly dependent on the GTHP pump energy use relative to the energy savings attributed to the difference in ground and air temperatures (DeltaT). In mild climates with small ?T, the pump energy use may overcome any advantage to utilizing a GHX. The majority of total levelized cost savings - ranging from 0.18/ft2 to 0.3/ft 2 - are due to reduced maintenance and lifetime capital cost normally associated with geothermal heat pump systems. Without these reductions (not validated for the GTHP system studied), the GTHP technology does not appear to offer significant advantages over PTHP in the climate zones studied here. The GTHP levelized cost was most sensitive to variations in installed cost and in some cases, energy use (influenced by climate zone choice), which together highlights the importance of climate selection for installation, and the need for larger market penetration of ground-source systems in order to bring down installed costs as the technology matures.

Simulated water sources and effects of pumping on surface and ground water, Sagamore and Monomoy flow lenses, Cape Cod, Massachusetts

USGS Publications Warehouse

Walter, Donald A.; Whealan, Ann T.

2005-01-01

The sandy sediments underlying Cape Cod, Massachusetts, compose an important aquifer that is the sole source of water for a region undergoing rapid development. Population increases and urbanization on Cape Cod lead to two primary environmental effects that relate directly to water supply: (1) adverse effects of land use on the quality of water in the aquifer and (2) increases in pumping that can adversely affect environmentally sensitive surface waters, such as ponds and streams. These considerations are particularly important on the Sagamore and Monomoy flow lenses, which underlie the largest and most populous areas on Cape Cod. Numerical models of the two flow lenses were developed to simulate ground-water-flow conditions in the aquifer and to (1) delineate areas at the water table contributing water to wells and (2) estimate the effects of pumping and natural changes in recharge on surface waters. About 350 million gallons per day (Mgal/d) of water recharges the aquifer at the water table in this area; most water (about 65 percent) discharges at the coast and most of the remaining water (about 28 percent) discharges into streams. A total of about 24.9 Mgal/d, or about 7 percent, of water in the aquifer is withdrawn for water supply; most pumped water is returned to the hydrologic system as return flow creating a state of near mass balance in the aquifer. Areas at the water table that contribute water directly to production wells total about 17 square miles; some water (about 10 percent) pumped from the wells flows through ponds prior to reaching the wells. Current (2003) steady-state pumping reduces simulated ground-water levels in some areas by more than 4 feet; projected (2020) pumping may reduce water levels by an additional 3 feet or more in these same areas. Current (2003) and future (2020) pumping reduces total streamflow by about 4 and 9 cubic feet per second (ft3/s), corresponding to about 5 percent and 9 percent, respectively, of total streamflow. Natural recharge varies with time, over both monthly and multiyear time scales. Monthly changes in recharge cause pond levels to vary between 1 and 2 feet in an average year; annual changes in recharge, which can be much larger than monthly variations, can cause pond levels to vary by more than 10 feet in some areas over a period of years. Streamflow, which also changes in response to changes in recharge, varies by a factor of two over an average year and can vary more over multiyear periods. On average, monthly pumping ranges from 15.8 Mgal/d in March to 45.3 Mgal/d in August. Pumping and the distribution of return flow can seasonally affect the hydrologic system by lowering ground-water and pond levels and by depleting streamflows, particularly in the summer months. Maximum drawdowns in March and August exceed 3 feet and 6 feet, respectively, for current (2003) pumping. Simulated drawdowns from projected (2020) pumping, relative to water levels representing 2003 pumping conditions, exceed 2 feet in March and 5 feet in August. Current (2003) and future (2020) pumping can decrease pond levels in some areas by more than 3 feet; drawdown generally is largest during the month of August of an average year. Over multiyear periods, seasonal pumping can lower pond levels in some areas by more than 4 feet; the effects of seasonal pumping are largest during periods of reduced recharge. Monthly streamflow depletion varies in individual streams but can exceed 2 ft3/s in some streams. The combined effects of seasonal pumping and drought can reduce pond levels by more than 10 feet below average levels. Water levels in Mary Dunn Pond, which is in an area of large current and projected pumping, are predicted (2020) to decline during drought conditions by about 10.6 feet: about 6.9 feet from lower recharge, about 2.3 feet from current (2003) pumping, and about 1.4 feet from additional future (2020) pumping. The results indicate that pumping generally does not cause substantial

A biomolecular detection method based on charge pumping in a nanogap embedded field-effect-transistor biosensor

NASA Astrophysics Data System (ADS)

Kim, Sungho; Ahn, Jae-Hyuk; Park, Tae Jung; Lee, Sang Yup; Choi, Yang-Kyu

2009-06-01

A unique direct electrical detection method of biomolecules, charge pumping, was demonstrated using a nanogap embedded field-effect-transistor (FET). With aid of a charge pumping method, sensitivity can fall below the 1 ng/ml concentration regime in antigen-antibody binding of an avian influenza case. Biomolecules immobilized in the nanogap are mainly responsible for the acute changes of the interface trap density due to modulation of the energy level of the trap. This finding is supported by a numerical simulation. The proposed detection method for biomolecules using a nanogap embedded FET represents a foundation for a chip-based biosensor capable of high sensitivity.

Overview and future direction for blackbody solar-pumped lasers

NASA Technical Reports Server (NTRS)

Deyoung, R. J.

1988-01-01

A review of solar-pumped blackbody lasers is given which addresses their present status and suggests future research directions. The blackbody laser concept is one system proposed to scale to multimegawatt power levels for space-to-space power transmissions for such applications as onboard spacecraft electrical or propulsion needs. Among the critical technical issues are the scalability to high powers and the laser wavelength which impacts the transmission optics size as well as the laser-to-electric converter at the receiver. Because present blackbody solar-pumped lasers will have laser wavelengths longer than 4 microns, simple photovoltaic converters cannot be used, and transmission optics will be large. Thus, future blackbody laser systems should emphasize near visible laser wavelengths.

Extending the wavelength range in the Oclaro high-brightness broad area modules

NASA Astrophysics Data System (ADS)

Pawlik, Susanne; Guarino, Andrea; Sverdlov, Boris; Müller, Jürgen; Button, Christopher; Arlt, Sebastian; Jaeggi, Dominik; Lichtenstein, Norbert

2010-02-01

The demand for high power laser diode modules in the wavelength range between 793 nm and 1060 nm has been growing continuously over the last several years. Progress in eye-safe fiber lasers requires reliable pump power at 793 nm, modules at 808 nm are used for small size DPSSL applications and fiber-coupled laser sources at 830 nm are used in printing industry. However, power levels achieved in this wavelength range have remained lower than for the 9xx nm range. Here we report on approaches to increasing the reliable power in our latest generations of high power pump modules in the wavelength range between 793 nm and 1060 nm.

Ultra-high speed vacuum pump system with first stage turbofan and second stage turbomolecular pump

DOEpatents

Jostlein, Hans

2006-04-04

An ultra-high speed vacuum pump evacuation system includes a first stage ultra-high speed turbofan and a second stage conventional turbomolecular pump. The turbofan is either connected in series to a chamber to be evacuated, or is optionally disposed entirely within the chamber. The turbofan employs large diameter rotor blades operating at high linear blade velocity to impart an ultra-high pumping speed to a fluid. The second stage turbomolecular pump is fluidly connected downstream from the first stage turbofan. In operation, the first stage turbofan operates in a pre-existing vacuum, with the fluid asserting only small axial forces upon the rotor blades. The turbofan imparts a velocity to fluid particles towards an outlet at a high volume rate, but moderate compression ratio. The second stage conventional turbomolecular pump then compresses the fluid to pressures for evacuation by a roughing pump.

Design of three-well indirect pumping terahertz quantum cascade lasers for high optical gain based on nonequilibrium Green's function analysis

NASA Astrophysics Data System (ADS)

Liu, Tao; Kubis, Tillmann; Jie Wang, Qi; Klimeck, Gerhard

2012-03-01

The nonequilibrium Green's function approach is applied to the design of three-well indirect pumping terahertz (THz) quantum cascade lasers (QCLs) based on a resonant phonon depopulation scheme. The effects of the anticrossing of the injector states and the dipole matrix element of the laser levels on the optical gain of THz QCLs are studied. The results show that a design that results in a more pronounced anticrossing of the injector states will achieve a higher optical gain in the indirect pumping scheme compared to the traditional resonant-tunneling injection scheme. This offers in general a more efficient coherent resonant-tunneling transport of electrons in the indirect pumping scheme. It is also shown that, for operating temperatures below 200 K and low lasing frequencies, larger dipole matrix elements, i.e., vertical optical transitions, offer a higher optical gain. In contrast, in the case of high lasing frequencies, smaller dipole matrix elements, i.e., diagonal optical transitions are better for achieving a higher optical gain.

7 CFR 58.219 - High pressure pumps and lines.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false High pressure pumps and lines. 58.219 Section 58.219....219 High pressure pumps and lines. High pressure lines may be cleaned-in-place and shall be of such construction that dead ends, valves and the high pressure pumps can be disassembled for hand cleaning. The high...

Identification of pumping influences in long-term water level fluctuations.

PubMed

Harp, Dylan R; Vesselinov, Velimir V

2011-01-01

Identification of the pumping influences at monitoring wells caused by spatially and temporally variable water supply pumping can be a challenging, yet an important hydrogeological task. The information that can be obtained can be critical for conceptualization of the hydrogeological conditions and indications of the zone of influence of the individual pumping wells. However, the pumping influences are often intermittent and small in magnitude with variable production rates from multiple pumping wells. While these difficulties may support an inclination to abandon the existing dataset and conduct a dedicated cross-hole pumping test, that option can be challenging and expensive to coordinate and execute. This paper presents a method that utilizes a simple analytical modeling approach for analysis of a long-term water level record utilizing an inverse modeling approach. The methodology allows the identification of pumping wells influencing the water level fluctuations. Thus, the analysis provides an efficient and cost-effective alternative to designed and coordinated cross-hole pumping tests. We apply this method on a dataset from the Los Alamos National Laboratory site. Our analysis also provides (1) an evaluation of the information content of the transient water level data; (2) indications of potential structures of the aquifer heterogeneity inhibiting or promoting pressure propagation; and (3) guidance for the development of more complicated models requiring detailed specification of the aquifer heterogeneity. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

Multi-frequency inversion-charge pumping for charge separation and mobility analysis in high-k/InGaAs metal-oxide-semiconductor field-effect transistors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Djara, V.; Cherkaoui, K.; Negara, M. A.

2015-11-28

An alternative multi-frequency inversion-charge pumping (MFICP) technique was developed to directly separate the inversion charge density (N{sub inv}) from the trapped charge density in high-k/InGaAs metal-oxide-semiconductor field-effect transistors (MOSFETs). This approach relies on the fitting of the frequency response of border traps, obtained from inversion-charge pumping measurements performed over a wide range of frequencies at room temperature on a single MOSFET, using a modified charge trapping model. The obtained model yielded the capture time constant and density of border traps located at energy levels aligned with the InGaAs conduction band. Moreover, the combination of MFICP and pulsed I{sub d}-V{sub g}more » measurements enabled an accurate effective mobility vs N{sub inv} extraction and analysis. The data obtained using the MFICP approach are consistent with the most recent reports on high-k/InGaAs.« less

[Effects of exogenous spermidine on lipid peroxidation and membrane proton pump activity of cucumber seedling leaves under high temperature stress].

PubMed

Tian, Jing; Guo, Shi-Rong; Sun, Jin; Wang, Li-Ping; Yang, Yan-Juan; Li, Bin

2011-12-01

Taking a relatively heat-resistant cucumber (Cucumis sativus) cultivar 'Jinchun No. 4' as test material, a sand culture experiment was conducted in growth chamber to investigate the effects of foliar spraying spermidine (Spd) on the lipid peroxidation, membrane proton pump activity, and corresponding gene expression of cucumber seedling leaves under high temperature stress. Compared with the control, foliar spraying Spd increased the plant height, stem diameter, dry and fresh mass, and leaf area significantly, and inhibited the increase of leaf relative conductivity, malondialdehyde (MDA) content, and lipoxygenase (LOX) activity effectively. Foliar spraying Spd also helped to the increase of leaf plasma membrane- and tonoplast H(+)-ATPase activity, but no significant difference was observed in the gene expression levels. These results suggested that exogenous Spd could significantly decrease the leaf lipid peroxidation and increase the proton pump activity, and thus, stabilize the leaf membrane structure and function, alleviate the damage induced by high temperature stress, and enhance the heat tolerance of cucumber seedlings.

Detecting drawdowns masked by environmental stresses with water-level models

USGS Publications Warehouse

Garcia, C.A.; Halford, K.J.; Fenelon, J.M.

2013-01-01

Detecting and quantifying small drawdown at observation wells distant from the pumping well greatly expands the characterized aquifer volume. However, this detection is often obscured by water level fluctuations such as barometric and tidal effects. A reliable analytical approach for distinguishing drawdown from nonpumping water-level fluctuations is presented and tested here. Drawdown is distinguished by analytically simulating all pumping and nonpumping water-level stresses simultaneously during the period of record. Pumping signals are generated with Theis models, where the pumping schedule is translated into water-level change with the Theis solution. This approach closely matched drawdowns simulated with a complex three-dimensional, hypothetical model and reasonably estimated drawdowns from an aquifer test conducted in a complex hydrogeologic system. Pumping-induced changes generated with a numerical model and analytical Theis model agreed (RMS as low as 0.007 m) in cases where pumping signals traveled more than 1 km across confining units and fault structures. Maximum drawdowns of about 0.05 m were analytically estimated from field investigations where environmental fluctuations approached 0.2 m during the analysis period.

The correlation between ouabain binding and potassium pump inhibition in human and sheep erythrocytes.

PubMed Central

Joiner, C H; Lauf, P K

1978-01-01

1. [3H]Ouabain binding to human and sheep red blood cells was shown to be specific for receptors associated with Na/K transport. Virtually all tritium binding was abolished by dilution with unlabelled drug. Saturation levels of binding were independent of glycoside concentration and were identical to those associated with 100% inhibition of K pumping. 2. [3H]Ouabain binding and 42K influx were measured simultaneously in order to correlate the degree of K pump inhibition with the amount of glycoside bound. Results by this method agreed exactly with those obtained by pre-exposing cells to drug, followed by washing and then measuring K influx. 3. Plots of [3H]oubain binding vs. K pump inhibition were rectilinear for human and low K (LK) sheep red cells, indicating one glycoside receptor per K pump site and functional homogeneity of pump sites. High K (HK) sheep red cells exhibited curved plots of binding versus inhibition, which were best explained in terms of one receptor per pump, but a heterogeneous population of pump sites. 4. External K reduced the rate of glycoside binding, but did not alter the relationship between binding and inhibition. 5. The number of K pump sites was estimated as 450--500 per human cell and 30--50 per LK sheep cell. HK sheep cells had 90--130 sites per cell, of which eighty to ninety were functionally dominant. The number of K pump sites on LK sheep cells was not changed by anti-L, although the maximum velocity of pump turnover was increased. PMID:722573

Service bay area, pump room level, showing ventilation fans and ...

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

Service bay area, pump room level, showing ventilation fans and ducts association with evaporative-cooling system. Note battery bank at far right. View to the east - Wellton-Mohawk Irrigation System, Pumping Plant No. 3, South of Interstate 8, Wellton, Yuma County, AZ

Liquid Propulsion: Propellant Feed System Design. Chapter 2.3.11

NASA Technical Reports Server (NTRS)

Cannon, James L.

2010-01-01

The propellant feed system of a liquid rocket engine determines how the propellants are delivered from the tanks to the thrust chamber. They are generally classified as either pressure fed or pump fed. The pressure-fed system is simple and relies on tank pressures to feed the propellants into the thrust chamber. This type of system is typically used for space propulsion applications and auxiliary propulsion applications requiring low system pressures and small quantities of propellants. In contrast, the pump-fed system is used for high pressure, high performance applications. The selection of one propellant feed system over another is determined based on design trade studies at both the engine and vehicle levels. This chapter first provides a brief overview of the basic configurations of pressure-fed systems. Pump-fed systems are then discussed with greater detail given to the turbomachinery design. Selected design requirements and configurations are provided.

Test facilities for high power electric propulsion

NASA Technical Reports Server (NTRS)

Sovey, James S.; Vetrone, Robert H.; Grisnik, Stanley P.; Myers, Roger M.; Parkes, James E.

1991-01-01

Electric propulsion has applications for orbit raising, maneuvering of large space systems, and interplanetary missions. These missions involve propulsion power levels from tenths to tens of megawatts, depending upon the application. General facility requirements for testing high power electric propulsion at the component and thrust systems level are defined. The characteristics and pumping capabilities of many large vacuum chambers in the United States are reviewed and compared with the requirements for high power electric propulsion testing.

Soft X-ray laser using pumping of 3P and 4P levels of He-like and H-like ions

DOEpatents

Hagelstein, Peter L.

1987-01-01

X-ray laser method and apparatus for producing coherent radiation at, for example, energies of at least 40 eV, using Be-like Cr, N-like Ni, He-like Na, B-like Cr, Be-like Mn or similar multiply ionized species to pump appropriate high energy transitions in He-like or H-like N, O, F, C or rare gases, with associated laser transition gains of 4-50 cm.sup.-1.

Soft x-ray laser using pumping of 3p and 4p levels of He-like and H-like ions

DOEpatents

Hagelstein, P.L.

1985-07-05

X-ray laser method and apparatus for producing coherent radiation at, for example, energies of at least 40 eV, using Be-like Cr, N-like Ni, He-like Na, B-like Cr, Be-like Mn or similar multiply ionized species to pump appropriate high energy transitions in He-like or H-like N, O, F, C or rare gases, with associated laser transition gains of 4 to 50 cm/sup -1/.

Soft x-ray laser using pumping of 3P and 4P levels of He-like and H-like ions

DOEpatents

Hagelstein, P.

1982-03-26

X-ray laser method and apparatus for producing coherent radiation at, for example, energies of 40 to 189 eV, using Be-like Cr, N-like Ni, He-like Na, B-like Cr, Be-like Mn or similar multiply ionized species to pump appropriate high energy transitions in He-like or H-like rare gases or N, O, F, or C gases, with associated laser transition gains of 20 to 50 cm/sup -1/.

On the possibility of developing quasi-CW high-power high-pressure laser on 4p-4s transition of ArI with electron beam—optical pumping: quenching of 4s (3P2) lower laser level

NASA Astrophysics Data System (ADS)

Ionin, A. A.; Kholin, I. V.; L'dov, A. Yu; Seleznev, L. V.; Ustinovskii, N. N.; Zayarnyi, D. A.

2017-12-01

A new electron beam-optical procedure is proposed for quasi-cw pumping of high-pressure large-volume He-Ar laser on the 4p[1/2]1-4s[3/2]20 argon atom transition at the wavelength of 912.5 nm. It consists of creation and maintenance of a necessary density of the 4s[3/2]20 metastable state in the gain medium by a fast electron beam and subsequent optical pumping of the upper laser level via the classical three-level scheme using a laser diode. Absorption probing is used to study collisional quenching of Ar* metastable in electron-beam-excited high-pressure He-Ar mixtures with a low content of argon. The rate constants for plasma-chemical reactions Ar*  +  He  +  Ar  >  Ar2*   +  He (3.6  ±  0.4)  ×  10-33 cm6 s-1, Ar*  +  2He  >  HeAr*  +  He (4.4  ±  0.9)  ×  10-36 cm6 s-1 and Ar*  +  He  >  Products  +  He (2.4  ±  0.3)  ×  10-15 cm3 s-1 were for the first time measured.

Self-compensation of thermal lens in high-power diode pumped solid-state lasers

NASA Astrophysics Data System (ADS)

Wang, Xiao-Jun

2010-02-01

We present a comprehensive model to describe the optic-thermal coupling in the diode pumped solid-state lasers (DPSSL). The thermal transition of particles at the upper laser level leads the heat-generation of laser crystals to depend on shape of the laser beam, while the laser field is also influenced by the temperature because of the thermal excitation of doped particles among various Stark levels. These effects, together with the usual thermal-optic effect that induces a fluctuation of the refraction index by an inhomogeneous temperature distribution, cause a complicated coupling between the laser field and the temperature field. We show that the optic-thermal coupling plays an important role in high-power DPSSL with larger size beam. That effect may yield a self-compensation for the thermal lens and improve the beam quality.

A new approach for assessing the future of aquifers supporting irrigated agriculture

NASA Astrophysics Data System (ADS)

Butler, James J.; Whittemore, Donald O.; Wilson, Blake B.; Bohling, Geoffrey C.

2016-03-01

Aquifers supporting irrigated agriculture are under stress worldwide as a result of large pumping-induced water deficits. To aid in the formulation of more sustainable management plans for such systems, we have developed a water balance approach for assessing the impact of proposed management actions and the prospects for aquifer sustainability. Application to the High Plains aquifer (HPA) in the state of Kansas in the United States reveals that practically achievable reductions in annual pumping (<22%) would have stabilized areally averaged water levels over much of the Kansas HPA from 1996 to 2013. This demonstrates that modest pumping reductions can have a significant impact and highlights the importance of reliable pumping data for determining the net inflow (capture) component of the water balance. The HPA is similar to many aquifers supporting critically needed agricultural production, so the presented approach should prove of value far beyond the area of this initial application.

GHz Yb:KYW oscillators in time-resolved spectroscopy

NASA Astrophysics Data System (ADS)

Li, Changxiu; Krauß, Nico; Schäfer, Gerhard; Ebner, Lukas; Kliebisch, Oliver; Schmidt, Johannes; Winnerl, Stephan; Hettich, Mike; Dekorsy, Thomas

2018-02-01

A high-speed asynchronous optical sampling system (ASOPS) based on Yb:KYW oscillators with 1-GHz repetition rate is reported. Two frequency-offset-stabilized diode-pumped Yb:KYW oscillators are employed as pump and probe source, respectively. The temporal resolution of this system within 1-ns time window is limited to 500 fs and the noise floor around 10-6 (ΔR/R) close to the shot-noise level is obtained within an acquisition time of a few seconds. Coherent acoustic phonons are investigated by measuring multilayer semiconductor structures with multiple quantum wells and aluminum/silicon membranes in this ASOPS system. A wavepacket-like phonon sequence at 360 GHz range is detected in the semiconductor structures and a decaying sequence of acoustic oscillations up to 200 GHz is obtained in the aluminum/silicon membranes. Coherent acoustic phonons generated from semiconductor structures are further manipulated by a double pump scheme through pump time delay control.

Precise control of molecular dynamics with a femtosecond frequency comb.

PubMed

Pe'er, Avi; Shapiro, Evgeny A; Stowe, Matthew C; Shapiro, Moshe; Ye, Jun

2007-03-16

We present a general and highly efficient scheme for performing narrow-band Raman transitions between molecular vibrational levels using a coherent train of weak pump-dump pairs of shaped ultrashort pulses. The use of weak pulses permits an analytic description within the framework of coherent control in the perturbative regime, while coherent accumulation of many pulse pairs enables near unity transfer efficiency with a high spectral selectivity, thus forming a powerful combination of pump-dump control schemes and the precision of the frequency comb. Simulations verify the feasibility and robustness of this concept, with the aim to form deeply bound, ultracold molecules.

20 W continuous-wave cladding-pumped Nd-doped fiber laser at 910 nm.

PubMed

Laroche, M; Cadier, B; Gilles, H; Girard, S; Lablonde, L; Robin, T

2013-08-15

We demonstrate a double-clad fiber laser operating at 910 nm with a record power of 20 W. Laser emission on the three-level scheme is enabled by the combination of a small inner cladding-to-core diameter ratio and a high brightness pump source at 808 nm. A laser conversion efficiency as high as 44% was achieved in CW operating regime by using resonant fiber Bragg reflectors at 910 nm that prevent the lasing at the 1060 nm competing wavelength. Furthermore, in a master oscillator power-amplifier scheme, an amplified power of 14.8 W was achieved at 914 nm in the same fiber.

Analysis of Compound Water Hazard in Coastal Urbanized Areas under the Future Climate

NASA Astrophysics Data System (ADS)

Shibuo, Y.; Taniguchi, K.; Sanuki, H.; Yoshimura, K.; Lee, S.; Tajima, Y.; Koike, T.; Furumai, H.; Sato, S.

2017-12-01

Several studies indicate the increased frequency and magnitude of heavy rainfalls as well as the sea level rise under the future climate, which implies that coastal low-lying urbanized areas may experience increased risk against flooding. In such areas, where river discharge, tidal fluctuation, and city drainage networks altogether influence urban inundation, it is necessary to consider their potential interference to understand the effect of compound water hazard. For instance, pump stations cannot pump out storm water when the river water level is high, and in the meantime the river water level shall increase when it receives pumped water from cities. At the further downstream, as the tidal fluctuation regulates the water levels in the river, it will also affect the functionality of pump stations and possible inundation from rivers. In this study, we estimate compound water hazard in the coastal low-lying urbanized areas of the Tsurumi river basin under the future climate. We developed the seamlessly integrated river, sewerage, and coastal hydraulic model that can simulate river water levels, water flow in sewerage network, and inundation from the rivers and/or the coast to address the potential interference issue. As a forcing, the pseudo global warming method, which applies the changes in GCM anomaly to re-analysis data, is employed to produce ensemble typhoons to drive the seamlessly integrated model. The results show that heavy rainfalls caused by the observed typhoon generally become stronger under the pseudo global climate condition. It also suggests that the coastal low-lying areas become extensively inundated if the onset of river flooding and storm surge coincides.

Evaluation of Future Fuels in a High Pressure Common Rail System - Part 1 Cummins XPI

DTIC Science & Technology

2012-10-01

compressed against the underside of the pump head to maintain contact with the pump camshaft. The underside of the pump head is shown in Figure 5...Figure 5. High Pressure Pump Head Unclassified 8 The two barrel retainers located on the underside of the pump head hold the ceramic plungers...which develop the high pressures within the pump. The plungers are driven into the barrels by the tappets as the shaft turns. They are forced back out

Pump room level, looking west in the service bay area. ...

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

Pump room level, looking west in the service bay area. Cable trays and two ventilation fans (part of the evaporative-cooling system) are visible at right. The vacuum pump is in the center in front of a concrete partition, and a water discharge pipe is visible beyond the partition at left - Wellton-Mohawk Irrigation System, Pumping Plant No. 1, Bounded by Gila River & Union Pacific Railroad, Wellton, Yuma County, AZ

885-nm Pumped Ceramic Nd:YAG Master Oscillator Power Amplifier Laser System

NASA Technical Reports Server (NTRS)

Yu, Anthony

2012-01-01

The performance of a traditional diode pumped solid-state laser that is typically pumped with 808-nm laser diode array (LDA) and crystalline Nd:YAG was improved by using 885-nm LDAs and ceramic Nd:YAG. The advantage is lower quantum defect, which will improve the thermal loading on laser gain medium, resulting in a higher-performance laser. The use of ceramic Nd:YAG allows a higher Nd dopant level that will make up the lower absorption at the 885-nm wavelength on Nd:YAG. When compared to traditional 808-nm pump, 885-nm diodes will have 30% less thermal load (or wasted heat) and will thus see a similar percentage improvement in the overall laser efficiency. In order to provide a more efficient laser system for future flight missions that require the use of low-repetition- rate (1% Nd. To make certain that the absorption at 885 nm is on the same par as the 808-nm diode, the Nd:YAG material needs to be doped with higher concentration of Nd. Ceramic Nd:YAG is the only material that can be tailored to specific needs.

Salt budget for West Pond, Utah, April 1987 to June 1989

USGS Publications Warehouse

Wold, S.R.; Waddell, K.M.

1994-01-01

During operation of the West Desert pumping project, April 10. 1987, to June 30, 1989, data were collected as part of a monitoring program to evaluate the effects of pumping brine from Great Salt Lake into West Pond in northern Utah. The removal of brine from Great Sail was part of an effort to lower the level of Great Salt Lake when the water level was at a high in 1986. These data were used to prepare a salt budget that indicates about 695 million tons of salt or about 14.2 percent of salt contained in Great Salt Lake was pumped into West Pond. Of the 695 million tons of salt pumped into West Pond, 315 million tons (45 percent) were dissolved in West Pond, 71 million tons (10.2 percent) formed a salt crust at the bottom of the pond, 10 million tons (1.4 percent) infiltrated the subsurface areas inundated by storage in the pond, 88 million tons (12.7 percent) were withdrawn by American Magnesium Corporation, and 123 million tons (17.7 percent) discharged from the pond through the Newfoundland weir. About 88 million tons (13 percent) of the salt pumped from the lake could not be accounted for in the salt budget. About 94 million tons of salt (1.9 percent of the total salt in Great Salt Lake) flowed back to Great Salt Lake.

Ten-watt level picosecond parametric mid-IR source broadly tunable in wavelength

NASA Astrophysics Data System (ADS)

Vyvlečka, Michal; Novák, Ondřej; Roškot, Lukáscaron; Smrž, Martin; Mužík, Jiří; Endo, Akira; Mocek, Tomáš

2018-02-01

Mid-IR wavelength range (between 2 and 8 μm) offers perspective applications, such as minimally-invasive neurosurgery, gas sensing, or plastic and polymer processing. Maturity of high average power near-IR lasers is beneficial for powerful mid-IR generation by optical parametric conversion. We utilize in-house developed Yb:YAG thin-disk laser of 100 W average power at 77 kHz repetition rate, wavelength of 1030 nm, and about 2 ps pulse width for pumping of a ten-watt level picosecond mid-IR source. Seed beam is obtained by optical parametric generation in a double-pass 10 mm long PPLN crystal pumped by a part of the fundamental near-IR beam. Tunability of the signal wavelength between 1.46 μm and 1.95 μm was achieved with power of several tens of miliwatts. Main part of the fundamental beam pumps an optical parametric amplification stage, which includes a walk-off compensating pair of 10 mm long KTP crystals. We already demonstrated the OPA output signal and idler beam tunability between 1.70-1.95 μm and 2.18-2.62 μm, respectively. The signal and idler beams were amplified up to 8.5 W and 5 W, respectively, at 42 W pump without evidence of strong saturation. Thus, increase in signal and idler output power is expected for pump power increase.

Upconversion-pumped luminescence efficiency of rare-earth-doped hosts sensitized with trivalent ytterbium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Page, R.H.; Schaffers, K.I.; Waide, P.A.

We discuss the upconversion luminescence efficiencies of phosphors that generate red, green, and blue light. The phosphors studied are single crystals and powders co-doped with Er{sup 3+} and Yb{sup 3+}, and with Tm{sup 3+} and Yb{sup 3+}. The Yb ions are pumped near 980 nm; transfers of two or three quanta to the co-doped rare earth ion generate visible luminescence. The main contribution embodied in this work is the quantitative measurement of this upconversion efficiency, based on the use of a calibrated integrating sphere, determination of the fraction of pump light absorbed, and careful control of the pump laser beammore » profile. The green phosphors are the most efficient, yielding efficiency values as high as 4 %, with the red and blue materials giving 1 - 2 %. Saturation was observed in all cases, suggesting that populations of upconversion steps of the ions are maximized at higher power. Quasi-CW modeling of the intensity- dependent upconversion efficiency was attempted; input data included level lifetimes, transition cross sections, and cross-relaxation rate coefficients. The saturation of the Yb,Er:fluoride media is explained as the pumping of Er{sup 3+} ions into a bottleneck (long-lived state)- the {sup 4}I{sub 13/2} metastable level, making them unavailable for further excitation transfer. 32 refs., 5 figs., 3 tabs.« less

Differentiating Natural and Anthropogenic Groundwater-Level Changes in Critical Habitats: An Example from Devils Hole, Nevada

NASA Astrophysics Data System (ADS)

Halford, K. J.; Jackson, T.; Fenelon, J.

2017-12-01

Endangered species such as the Devils Hole pupfish can be affected by decadal groundwater-level changes of less than 1 ft. These relatively minor changes in long-term water levels primarily result from temporal variations in recharge and groundwater development. Natural groundwater-level changes are the summation of episodic rises from infrequent recharge events and steady declines from regional groundwater discharge. Rising water levels have been observed in Devils Hole and across southern Nevada in response to wetter conditions during 1970-2016 relative to the 1900-1970 period. Interpretation of water-level changes in Devils Hole were made tractable by differentiating naturally occurring rises from pumping effects with analytical water-level models. Effects of local and regional pumping on water-level changes in Devils Hole were differentiated easily with a calibrated groundwater-flow model after removing natural rising trends. Annual average water levels declined 2.3 ft from 1968-1972 in response to local pumping within 2 mi of Devils Hole and rose 1.7 ft from 1973-2016 in response to the cumulative effects of recharge, recovery from the cessation of local pumping, and long-term declines of regional pumping.

Watt-level ~2 μm laser output in Tm3+-doped tungsten tellurite glass double-cladding fiber.

PubMed

Li, Kefeng; Zhang, Guang; Hu, Lili

2010-12-15

We report, for the first time to the best of our knowledge, a watt level cw fiber laser at ~2 μm from a piece of 40-cm-long newly developed highly thulium-doped (3.76 × 10(20) ions/cm(3)) tungsten tellurite glass double cladding fiber pumped by a commercial 800 nm laser diode. The maximum output power of the fiber laser reaches 1.12 W. The slope efficiency and the optical-optical efficiency with respect to the absorbed pump are 20% and 16%, respectively. The lasing threshold is 1.46 W, and the lasing wavelength is centered at 1937 nm.

Multi-resonance frequency spin dependent charge pumping and spin dependent recombination - applied to the 4H-SiC/SiO2 interface

NASA Astrophysics Data System (ADS)

Anders, M. A.; Lenahan, P. M.; Lelis, A. J.

2017-12-01

We report on a new electrically detected magnetic resonance (EDMR) approach involving spin dependent charge pumping (SDCP) and spin dependent recombination (SDR) at high (K band, about 16 GHz) and ultra-low (360 and 85 MHz) magnetic resonance frequencies to investigate the dielectric/semiconductor interface in 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs). A comparison of SDCP and SDR allows for a comparison of deep level defects and defects with energy levels throughout most of the bandgap. Additionally, a comparison of high frequency and ultra-low frequency measurements allows for (1) the partial separation of spin-orbit coupling and hyperfine effects on magnetic resonance spectra, (2) the observation of otherwise forbidden half-field effects, which make EDMR, at least, in principle, quantitative, and (3) the observation of Breit-Rabi shifts in superhyperfine measurements. (Observation of the Breit-Rabi shift helps in both the assignment and the measurement of superhyperfine parameters.) We find that, as earlier work also indicates, the SiC silicon vacancy is the dominating defect in n-MOSFETs with as-grown oxides and that post-oxidation NO anneals significantly reduce their population. In addition, we provide strong evidence that NO anneals result in the presence of nitrogen very close to a large fraction of the silicon vacancies. The results indicate that the presence of nearby nitrogen significantly shifts the silicon vacancy energy levels. Our results also show that the introduction of nitrogen introduces a disorder at the interface. This nitrogen induced disorder may provide at least a partial explanation for the relatively modest improvement in mobility after the NO anneals. Finally, we compare the charge pumping and SDCP response as a function of gate amplitude and charge pumping frequency.

Proton Pump Inhibition Increases Rapid Eye Movement Sleep in the Rat

PubMed Central

Jha, Sushil K.

2014-01-01

Increased bodily CO2 concentration alters cellular pH as well as sleep. The proton pump, which plays an important role in the homeostatic regulation of cellular pH, therefore, may modulate sleep. We investigated the effects of the proton pump inhibitor “lansoprazole” on sleep-wakefulness. Male Wistar rats were surgically prepared for chronic polysomnographic recordings. Two different doses of lansoprazole (low: 1 mg/kg; high: 10 mg/kg) were injected intraperitoneally in the same animal (n = 7) and sleep-wakefulness was recorded for 6 hrs. The changes in sleep-wakefulness were compared statistically. Percent REM sleep amount in the vehicle and lansoprazole low dose groups was 9.26 ± 1.03 and 9.09 ± 0.54, respectively, which increased significantly in the lansoprazole high dose group by 31.75% (from vehicle) and 34.21% (from low dose). Also, REM sleep episode numbers significantly increased in lansoprazole high dose group. Further, the sodium-hydrogen exchanger blocker “amiloride” (10 mg/kg; i.p.) (n = 5) did not alter sleep-wake architecture. Our results suggest that the proton pump plays an important role in REM sleep modulation and supports our view that REM sleep might act as a sentinel to help maintain normal CO2 level for unperturbed sleep. PMID:24701564

Observation of the Rabi oscillation of light driven by an atomic spin wave.

PubMed

Chen, L Q; Zhang, Guo-Wan; Bian, Cheng-Ling; Yuan, Chun-Hua; Ou, Z Y; Zhang, Weiping

2010-09-24

Coherent conversion between a Raman pump field and its Stokes field is observed in a Raman process with a strong atomic spin wave initially prepared by another Raman process operated in the stimulated emission regime. The oscillatory behavior resembles the Rabi oscillation in atomic population in a two-level atomic system driven by a strong light field. The Rabi-like oscillation frequency is found to be related to the strength of the prebuilt atomic spin wave. High conversion efficiency of 40% from the Raman pump field to the Stokes field is recorded and it is independent of the input Raman pump field. This process can act as a photon frequency multiplexer and may find wide applications in quantum information science.

Watt-level short-length holmium-doped ZBLAN fiber lasers at 1.2  μm.

PubMed

Zhu, Xiushan; Zong, Jie; Wiersma, Kort; Norwood, R A; Prasad, Narasimha S; Obland, Michael D; Chavez-Pirson, Arturo; Peyghambarian, N

2014-03-15

In-band core-pumped Ho3+-doped ZBLAN fiber lasers at the 1.2 μm region were investigated with different gain fiber lengths. A 2.4 W 1190 nm all-fiber laser with a slope efficiency of 42% was achieved by using a 10 cm long gain fiber pumped at a maximum available 1150 nm pump power of 5.9 W. A 1178 nm all-fiber laser was demonstrated with an output power of 350 mW and a slope efficiency of 6.5%. High Ho3+ doping in ZBLAN is shown to be effective in producing single-frequency fiber lasers and short-length fiber amplifiers immune from stimulated Brillouin scattering.

Resonantly diode-pumped Er:YAG laser: 1470-nm versus 1530-nm CW pumping case

NASA Astrophysics Data System (ADS)

Kudryashov, Igor; Ter-Gabrielyan, Nikolai; Dubinskii, Mark

2009-05-01

Growing interest to high power lasers in the eye-safe spectral domain initiated a new wave of activity in developing solid-state lasers based on bulk Er3+-doped materials. The resonant pumping of SSL allows for shifting significant part of thermal load from gain medium itself to the pump diodes, thus greatly reducing gain medium thermal distortions deleterious to SSL power scaling with high beam quality. The two major resonant pumping bands in Er:YAG are centered around 1470 and 1532 nm. Pumping into each of these bands has its pros and contras. The best approach to resonant pumping of Er:YAG active media in terms of pump wavelength is yet to be determined. We report the investigation results of high power diode-pumped Er:YAG laser aimed at direct comparison of resonant pumping at 1470 and 1532 nm. Two sources used for pumping were: 1530-nm 10-diode bar stack (>300 W CW) and 1470-nm 10-diode bar stack (>650 W CW). Both pumps were spectrally narrowed by external volume Bragg gratings. The obtained spectral width of less than 1 nm allowed for 'in-line' pumping of Er3+ in either band. The obtained CW power of over 87 W is, to the best of our knowledge, the record high power reported for resonantly pumped Er:YAG DPSSL at room temperature.

Method and device for remotely monitoring an area using a low peak power optical pump

DOEpatents

Woodruff, Steven D.; Mcintyre, Dustin L.; Jain, Jinesh C.

2014-07-22

A method and device for remotely monitoring an area using a low peak power optical pump comprising one or more pumping sources, one or more lasers; and an optical response analyzer. Each pumping source creates a pumping energy. The lasers each comprise a high reflectivity mirror, a laser media, an output coupler, and an output lens. Each laser media is made of a material that emits a lasing power when exposed to pumping energy. Each laser media is optically connected to and positioned between a corresponding high reflectivity mirror and output coupler along a pumping axis. Each output coupler is optically connected to a corresponding output lens along the pumping axis. The high reflectivity mirror of each laser is optically connected to an optical pumping source from the one or more optical pumping sources via an optical connection comprising one or more first optical fibers.

Measurement of the photoionization cross section from the laser-populated 3D metastable levels in barium

NASA Technical Reports Server (NTRS)

Carlsten, J. L.; Mcilrath, T. J.; Parkinson, W. H.

1974-01-01

Measurements of the absolute photoionization cross section from the 6s5d 3D metastable level of barium are presented. The 3D levels were selectively populated with a high-power tuneable dye laser. The number density was determined by observing the resulting depopulation of the ground state when pumping occurred.

Simulation of the shallow groundwater-flow system in the Forest County Potawatomi Community, Forest County, Wisconsin

USGS Publications Warehouse

Fienen, Michael N.; Saad, David A.; Juckem, Paul F.

2013-01-01

The shallow groundwater system in the Forest County Potawatomi Comminity, Forest County, Wisconsin, was simulated by expanding and recalibrating a previously calibrated regional model. The existing model was updated using newly collected water-level measurements, inclusion of surface-water features beyond the previous near-field boundary, and refinements to surface-water features. The updated model then was used to calculate the area contributing recharge for seven existing and three proposed pumping locations on lands of the Forest County Potawatomi Community. The existing wells were the subject of a 2004 source-water evaluation in which areas contributing recharge were calculated using the fixed-radius method. The motivation for the present (2012) project was to improve the level of detail of areas contributing recharge for the existing wells and to provide similar analysis for the proposed wells. Delineated 5- and 10-year areas contributing recharge for existing and proposed wells extend from the areas of pumping to delineate the area at the surface contributing recharge to the wells. Steady-state pumping was simulated for two scenarios: a base-pumping scenario using pumping rates that reflect what the Community currently (2012) pumps (or plans to in the case of proposed wells), and a high-pumping scenario in which the rate was set to the maximum expected from wells installed in this area, according to the Forest County Potawatomi Community Natural Resources Department. In general, the 10-year areas contributing recharge did not intersect surface-water bodies. The 5- and 10-year areas contributing recharge simulated at the maximum pumping rate at Bug Lake Road may intersect Bug Lake. At the casino near the Town of Carter, Wisconsin, the 10-year areas contributing recharge intersect infiltration ponds. At the Devils Lake and Lois Crow Drive wells, areas contributing recharge are near cultural features, including residences.

Energy consumption behavior of submersible pumps using in the Barind area of Bangladesh

NASA Astrophysics Data System (ADS)

Haque, M. E.; Islam, M. R.; Masud, M. H.; Ferdous, J.; Haniu, H.

2017-06-01

In this work the ground water level and water pumping for irrigation and drinking purposes in Barind area of Bangladesh have been studied. The depth of ground water level remains under 30ft throughout the year that enforcing the use of submersible pumps in most parts of Barind zone. The Barind Multipurpose Development Authority (BMDA) and Rajshahi WASA are the major water supplying authority in the Northern Part of Bangladesh by using 14386 and 87 nos of submersible pumps, respectively. An investigation for the values of life cycle cost elements of submersible pumps has also been carried out. The performance of the pumps running in different sites in Barind area were investigated and compared with the lab test results of new pumps. Energy consumption cost is dominating the life cycle cost of the pumps using in Barind region and improper matching of pump standard running conditions and operation/system requirements are the main causes of lower efficiency. It is found that the efficiency of the running pumps is reduced by 20 - 40% than that of lab test results.

Seasonal water-level perturbations beneath the high plains of the Llano Estacado.

USDA-ARS?s Scientific Manuscript database

The Llano Estacado of North America is a vast elevated plain favorably situated above a large portion of the Ogallala Aquifer.The Ogallala Aquifer provides an essential source of groundwater for a highly productive irrigated agricultural system. Each year, groundwater is pumped from the aquifer to i...

Seasonal water-level perturbations beneath the high plains of the Llano Estacado

USDA-ARS?s Scientific Manuscript database

The Llano Estacado of North America is a vast elevated plain favorably situated above a large portion of the Ogallala Aquifer. The Ogallala Aquifer provides an essential source of freshwater for a highly productive irrigated agricultural system. Each year, groundwater is pumped from the aquifer to ...

Georgia's Ground-Water Resources and Monitoring Network, 2006

USGS Publications Warehouse

Nobles, Patricia L.

2006-01-01

The U.S. Geological Survey (USGS) ground-water network for Georgia currently consists of 170 wells in which ground-water levels are continuously monitored. Most of the wells are locatedin the Coastal Plain in the southern part of the State where ground-water pumping stress is high. In particular, there are large concentrations of wells in coastal and southwestern Georgia areas, where there are issues related to ground-water pumping, saltwater intrusion along the coast, and diminished streamflow in southwestern Georgia due to irrigation pumping. The map at right shows the USGS ground-water monitoring network for Georgia. Ground-water levels are monitored in 170 wells statewide, of which 19 transmit data in real time via satellite and posted on the World Wide Web at http://waterdata.usgs.gov/ga/nwis/current/?type=gw . A greater concentration of wells occurs in the Coastal Plain where there are several layers of aquifers and in coastal and southwestern Georgia areas, which are areas with specific ground-water issues.

Continuous-wave infrared optical gain and amplified spontaneous emission at ultralow threshold by colloidal HgTe quantum dots.

PubMed

Geiregat, Pieter; Houtepen, Arjan J; Sagar, Laxmi Kishore; Infante, Ivan; Zapata, Felipe; Grigel, Valeriia; Allan, Guy; Delerue, Christophe; Van Thourhout, Dries; Hens, Zeger

2018-01-01

Colloidal quantum dots (QDs) raise more and more interest as solution-processable and tunable optical gain materials. However, especially for infrared active QDs, optical gain remains inefficient. Since stimulated emission involves multifold degenerate band-edge states, population inversion can be attained only at high pump power and must compete with efficient multi-exciton recombination. Here, we show that mercury telluride (HgTe) QDs exhibit size-tunable stimulated emission throughout the near-infrared telecom window at thresholds unmatched by any QD studied before. We attribute this unique behaviour to surface-localized states in the bandgap that turn HgTe QDs into 4-level systems. The resulting long-lived population inversion induces amplified spontaneous emission under continuous-wave optical pumping at power levels compatible with solar irradiation and direct current electrical pumping. These results introduce an alternative approach for low-threshold QD-based gain media based on intentional trap states that paves the way for solution-processed infrared QD lasers and amplifiers.

Fluorescence properties and energy transfer study of Er3+/Nd3+ doped fluorophosphate glass pumped at 800 and 980 nm for mid-infrared laser applications

NASA Astrophysics Data System (ADS)

Tian, Ying; Xu, Rongrong; Hu, Lili; Zhang, Junjie

2012-04-01

The fluorescence properties of 2.7 μm emission as well as near infrared emissions in Er3+/Nd3+ doped fluorophosphate glasses are investigated under 800 and 980 nm excitation. The fluorescence dynamics and energy transfer processes between Er and Nd ions in different pumping schemes are reported. Three Judd-Ofelt intensity parameters, energy transfer microparameters, and efficiency have been determined using the Judd-Ofelt and Förster-Dexter theories. The calculated energy transfer efficiency of the Er3+:4I13/2 level to the Nd3+:4I15/2 level is as high as 83.91%. The results indicate that Nd3+ may be an efficient sensitizer for Er3+ to obtain mid-infrared emission and the more suitable pumping scheme of 2.7 μm laser applications for Er3+/Nd3+ doped fluorophosphate glass is 980 nm excitation.

Continuous-wave infrared optical gain and amplified spontaneous emission at ultralow threshold by colloidal HgTe quantum dots

NASA Astrophysics Data System (ADS)

Geiregat, Pieter; Houtepen, Arjan J.; Sagar, Laxmi Kishore; Infante, Ivan; Zapata, Felipe; Grigel, Valeriia; Allan, Guy; Delerue, Christophe; van Thourhout, Dries; Hens, Zeger

2018-01-01

Colloidal quantum dots (QDs) raise more and more interest as solution-processable and tunable optical gain materials. However, especially for infrared active QDs, optical gain remains inefficient. Since stimulated emission involves multifold degenerate band-edge states, population inversion can be attained only at high pump power and must compete with efficient multi-exciton recombination. Here, we show that mercury telluride (HgTe) QDs exhibit size-tunable stimulated emission throughout the near-infrared telecom window at thresholds unmatched by any QD studied before. We attribute this unique behaviour to surface-localized states in the bandgap that turn HgTe QDs into 4-level systems. The resulting long-lived population inversion induces amplified spontaneous emission under continuous-wave optical pumping at power levels compatible with solar irradiation and direct current electrical pumping. These results introduce an alternative approach for low-threshold QD-based gain media based on intentional trap states that paves the way for solution-processed infrared QD lasers and amplifiers.

Metal halogen battery construction with improved technique for producing halogen hydrate

DOEpatents

Fong, Walter L.; Catherino, Henry A.; Kotch, Richard J.

1983-01-01

An improved electrical energy storage system comprising, at least one cell having a positive electrode and a negative electrode separated by aqueous electrolyte, a store means wherein halogen hydrate is formed and stored as part of an aqueous material having a liquid level near the upper part of the store, means for circulating electrolyte through the cell, conduit means for transmitting halogen gas formed in the cell to a hydrate forming apparatus associated with the store, said hydrate forming apparatus including, a pump to which there is introduced quantities of the halogen gas and chilled water, said pump being located in the store and an outlet conduit leading from the pump and being substantially straight and generally vertically disposed and having an exit discharge into the gas space above the liquid level in the store, and wherein said hydrate forming apparatus is highly efficient and very resistant to plugging or jamming. The disclosure also relates to an improved method for producing chlorine hydrate in zinc chlorine batteries.

Looking southwest in the service bay area, pump room level, ...

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

Looking southwest in the service bay area, pump room level, at the ventilation fan ducts associated with the evaporative cooling system. Stairs to the operating deck above the intakes are at the far left - Wellton-Mohawk Irrigation System, Pumping Plant No. 2, Bounded by Interstate 8 to south, Wellton, Yuma County, AZ

Development of electric drive for centrifugal mine pumps in Solikamsk Potassium Mine Group Based on Industrial OMRON Controller

NASA Astrophysics Data System (ADS)

Kostarev, S. N.; Sereda, T. G.; Tatarnikova, N. A.; Kochetova, O. V.

2018-03-01

The electric drive for automation pumping out of filtration waters in the Second Solikamsk Potasssium Mine Group is developed. The emergency situation of flooding of the Mine has been considered in the course of development of the Upper Kama deposits of potash-magnesium salts. The functional scheme of automation of a drive of the pump is developed. The scheme is stipulated with manual and automatic control. To decrease the risk of flooding of mine, it is recommended to establish gauges of both bottom and top level control of a brine and other equipment in the collector of a brine: the gauge of measurementof a level, the gauge of the signal system of a level, the gauge of the pump control, the gauge of the signal system of a level with remote data transmission. For regulation of the charge of sewage, the P-regulator with the executive mechanism is stipulated. The ladder diagram of a pump control is developed to improve the work of centrifugal pumps and to prevent the cases of mines flooding.

Theoretical study of the effect of pump wavelength drift on mode instability in a high-power fiber amplifier

NASA Astrophysics Data System (ADS)

Liu, Yakun; Tao, Rumao; Su, Rongtao; Wang, Xiaolin; Ma, Pengfei; Zhang, Hanwei; Zhou, Pu; Si, Lei

2018-04-01

This paper presents an investigation of the effect of pump wavelength drift on the threshold of mode instability (MI) in high-power ytterbium-doped fiber lasers. By using a semi-analytical model, we study the effects of pump wavelength drift with a central pump wavelength around 976 nm and 915 nm, respectively. The influences of the pump absorption coefficient and total pump absorption are considered simultaneously. The results indicate that the effect of pump wavelength drift around 976 nm is stronger than that around 915 nm. For more efficient suppression of MI by shifting the pump wavelength, efficient absorption of pump power is required. The MI thresholds for fibers with different total pump absorptions and cladding diameters are compared. When the total pump absorption is increased, the gain saturation is enhanced, which results in the MI being mitigated more effectively and being more sensitive to pump wavelength drift. The MI threshold in gain fibers with larger inner cladding diameter is higher but more dependent upon pump wavelength. The results of this work can help in optimizing the pump wavelength and fiber parameters and suppressing MI in high-power fiber lasers.

In Their Own Words: Getting Pumped for Calculus

ERIC Educational Resources Information Center

Cardetti, Fabiana; McKenna, P. J.

2011-01-01

By understanding what motivates students to learn mathematics, instructors can adapt their teaching strategies to help students achieve a level of engagement conducive to learning mathematics. There is a substantial body of research on motivations and academic achievement at the elementary and high school levels, but less is known at the college…

53. (Credit JTL) Interior view looking southwest at two high ...

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

53. (Credit JTL) Interior view looking southwest at two high service engines with Worthington-Snow engine in foreground. Electric high service booster pump is located on the far right between the two high service pumping engines. Grating is immediate foreground covers # 3 low service pump pit. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

Environmental Effects on Fatigue Crack Growth in High Performance Aluminum Alloys

DTIC Science & Technology

2009-03-13

tested for leaks to a rate of 2x 10൒ cm3/s with helium. All devices connected to the chamber, including pumps , gages and valves, are ultra-high- vacuum ...Pfeiffer TMU-262P), backed by a 5 L/s scroll pump (ULVAC DIS-250). This pump combination eliminates the possibility of contamination by pumping fluid used...both pumps are connected directly to the vacuum chamber to achieve optimum pump -down speeds. Pumping down the chamber is further facilitated by use of

Temporal Interplay between Efflux Pumps and Target Mutations in Development of Antibiotic Resistance in Escherichia coli

PubMed Central

Singh, Renu; Swick, Michelle C.; Ledesma, Kimberly R.; Yang, Zhen; Hu, Ming; Zechiedrich, Lynn

2012-01-01

The emergence of resistance presents a debilitating change in the management of infectious diseases. Currently, the temporal relationship and interplay between various mechanisms of drug resistance are not well understood. A thorough understanding of the resistance development process is needed to facilitate rational design of countermeasure strategies. Using an in vitro hollow-fiber infection model that simulates human drug treatment, we examined the appearance of efflux pump (acrAB) overexpression and target topoisomerase gene (gyrA and parC) mutations over time in the emergence of quinolone resistance in Escherichia coli. Drug-resistant isolates recovered early (24 h) had 2- to 8-fold elevation in the MIC due to acrAB overexpression, but no point mutations were noted. In contrast, high-level (≥64× MIC) resistant isolates with target site mutations (gyrA S83L with or without parC E84K) were selected more readily after 120 h, and regression of acrAB overexpression was observed at 240 h. Using a similar dosing selection pressure, the emergence of levofloxacin resistance was delayed in a strain with acrAB deleted compared to the isogenic parent. The role of efflux pumps in bacterial resistance development may have been underappreciated. Our data revealed the interplay between two mechanisms of quinolone resistance and provided a new mechanistic framework in the development of high-level resistance. Early low-level levofloxacin resistance conferred by acrAB overexpression preceded and facilitated high-level resistance development mediated by target site mutation(s). If this interpretation is correct, then these findings represent a paradigm shift in the way quinolone resistance is thought to develop. PMID:22232279

Glutathione S-Transferase Gene Polymorphisms: Modulator of Genetic Damage in Gasoline Pump Workers.

PubMed

Priya, Kanu; Yadav, Anita; Kumar, Neeraj; Gulati, Sachin; Aggarwal, Neeraj; Gupta, Ranjan

2015-01-01

This study investigated genetic damage in gasoline pump workers using the cytokinesis blocked micronucleus (CBMN) assay. Blood and urine samples were collected from 50 gasoline pump workers and 50 control participants matched with respect to age and other confounding factors except for exposure to benzene through gasoline vapors. To determine the benzene exposure, phenol was analyzed in urinary samples of exposed and control participants. Urinary mean phenol level was found to be significantly high (P < 0.05) in exposed workers. The CBMN frequency was found to be significantly higher in gasoline pump workers (6.70 ± 1.78) when compared to control individuals (2.20 ± 0.63; P < 0.05). We also investigated influence of polymorphisms of GSTM1, GSTT1, and GSTP1 genes on CBMN frequency. The individuals having GSTM1 and GSTT1 null genotypes had significantly higher frequency of CBMN (P < 0.05). Our study indicates that chronic and long-term exposure of gasoline vapors can increase genotoxic risk in gasoline pump workers. © The Author(s) 2015.

High-Pressure Open-Channel On-Chip Electroosmotic Pump for Nanoflow High Performance Liquid Chromatography

PubMed Central

2015-01-01

Here, we construct an open-channel on-chip electroosmotic pump capable of generating pressures up to ∼170 bar and flow rates up to ∼500 nL/min, adequate for high performance liquid chromatographic (HPLC) separations. A great feature of this pump is that a number of its basic pump units can be connected in series to enhance its pumping power; the output pressure is directly proportional to the number of pump units connected. This additive nature is excellent and useful, and no other pumps can work in this fashion. We demonstrate the feasibility of using this pump to perform nanoflow HPLC separations; tryptic digests of bovine serum albumin (BSA), transferrin factor (TF), and human immunoglobulins (IgG) are utilized as exemplary samples. We also compare the performance of our electroosmotic (EO)-driven HPLC with Agilent 1200 HPLC; comparable efficiencies, resolutions, and peak capacities are obtained. Since the pump is based on electroosmosis, it has no moving parts. The common material and process also allow this pump to be integrated with other microfabricated functional components. Development of this high-pressure on-chip pump will have a profound impact on the advancement of lab-on-a-chip devices. PMID:24495233

Energy pumping analysis of skating motion in a half pipe and on a level surface

NASA Astrophysics Data System (ADS)

Feng, Z. C.; Xin, Ming

2015-01-01

In this paper, an energy pumping mechanism for locomotion is analysed. The pumping is accomplished by exerting forces perpendicular to the direction of motion. The paper attempts to demonstrate an interesting application of the classical mechanics to two sporting events: a person skating in a half pipe and a person travelling on a level surface on a skateboard. The equations of motion based on simplified mechanical models are derived using the Lagrange mechanics. The energy-pumping phenomenon is revealed through numerical simulations with simple pumping actions. The result presented in this paper can be used as an interesting class project in undergraduate mechanics or physics courses. It also motivates potential new applications of energy pumping in many engineering fields.

Millijoule-level 20 ps Nd:YAG oscillator-amplifier laser system for investigation of stimulated Raman scattering and optical parametric generation

NASA Astrophysics Data System (ADS)

Jelínek, Michal; Kubecek, Vàclav

2012-06-01

We report on quasi-continuously pumped oscillator-amplifier laser system. The laser oscillator was based on highly 2.4 at.% doped crystalline Nd:YAG in a bounce geometry and passively mode locked by a semiconductor saturable absorber mirror. Using the cavity dumping technique, 19 ps pulses with the energy of 20 μJ and Gaussian spatial beam profile were generated directly from the oscillator at the repetition rate up to 50 Hz. For applications requiring more energetic pulses the amplification was studied using either an identical highly doped Nd:YAG module in bounce geometry or flashlamp pumped Nd:YAG laser rod. Using compact all diode pumped oscillator-amplifier system, 130 μJ pulses were generated. The flashlamp pumped amplifier with 100 mm long Nd:YAG enabled to obtain higher energy. In the single pass configuration the pulse was amplified to 4.5 mJ, using the double pass configuration the pulse energy was further increased up to 20 mJ with the duration of 25 ps at 10 Hz. The developed laser system was used for investigation of stimulated Raman scattering in Strontium Barium Niobate and optical parametric generation in CdSiP2.

A water management decision support system contributing to sustainability

NASA Astrophysics Data System (ADS)

Horváth, Klaudia; van Esch, Bart; Baayen, Jorn; Pothof, Ivo; Talsma, Jan; van Heeringen, Klaas-Jan

2017-04-01

Deltares and Eindhoven University of Technology are developing a new decision support system (DSS) for regional water authorities. In order to maintain water levels in the Dutch polder system, water should be drained and pumped out from the polders to the sea. The time and amount of pumping depends on the current sea level, the water level in the polder, the weather forecast and the electricity price forecast and possibly local renewable power production. This is a multivariable optimisation problem, where the goal is to keep the water level in the polder within certain bounds. By optimizing the operation of the pumps the energy usage and costs can be reduced, hence the operation of the regional water authorities can be more sustainable, while also anticipating on increasing share of renewables in the energy mix in a cost-effective way. The decision support system, based on Delft-FEWS as operational data-integration platform, is running an optimization model built in RTC-Tools 2, which is performing real-time optimization in order to calculate the pumping strategy. It is taking into account the present and future circumstances. As being the core of the real time decision support system, RTC-Tools 2 fulfils the key requirements to a DSS: it is fast, robust and always finds the optimal solution. These properties are associated with convex optimization. In such problems the global optimum can always be found. The challenge in the development is to maintain the convex formulation of all the non-linear components in the system, i.e. open channels, hydraulic structures, and pumps. The system is introduced through 4 pilot projects, one of which is a pilot of the Dutch Water Authority Rivierenland. This is a typical Dutch polder system: several polders are drained to the main water system, the Linge. The water from the Linge can be released to the main rivers that are subject to tidal fluctuations. In case of low tide, water can be released via the gates. In case of high tide, water should be pumped. The goal of the pilot is to make the operation of the regional water authority more sustainable and cost-efficient. Sustainability can be achieved by minimizing the CO2 production trough minimizing the energy used for pumping. This work is showing the functionalities of the new decision support system, using RTC-Tools 2, through the example of a pilot project.

Total internal reflection-based side-pumping configuration for terawatt ultraviolet amplifier and laser oscillator development

NASA Astrophysics Data System (ADS)

Cadatal-Raduban, Marilou; Pham, Minh Hong; Pham, Duong Van; Bui, Duong Thi Thuy; Yamanoi, Kohei; Takeda, Kohei; Empizo, Melvin John F.; Mui, Luong Viet; Shimizu, Toshihiko; Nguyen, Hung Dai; Sarukura, Nobuhiko; Fukuda, Tsuguo

2018-06-01

A two-side-pumping scheme that is based on total internal reflection in a diamond-cut Ce3+:LiCaAlF6 crystal suitable for the development of an ultraviolet laser and femtosecond amplifier system is proposed. Experimental fluorescence images and lasing results that demonstrate total internal reflection of the excitation beam using this diamond-cut crystal are presented. Calculations for the optimized crystal geometry that facilitate high extraction efficiency and homogeneity of the absorbed excitation beam are also discussed. About 50% increase in extraction efficiency compared to previously reported chirped-pulse femtosecond ultraviolet amplifier operating at 50-GW peak power is expected using this total internal reflection-based two-side-pumping configuration and a diamond-cut Ce3+:LiCaAlF6 crystal with a geometry of {φ _1} = 103°, {φ _2} = {φ _4} = 82°, {φ _3} = 93°, a length of 1.23 cm, a height of 2 cm, and an absorption coefficient of 1.5 cm-1. Our results can be used as a guide during the crystal growth process by providing the appropriate crystal geometry and size for a particular absorption coefficient to achieve high extraction efficiency. With the appropriate crystal combined with multiple-beam pumping afforded by the side-pumping scheme, the development of an all-solid-state ultraviolet laser operating at terawatt level would be within reach.

Soft X-ray laser using pumping of 3P and 4P levels of He-like and H-like ions

DOEpatents

Hagelstein, P.L.

1987-04-21

X-ray laser method and apparatus are disclosed for producing coherent radiation at, for example, energies of at least 40 eV, using Be-like Cr, N-like Ni, He-like Na, B-like Cr, Be-like Mn or similar multiply ionized species to pump appropriate high energy transitions in He-like or H-like N, O, F, C or rare gases, with associated laser transition gains of 4-50 cm[sup [minus]1]. 8 figs.

Semiconductor Laser Diode Pumps for Inertial Fusion Energy Lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deri, R J

2011-01-03

Solid-state lasers have been demonstrated as attractive drivers for inertial confinement fusion on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) and at the Omega Facility at the Laboratory for Laser Energetics (LLE) in Rochester, NY. For power plant applications, these lasers must be pumped by semiconductor diode lasers to achieve the required laser system efficiency, repetition rate, and lifetime. Inertial fusion energy (IFE) power plants will require approximately 40-to-80 GW of peak pump power, and must operate efficiently and with high system availability for decades. These considerations lead to requirements on the efficiency, price, and productionmore » capacity of the semiconductor pump sources. This document provides a brief summary of these requirements, and how they can be met by a natural evolution of the current semiconductor laser industry. The detailed technical requirements described in this document flow down from a laser ampl9ifier design described elsewhere. In brief, laser amplifiers comprising multiple Nd:glass gain slabs are face-pumped by two planar diode arrays, each delivering 30 to 40 MW of peak power at 872 nm during a {approx} 200 {micro}s quasi-CW (QCW) pulse with a repetition rate in the range of 10 to 20 Hz. The baseline design of the diode array employs a 2D mosaic of submodules to facilitate manufacturing. As a baseline, they envision that each submodule is an array of vertically stacked, 1 cm wide, edge-emitting diode bars, an industry standard form factor. These stacks are mounted on a common backplane providing cooling and current drive. Stacks are conductively cooled to the backplane, to minimize both diode package cost and the number of fluid interconnects for improved reliability. While the baseline assessment in this document is based on edge-emitting devices, the amplifier design does not preclude future use of surface emitting diodes, which may offer appreciable future cost reductions and increased reliability. The high-level requirements on the semiconductor lasers involve reliability, price points on a price-per-Watt basis, and a set of technical requirements. The technical requirements for the amplifier design in reference 1 are discussed in detail and are summarized in Table 1. These values are still subject to changes as the overall laser system continues to be optimized. Since pump costs can be a significant fraction of the overall laser system cost, it is important to achieve sufficiently low price points for these components. At this time, the price target for tenth-of-akind IFE plant is $0.007/Watt for packaged devices. At this target level, the pumps account for approximately one third of the laser cost. The pump lasers should last for the life of the power plant, leading to a target component lifetime requirement of roughly 14 Ghosts, corresponding to a 30 year plant life and 15 Hz repetition rate. An attractive path forward involes pump operation at high output power levels, on a Watts-per-bar (Watts/chip) basis. This reduces the cost of pump power (price-per-Watt), since to first order the unit price does not increase with power/bar. The industry has seen a continual improvement in power output, with current 1 cm-wide bars emitting up to 500 W QCW (quasi-continuous wave). Increased power/bar also facilitates achieving high irradiance in the array plane. On the other hand, increased power implies greater heat loads and (possibly) higher current drive, which will require increased attention to thermal management and parasitic series resistance. Diode chips containing multiple p-n junctions and quantum wells (also called nanostack structures) may provide an additional approach to reduce the peak current.« less

Monitoring the ground water level change during the pump test by using the Electric resistivity tomography

NASA Astrophysics Data System (ADS)

Hsu, H.; Chang, P. Y.; Yao, H. J.

2017-12-01

For hydrodynamics study of the unconfined aquifer in gravel formation, a pumping test was established to estimate the hydraulic conductivity in the midstream of Zhoushui River in Taiwan. The hydraulic parameters and the cone of depression could be estimated by monitoring the groundwater drawdown in an observation well which was in a short distance far from the pumping well. In this study we carried out the electric resistivity image monitoring during the whole pumping test. The electric resistivity data was measured with the surface and downhole electrodes which would produce a clear subsurface image of groundwater level through a larger distance than the distance between pumping and observation wells. The 2D electric image could also describe how a cone of depression truly created at subsurface. The continuous records could also show the change of groundwater level during the whole pumping test which could give a larger scale of the hydraulic parameters.

Effects of Proposed Additional Ground-Water Withdrawals from the Mississippi River Valley Alluvial Aquifer on Water Levels in Lonoke County, Arkansas

USGS Publications Warehouse

Czarnecki, John B.

2006-01-01

The Grand Prairie Water Users Association, located in Lonoke County, Arkansas, plans to increase ground-water withdrawals from the Mississippi River Valley alluvial aquifer from their current (2005) rate of about 400 gallons per minute to 1,400 gallons per minute (2,016,000 gallons per day). The effect of pumping from a proposed well was simulated using a digital model of ground-water flow. The proposed additional withdrawals were added to an existing pumping cell specified in the model, with increased pumping beginning in 2005, and specified to pump at a total combined rate of 2,016,000 gallons per day for a period of 46 years. In addition, pumping from wells owned by Cabot Water Works, located about 2 miles from the proposed pumping, was added to the model beginning in 2001 and continuing through to the end of 2049. Simulated pumping causes a cone of depression to occur in the alluvial aquifer with a maximum decline in water level of about 8.5 feet in 46 years in the model cell of the proposed well compared to 1998 withdrawals. However, three new dry model cells occur south of the withdrawal well after 46 years. This total water-level decline takes into account the cumulative effect of all wells pumping in the vicinity, although the specified pumping rate from all other model cells in 2005 is less than for actual conditions in 2005. After 46 years with the additional pumping, the water-level altitude in the pumped model cell was about 177.4 feet, which is 41.7 feet higher than 135.7 feet, the altitude corresponding to half of the original saturated thickness of the alluvial aquifer (a metric used to determine if the aquifer should be designated as a Critical Ground-Water Area (Arkansas Natural Resources Commission, 2006)).

Anomalously high intercombination line ratios in symbiotic stars - Extreme Bowen pumping?

NASA Technical Reports Server (NTRS)

Kastner, S. O.; Bhatia, A. K.; Feibelman, W. A.

1989-01-01

International Ultraviolet Explorer observations of the ratio of the O III intercombination lines near 1660 A are assembled, showing that the observed ratios in symbiotic stars are significantly higher than the theoretically predicted optically thin limit of 2.5. The presence of an enhancing physical process is thereby indicated. It is suggested that Bowen pumping of the lower level of the 1666.2 A line in an 'external saturation' limit, coupled with appreciable optical depth, could logically explain the high ratios. Some tentative evidence for this is presented and the relevance of far-infrared observations of the O III 51.8 and 88.3 micron lines in symbiotic sources is emphasized.

Assessment of single-shell tank residual-liquid issues at Hanford Site, Washington

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murthy, K.S.; Stout, L.A.; Napier, B.A.

1983-06-01

This report provides an assessment of the overall effectiveness and implications of jet pumping the interstitial liquids (IL) from single-shell tanks at Hanford. The jet-pumping program, currently in progress at Hanford, involves the planned removal of IL contained in 89 of the 149 single-shell tanks and its transfer to double-shell tanks after volume reduction by evaporation. The purpose of this report is to estimate the public and worker doses associated with (1) terminating pumping immediately, (2) pumping to a 100,000-gal limit per tank, (3) pumping to a 50,000-gal limit per tank, and (4) pumping to the maximum practical liquid removalmore » level of 30,000 gal. Assessment of the cost-effectiveness of these various levels of pumping in minimizing any undue health and safety risks to the public or worker is also presented.« less

Theoretical study of optical pump process in solid gain medium based on four-energy-level model

NASA Astrophysics Data System (ADS)

Ma, Yongjun; Fan, Zhongwei; Zhang, Bin; Yu, Jin; Zhang, Hongbo

2018-04-01

A semiclassical algorithm is explored to a four-energy level model, aiming to find out the factors that affect the dynamics behavior during the pump process. The impacts of pump intensity Ω p , non-radiative transition rate γ 43 and decay rate of electric dipole δ 14 are discussed in detail. The calculation results show that large γ 43, small δ 14, and strong pumping Ω p are beneficial to the establishing of population inversion. Under strong pumping conditions, the entire pump process can be divided into four different phases, tentatively named far-from-equilibrium process, Rabi oscillation process, quasi dynamic equilibrium process and ‘equilibrium’ process. The Rabi oscillation can slow the pumping process and cause some instability. Moreover, the duration of the entire process is negatively related to Ω p and γ 43 whereas positively related to δ 14.

Low-cost water-lifting from groundwater sources: a comparison of the EMAS Pump with the Rope Pump

NASA Astrophysics Data System (ADS)

MacCarthy, Michael F.; Carpenter, Jacob D.; Mihelcic, James R.

2017-08-01

In sub-Saharan Africa, low-cost groundwater supply systems offer great opportunities for the current unserved population of >300 million to access drinking water. A comparative study was performed in Uganda of the EMAS Pump (designed by Escuela Móvil Aguas y Saneamiento Básico) with the trade-named Rope Pump, two low-cost manual water-lifting devices appropriate to pumping from shallow groundwater sources. Pumping rates, energy expended, material costs, and construction requirements were analyzed. Focus was on low-cost application for use in shallow groundwater systems at the household level in developing countries, particularly in sub-Saharan Africa. The study site was northern Uganda, with testing performed at several drilled boreholes. Two variants of each pump were tested by a male and female user, pumping from multiple static water-level depths ranging from 5 to 28 m. Results demonstrated the most common version of the EMAS Pump to perform similarly to the comparable version of the Rope Pump in terms of average pumping rate at depth range 5 to 18 m (93-111%), but less so at deeper depths (63-85%). Normalized pumping rates (considering energy expended) accentuated differences between these versions of the EMAS Pump and Rope Pump (47-97%). Cost of materials to construct the EMAS Pump were 21-60% those of the Rope Pump, and EMAS Pump construction requirements were also less. Based on the assessed factors, it is concluded that the EMAS Pump has potential for success in "self-supply" groundwater systems in sub-Saharan Africa and is particularly appropriate to link with low-cost shallow groundwater sources.

Siphon effects on continuous subcutaneous insulin infusion pump delivery performance.

PubMed

Zisser, Howard C; Bevier, Wendy; Dassau, Eyal; Jovanovic, Lois

2010-01-01

The objective was to quantify hydrostatic effects on continuous subcutaneous insulin infusion (CSII) pumps during basal and bolus insulin delivery. We tested CSII pumps from Medtronic Diabetes (MiniMed 512 and 515), Smiths Medical (Deltec Cozmo 1700), and Insulet (OmniPod) using insulin aspart (Novolog, Novo Nordisk). Pumps were filled and primed per manufacturer's instructions. The fluid level change was measured using an inline graduated glass pipette (100 microl) when the pipette was moved in relation to the pump (80 cm Cosmo and 110 cm Medtronics) and when level. Pumps were compared during 1 and 5 U boluses and basal insulin delivery of 1.0 and 1.5 U/h. Pronounced differences were seen during basal delivery in pumps using 80-100 cm tubing. For the 1 U/h rate, differences ranged from 74.5% of the expected delivery when the pumps were below the pipettes and pumping upward to 123.3% when the pumps were above the pipettes and pumping downward. For the 1.5 U/h rate, differences ranged from 86.7% to 117.0% when the pumps were below or above the pipettes, respectively. Compared to pumps with tubing, OmniPod performed with significantly less variation in insulin delivery. Changing position of a conventional CSII pump in relation to its tubing results in significant changes in insulin delivery. The siphon effect in the tubing may affect the accuracy of insulin delivery, especially during low basal rates. This effect has been reported when syringe pumps were moved in relation to infusion sites but has not been reported with CSII pumps. 2010 Diabetes Technology Society.

Power and polarization dependences of ultra-narrow electromagnetically induced absorption (EIA) spectra of 85 Rb atoms in degenerate two-level system

NASA Astrophysics Data System (ADS)

Qureshi, Muhammad Mohsin; Rehman, Hafeez Ur; Noh, Heung-Ryoul; Kim, Jin-Tae

2016-05-01

We have investigated ultra-narrow EIA spectral features with respect to variations of polarizations and powers of pump laser beam in a degenerate two-level system of the transition of 85 Rb D2 transition line. Polarizations of the probe laser beam in two separate experiments were fixed at right circular and horizontal linear polarizations, respectively while the polarizations of the pump lasers were varied from initial polarizations same as the probe laser beams to orthogonal to probe polarizations. One homemade laser combined with AOMs was used to the pump and probe laser beams instead of two different lasers to overcome broad linewidths of the homemade lasers. Theoretically, probe absorption coefficients have been calculated from optical Bloch equations of the degenerate two level system prepared by a pump laser beam. In the case of the circular polarization, EIA signal was obtained as expected theoretically although both pump and probe beams have same polarization. The EIA signal become smaller as power increases and polarizations of the pump and probe beams were same. When the polarization of the pump beam was linear polarization, maximum EIA signal was obtained theoretically and experimentally. Experimental EIA spectral shapes with respect to variations of the pump beam polarization shows similar trends as the theoretical results.

High efficiency 2 micrometer laser utilizing wing-pumped Tm.sup.3+ and a laser diode array end-pumping architecture

DOEpatents

Beach, Raymond J.

1997-01-01

Wing pumping a Tm.sup.3+ doped, end pumped solid state laser generates 2 .mu.m laser radiation at high average powers with high efficiency. Using laser diode arrays to end-pump the laser rod or slab in the wing of the Tm.sup.3+ absorption band near 785 nm results in 2-for-1 quantum efficiency in Tm.sup.3+ because high Tm.sup.3+ concentrations can be used. Wing pumping allows the thermal power generated in the rod or slab to be distributed over a large enough volume to make thermal management practical in the laser gain medium even at high average power operation. The approach is applicable to CW, Q-switched, and rep-pulsed free-laser operation.

High efficiency 2 micrometer laser utilizing wing-pumped Tm{sup 3+} and a laser diode array end-pumping architecture

DOEpatents

Beach, R.J.

1997-11-18

Wing pumping a Tm{sup 3+} doped, end pumped solid state laser generates 2 {micro}m laser radiation at high average powers with high efficiency. Using laser diode arrays to end-pump the laser rod or slab in the wing of the Tm{sup 3+} absorption band near 785 nm results in 2-for-1 quantum efficiency in Tm{sup 3+} because high Tm{sup 3+} concentrations can be used. Wing pumping allows the thermal power generated in the rod or slab to be distributed over a large enough volume to make thermal management practical in the laser gain medium even at high average power operation. The approach is applicable to CW, Q-switched, and rep-pulsed free-laser operation. 7 figs.

Dependence on Excitation Density of Multiphonon Decay in Er-doped ZBLAN Glass

NASA Astrophysics Data System (ADS)

Bycenski, Kenneth; Collins, John

2001-11-01

The dependence of multiphonon decay of rare earth ions in solids on the intensity of the pump beam, first reported by Auzel et al., is examined for the 4S3/2 and 2H11/2 levels of Er-doped ZBLAN glass. Using a frequency-doubled, Q-switched Nd:YAG laser as a pump source, the kinetics of the 4S3/2 level was studied at different pump intensities and temperatures. Lifetime curves show a rise time, which represents the feeding of the 4S3/2 level by the 2H11/2, and a decay time that vary with the intensity of the pump beam, i.e. on the concentration of excited centers. The measured decay times of the 4S3/2 are consistent with those previously reported [2]. In this poster we report on the temperature dependence of this process, and we look at the dependence of the feeding of the 4S3/2 level as pump intensity changes. A rate equation model shows that the intensity dependence of the rise time on pump intensity is due, in part, to a slowing down of the nonradiative decay from the 2H11/2 level as the pump intensity is increased. We discuss these results in terms of the phonon bottleneck mechanism proposed in reference 1. 1. F. Auzel and F. Pelle, Phys. Rev. B 55, 17 (1106-09) 1997. 2. F Auzel, private communications.

ac electroosmotic pumping induced by noncontact external electrodes.

PubMed

Wang, Shau-Chun; Chen, Hsiao-Ping; Chang, Hsueh-Chia

2007-09-21

Electroosmotic (EO) pumps based on dc electroosmosis is plagued by bubble generation and other electrochemical reactions at the electrodes at voltages beyond 1 V for electrolytes. These disadvantages limit their throughput and offset their portability advantage over mechanical syringe or pneumatic pumps. ac electroosmotic pumps at high frequency (>100 kHz) circumvent the bubble problem by inducing polarization and slip velocity on embedded electrodes,1 but they require complex electrode designs to produce a net flow. We report a new high-throughput ac EO pump design based on induced-polarization on the entire channel surface instead of just on the electrodes. Like dc EO pumps, our pump electrodes are outside of the load section and form a cm-long pump unit consisting of three circular reservoirs (3 mm in diameter) connected by a 1x1 mm channel. The field-induced polarization can produce an effective Zeta potential exceeding 1 V and an ac slip velocity estimated as 1 mmsec or higher, both one order of magnitude higher than earlier dc and ac pumps, giving rise to a maximum throughput of 1 mulsec. Polarization over the entire channel surface, quadratic scaling with respect to the field and high voltage at high frequency without electrode bubble generation are the reasons why the current pump is superior to earlier dc and ac EO pumps.

A highly reliable cryogenic mixing pump with no mechanical moving parts

NASA Astrophysics Data System (ADS)

Chen, W.; Niblick, A. L.

2017-12-01

This paper presents the design and preliminary test results of a novel cryogenic mixing pump based on magnetocaloric effect. The mixing pump is developed to enable long-term cryogenic propellant storage in space by preventing thermal stratification of cryogens in storage tanks. The mixing pump uses an innovative thermodynamic process to generate fluid jets to promote fluid mixing, eliminating the need for mechanical pumps. Its innovative mechanism uses a solid magnetocaloric material to alternately vaporize and condense the cryogen in the pumping chamber, and thus control the volume of the fluid inside the pumping chamber to produce pumping action. The pump is capable of self-priming and can generate a high-pressure rise. This paper discusses operating mechanism and design consideration of the pump, introduces the configuration of a brassboard cryogenic pump, and presents the preliminary test results of the pump with liquid nitrogen.

Tapping unsustainable groundwater stores for agricultural production in the High Plains Aquifer of Kansas, projections to 2110.

PubMed

Steward, David R; Bruss, Paul J; Yang, Xiaoying; Staggenborg, Scott A; Welch, Stephen M; Apley, Michael D

2013-09-10

Groundwater provides a reliable tap to sustain agricultural production, yet persistent aquifer depletion threatens future sustainability. The High Plains Aquifer supplies 30% of the nation's irrigated groundwater, and the Kansas portion supports the congressional district with the highest market value for agriculture in the nation. We project groundwater declines to assess when the study area might run out of water, and comprehensively forecast the impacts of reduced pumping on corn and cattle production. So far, 30% of the groundwater has been pumped and another 39% will be depleted over the next 50 y given existing trends. Recharge supplies 15% of current pumping and would take an average of 500-1,300 y to completely refill a depleted aquifer. Significant declines in the region's pumping rates will occur over the next 15-20 y given current trends, yet irrigated agricultural production might increase through 2040 because of projected increases in water use efficiencies in corn production. Water use reductions of 20% today would cut agricultural production to the levels of 15-20 y ago, the time of peak agricultural production would extend to the 2070s, and production beyond 2070 would significantly exceed that projected without reduced pumping. Scenarios evaluate incremental reductions of current pumping by 20-80%, the latter rate approaching natural recharge. Findings substantiate that saving more water today would result in increased net production due to projected future increases in crop water use efficiencies. Society has an opportunity now to make changes with tremendous implications for future sustainability and livability.

Tapping unsustainable groundwater stores for agricultural production in the High Plains Aquifer of Kansas, projections to 2110

PubMed Central

Steward, David R.; Bruss, Paul J.; Yang, Xiaoying; Staggenborg, Scott A.; Welch, Stephen M.; Apley, Michael D.

2013-01-01

Groundwater provides a reliable tap to sustain agricultural production, yet persistent aquifer depletion threatens future sustainability. The High Plains Aquifer supplies 30% of the nation’s irrigated groundwater, and the Kansas portion supports the congressional district with the highest market value for agriculture in the nation. We project groundwater declines to assess when the study area might run out of water, and comprehensively forecast the impacts of reduced pumping on corn and cattle production. So far, 30% of the groundwater has been pumped and another 39% will be depleted over the next 50 y given existing trends. Recharge supplies 15% of current pumping and would take an average of 500–1,300 y to completely refill a depleted aquifer. Significant declines in the region’s pumping rates will occur over the next 15–20 y given current trends, yet irrigated agricultural production might increase through 2040 because of projected increases in water use efficiencies in corn production. Water use reductions of 20% today would cut agricultural production to the levels of 15–20 y ago, the time of peak agricultural production would extend to the 2070s, and production beyond 2070 would significantly exceed that projected without reduced pumping. Scenarios evaluate incremental reductions of current pumping by 20–80%, the latter rate approaching natural recharge. Findings substantiate that saving more water today would result in increased net production due to projected future increases in crop water use efficiencies. Society has an opportunity now to make changes with tremendous implications for future sustainability and livability. PMID:23980153

Properties of a monopivot centrifugal blood pump manufactured by 3D printing.

PubMed

Nishida, Masahiro; Negishi, Takumi; Sakota, Daisuke; Kosaka, Ryo; Maruyama, Osamu; Hyakutake, Toru; Kuwana, Katsuyuki; Yamane, Takashi

2016-12-01

An impeller the same geometry as the impeller of a commercial monopivot cardiopulmonary bypass pump was manufactured using 3D printing. The 3D-printed impeller was integrated into the pump casing of the commercially available pump to form a 3D-printed pump model. The surface roughness of the impeller, the hydraulic performance, the axial displacement of the rotating impeller, and the hemolytic properties of the 3D-printed model were measured and compared with those of the commercially available model. Although the surface roughness of the 3D-printed model was significantly larger than that of the commercially available model, the hydraulic performance of the two models almost coincided. The hemolysis level of the 3D-printed model roughly coincided with that of the commercially available model under low-pressure head conditions, but increased greatly under high-pressure head conditions, as a result of the narrow gap between the rotating impeller and the pump casing. The gap became narrow under high-pressure head conditions, because the axial thrust applied to the impeller increased with increasing impeller rotational speed. Moreover, the axial displacement of the rotating impeller was twice that of the commercially available model, confirming that the elastic deformation of the 3D-printed impeller was larger than that of the commercially available impeller. These results suggest that trial models manufactured by 3D printing can reproduce the hydraulic performance of the commercial product. However, both the surface roughness and the deformation of the trial models must be considered to precisely evaluate the hemolytic properties of the model.

Primary investigations on the potential of a novel diode pumped Er:YAG laser system for middle ear surgery

NASA Astrophysics Data System (ADS)

Stock, Karl; Wurm, Holger; Hausladen, Florian

2016-02-01

Flashlamp pumped Er:YAG lasers are successfully used clinically for both precise soft and hard tissue ablation. Since several years a novel diode pumped Er:YAG laser system (Pantec Engineering AG) is available, with mean laser power up to 40 W and pulse repetition rate up to 1 kHz. The aim of the study was to investigate the suitability of the laser system specifically for stapedotomy. Firstly an experimental setup was realized with a beam focusing unit and a computer controlled translation stage to move the samples (slices of porcine bone) with a defined velocity while irradiation with various laser parameters. A microphone was positioned in a defined distance to the ablation point and the resulting acoustic signal of the ablation process was recorded. For comparison, measurements were also performed with a flash lamp pumped Er:YAG laser system. After irradiation the resulting ablation quality and efficacy were determined using light microscopy. Using a high speed camera and "Töpler-Schlierentechnik" the cavitation bubble in water after perforation of a bone slice was investigated. The results show efficient bone ablation using the diode pumped Er:YAG laser system. Also a decrease of the sound level and of the cavitation bubble volume was observed with decreasing pulse duration. Higher repetition rates lead to a slightly increase of thermal side effects but have no influence on the ablation efficiency. In conclusion, these first experiments demonstrate the high potential of the diode pumped Er:YAG laser system for use in middle ear surgery.

Pump RIN-induced impairments in unrepeatered transmission systems using distributed Raman amplifier.

PubMed

Cheng, Jingchi; Tang, Ming; Lau, Alan Pak Tao; Lu, Chao; Wang, Liang; Dong, Zhenhua; Bilal, Syed Muhammad; Fu, Songnian; Shum, Perry Ping; Liu, Deming

2015-05-04

High spectral efficiency modulation format based unrepeatered transmission systems using distributed Raman amplifier (DRA) have attracted much attention recently. To enhance the reach and optimize system performance, careful design of DRA is required based on the analysis of various types of impairments and their balance. In this paper, we study various pump RIN induced distortions on high spectral efficiency modulation formats. The vector theory of both 1st and higher-order stimulated Raman scattering (SRS) effect using Jones-matrix formalism is presented. The pump RIN will induce three types of distortion on high spectral efficiency signals: intensity noise stemming from SRS, phase noise stemming from cross phase modulation (XPM), and polarization crosstalk stemming from cross polarization modulation (XPolM). An analytical model for the statistical property of relative phase noise (RPN) in higher order DRA without dealing with complex vector theory is derived. The impact of pump RIN induced impairments are analyzed in polarization-multiplexed (PM)-QPSK and PM-16QAM-based unrepeatered systems simulations using 1st, 2nd and 3rd-order forward pumped Raman amplifier. It is shown that at realistic RIN levels, negligible impairments will be induced to PM-QPSK signals in 1st and 2nd order DRA, while non-negligible impairments will occur in 3rd order case. PM-16QAM signals suffer more penalties compared to PM-QPSK with the same on-off gain where both 2nd and 3rd order DRA will cause non-negligible performance degradations. We also investigate the performance of digital signal processing (DSP) algorithms to mitigate such impairments.

Review and Assessment of Commercial Vendors/Options for Feeding and Pumping Biomass Slurries for Hydrothermal Liquefaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berglin, Eric J.; Enderlin, Carl W.; Schmidt, Andrew J.

2012-11-01

The National Advanced Biofuels Consortium is working to develop improved methods for producing high-value hydrocarbon fuels. The development of one such method, the hydrothermal liquefaction (HTL) process, is being led by the Pacific Northwest National Laboratory (PNNL). The HTL process uses a wet biomass slurry at elevated temperatures (i.e., 300 to 360°C [570 to 680°F]) and pressures above the vapor pressure of water (i.e., 15 to 20 MPa [2200 to 3000 psi] at these temperatures) to facilitate a condensed-phase reaction medium. The process has been successfully tested at bench-scale and development and testing at a larger scale is required tomore » prove the viability of the process at production levels. Near-term development plans include a pilot-scale system on the order of 0.5 to 40 gpm, followed by a larger production-scale system on the order of 2000 dry metric tons per day (DMTPD). A significant challenge to the scale-up of the HTL process is feeding a highly viscous fibrous biomass wood/corn stover feedstock into a pump system that provides the required 3000 psi of pressure for downstream processing. In October 2011, PNNL began investigating commercial feed and pumping options that would meet these HTL process requirements. Initial efforts focused on generating a HTL feed and pump specification and then providing the specification to prospective vendors to determine the suitability of their pumps for the pilot-scale and production-scale plants. Six vendors were identified that could provide viable equipment to meet HTL feed and/or pump needs. Those six vendors provided options consisting three types of positive displacement pumps (i.e., diaphragm, piston, and lobe pumps). Vendors provided capabilities and equipment related to HTL application. This information was collected, assessed, and summarized and is provided as appendices to this report.« less

Myocardial revascularization with miniaturized extracorporeal circulation versus off pump: Evaluation of systemic and myocardial inflammatory response in a prospective randomized study.

PubMed

Formica, Francesco; Broccolo, Francesco; Martino, Antonello; Sciucchetti, Jennifer; Giordano, Vincenzo; Avalli, Leonello; Radaelli, Gianluigi; Ferro, Orazio; Corti, Fabrizio; Cocuzza, Clementina; Paolini, Giovanni

2009-05-01

This prospective randomized study sought to verify the systemic inflammatory response, inflammatory myocardial damage, and early clinical outcome in coronary surgery with the miniaturized extracorporeal circulation system or on the beating heart. Sixty consecutive patients were randomized to miniaturized extracorporeal circulation (n = 30) or off-pump coronary revascularization (off-pump coronary artery bypass grafting, n = 30). Intraoperative and postoperative data were recorded. Plasma levels of interleukin-6 and tumor necrosis factor-alpha were measured from systemic blood intraoperatively, at the end of operation, and 24 and 48 hours thereafter. Levels of the same markers and blood lactate were measured from coronary sinus blood intraoperatively to evaluate myocardial inflammation. Markers of myocardial damage were also analyzed. One patient died in the off-pump coronary artery bypass grafting group. There was no statistical difference in early clinical outcome in both groups. Release of interleukin-6 was higher in the off-pump coronary artery bypass grafting group 24 hours after the operation (P = .03), whereas levels of tumor necrosis factor-alpha were not different in both groups. Cardiac release of interleukin-6, tumor necrosis factor-alpha, and blood lactate were not different in both groups. Release of troponin T was not significantly different in both groups. Levels of creatine kinase mass were statistically higher in the miniaturized extracorporeal circulation group than in the off-pump coronary artery bypass grafting group, but only at the end of the operation (P < .0001). Hemoglobin levels were significantly higher in the miniaturized extracorporeal circulation group than in the off-pump coronary artery bypass grafting group after 24 hours (P = .01). Miniaturized extracorporeal circulation can be considered similar to off-pump surgery in terms of systemic inflammatory response, myocardial inflammation and damage, and early outcome.

Study on the amplifier experiment of end-pumped long pulse slab laser

NASA Astrophysics Data System (ADS)

Jin, Quanwei; Chen, Xiaoming; Jiang, JianFeng; Pang, Yu; Tong, Lixin; Li, Mi; Hu, Hao; Lv, Wenqiang; Gao, Qingsong; Tang, Chun

2018-03-01

The amplifier experiment research of end-pumped long pulse slab laser is developed, the results of out-put energy, optical-optical efficiency and pulse waveform are obtained at different experiment conditions, such as peak pumped power, amplifier power and pumped pulse width. The seed laser is CW fundamental transverse-mode operation fiber laser, the laser medium is composited Nd:YAG slab. Under end-pumped and the 2 passes, the laser obtain 7.65J out-put energy and 43.1% optical-optical efficiency with 45kW peak-pumped power and 386μs pump pulse width. The experimental results provide the basic for the optimization design to high frequency, high energy and high beam-quality slab lasers.

Advanced thermal management of high-power quantum cascade laser arrays for infrared countermeasures

NASA Astrophysics Data System (ADS)

Barletta, Philip; Diehl, Laurent; North, Mark T.; Yang, Bao; Baldasaro, Nick; Temple, Dorota

2017-10-01

Next-generation infrared countermeasure (IRCM) systems call for compact and lightweight high-power laser sources. Specifically, optical output power of tens of Watts in the mid-wave infrared (MWIR) is desired. Monolithically fabricated arrays of quantum cascade lasers (QCLs) have the potential to meet these requirements. Single MWIR QCL emitters operating in continuous wave at room temperature have demonstrated multi-Watt power levels with wall-plug efficiency of up to 20%. However, tens of Watts of output power from an array of QCLs translates into the necessity of removing hundreds of Watts per cm2, a formidable thermal management challenge. A potential thermal solution for such high-power QCL arrays is active cooling based on high-performance thin-film thermoelectric coolers (TFTECs), in conjunction with pumped porous-media heat exchangers. The use of active cooling via TFTECs makes it possible to not only pump the heat away, but also to lower the QCL junction temperature, thus improving the wall-plug efficiency of the array. TFTECs have shown the ability to pump >250W/cm2 at ΔT=0K, which is 25 times greater than that typically seen in commercially available bulk thermoelectric devices.

Application of a pressure-relieving air compliance chamber in a single-pulsatile extracorporeal life support system: an experimental study.

PubMed

Kim, Tae Sik; Sun, Kyung; Lee, Kyu Baek; Lee, Hye Won; Baek, Kwang Je; Park, Sung Young; Son, Ho Sung; Kim, Kwang Taik; Kim, Hyoung Mook

2004-12-01

Nonpulsatile blood pumps are mainly used in extracorporeal life support systems. Although pulsating blood flow is known to be physiological, a pulsatile pump is not commonly applied in a circuit with a membrane oxygenator because of damage to the blood cells. The hypothesis that the placement of a pressure-relieving compliance chamber in a circuit might reduce blood cell trauma was tested. An extracorporeal life support circuit was constructed in an acute lung injury model of dogs by oleic acid infusion. The animals were divided into three groups. In group I (n = 6) a nonpulsatile centrifugal pump was used as a control. In group II (n = 4) a single-pulsatile pump was used, and in group III (n = 6) a single-pulsatile pump equipped with a compliance chamber was used. Pump flow was maintained at 1.8-2.0 L/min for 2 h. Hemodynamics and blood gas analyses indicated that the pulsatile groups II and III had better results than the nonpulsatile group I. The plasma-free hemoglobin level, which indicates blood cell trauma, was the lowest in group I and the highest in group II but was significantly decreased in group III. A pressure-relieving compliance chamber could significantly reduce high circuit pressures and blood cell trauma.

A novel high temperature superconducting magnetic flux pump for MRI magnets

NASA Astrophysics Data System (ADS)

Bai, Zhiming; Yan, Guo; Wu, Chunli; Ding, Shufang; Chen, Chuan

2010-10-01

This paper presents a kind of minitype magnetic flux pump made of high temperature superconductor. This kind of novel high temperature superconducting (HTS) flux pump has not any mechanical revolving parts or thermal switches. The excitation current of copper coils in magnetic pole system is controlled by a singlechip. The structure design and operational principle have been described. The operating performance of the new model magnetic flux pump has been preliminarily tested. The experiments show that the maximum pumping current is approximately 200 A for Bi2223 flux pump and 80 A for MgB 2 flux pump operating at 20 K. By comparison, it is discovered that the operating temperature range is wider, the ripple is smaller and the pumping frequency is higher in Bi2223 flux pump than those in MgB 2 flux pump. These results indicate that the newly developed Bi2223 magnetic flux pump may efficiently compensate the magnetic field decay in HTS magnet and make the magnet operate in persistent current mode, this point is significant to the magnetic resonance imaging (MRI) magnets. This new flux pump is under construction presently. It is expected that the Bi2223 flux pump would be applied to the superconducting MRI magnets by further optimizing structure and improving working process.

Time-resolved polarization imaging by pump-probe (stimulated emission) fluorescence microscopy.

PubMed Central

Buehler, C; Dong, C Y; So, P T; French, T; Gratton, E

2000-01-01

We report the application of pump-probe fluorescence microscopy in time-resolved polarization imaging. We derived the equations governing the pump-probe stimulated emission process and characterized the pump and probe laser power levels for signal saturation. Our emphasis is to use this novel methodology to image polarization properties of fluorophores across entire cells. As a feasibility study, we imaged a 15-microm orange latex sphere and found that there is depolarization that is possibly due to energy transfer among fluorescent molecules inside the sphere. We also imaged a mouse fibroblast labeled with CellTracker Orange CMTMR (5-(and-6)-(((4-chloromethyl)benzoyl)amino)tetramethyl-rhodamine). We observed that Orange CMTMR complexed with gluthathione rotates fast, indicating the relatively low fluid-phase viscosity of the cytoplasmic microenvironment as seen by Orange CMTMR. The measured rotational correlation time ranged from approximately 30 to approximately 150 ps. This work demonstrates the effectiveness of stimulated emission measurements in acquiring high-resolution, time-resolved polarization information across the entire cell. PMID:10866979

Laser diode and pumped Cr:Yag passively Q-switched yellow-green laser at 543 nm

NASA Astrophysics Data System (ADS)

Yao, Y.; Ling, Zhao; Li, B.; Qu, D. P.; Zhou, K.; Zhang, Y. B.; Zhao, Y.; Zheng, Q.

2013-03-01

Efficient and compact yellow green pulsed laser output at 543 nm is generated by frequency doubling of a passively Q-switched end diode-pumped Nd:YVO4 laser at 1086 nm under the condition of sup-pressing the higher gain transition near 1064 nm. With 15 W of diode pump power and the frequency doubling crystal LBO, as high as 1.58 W output power at 543 nm is achieved. The optical to optical conversion efficiency from the corresponding Q-switched fundamental output to the yellow green output is 49%. The peak power of the Q-switched yellow green pulse laser is up to 30 kW with 5 ns pulse duration. The output power stability over 8 hours is better than 2.56% at the maximum output power. To the best of our knowledge, this is the highest watt-level laser at 543 nm generated by frequency doubling of a passively Q-switched end diode pumped Nd:YVO4 laser at 1086 nm.

High power high repetition rate VCSEL array side-pumped pulsed blue laser

NASA Astrophysics Data System (ADS)

van Leeuwen, Robert; Zhao, Pu; Chen, Tong; Xu, Bing; Watkins, Laurence; Seurin, Jean-Francois; Xu, Guoyang; Miglo, Alexander; Wang, Qing; Ghosh, Chuni

2013-03-01

High power, kW-class, 808 nm pump modules based on the vertical-cavity surface-emitting laser (VCSEL) technology were developed for side-pumping of solid-state lasers. Two 1.2 kW VCSEL pump modules were implemented in a dual side-pumped Q-switched Nd:YAG laser operating at 946 nm. The laser output was frequency doubled in a BBO crystal to produce pulsed blue light. With 125 μs pump pulses at a 300 Hz repetition rate 6.1 W QCW 946 nm laser power was produced. The laser power was limited by thermal lensing in the Nd:YAG rod.

Submersible canned motor transfer pump

DOEpatents

Guardiani, R.F.; Pollick, R.D.; Nyilas, C.P.; Denmeade, T.J.

1997-08-19

A transfer pump is described which is used in a waste tank for transferring high-level radioactive liquid waste from a waste tank and having a column assembly, a canned electric motor means, and an impeller assembly with an upper impeller and a lower impeller connected to a shaft of a rotor assembly. The column assembly locates a motor housing with the electric motor means adjacent to the impeller assembly which creates an hydraulic head, and which forces the liquid waste, into the motor housing to cool the electric motor means and to cool and/or lubricate the radial and thrust bearing assemblies. Hard-on-hard bearing surfaces of the bearing assemblies and a ring assembly between the upper impeller and electric motor means grind large particles in the liquid waste flow. Slots in the static bearing member of the radial bearing assemblies further grind down the solid waste particles so that only particles smaller than the clearances in the system can pass there through, thereby resisting damage to and the interruption of the operation of the transfer pump. The column assembly is modular so that sections can be easily assembled, disassembled and/or removed. A second embodiment employs a stator jacket which provides an alternate means for cooling the electric motor means and lubricating and/or cooling the bearing assemblies, and a third embodiment employs a variable level suction device which allows liquid waste to be drawn into the transfer pump from varying and discrete levels in the waste tank. 17 figs.

Submersible canned motor transfer pump

DOEpatents

Guardiani, Richard F.; Pollick, Richard D.; Nyilas, Charles P.; Denmeade, Timothy J.

1997-01-01

A transfer pump used in a waste tank for transferring high-level radioactive liquid waste from a waste tank and having a column assembly, a canned electric motor means, and an impeller assembly with an upper impeller and a lower impeller connected to a shaft of a rotor assembly. The column assembly locates a motor housing with the electric motor means adjacent to the impeller assembly which creates an hydraulic head, and which forces the liquid waste, into the motor housing to cool the electric motor means and to cool and/or lubricate the radial and thrust bearing assemblies. Hard-on-hard bearing surfaces of the bearing assemblies and a ring assembly between the upper impeller and electric motor means grind large particles in the liquid waste flow. Slots in the static bearing member of the radial bearing assemblies further grind down the solid waste particles so that only particles smaller than the clearances in the system can pass therethrough, thereby resisting damage to and the interruption of the operation of the transfer pump. The column assembly is modular so that sections can be easily assembled, disassembled and/or removed. A second embodiment employs a stator jacket which provides an alternate means for cooling the electric motor means and lubricating and/or cooling the bearing assemblies, and a third embodiment employs a variable level suction device which allows liquid waste to be drawn into the transfer pump from varying and discrete levels in the waste tank.

High-frequency monitoring reveals nutrient sources and transport processes in an agriculture-dominated lowland water system

NASA Astrophysics Data System (ADS)

van der Grift, Bas; Broers, Hans Peter; Berendrecht, Wilbert; Rozemeijer, Joachim; Osté, Leonard; Griffioen, Jasper

2016-05-01

Many agriculture-dominated lowland water systems worldwide suffer from eutrophication caused by high nutrient loads. Insight in the hydrochemical functioning of embanked polder catchments is highly relevant for improving the water quality in such areas or for reducing export loads to downstream water bodies. This paper introduces new insights in nutrient sources and transport processes in a polder in the Netherlands situated below sea level using high-frequency monitoring technology at the outlet, where the water is pumped into a higher situated lake, combined with a low-frequency water quality monitoring programme at six locations within the drainage area. Seasonal trends and short-scale temporal dynamics in concentrations indicated that the NO3 concentration at the pumping station originated from N loss from agricultural lands. The NO3 loads appear as losses via tube drains after intensive rainfall events during the winter months due to preferential flow through the cracked clay soil. Transfer function-noise modelling of hourly NO3 concentrations reveals that a large part of the dynamics in NO3 concentrations during the winter months can be related to rainfall. The total phosphorus (TP) concentration and turbidity almost doubled during operation of the pumping station, which points to resuspension of particulate P from channel bed sediments induced by changes in water flow due to pumping. Rainfall events that caused peaks in NO3 concentrations did not results in TP concentration peaks. The rainfall induced and NO3 enriched quick interflow, may also be enriched in TP but retention of TP due to sedimentation of particulate P then results in the absence of rainfall induced TP concentration peaks. Increased TP concentrations associated with run-off events is only observed during a rainfall event at the end of a freeze-thaw cycle. All these observations suggest that the P retention potential of polder water systems is primarily due to the artificial pumping regime that buffers high flows. As the TP concentration is affected by operation of the pumping station, timing of sampling relative to the operating hours of the pumping station should be accounted for when calculating P export loads, determining trends in water quality, or when judging water quality status of polder water systems.

Advanced high-temperature electromagnetic pump

NASA Technical Reports Server (NTRS)

Gahan, J. W.; Powell, A. H.

1972-01-01

Three phase helical, electromagnetic induction pump for use as boiler feed pump in potassium Rankine-cycle power system is described. Techniques for fabricating components of pump are discussed. Specifications of pump are analyzed.

Ground-water levels in alluvium on the South coast of Puerto Rico, February 1978

USGS Publications Warehouse

Diaz, Jose R.

1979-01-01

Ground-water levels in the alluvial aquifer of the south coast of Puerto Rico in February 1978 were similar to or slightly higher than those of February 1977. Water levels rose about 2 to 3 meters in the northern section near the foothills in the coastal plain area from Salinas to Patillas and in the Guanica-Penuelas area. Pumpage remained unchanged in most of the areas under study. Pumping-water levels were above mean sea level in all industrial well fields. Pumping and static water levels were below mean sea level (1 to 3 meters), in public supply and irrigation wells in the areas of Playa de Ponce, Descalabrado-Punta Petrona, and in the vicinity of the town of Salinas. These levels are considered to be normal for the dry season in these highly irrigated areas. Sixty-four water samples collected from irrigation, industrial and salinity observation wells exhibited similar or lower chloride concentration than in previous years. The average chloride concentration for 1978 was 57 milligrams per liter. (USGS)

Large-area high-power VCSEL pump arrays optimized for high-energy lasers

NASA Astrophysics Data System (ADS)

Wang, Chad; Geske, Jonathan; Garrett, Henry; Cardellino, Terri; Talantov, Fedor; Berdin, Glen; Millenheft, David; Renner, Daniel; Klemer, Daniel

2012-06-01

Practical, large-area, high-power diode pumps for one micron (Nd, Yb) as well as eye-safer wavelengths (Er, Tm, Ho) are critical to the success of any high energy diode pumped solid state laser. Diode efficiency, brightness, availability and cost will determine how realizable a fielded high energy diode pumped solid state laser will be. 2-D Vertical-Cavity Surface-Emitting Laser (VCSEL) arrays are uniquely positioned to meet these requirements because of their unique properties, such as low divergence circular output beams, reduced wavelength drift with temperature, scalability to large 2-D arrays through low-cost and high-volume semiconductor photolithographic processes, high reliability, no catastrophic optical damage failure, and radiation and vacuum operation tolerance. Data will be presented on the status of FLIR-EOC's VCSEL pump arrays. Analysis of the key aspects of electrical, thermal and mechanical design that are critical to the design of a VCSEL pump array to achieve high power efficient array performance will be presented.

Proton-pumping rhodopsins are abundantly expressed by microbial eukaryotes in a high-Arctic fjord.

PubMed

Vader, Anna; Laughinghouse, Haywood D; Griffiths, Colin; Jakobsen, Kjetill S; Gabrielsen, Tove M

2018-02-01

Proton-pumping rhodopsins provide an alternative pathway to photosynthesis by which solar energy can enter the marine food web. Rhodopsin genes are widely found in marine bacteria, also in the Arctic, and were recently reported from several eukaryotic lineages. So far, little is known about rhodopsin expression in Arctic eukaryotes. In this study, we used metatranscriptomics and 18S rDNA tag sequencing to examine the mid-summer function and composition of marine protists (size 0.45-10 µm) in the high-Arctic Billefjorden (Spitsbergen), especially focussing on the expression of microbial proton-pumping rhodopsins. Rhodopsin transcripts were highly abundant, at a level similar to that of genes involved in photosynthesis. Phylogenetic analyses placed the environmental rhodopsins within disparate eukaryotic lineages, including dinoflagellates, stramenopiles, haptophytes and cryptophytes. Sequence comparison indicated the presence of several functional types, including xanthorhodopsins and a eukaryotic clade of proteorhodopsin. Transcripts belonging to the proteorhodopsin clade were also abundant in published metatranscriptomes from other oceanic regions, suggesting a global distribution. The diversity and abundance of rhodopsins show that these light-driven proton pumps play an important role in Arctic microbial eukaryotes. Understanding this role is imperative to predicting the future of the Arctic marine ecosystem faced by a changing light climate due to diminishing sea-ice. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Amplified emission and lasing in a plasmonic nanolaser with many three-level molecules

NASA Astrophysics Data System (ADS)

Zhang, Yuan; Mølmer, Klaus

2018-01-01

Steady-state plasmonic lasing is studied theoretically for a system consisting of many dye molecules arranged regularly around a gold nanosphere. A three-level model with realistic molecular dissipation is employed to analyze the performance as a function of the pump field amplitude and number of molecules. Few molecules and moderate pumping produce a single narrow emission peak because the excited molecules transfer energy to a single dipole plasmon mode by amplified spontaneous emission. Under strong pumping, the single peak splits into broader and weaker emission peaks because two molecular excited levels interfere with each other through coherent coupling with the pump field and with the dipole plasmon field. A large number of molecules gives rise to a Poisson-like distribution of plasmon number states with a large mean number characteristic of lasing action. These characteristics of lasing, however, deteriorate under strong pumping because of the molecular interference effect.

Fuel system for rotary distributor fuel injection pump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klopfer, K.H.; Kelly, W.W.

1993-06-01

In a fuel injection pump having a drive shaft, a pump rotor driven by the drive shaft, reciprocating pumping means with periodic intake and pumping strokes to periodically receive an intake charge of fuel and deliver fuel at high pressure for fuel injection is described; a distributor head with a plurality of angularly spaced distributor outlets, the pump rotor providing a distributor rotor with a distributor port connected to the pumping means, the distributor rotor being rotatably mounted in the distributor head for sequential registration of the distributor port with the distributor outlets for distributing said high pressure delivery ofmore » fuel thereto; a fuel system for supplying fuel to the pumping means, having an end chamber at one end of the pump rotor and a fuel supply pump driven by the drive shaft and having an inlet and outlet, the supply pump outlet being connected to the end chamber for supplying fuel thereto, and a pressure regulator for regulating the fuel pressure in the end chamber; and a control valve connected between the pumping means and the end chamber and selectively opened during the intake strokes to supply fuel to the pumping means from the end chamber and during the pumping strokes to spill fuel from the pumping means into the end chamber to terminate said high pressure delivery of fuel; the improvement wherein the fuel system comprises a fuel return passage connected in series with the end chamber downstream thereof, wherein the pressure regulator is mounted in the return passage for regulating the upstream fuel pressure, including the upstream fuel pressure within the end chamber, and is connected for conducting excess fuel for return to the supply pump inlet, and wherein the supply pump is driven by the drive shaft to supply fuel at a rate exceeding the rate of said high pressure delivery of fuel for fuel injection and to provide excess fuel flow continuously through the end chamber and return passage to the pressure regulator.« less

The CentriMag: a new optimized centrifugal blood pump with levitating impeller.

PubMed

Mueller, Juerg Peter; Kuenzli, Andreas; Reuthebuch, Oliver; Dasse, Kurt; Kent, Stella; Zuend, Gregor; Turina, Marko Ivan; Lachat, Mario Louis

2004-01-01

Blood pumps are routinely used for circulatory and pulmonary support. However, blood trauma and pump failure remain severe drawbacks of currently available pump models. This study evaluated the first clinical application of a new, totally bearingless centrifugal blood pump (CentriMag). A centrifugal pump consisting of an electromagnetic suspended impeller was used as a blood pump during beating-heart coronary artery bypass grafting in 11 patients (mean weight, 77.4 kg). Heparin in a bolus of 150 IU/kg body weight was administered, and activated clotting time was maintained at approximately 180 to 250 seconds during extracorporeal circulation. Pump-induced blood trauma was evaluated by measurement of plasma free hemoglobin (PFH), lactate dehydrogenase (LDH), hematocrit, total bilirubin, and platelet levels. Mean pump flow was 3.3 +/- 0.62 L/min, and mean pressure gradient through the oxygenator was 69 +/- 4 mm Hg. No pump dysfunction occurred during a mean application time of 105 +/- 26 minutes. Inspection of the pump housings showed no internal thrombus formation despite low-dose heparinization. Only slight hemolysis was observed with a mean PFH level of 1.96 micromol/L; LDH, 460 U/L; hematocrit, 33%; total bilirubin, 25 micromol/L; and platelets, 191 x 10(3)/microL. The bearingless CentriMag blood pump is a safe and reliable new device that produces only minimal hemolysis. It seems to be suited for long-term evaluation as a blood pump for extracorporeal membrane oxygenation or as ventricular assist device.

High-efficiency, 154  W CW, diode-pumped Raman fiber laser with brightness enhancement.

PubMed

Glick, Yaakov; Fromzel, Viktor; Zhang, Jun; Ter-Gabrielyan, Nikolay; Dubinskii, Mark

2017-01-20

We demonstrate a high-power, high-efficiency Raman fiber laser pumped directly by laser diode modules at 978 nm. 154 W of CW power were obtained at a wavelength of 1023 nm with an optical to optical efficiency of 65%. A commercial graded-index (GRIN) core fiber acts as the Raman fiber in a power oscillator configuration, which includes spectral selection to prevent generation of the second Stokes. In addition, brightness enhancement of the pump beam by a factor of 8.4 is attained due to the Raman gain distribution profile in the GRIN fiber. To the best of our knowledge this is the highest power and highest efficiency Raman fiber laser demonstrated in any configuration allowing brightness enhancement (i.e., in either cladding-pumped configuration or with GRIN fibers, excluding step-index core pumped), regardless of pumping scheme (i.e., either diode pumped or fiber laser pumped).

Apical membrane permeability and kinetic properties of the sodium pump in rabbit urinary bladder.

PubMed

Lewis, S A; Wills, N K

1983-08-01

Previous studies have shown that aldosterone stimulates the rate of Na+ transport across the rabbit urinary bladder epithelium by increasing the apical membrane permeability to Na+. Paradoxically, ion-sensitive and conventional micro-electrode measurements demonstrated that intracellular Na+ activity aiNa+ was essentially unchanged by aldosterone, i.e. aiNa+ was constant regardless of the rate of Na+ transport. The present study was designed to resolve this apparent contradiction. The effects of elevated, endogenous aldosterone levels produced by low-Na+ diet (Lewis & Diamond, 1976) on urinary bladder Na+ transport were investigated in vitro using Ussing-type chambers and intracellular conventional and ion-sensitive microelectrodes. Apical membrane selectivity and kinetics of the Na+ pump were assessed as a function of hormone stimulation. The aldosterone-stimulated increase in Na+ transport was accounted for by increases in both the relative selective permeability of the apical membrane to Na+ and an increase in its absolute Na+ permeability. The kinetics of the Na+ pump were evaluated electrically by loading the cells with Na+ (monitored with Na+-sensitive micro-electrodes) or alternatively by manipulating serosal solution K+ concentration and measuring changes in the basolateral membrane electromotive forces and resistance. From these measurements the current generated by the pump was calculated as a function of intracellular Na+ or extracellular K+. The kinetics of the pump were not altered by aldosterone. A model of highly co-operative binding estimated Km for Na+ as 14.2 mM and 2.3 mM for K+. Hill coefficients for these ions were 2.8 and 1.8, respectively, consistent with a pump stoichiometry of 3 Na+ to 2 K+. The kinetic properties of the Na-K pump indicate that physiological levels of aiNa+ are poised at the foot of a step kinetic curve which energetically favours Na+ extrusion.

Analysis of complex pumping interactions during an aquifer test conducted at a well field in the coastal plain near Augusta, Georgia, October 2009

USGS Publications Warehouse

Gonthier, Gerald J.

2009-01-01

A 24-hour aquifer test was conducted in Well Field 2 near Augusta, Georgia, October 21–22, 2009, to characterize the hydraulic properties of the Midville aquifer system. The selected well was pumped at a rate of 684 gallons per minute. At the initiation of aquifer-test pumping, water levels in each of eight wells monitored for the test were still recovering from the well-field production. Because water levels had not stabilized, data analyses were needed to account for the ongoing recovery. Hydraulic properties of the Midville aquifer system were estimated by an approach based on the Theis model and superposition. The Midville aquifer system was modeled as a Theis aquifer. The principle of superposition was used to sum the effects of multiple pumping and recovery events from a single pumped well and to sum the effects of all pumped wells as the estimated total drawdown at a monitored well. Simulated drawdown at each monitored well was determined by using a spreadsheet (SUMTheis) function of aquifer transmissivity and storativity. Simulated drawdown values were transformed into simulated water levels, accounting for longterm water-level trends. The transmissivity and storativity values that were used to calibrate the simulated water levels to measured water levels (roughly 4,000 square feet per day and 2E-04, respectively) provide estimates of the transmissivity and storativity of the Midville aquifer system in the vicinity of Well Field 2. The approach used in this study can be applied to similar well-field tests in which incomplete drawdown recovery or other known pumping is evident.

ac electroosmotic pumping induced by noncontact external electrodes

PubMed Central

Wang, Shau-Chun; Chen, Hsiao-Ping; Chang, Hsueh-Chia

2007-01-01

Electroosmotic (EO) pumps based on dc electroosmosis is plagued by bubble generation and other electrochemical reactions at the electrodes at voltages beyond 1 V for electrolytes. These disadvantages limit their throughput and offset their portability advantage over mechanical syringe or pneumatic pumps. ac electroosmotic pumps at high frequency (>100 kHz) circumvent the bubble problem by inducing polarization and slip velocity on embedded electrodes,1 but they require complex electrode designs to produce a net flow. We report a new high-throughput ac EO pump design based on induced-polarization on the entire channel surface instead of just on the electrodes. Like dc EO pumps, our pump electrodes are outside of the load section and form a cm-long pump unit consisting of three circular reservoirs (3 mm in diameter) connected by a 1×1 mm channel. The field-induced polarization can produce an effective Zeta potential exceeding 1 V and an ac slip velocity estimated as 1 mm∕sec or higher, both one order of magnitude higher than earlier dc and ac pumps, giving rise to a maximum throughput of 1 μl∕sec. Polarization over the entire channel surface, quadratic scaling with respect to the field and high voltage at high frequency without electrode bubble generation are the reasons why the current pump is superior to earlier dc and ac EO pumps. PMID:19693362

Pump efficiency in solar-energy systems

NASA Technical Reports Server (NTRS)

1978-01-01

Study investigates characteristics of typical off-the-shelf pumping systems that might be used in solar systems. Report includes discussion of difficulties in predicting pump efficiency from manufacturers' data. Sample calculations are given. Peak efficiencies, flow-rate control, and noise levels are investigated. Review or theory of pumps types and operating characteristics is presented.

Stacking open-capillary electroosmotic pumps in series to boost the pumping pressure to drive high-performance liquid chromatographic separations.

PubMed

He, Chiyang; Zhu, Zaifang; Gu, Congying; Lu, Joann; Liu, Shaorong

2012-03-02

Numerous micropumps have been developed, but few of them can produce adequate flow rate and pressure for high-performance liquid chromatography (HPLC) applications. We have recently developed an innovative hybrid electroosmotic pump (EOP) to solve this problem. The basic unit of a hybrid pump consists of a +EOP (the pumping element is positively charged) and a -EOP (the pumping element is negatively charged). The outlet of the +EOP is then joined with the inlet of the -EOP, forming a basic pump unit, while the anode of a positive high voltage (HV) power supply is placed at the joint. The inlet and outlet of this pump unit are electrically grounded. With this configuration, we can stack many of such pump units in series to boost the pumping power. In this work, we describe in details how an open-capillary hybrid EOP is constructed and characterize this pump systematically. We also show that a hybrid EOP with ten serially stacked pump units can deliver a maximum pressure of 21.5 MPa (∼3100 psi). We further demonstrate the feasibility of using this hybrid EOP to drive eluents for HPLC separations of proteins and peptides. Copyright © 2012 Elsevier B.V. All rights reserved.

Stacking open-capillary electroosmotic pumps in series to boost the pumping pressure to drive high-performance liquid chromatographic separations

DOE PAGES

He, Chiyang; Zhu, Zaifang; Gu, Congying; ...

2012-01-09

Numerous micropumps have been developed, but few of them can produce adequate flow rate and pressure for high-performance liquid chromatography (HPLC) applications. We have recently developed an innovative hybrid electroosmotic pump (EOP) to solve this problem. The basic unit of a hybrid pump consists of a +EOP (the pumping element is positively charged) and a -EOP (the pumping element is negatively charged). The outlet of the +EOP is then joined with the inlet of the -EOP, forming a basic pump unit, while the anode of a positive high voltage (HV) power supply is placed at the joint. The inlet andmore » outlet of this pump unit are electrically grounded. With this configuration, we can stack many of such pump units in series to boost the pumping power. In this work, we describe in details how an open-capillary hybrid EOP is constructed and characterize this pump systematically. We also show that a hybrid EOP with ten serially stacked pump units can deliver a maximum pressure of 21.5 MPa (~3100 psi). Here, we further demonstrate the feasibility of using this hybrid EOP to drive eluents for HPLC separations of proteins and peptides.« less

Compact and highly efficient laser pump cavity

DOEpatents

Chang, Jim J.; Bass, Isaac L.; Zapata, Luis E.

1999-01-01

A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

Coherent population trapping resonances at lower atomic levels of Doppler broadened optical lines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Şahin, E; Hamid, R; Çelik, M

2014-11-30

We have detected and analysed narrow high-contrast coherent population trapping (CPT) resonances, which are induced in absorption of a weak monochromatic probe light beam by counterpropagating two-frequency pump radiation in a cell with rarefied caesium vapour. The experimental investigations have been performed by the example of nonclosed three level Λ-systems formed by spectral components of the D{sub 2} line of caesium atoms. The applied method allows one to analyse features of the CPT phenomenon directly at a given low long-lived level of the selected Λ-system even in sufficiently complicated spectra of atomic gases with large Doppler broadening. We have establishedmore » that CPT resonances in transmission of the probe beam exhibit not only a higher contrast but also a much lesser width in comparison with well- known CPT resonances in transmission of the corresponding two-frequency pump radiation. The results obtained can be used in selective photophysics, photochemistry and ultra-high resolution atomic (molecular) spectroscopy. (laser applications and other topics in quantum electronics)« less

Simulated response to pumping stress in the Sparta aquifer of southeastern Arkansas and north-central Louisiana, 1998-2027

USGS Publications Warehouse

Hays, Phillip D.; Lovelace, John K.; Reed, Thomas B.

1998-01-01

The Sparta aquifer in southeastern Arkansas and north-central Louisiana is a major water resource for municipal, industrial, and agricultural uses. In recent years, the demand for water in some areas has resulted in withdrawals from the Sparta that significantly exceed recharge to the aquifer. Considerable drawdown has occurred in the potentiometric surface, and water users and managers alike have begun to question the ability of the aquifer to supply water for the long term. Large cones of depression are centered beneath the Grand Prairie area and the cities of Pine Bluff and El Dorado in Arkansas, and Monroe in Louisiana. Water levels in the aquifer have declined at rates greater than 1 foot per year for more than a decade in much of southern Arkansas and northern Louisiana and are now below the top of the formation in parts of Union and Columbia Counties, Arkansas, and in several areas of Louisiana. Problems related to over draft in the Sparta could result in increased drilling and pumping costs, loss of yield, salt-water intrusion, and decrease in water quality in areas of large drawdown. The effects of current ground-water withdrawals and potential future withdrawals on water availability are major concerns of water managers and users as well as the general public in the two States. The Sparta model-a regional scale, digital ground-water flow model-was first calibrated in the mid-1980's. The model was updated and reverified using 1995-97 data. Visual inspection of the observed (1996-97) and simulated potentiometric surfaces, statistical analysis of the error for the original calibration and current reverification, and comparison of observed versus simulated hydro graphs indicates that the model is simulating conditions in the aquifer within acceptable error, and the quality of current (1998) model results is similar to the original model calibration results. When stressed with current withdrawal volumes and distributions, the model is able to simulate currently observed heads effectively as heads were simulated in the original calibration period. Five pumping scenarios were simulated over a 30-year period based on (1) current pumping rates, (2) current rates of change in pumping, (3) decreased pumping in selected areas, (4) increased pumping in selected areas, and (5) redistribution and increase of pumping in selected areas. Model results show that although continued pumping at current rates will result in relatively minor declines in water levels (scenario 1 above), continued pumping at currently observed rates of change will result in drastic declines across large areas of focused withdrawals (scenario 2). Under the first scenario-in which current pumping rates are input to the model for the 30-year simulation period-water levels in the middle of the cones of depression centered on El Dorado and Monroe decrease less than 10 feet. In the second scenario-in which the current rate of change in pumpage is applied to the model-substantial declines occur in the proximity of most major pumpage centers. During the 1998-2027 model period, predicted water levels decline from 307 feet below sea level to 438 feet below sea level near El Dorado, from 58 feet below sea level to 277 feet below sea level near Pine Bluff, but only by about 25 feet-from 202 feet below sea level to 225 feet below sea level near Monroe. In the third scenario-in which minimum predicted water use figures supplied by selected facilities in Arkansas and decreased pumping estimates for Louisiana are applied to the model-simulated water levels are substantially higher at cones of depression around the major pumping centers of Monroe and El Dorado as compared to initial (1997) values. During the 1998-2027 model period, predicted water levels near Monroe increase from 202 feet below sea level to 133 feet below sea level; water levels near El Dorado increase from 307 feet below sea level to 123 feet below sea level. For the fourth scenario-in which maxi mum pr

Vacuum system of the cyclotrons in VECC, Kolkata

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy, Anindya; Bhole, R.B.; Akhtar, J.

2011-07-01

The vacuum system of the K=130 Room Temperature Cyclotron (RTC) (operational since 1978) has been recently modernized and the same of the K{sub bend}=520 Superconducting Cyclotron (SCC), currently under commissioning, is being deployed for remote monitoring and control. The vacuum system of RTC is designed to achieve and maintain vacuum level of 2 X 10{sup -6} mbar inside 23 m{sup 3} volume of Resonator tank and DEE tank. This has been upgraded by replacing several valves, Freon units, gauges and pumps. The relay based manual control system has been replaced by PLC based automated system. The SCC vacuum system alsomore » has an elaborate arrangement comprising of turbo molecular pumping modules with associated isolation valves and characteristic gauges. This paper describes essential elements, typically used to obtain high (1X10{sup -7} mbar) vacuum using rotary pumps, diffusion pumps and cold traps/turbo-molecular pumps and other system components such as valves, gauges and baffles. The supervisory control methodology/scheme of both the vacuum systems, developed in-house using EPICS (Experimental Physics and Industrial Control System), a standard open-source software tool for designing distributed control system, is also elaborated here. (author)« less

Flexible and scalable wavelength multicast of coherent optical OFDM with tolerance against pump phase-noise using reconfigurable coherent multi-carrier pumping.

PubMed

Lu, Guo-Wei; Bo, Tianwai; Sakamoto, Takahide; Yamamoto, Naokatsu; Chan, Calvin Chun-Kit

2016-10-03

Recently the ever-growing demand for dynamic and high-capacity services in optical networks has resulted in new challenges that require improved network agility and flexibility in order for network resources to become more "consumable" and dynamic, or elastic, in response to requests from higher network layers. Flexible and scalable wavelength conversion or multicast is one of the most important technologies needed for developing agility in the physical layer. This paper will investigate how, using a reconfigurable coherent multi-carrier as a pump, the multicast scalability and the flexibility in wavelength allocation of the converted signals can be effectively improved. Moreover, the coherence in the multiple carriers prevents the phase noise transformation from the local pump to the converted signals, which is imperative for the phase-noise-sensitive multi-level single- or multi-carrier modulated signal. To verify the feasibility of the proposed scheme, we experimentally demonstrate the wavelength multicast of coherent optical orthogonal frequency division multiplexing (CO-OFDM) signals using a reconfigurable coherent multi-carrier pump, showing flexibility in wavelength allocation, scalability in multicast, and tolerance against pump phase noise. Less than 0.5 dB and 1.8 dB power penalties at a bit-error rate (BER) of 10^-3 are obtained for the converted CO-OFDM-quadrature phase-shift keying (QPSK) and CO-OFDM-16-ary quadrature amplitude modulation (16QAM) signals, respectively, even when using a distributed feedback laser (DFB) as a pump source. In contrast, with a free-running pumping scheme, the phase noise from DFB pumps severely deteriorates the CO-OFDM signals, resulting in a visible error-floor at a BER of 10^-2 in the converted CO-OFDM-16QAM signals.

Incorporating high-pressure electroosmotic pump and a nano-flow gradient generator into a miniaturized liquid chromatographic system for peptide analysis.

PubMed

Chen, Apeng; Lynch, Kyle B; Wang, Xiaochun; Lu, Joann J; Gu, Congying; Liu, Shaorong

2014-09-24

We integrate a high-pressure electroosmotic pump (EOP), a nanoflow gradient generator, and a capillary column into a miniaturized liquid chromatographic system that can be directly coupled with a mass spectrometer for proteomic analysis. We have recently developed a low-cost high-pressure EOP capable of generating pressure of tens of thousands psi, ideal for uses in miniaturized HPLC. The pump worked smoothly when it was used for isocratic elutions. When it was used for gradient elutions, generating reproducible gradient profiles was challenging; because the pump rate fluctuated when the pump was used to pump high-content organic solvents. This presents an issue for separating proteins/peptides since high-content organic solvents are often utilized. In this work, we solve this problem by incorporating our high-pressure EOP with a nano-flow gradient generator so that the EOP needs only to pump an aqueous solution. With this combination, we develop a capillary-based nano-HPLC system capable of performing nano-flow gradient elution; the pump rate is stable, and the gradient profiles are reproducible and can be conveniently tuned. To demonstrate its utility, we couple it with either a UV absorbance detector or a mass spectrometer for peptide separations. Copyright © 2014. Published by Elsevier B.V.

Optimal Operation of Variable Speed Pumping System in China's Eastern Route Project of S-to-N Water Diversion Project

NASA Astrophysics Data System (ADS)

Cheng, Jilin; Zhang, Lihua; Zhang, Rentian; Gong, Yi; Zhu, Honggeng; Deng, Dongsheng; Feng, Xuesong; Qiu, Jinxian

2010-06-01

A dynamic planning model for optimizing operation of variable speed pumping system, aiming at minimum power consumption, was proposed to achieve economic operation. The No. 4 Jiangdu Pumping Station, a source pumping station in China's Eastern Route of South-to-North Water Diversion Project, is taken as a study case. Since the sump water level of Jiangdu Pumping Station is affected by the tide of Yangtze River, the daily-average heads of the pumping system varies yearly from 3.8m to 7.8m and the tide level difference in one day up to 1.2m. Comparisons of operation electricity cost between optimized variable speed and fixed speed operations of pumping system were made. When the full load operation mode is adopted, whether or not electricity prices in peak-valley periods are considered, the benefits of variable speed operation cannot compensate the energy consumption of the VFD. And when the pumping system operates in part load and the peak-valley electricity prices are considered, the pumping system should cease operation or lower its rotational speed in peak load hours since the electricity price are much higher, and to the contrary the pumping system should raise its rotational speed in valley load hours to pump more water. The computed results show that if the pumping system operates in 80% or 60% loads, the energy consumption cost of specified volume of water will save 14.01% and 26.69% averagely by means of optimal variable speed operation, and the investment on VFD will be paid back in 2 or 3 years. However, if the pumping system operates in 80% or 60% loads and the energy cost is calculated in non peak-valley electricity price, the repayment will be lengthened up to 18 years. In China's S-to-N Water Diversion Project, when the market operation and peak-valley electricity prices are taken into effect to supply water and regulate water levels in regulation reservoirs as Hongzehu Lake, Luomahu Lake, etc. the economic operation of water-diversion pumping stations will be vital, and the adoption of VFDs to achieve optimal operation may be a good choice.

Liquid metal electric pump

DOEpatents

Abbin, J.P.; Andraka, C.E.; Lukens, L.L.; Moreno, J.B.

1992-01-14

An electrical pump for pumping liquid metals to high pressures in high temperature environments without the use of magnets or moving mechanical parts. The pump employs a non-porous solid electrolyte membrane, typically ceramic, specific to the liquid metal to be pumped. A DC voltage is applied across the thickness of the membrane causing ions to form and enter the membrane on the electrically positive surface, with the ions being neutralized on the opposite surface. This action provides pumping of the liquid metal from one side of the non-porous solid electrolyte membrane to the other. 3 figs.

The research on the design and performance of 7×1 pump combiners

NASA Astrophysics Data System (ADS)

Cao, Yang; Sheng, Quan; Fu, Shijie; Zhang, Haiwei; Bai, Xiaolei; Shi, Wei; Yao, Jianquan

2018-02-01

The 7×1 end-pumped pump combiners employing 105/125 μm multimode fibers as pump fibers are investigated. Based on the results of our theoretical analysis, sufficient taper length (TL) and low refractive index (RI) of the capillary have been adopted to fabricate high transmission efficiency combiners. A 7×1 end-pumped pump combiner with an average transmission efficiency of 98.9% and a total return loss of 1.1‰ is fabricated in experiments, which could find its application in high-power fiber laser systems.

Liquid metal electric pump

DOEpatents

Abbin, Joseph P.; Andraka, Charles E.; Lukens, Laurance L.; Moreno, James B.

1992-01-01

An electrical pump for pumping liquid metals to high pressures in high temperature environments without the use of magnets or moving mechanical parts. The pump employs a non-porous solid electrolyte membrane, typically ceramic, specific to the liquid metal to be pumped. A DC voltage is applied across the thickness of the membrane causing ions to form and enter the membrane on the electrically positive surface, with the ions being neutralized on the opposite surface. This action provides pumping of the liquid metal from one side of the non-porous solid electrolyte membrane to the other.

Injection Process Control of the Well at the Hydrodynamic Research of Coalbed

NASA Astrophysics Data System (ADS)

Odnokopylov, I. G.; Galtseva, O. V.; Krasnov, I. Yu; Smirnov, A. O.; Karpov, M. S.; Surzhikova, O. A.; Kuznetsov, V. V.; Li, J.

2017-04-01

This scientific work is devoted to the study results of water injection process into the well at the hydrodynamic research by using the high pressure unregulated pump. The injection process should be accompanied by the retention of some hydraulic parameters at constant level during some time. Various variants for use of mechatronic nodes for automatization of water injection process are considered. Scheme for reducing the load on the pump and equipment in hydraulic system and also for improving the quality control system with high accuracy is shown. Simulation results of injection process into the well at the pressure and consumption fixation and recommendations for the use of the proposed schemes depending on the technological process are given.

Method and apparatus for producing laser radiation following two-photon excitation of a gaseous medium

DOEpatents

Bischel, William K. [Menlo Park, CA; Jacobs, Ralph R. [Livermore, CA; Prosnitz, Donald [Hamden, CT; Rhodes, Charles K. [Palo Alto, CA; Kelly, Patrick J. [Fort Lewis, WA

1979-02-20

Method and apparatus for producing laser radiation by two-photon optical pumping of an atomic or molecular gaseous medium and subsequent lasing action. A population inversion is created as a result of two-photon absorption of the gaseous species. Stark tuning is utilized, if necessary, in order to tune the two-photon transition into exact resonance. In particular, gaseous ammonia (NH.sub.3) or methyl fluoride (CH.sub.3 F) is optically pumped by a pair of CO.sub.2 lasers to create a population inversion resulting from simultaneous two-photon excitation of a high-lying vibrational state, and laser radiation is produced by stimulated emission of coherent radiation from the inverted level.

Method and apparatus for producing laser radiation following two-photon excitation of a gaseous medium

DOEpatents

Bischel, W.K.; Jacobs, R.R.; Prosnitz, D.P.; Rhodes, C.K.; Kelly, P.J.

1979-02-20

Method and apparatus are disclosed for producing laser radiation by two-photon optical pumping of an atomic or molecular gaseous medium and subsequent lasing action. A population inversion is created as a result of two-photon absorption of the gaseous species. Stark tuning is utilized, if necessary, in order to tune the two-photon transition into exact resonance. In particular, gaseous ammonia (NH[sub 3]) or methyl fluoride (CH[sub 3]F) is optically pumped by a pair of CO[sub 2] lasers to create a population inversion resulting from simultaneous two-photon excitation of a high-lying vibrational state, and laser radiation is produced by stimulated emission of coherent radiation from the inverted level. 3 figs.

Broadband gate-tunable terahertz plasmons in graphene heterostructures

NASA Astrophysics Data System (ADS)

Yao, Baicheng; Liu, Yuan; Huang, Shu-Wei; Choi, Chanyeol; Xie, Zhenda; Flor Flores, Jaime; Wu, Yu; Yu, Mingbin; Kwong, Dim-Lee; Huang, Yu; Rao, Yunjiang; Duan, Xiangfeng; Wong, Chee Wei

2018-01-01

Graphene, a unique two-dimensional material comprising carbon in a honeycomb lattice1, has brought breakthroughs across electronics, mechanics and thermal transport, driven by the quasiparticle Dirac fermions obeying a linear dispersion2,3. Here, we demonstrate a counter-pumped all-optical difference frequency process to coherently generate and control terahertz plasmons in atomic-layer graphene with octave-level tunability and high efficiency. We leverage the inherent surface asymmetry of graphene for strong second-order nonlinear polarizability4,5, which, together with tight plasmon field confinement, enables a robust difference frequency signal at terahertz frequencies. The counter-pumped resonant process on graphene uniquely achieves both energy and momentum conservation. Consequently, we demonstrate a dual-layer graphene heterostructure with terahertz charge- and gate-tunability over an octave, from 4.7 THz to 9.4 THz, bounded only by the pump amplifier optical bandwidth. Theoretical modelling supports our single-volt-level gate tuning and optical-bandwidth-bounded 4.7 THz phase-matching measurements through the random phase approximation, with phonon coupling, saturable absorption and below the Landau damping, to predict and understand graphene plasmon physics.

Reconnaissance of ground-water resources of the Squaxin Island Indian Reservation, Washington

USGS Publications Warehouse

Lum, W.E.; Walters, Kenneth Lyle

1976-01-01

A supply of fresh ground water for the Squaxin Island Indian Reservation, Washington, exists in saturated deposits underlying the 3.09-square-mile island. Four test wells tapped a water-bearing zone of sand and gravel and had yields ranging from 27 to 170 gpm, with drawdowns of about 5 feet to about 65 feet. Except for high concentrations of iron and manganese (which can be treated and reduced for domestic use), the water quality is good. Conditions for drain-field waste disposal from septic tanks are good in at least the northern two-thirds of the island. The danger of inducing seawater encroachment can be minimized by maintaining pumping levels above sea level, using a network of several wells pumped intermittently into a storage facility, and spacing these wells to spread out the effects of pumping. In the northern half of the island, wells 100 to 200 feet deep may yield 25 to 100 gpm with minimum chances of seawater encroachment. The southern half of the island has a smaller apparent potential for ground-water development and an increased possibility of seawater encroachment. (Woodard-USGS)

Description and comparison of selected models for hydrologic analysis of ground-water flow, St Joseph River basin, Indiana

USGS Publications Warehouse

Peters, J.G.

1987-01-01

The Indiana Department of Natural Resources (IDNR) is developing water-management policies designed to assess the effects of irrigation and other water uses on water supply in the basin. In support of this effort, the USGS, in cooperation with IDNR, began a study to evaluate appropriate methods for analyzing the effects of pumping on ground-water levels and streamflow in the basin 's glacial aquifer systems. Four analytical models describe drawdown for a nonleaky, confined aquifer and fully penetrating well; a leaky, confined aquifer and fully penetrating well; a leaky, confined aquifer and partially penetrating well; and an unconfined aquifer and partially penetrating well. Analytical equations, simplifying assumptions, and methods of application are described for each model. In addition to these four models, several other analytical models were used to predict the effects of ground-water pumping on water levels in the aquifer and on streamflow in local areas with up to two pumping wells. Analytical models for a variety of other hydrogeologic conditions are cited. A digital ground-water flow model was used to describe how a numerical model can be applied to a glacial aquifer system. The numerical model was used to predict the effects of six pumping plans in 46.5 sq mi area with as many as 150 wells. Water budgets for the six pumping plans were used to estimate the effect of pumping on streamflow reduction. Results of the analytical and numerical models indicate that, in general, the glacial aquifers in the basin are highly permeable. Radial hydraulic conductivity calculated by the analytical models ranged from 280 to 600 ft/day, compared to 210 and 360 ft/day used in the numerical model. Maximum seasonal pumping for irrigation produced maximum calculated drawdown of only one-fourth of available drawdown and reduced streamflow by as much as 21%. Analytical models are useful in estimating aquifer properties and predicting local effects of pumping in areas with simple lithology and boundary conditions and with few pumping wells. Numerical models are useful in regional areas with complex hydrogeology with many pumping wells and provide detailed water budgets useful for estimating the sources of water in pumping simulations. Numerical models are useful in constructing flow nets. The choice of which type of model to use is also based on the nature and scope of questions to be answered and on the degree of accuracy required. (Author 's abstract)

Geohydrology and Numerical Simulation of Alternative Pumping Distributions and the Effects of Drought on the Ground-Water Flow System of Tinian, Commonwealth of the Northern Mariana Islands

USGS Publications Warehouse

Gingerich, Stephen B.

2002-01-01

Ground water in a freshwater lens is the main source of freshwater on Tinian, Commonwealth of the Northern Mariana Islands. Four major geologic units make up the island with high-permeability limestone units overlying low-permeability volcanic rocks. Estimates of limestone hydraulic conductivity range from 21 to 23,000 feet per day. Estimates of water-budget components for Tinian are 82 inches per year of rainfall, about 6 inches per year of runoff, 46 inches per year of evapotranspiration, and 30 inches per year of recharge. From 1990?97, ground-water withdrawal from the Municipal well, the major source of water, averaged about 780 gallons per minute. A two-dimensional, steady-state, ground-water flow model using the computer code SHARP was developed for Tinian, to enhance the understanding of (1) the distribution of aquifer hydraulic properties, (2) the conceptual framework of the ground-water flow system, and (3) the effects of various pumping distributions and drought on water levels and the freshwater/saltwater transition zone. For modeling purposes, Tinian was divided into three horizontal hydraulic-conductivity zones: (1) highly permeable limestone, (2) less-permeable, clay-rich limestone, and (3) low-permeability volcanic rocks. The following horizontal hydraulic conductivities were estimated: (1) 10,500 feet per day for the highly permeable limestone, (2) 800 feet per day for the less-permeable clay-rich limestone, and (3) 0.2 foot per day for the volcanic rocks. To estimate the hydrologic effects of different pumping distributions on the aquifer, three different steady-state pumping scenarios were simulated, (1) a scenario with no ground-water pumping, (2) a 2001-pumping scenario, and (3) a maximum-pumping scenario. The results of the no-pumping scenario showed that the freshwater/saltwater interface beneath the Municipal well would be about 7 feet deeper and ground-water discharge to the coast would be higher along both the east and west coasts of the island when compared with 1990-97 pumping conditions. For the maximum pumping scenario, the model-calculated freshwater/saltwater interface is about 7 feet shallower than the position calculated in the base-case scenario. To estimate the hydrologic effects of drought on the freshwater lens, the 2001- and maximum-pumping scenarios were simulated using three combinations of aquifer porosity values covering a range of possible limestone properties. In all scenarios, recharge was reduced to 10 percent of average estimated recharge and the transient response was simulated for 1 year. These simulations demonstrated that the ground-water resource is adequate to withstand a drought similar to that experienced in 1998 using existing infrastructure.

Lasing of multiperiod quantum-cascade lasers in the spectral range of (5.6–5.8)-μm under current pumping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Egorov, A. Yu., E-mail: anton@beam.ioffe.ru; Babichev, A. V.; Karachinsky, L. Ya.

2015-11-15

The lasing of multiperiod quantum-cascade lasers in the spectral range of (5.6–5.8)-μm under current pumping are demonstrated. The quantum-cascade laser heterostructure is grown by molecular-beam epitaxy technique. Despite the relatively short laser cavity length and high level of external loss the laser shows the lasing in the temperature range of 80–220 K. The threshold current density below 4 kA/cm{sup 2} at 220 K with the characteristic temperature T{sub 0} = 123 K was demonstrated.

Generation of multi-millijoule red-shifted pulses for seeding stimulated Raman backscattering amplifiers.

PubMed

Landgraf, Björn; Hoffmann, Andreas; Kartashov, Daniil; Gärtner, Felix; Samsonova, Zhanna; Polynkin, Pavel; Jacoby, Joachim; Kühl, Thomas; Spielmann, Christian

2015-03-23

The efficient generation of redshifted pulses from chirped femtosecond joule level Bessel beam pulses in gases is studied. The redshift spans from a few 100 cm⁻¹ to several 1000 cm⁻¹ corresponding to a shift of 50-500 nm for Nd:glass laser systems. The generated pulses have an almost perfect Gaussian beam profile insensitive of the pump beam profile, and are much shorter than the pump pulses. The highest measured energy is as high as 30 mJ, which is significantly higher than possible with solid state nonlinear frequency shifters.

Diode-laser pumping into the emitting level for efficient lasing of depressed cladding waveguides realized in Nd:YVO4 by the direct femtosecond-laser writing technique.

PubMed

Pavel, Nicolaie; Salamu, Gabriela; Jipa, Florin; Zamfirescu, Marian

2014-09-22

Depressed cladding waveguides have been realized in Nd:YVO(4) employing direct writing technique with a femtosecond-laser beam. It was shown that the output performances of such laser devices are improved by the reduction of the quantum defect between the pump wavelength and the laser wavelength. Thus, under the classical pump at 808 nm (i.e. into the (4)F(5/2) level), a 100-μm diameter circular waveguide inscribed in a 0.7-at.% Nd:YVO(4) outputted 1.06-μm laser pulses with 3.0-mJ energy, at 0.30 optical efficiency and slope efficiency of 0.32. The pump at 880 nm (i.e.directly into the (4)F(3/2) emitting level) increased the pulse energy at 3.8 mJ and improved both optical efficiency and slope efficiency at 0.36 and 0.39, respectively. The same waveguide yielded continuous-wave 1.5-W output power at 1.06 μm under the pump at 880 nm. Laser emission at 1.34 μm was also improved using the pump into the (4)F(3/2) emitting level of Nd:YVO(4).

Squeezed light from conventionally pumped multi-level lasers

NASA Technical Reports Server (NTRS)

Ralph, T. C.; Savage, C. M.

1992-01-01

We have calculated the amplitude squeezing in the output of several conventionally pumped multi-level lasers. We present results which show that standard laser models can produce significantly squeezed outputs in certain parameter ranges.

Kilowatt-level direct-'refractive index matching liquid'-cooled Nd:YLF thin disk laser resonator.

PubMed

Ye, Zhibin; Liu, Chong; Tu, Bo; Wang, Ke; Gao, Qingsong; Tang, Chun; Cai, Zhen

2016-01-25

A direct-liquid-cooled Nd:YLF thin disk laser resonator is presented, which features the use of refractive index matching liquid (RIML) as coolant. Highly uniform pump intensity distribution with rectangular shape is realized by using metallic planar waveguides. Much attention has been paid on the design of the gain module, including how to achieve excellent cooling ability with multi-channel coolers and how to choose the doping levels of the crystals for realizing well-distributed pump absorption. The flow velocity of the coolant is found to be a key parameter for laser performance and optimized to keep it in laminar flow status for dissipating unwanted heat load. A single channel device is used to measure the convective heat transfer coefficient (CHTC) at different flow velocities. Accordingly, the thermal stress in the disk is analyzed numerically and the maximum permissible thermal load is estimated. Experimentally, with ten pieces of a-cut Nd:YLF thin disks of different doping levels, a linear polarized laser with an average output power of 1120 W is achieved at the pump power of 5202 W, corresponding to an optical-optical efficiency of 21.5%, and a slope efficiency of 30.8%. Furthermore, the wavefront aberration of the gain module is measured to be quite weak, with a peak to valley (PV) value of 4.0 μm when it is pumped at 5202 W, which enables the feasibility of its application in an unstable resonator. To the best of our knowledge, this is the first demonstration of kilowatt-level direct-'refractive index matching liquid'-cooled Nd:YLF thin disk laser resonator.

In-well time-of-travel approach to evaluate optimal purge duration during low-flow sampling of monitoring wells

USGS Publications Warehouse

Harte, Philip T.

2017-01-01

A common assumption with groundwater sampling is that low (<0.5 L/min) pumping rates during well purging and sampling captures primarily lateral flow from the formation through the well-screened interval at a depth coincident with the pump intake. However, if the intake is adjacent to a low hydraulic conductivity part of the screened formation, this scenario will induce vertical groundwater flow to the pump intake from parts of the screened interval with high hydraulic conductivity. Because less formation water will initially be captured during pumping, a substantial volume of water already in the well (preexisting screen water or screen storage) will be captured during this initial time until inflow from the high hydraulic conductivity part of the screened formation can travel vertically in the well to the pump intake. Therefore, the length of the time needed for adequate purging prior to sample collection (called optimal purge duration) is controlled by the in-well, vertical travel times. A preliminary, simple analytical model was used to provide information on the relation between purge duration and capture of formation water for different gross levels of heterogeneity (contrast between low and high hydraulic conductivity layers). The model was then used to compare these time–volume relations to purge data (pumping rates and drawdown) collected at several representative monitoring wells from multiple sites. Results showed that computation of time-dependent capture of formation water (as opposed to capture of preexisting screen water), which were based on vertical travel times in the well, compares favorably with the time required to achieve field parameter stabilization. If field parameter stabilization is an indicator of arrival time of formation water, which has been postulated, then in-well, vertical flow may be an important factor at wells where low-flow sampling is the sample method of choice.

Simulated Ground-Water Withdrawals by Cabot WaterWorks from the Mississippi River Valley Alluvial Aquifer, Lonoke County, Arkansas

USGS Publications Warehouse

Czarnecki, John B.

2007-01-01

Cabot WaterWorks, located in Lonoke County, Arkansas, plans to increase ground-water withdrawals from the Mississippi River Valley alluvial aquifer from a 2004 rate of approximately 2.24 million gallons per day to between 4.8 and 8 million gallons per day by the end of 2049. The effects of increased pumping from several wells were simulated using a digital model of ground-water flow. The proposed additional withdrawals by Cabot WaterWorks were specified in three 1-square-mile model cells with increased pumping beginning in 2007. Increased pumping was specified at various combined rates for a period of 44 years. In addition, augmented pumping from wells owned by Grand Prairie Water Users Association, located about 2 miles from the nearest Cabot WaterWorks wells, was added to the model beginning in 2007 and continuing through to the end of 2049 in 10 of the 16 scenarios analyzed. Eight of the scenarios included reductions in pumping rates in model cells corresponding to either the Grand Prairie Water Users Association wells or to wells contained within the Grand Prairie Area Demonstration Project. Drawdown at the end of 44 years of pumping at 4.8 million gallons per day from the Cabot WaterWorks wells ranged from 15 to 25 feet in the three model cells; pumping at 8 million gallons per day resulted in water-level drawdown ranging from about 15 to 40 feet. Water levels in those cells showed no indication of leveling out at the end of the simulation period, indicating non-steady-state conditions after 44 years of pumping. From one to four new dry cells occurred in each of the scenarios by the end of 2049 when compared to a baseline scenario in which pumping was maintained at 2004 rates, even in scenarios with reduced pumping in the Grand Prairie Area Demonstration Project; however, reduced pumping produced cells that were no longer dry when compared to the baseline scenario at the end of 2049. Saturated thickness at the end of 2049 in the three Cabot WaterWorks wells ranged from about 52 to 68.5 feet for pumping rates of 4.8 million gallons per day, and from about 38 to 64 feet for pumping rates of 8 million gallons per day, the latter causing water level to fall below half the aquifer thickness in the most heavily pumped of the three cells.

The generation of a continuous-wave Nd:YVO4/LBO laser at 543 nm by direct in-band diode pumping at 888 nm

NASA Astrophysics Data System (ADS)

Fu, S. C.; Wang, X.; Chu, H.

2013-02-01

We report the generation of a green laser at 543 nm by intracavity frequency doubling of the continuous-wave (cw) laser operation of a 1086 nm Nd:YVO4 laser under 888 nm diode pumping into the emitting level 4F3/2. An LiB3O5 (LBO) crystal, cut for critical type I phase matching at room temperature, is used for the laser second-harmonic generation. At an incident pump power of 17.8 W, as high as 4.53 W cw output power at 543 nm is achieved. The optical-to-optical conversion efficiency is up to 25.4%, and the fluctuation of the green output power is better than 2.3% in a 30 min period.

All-solid-state continuous-wave frequency doubling Nd:LuVO4/LBO laser with 2.17 W output power at 543 nm

NASA Astrophysics Data System (ADS)

Li, B.; Zhao, L.; Zhang, Y. B.; Zheng, Q.; Zhao, Y.; Yao, Y.

2013-03-01

Efficient and compact green-yellow laser output at 543 nm is generated by intracavity frequency doubling of a CW diode-pumped Nd:LuVO4 laser at 1086 nm under the condition of suppressing the higher gain transition near 1064 nm. With 16 W of diode pump power and the frequency-doubling crystal LBO, as high as 2.17 W of CW output power at 543 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 13.6% and the output power stability over 8 hours is better than 2.86%. To the best of our knowledge, this is the highest watt-level laser at 543 nm generated by intracavity frequency doubling of a diode pumped Nd:LuVO4 laser at 1086 nm.

Simulated effects of ground-water management scenarios on the Santa Fe group aquifer system, Middle Rio Grande Basin, New Mexico, 2001-40

USGS Publications Warehouse

Bexfield, Laura M.; McAda, Douglas P.

2003-01-01

Future conditions in the Santa Fe Group aquifer system through 2040 were simulated using the most recent revision of the U.S. Geological Survey groundwater- flow model for the Middle Rio Grande Basin. Three simulations were performed to investigate the likely effects of different scenarios of future groundwater pumping by the City of Albuquerque on the ground-water system. For simulation I, pumping was held constant at known year-2000 rates. For simulation II, pumping was increased to simulate the use of pumping to meet all projected city water demand through 2040. For simulation III, pumpingwas reduced in accordance with a plan by the City of Albuquerque to use surfacewater to meet most of the projectedwater demand. The simulations indicate that for each of the three pumping scenarios, substantial additional watertable declines would occur in some areas of the basin through 2040. However, the reduced pumping scenario of simulation III also results in water-table rise over a broad area of the city. All three scenarios indicate that the contributions of aquifer storage and river leakage to the ground-water system would change between 2000 and 2040. Comparisons among the results for simulations I, II, and III indicate that the various pumping scenarios have substantially different effects on water-level declines in the Albuquerque area and on the contribution of each water-budget component to the total budget for the ground-water system. Between 2000 and 2040, water-level declines for continued pumping at year-2000 rates are as much as 120 feet greater than for reduced pumping; water-level declines for increased pumping to meet all projected city demand are as much as 160 feet greater. Over the same time period, reduced pumping results in retention in aquifer storage of about 1,536,000 acre-feet of ground water as compared with continued pumping at year- 2000 rates and of about 2,257,000 acre-feet as compared with increased pumping. The quantity of water retained in the Rio Grande as a result of reduced pumping and the associated decrease in induced recharge from the river is about 731,000 acre-feet as compared with continued pumping at year-2000 rates and about 872,000 acre-feet as compared with increased pumping. Reduced pumping results in slight increases in the quantity of water lost from the groundwater system to evapotranspiration and agriculturaldrain flow compared with the other pumping scenarios.

Methodology for energy strategy to prescreen the feasibility of Ground Source Heat Pump systems in residential and commercial buildings in the United States

DOE PAGES

Cho, Soolyeon; Ray, Saurabh; Im, Piljae; ...

2017-09-21

Geothermal resources have potential to reduce dependence on fossil fuels. The viability of geothermal heat pumps or ground source heat pumps (GSHPs) is significant as a potential alternative energy source with substantial savings potential. While the prospect of these systems is promising for energy efficiency, careful feasibility analysis is required before implementation. Here, this paper presents the results of evaluation of the application feasibility for GSHPs in buildings across seven climate zones in three United States regions. A comprehensive methodology is developed to measure the integrated feasibility of GSHPs using compiled data for energy use intensity, energy cost and designmore » parameters. Four different feasibility metrics are utilized: ground temperature, outdoor weather condition, energy savings potential, and cost benefits. For each metric, a corresponding feasibility score system is developed. The defined integrated feasibility score classifies the locations into five different feasibility levels ranging from Fair (0–20), Moderate (21–40), Good (41–60), High (61–80), and Very High (81–100). Conclusions show the GSHP feasibility level is High for 3 sites, Good for 8 sites and Moderate for 4 sites. Through the methodology, it is possible to develop a practical energy strategy for more economic and sustainable GSHP systems at an early design stage in the various viewpoints of geometries, climate conditions, operational factors, and energy costs.« less

Methodology for energy strategy to prescreen the feasibility of Ground Source Heat Pump systems in residential and commercial buildings in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cho, Soolyeon; Ray, Saurabh; Im, Piljae

Geothermal resources have potential to reduce dependence on fossil fuels. The viability of geothermal heat pumps or ground source heat pumps (GSHPs) is significant as a potential alternative energy source with substantial savings potential. While the prospect of these systems is promising for energy efficiency, careful feasibility analysis is required before implementation. Here, this paper presents the results of evaluation of the application feasibility for GSHPs in buildings across seven climate zones in three United States regions. A comprehensive methodology is developed to measure the integrated feasibility of GSHPs using compiled data for energy use intensity, energy cost and designmore » parameters. Four different feasibility metrics are utilized: ground temperature, outdoor weather condition, energy savings potential, and cost benefits. For each metric, a corresponding feasibility score system is developed. The defined integrated feasibility score classifies the locations into five different feasibility levels ranging from Fair (0–20), Moderate (21–40), Good (41–60), High (61–80), and Very High (81–100). Conclusions show the GSHP feasibility level is High for 3 sites, Good for 8 sites and Moderate for 4 sites. Through the methodology, it is possible to develop a practical energy strategy for more economic and sustainable GSHP systems at an early design stage in the various viewpoints of geometries, climate conditions, operational factors, and energy costs.« less

Pumping tests of well Campbell et al. No. 2, Gila Hot Springs, Grant County, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwab, G.E.; Summers, W.K.; Colpitts, R.M. Jr.

1982-03-01

Well Campbell et al. No. 2 near Gila Hot Springs in southwestern New Mexico (Section 5, Township 13 South, Range 13 West) was pumped for a five-step test and a 48-hour constant-rate test during October 1981. Measurements included depth to water in the pumping well and two observation wells, and discharge rates at the pumping well and two springs. The water level in the pumping well responded during both tests. However, water-level changes in the observation wells were too small for analytical use and discharge rates from the springs showed no change. Chemical analyses of water samples collected from twomore » springs and the pumping well show very similar water chemistries. Estimates of hydraulic properties show transmissivity from 12,000 to 14,000 gpd/ft and a storativity of 0.05. Combining these parameters with well data gives the first-year optimum discharge rate as 50 gpm with 20 feet of drawdown. Pumping this well at 50 gpm for forty years should produce only small water-level changes in wells a few hundred feet away. It would diminish the flow of the springs, and for planning purposes the combined discharge of the springs and well should be considered constant.« less

Quasi-phase-matching of only even-order high harmonics.

PubMed

Diskin, Tzvi; Cohen, Oren

2014-03-24

High harmonic spectrum of a quasi-monochromatic pump that interacts with isotropic media consists of only odd-order harmonics. Addition of a secondary pump, e.g. a static field or the second harmonic of the primary pump, can results with generation of both odd and even harmonics of the primary pump. We propose a method for quasi-phase matching of only the even-order harmonics of the primary pump. We formulate a theory for this process and demonstrate it numerically. We also show that it leads to attosecond pulse trains with constant carrier envelop phase and high repetition rate.

Mechanism for pumping lasers with squeezed light

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haake, F.; Walls, D.F.; Collett, M.J.

1989-03-15

In this paper we demonstrate how the squeezed-pump-laser model of Marte and Walls (Phys. Rev. A 37, 1235 (1988)) may be realized in practice. We consider a three-level atomic medium interacting with two cavity modes pumped with squeezed light. We show that this pumping mechanism both achieves atomic inversion and squeezes the fluctuations on the lasing transition.

Optimum conditions for producing Cs2 molecular condensates by stimulated Raman adiabatic passage

NASA Astrophysics Data System (ADS)

Feng, Zhifang; Li, Weidong; Wang, Lirong; Xiao, Liantuan; Jia, Suotang

2009-10-01

The optimum conditions for producing Cs2 molecular condensates from Cs atomic condensates with high transfer efficiency by stimulated Raman adiabatic passage are presented. Under the extended “two-photon” resonance condition, including the two-photon process, the mean-field correction, and the tunneling coupling between two upper excited molecular levels, a high and stable conversion efficiency is realized. The high conversion efficiency could be achieved by following two methods under experimentally less demanding conditions (relatively small effective Rabi frequency for pump laser pulse). One is adjusting the detuning difference between two laser pulses for same effective Rabi frequencies with up to 87.2% transfer efficiency. Another one is adjusting the effective Rabi frequency, the detuning of dump laser for given effective Rabi frequency, and the detuning of pump laser with up to 80.7% transfer efficiency.

High-energy high-efficiency Nd:YLF laser end-pump by 808 nm diode

NASA Astrophysics Data System (ADS)

Ma, Qinglei; Mo, Haiding; Zhao, Jay

2018-04-01

A model is developed to calculate the optimal pump position for end-pump configuration. The 808 nm wing pump is employed to spread the absorption inside the crystal. By the optimal laser cavity design, a high-energy high-efficiency Nd:YLF laser operating at 1053 nm is presented. In cw operation, a 13.6 W power is obtained with a slope efficiency of 51% with respect to 30 W incident pump power. The beam quality is near diffraction limited with M2 ∼ 1.02. In Q-switch operation, a pulse energy of 5 mJ is achieved with a peak power of 125 kW at 1 kHz repetition rate.

Designing a Broadband Pump for High-Quality Micro-Lasers via Modified Net Radiation Method.

PubMed

Nechayev, Sergey; Reusswig, Philip D; Baldo, Marc A; Rotschild, Carmel

2016-12-07

High-quality micro-lasers are key ingredients in non-linear optics, communication, sensing and low-threshold solar-pumped lasers. However, such micro-lasers exhibit negligible absorption of free-space broadband pump light. Recently, this limitation was lifted by cascade energy transfer, in which the absorption and quality factor are modulated with wavelength, enabling non-resonant pumping of high-quality micro-lasers and solar-pumped laser to operate at record low solar concentration. Here, we present a generic theoretical framework for modeling the absorption, emission and energy transfer of incoherent radiation between cascade sensitizer and laser gain media. Our model is based on linear equations of the modified net radiation method and is therefore robust, fast converging and has low complexity. We apply this formalism to compute the optimal parameters of low-threshold solar-pumped lasers. It is revealed that the interplay between the absorption and self-absorption of such lasers defines the optimal pump absorption below the maximal value, which is in contrast to conventional lasers for which full pump absorption is desired. Numerical results are compared to experimental data on a sensitized Nd 3+ :YAG cavity, and quantitative agreement with theoretical models is found. Our work modularizes the gain and sensitizing components and paves the way for the optimal design of broadband-pumped high-quality micro-lasers and efficient solar-pumped lasers.

Designing a Broadband Pump for High-Quality Micro-Lasers via Modified Net Radiation Method

PubMed Central

Nechayev, Sergey; Reusswig, Philip D.; Baldo, Marc A.; Rotschild, Carmel

2016-01-01

High-quality micro-lasers are key ingredients in non-linear optics, communication, sensing and low-threshold solar-pumped lasers. However, such micro-lasers exhibit negligible absorption of free-space broadband pump light. Recently, this limitation was lifted by cascade energy transfer, in which the absorption and quality factor are modulated with wavelength, enabling non-resonant pumping of high-quality micro-lasers and solar-pumped laser to operate at record low solar concentration. Here, we present a generic theoretical framework for modeling the absorption, emission and energy transfer of incoherent radiation between cascade sensitizer and laser gain media. Our model is based on linear equations of the modified net radiation method and is therefore robust, fast converging and has low complexity. We apply this formalism to compute the optimal parameters of low-threshold solar-pumped lasers. It is revealed that the interplay between the absorption and self-absorption of such lasers defines the optimal pump absorption below the maximal value, which is in contrast to conventional lasers for which full pump absorption is desired. Numerical results are compared to experimental data on a sensitized Nd3+:YAG cavity, and quantitative agreement with theoretical models is found. Our work modularizes the gain and sensitizing components and paves the way for the optimal design of broadband-pumped high-quality micro-lasers and efficient solar-pumped lasers. PMID:27924844

Single frequency 1560nm Er:Yb fiber amplifier with 207W output power and 50.5% slope efficiency

NASA Astrophysics Data System (ADS)

Creeden, Daniel; Pretorius, Herman; Limongelli, Julia; Setzler, Scott D.

2016-03-01

High power fiber lasers/amplifiers in the 1550nm spectral region have not scaled as rapidly as Yb-, Tm-, or Ho-doped fibers. This is primarily due to the low gain of the erbium ion. To overcome the low pump absorption, Yb is typically added as a sensitizer. Although this helps the pump absorption, it also creates a problem with parasitic lasing of the Yb ions under strong pumping conditions, which generally limits output power. Other pump schemes have shown high efficiency through resonant pumping of erbium only without the need for Yb as a sensitizer [1-2]. Although this can enable higher power scaling due to a decrease in the thermal loading, resonant pumping methods require long fiber lengths due to pump bleaching, which may limit the power scaling which can be achieved for single frequency output. By using an Er:Yb fiber and pumping in the minima of the Yb pump absorption at 940nm, we have been able to simultaneously generate high power, single frequency output at 1560nm while suppressing the 1-micron ASE and enabling higher efficiency compared to pumping at the absorption peak at 976nm. We have demonstrated single frequency amplification (540Hz linewidth) to 207W average output power with 49.3% optical efficiency (50.5% slope efficiency) in an LMA Er:Yb fiber. We believe this is the highest reported efficiency from a high power 9XXnm pumped Er:Yb-doped fiber amplifier. This is significantly more efficient that the best-reported efficiency for high power Er:Yb doped fibers, which, to-date, has been limited to ~41% slope efficiency [3].

Exposure to chemical hazards in petrol pumps stations in Ahvaz City, Iran.

PubMed

Zoleikha, Sayyahi; Mirzaei, Ramazan; Roksana, Mirkazemi

2017-01-02

The objective of this study was to assess the level of exposure to BTEX (benzene, toluene, ethylbenzene, xylenes) in petrol pump stations in Ahvaz City. Two of the biggest fuelling stations were selected randomly among total 12 fuel stations of Ahvaz City, Iran, during September 2013. Thirty air samples were taken from different positions in the fuelling stations and 15 samples were taken from the personal breathing zone of operators and of customers in fuelling stations. Measuring the ambient concentration of benzene, toluene, ethylbenzene, and xylenes was done according to the method advised by National Institute for Occupational Safety and Health (NIOSH) 1501. This study showed that the concentration of benzene was very high (compared with the Iranian occupational exposure limit [OEL] standard) in ambient air of petrol stations in Ahvaz, which is considered as a high risk to the health of workers. Controlling the level of benzene in petrol stations is necessary. A new designed petrol nozzle was proposed for this purpose.

Modeling of Yb3+/Er3+-codoped microring resonators

NASA Astrophysics Data System (ADS)

Vallés, Juan A.; Gălătuş, Ramona

2015-03-01

The performance of a highly Yb3+/Er3+-codoped phosphate glass add-drop microring resonator is numerically analyzed. The model assumes resonant behaviour of both pump and signal powers and the dependences of pump intensity build-up inside the microring resonator and of the signal transfer functions to the device through and drop ports are evaluated. Detailed equations for the evolution of the rare-earth ions levels population densities and the propagation of the optical powers inside the microring resonator are included in the model. Moreover, due to the high dopant concentrations considered, the microscopic statistical formalism based on the statistical average of the excitation probability of the Er3+ ion in a microscopic level has been used to describe energy-transfer inter-atomic mechanisms. Realistic parameters and working conditions are used for the calculations. Requirements to achieve amplification and laser oscillation within these devices are obtainable as a function of rare earth ions concentration and coupling losses.

XeCl laser pumped iodine laser using t-C4F9I

NASA Technical Reports Server (NTRS)

Hwang, In Heon; Han, Kwang S.

1989-01-01

An iodine photodissociation laser using t-C4F9I as the active material was pumped by an XeCl laser. An iodine laser output energy of 3 mJ with pulse duration of 25 ns was obtained when the pumping pulse energy was 80 mJ, the iodide pressure was 70 torr, and the reflectance of the output mirror was 85 percent. The high pumping efficiency and low threshold pump power achieved in this experiment are attributable to the high absorption cross section at the pump laser wavelength (308 nm) of the iodide used.

Alternative backing up pump for turbomolecular pumps

DOEpatents

Myneni, Ganapati Rao

2003-04-22

As an alternative to the use of a mechanical backing pump in the application of wide range turbomolecular pumps in ultra-high and extra high vacuum applications, palladium oxide is used to convert hydrogen present in the evacuation stream and related volumes to water with the water then being cryo-pumped to a low pressure of below about 1.e.sup.-3 Torr at 150.degree. K. Cryo-pumping is achieved using a low cost Kleemenco cycle cryocooler, a somewhat more expensive thermoelectric cooler, a Venturi cooler or a similar device to achieve the required minimization of hydrogen partial pressure.

Investigation on high transmission efficiency 7 × 1 pump combiner

NASA Astrophysics Data System (ADS)

Cao, Yang; Shi, Wei; Sheng, Quan; Fu, Shijie; Zhang, Haiwei; Bai, Xiaolei; Qi, Liang; Yao, Jianquan

2016-12-01

The 7×1 end-pumped combiner employing 105/125 μm multimode fibers as pump fibers is investigated. The theoretical analysis reveals that sufficient taper length and low refractive index of the capillary should be adopted to fabricate high transmission efficiency combiners. Based on the simulation results, we fabricate a 7×1 end-pumped pump combiner with an average transmission efficiency of 98.9% and a total return loss of 1.1‰. The measured internal operating temperature of this combiner indicates it can endure pump power of the order of kilowatts.

Liquid metal pump for nuclear reactors

DOEpatents

Allen, H.G.; Maloney, J.R.

1975-10-01

A pump for use in pumping high temperature liquids at high pressures, particularly liquid metals used to cool nuclear reactors is described. It is of the type in which the rotor is submerged in a sump but is fed by an inlet duct which bypasses the sump. A chamber, kept full of fluid, surrounds the pump casing into which fluid is bled from the pump discharge and from which fluid is fed to the rotor bearings and hence to the sump. This equalizes pressure inside and outside the pump casing and reduces or eliminates the thermal shock to the bearings and sump tank.

New laser materials for laser diode pumping

NASA Technical Reports Server (NTRS)

Jenssen, H. P.

1990-01-01

The potential advantages of laser diode pumped solid state lasers are many with high overall efficiency being the most important. In order to realize these advantages, the solid state laser material needs to be optimized for diode laser pumping and for the particular application. In the case of the Nd laser, materials with a longer upper level radiative lifetime are desirable. This is because the laser diode is fundamentally a cw source, and to obtain high energy storage, a long integration time is necessary. Fluoride crystals are investigated as host materials for the Nd laser and also for IR laser transitions in other rare earths, such as the 2 micron Ho laser and the 3 micron Er laser. The approach is to investigate both known crystals, such as BaY2F8, as well as new crystals such as NaYF8. Emphasis is on the growth and spectroscopy of BaY2F8. These two efforts are parallel efforts. The growth effort is aimed at establishing conditions for obtaining large, high quality boules for laser samples. This requires numerous experimental growth runs; however, from these runs, samples suitable for spectroscopy become available.

Spatially resolved measurement of the core temperature in a high-power thulium fiber system

NASA Astrophysics Data System (ADS)

Walbaum, Till; Heinzig, Matthias; Beier, Franz; Liem, Andreas; Schreiber, Thomas; Eberhardt, Ramona; Tünnermann, Andreas

2016-03-01

We present measurements of the temperature increase inside the active fiber of a thulium fiber amplifier during high power operation. At a pump power of over 100 W at a wavelength of 793 nm, we measure the core temperature distribution along the first section of a large mode area (LMA) highly thulium doped active fiber by use of an optical backscatter reflectometer. A mode field adaptor is used to maintain single mode operation in the LMA fiber. An increase in temperature of over 100 K can be observed in spite of conductive cooling, located at the pumped fiber end and jeopardizing the fiber coating. The recoated splice can be clearly identified as the hottest fiber region. This allows us to estimate the maximum thermally acceptable pump power for this amplifier. We also observe that the temperature can be decreased by increasing the seed power, which is in agreement with theoretical predictions on the increase of cross relaxation efficiency by depletion of the upper laser level. This underlines the role of power scaling of the respective seed power of a thulium amplifier stage as a means of thermal management.

Theoretical and experimental study on reabsorption effect and temperature characteristic of a quasi-three-level 946nm Nd:YAG laser

NASA Astrophysics Data System (ADS)

Huang, Jing; Wan, Yuan; Chen, Weibiao

2015-02-01

The influence of temperature and incident pump power on reabsorption loss is theoretically discussed. Temperature characteristic and reabsorption loss rate of a diode-pumped quasi-three-level 946 nm Nd:YAG laser are investigated. Reabsorption effect has a significant impact on laser performance. The results indicate that reabsorption loss increases as the working temperature rises and decreases with the increased incident pump power.

Post audit of a numerical prediction of wellfield drawdown in a semiconfined aquifer system

USGS Publications Warehouse

Stewart, M.; Langevin, C.

1999-01-01

A numerical ground water flow model was created in 1978 and revised in 1981 to predict the drawdown effects of a proposed municipal wellfield permitted to withdraw 30 million gallons per day (mgd; 1.1 x 105 m3/day) of water from the semiconfined Floridan Aquifer system. The predictions are based on the assumption that water levels in the semiconfined Floridan Aquifer reach a long-term, steady-state condition within a few days of initiation of pumping. Using this assumption, a 75 day simulation without water table recharge, pumping at the maximum permitted rates, was considered to represent a worst-case condition and the greatest drawdowns that could be experienced during wellfield operation. This method of predicting wellfield effects was accepted by the permitting agency. For this post audit, observed drawdowns were derived by taking the difference between pre-pumping and post-pumping potentiometric surface levels. Comparison of predicted and observed drawdowns suggests that actual drawdown over a 12 year period exceeds predicted drawdown by a factor of two or more. Analysis of the source of error in the 1981 predictions suggests that the values used for transmissivity, storativity, specific yield, and leakance are reasonable at the wellfield scale. Simulation using actual 1980-1992 pumping rates improves the agreement between predicted and observed drawdowns. The principal source of error is the assumption that water levels in a semiconfined aquifer achieve a steady-state condition after a few days or weeks of pumping. Simulations using a version of the 1981 model modified to include recharge and evapotranspiration suggest that it can take hundreds of days or several years for water levels in the linked Surficial and Floridan Aquifers to reach an apparent steady-state condition, and that slow declines in levels continue for years after the initiation of pumping. While the 1981 'impact' model can be used for reasonably predicting short-term, wellfield-scale effects of pumping, using a 75 day long simulation without recharge to predict the long-term behavior of the wellfield was an inappropriate application, resulting in significant underprediction of wellfield effects.A numerical ground water flow model was created in 1978 and revised in 1981 to predict the drawdown effects of a proposed municipal wellfield permitted to withdraw 30 million gallons per day (mgd; 1.1??105 m3/day) of water from the semiconfined Floridan Aquifer system. The predictions are based on the assumption that water levels in the semiconfined Floridan Aquifer reach a long-term, steady-state condition within a few days of initiation of pumping. Using this assumption, a 75 day simulation without water table recharge, pumping at the maximum permitted rates, was considered to represent a worst-case condition and the greatest drawdowns that could be experienced during wellfield operation. This method of predicting wellfield effects was accepted by the permitting agency. For this post audit, observed drawdowns were derived by taking the difference between pre-pumping and post-pumping potentiometric surface levels. Comparison of predicted and observed drawdowns suggests that actual drawdown over a 12 year period exceeds predicted drawdown by a factor of two or more. Analysis of the source of error in the 1981 predictions suggests that the values used for transmissivity, storativity, specific yield, and leakance are reasonable at the wellfield scale. Simulation using actual 1980-1992 pumping rates improves the agreement between predicted and observed drawdowns. The principal source of error is the assumption that water levels in a semiconfined aquifer achieve a steady-state condition after a few days or weeks of pumping. Simulations using a version of the 1981 model modified to include recharge and evapotranspiration suggest that it can take hundreds of days or several years for water levels in the linked Surficial and Floridan Aquifers to reach an apparent stead

Exposure to regular gasoline and ethanol oxyfuel during refueling in Alaska.

PubMed Central

Backer, L C; Egeland, G M; Ashley, D L; Lawryk, N J; Weisel, C P; White, M C; Bundy, T; Shortt, E; Middaugh, J P

1997-01-01

Although most people are thought to receive their highest acute exposures to gasoline while refueling, relatively little is actually known about personal, nonoccupational exposures to gasoline during refueling activities. This study was designed to measure exposures associated with the use of an oxygenated fuel under cold conditions in Fairbanks, Alaska. We compared concentrations of gasoline components in the blood and in the personal breathing zone (PBZ) of people who pumped regular unleaded gasoline (referred to as regular gasoline) with concentrations in the blood of those who pumped an oxygenated fuel that was 10% ethanol (E-10). A subset of participants in a wintertime engine performance study provided blood samples before and after pumping gasoline (30 using regular gasoline and 30 using E-10). The biological and environmental samples were analyzed for selected aromatic volatile organic compounds (VOCs) found in gasoline (benzene, ethylbenzene, toluene, m-/p-xylene, and o-xylene); the biological samples were also analyzed for three chemicals not found in gasoline (1,4-dichlorobenzene, chloroform, and styrene). People in our study had significantly higher levels of gasoline components in their blood after pumping gasoline than they had before pumping gasoline. The changes in VOC levels in blood were similar whether the individuals pumped regular gasoline or the E-10 blend. The analysis of PBZ samples indicated that there were also measurable levels of gasoline components in the air during refueling. The VOC levels in PBZ air were similar for the two groups. In this study, we demonstrate that people are briefly exposed to low (ppm and sub-ppm) levels of known carcinogens and other potentially toxic compounds while pumping gasoline, regardless of the type of gasoline used. Images Figure 1. Figure 2. Figure 3. PMID:9347900

Metabolic control after years of completing a clinical trial on sensor-augmented pump therapy.

PubMed

Quirós, Carmen; Giménez, Marga; Orois, Aida; Conget, Ignacio

2015-11-01

Sensor-augmented pump (SAP) therapy has been shown to be effective and safe for improving metabolic control in patients with type 1 diabetes mellitus (T1DM) in a number of trials. Our objective was to assess glycemic control in a group of T1DM patients on insulin pump or SAP therapy after years of participating in the SWITCH (Sensing With Insulin pump Therapy To Control HbA1c) trial and their return to routine medical monitoring. A retrospective, observational study of 20 patients who participated in the SWITCH trial at our hospital from 2008 to 2010. HbA1c values were compared at the start, during (at the end of the periods with/without SAP use - Sensor On/Sensor Off period respectively - of the cross-over design), and 3 years after study completion. HbA1c values of patients who continued SAP therapy (n=6) or only used insulin pump (n=14) were also compared. Twenty patients with T1DM (44.4±9.3 years, 60% women, baseline HbA1c level 8.43±0.55%) were enrolled into the SWITCH study). Three years after study completion, HbA1c level was 7.79±0.77 in patients on pump alone, with no significant change from the value at the end of the Off period of the study (7.85±0.57%; p=0.961). As compared to the end of the On period, HbA1c worsened less in patients who remained on SAP than in those on pump alone (0.18±0.42 vs. 0.55±0.71%; p=0.171), despite the fact that levels were similar at study start (8.41±0.60 vs. 8.47±0.45; p=0.831) and at the end of the On period (7.24±0.48 vs. 7.38±0.61; p=0.566). Frequency of CGM use in patients who continued SAP therapy was high (61.2% of the time in the last 3 months). Our study suggests that the additional benefit of SAP therapy achieved in a clinical trial may persist in the long term in routine clinical care of patients with T1DM. Copyright © 2015 SEEN. Published by Elsevier España, S.L.U. All rights reserved.

Latest development of high-power fiber lasers in SPI

NASA Astrophysics Data System (ADS)

Norman, Stephen; Zervas, Mikhail N.; Appleyard, Andrew; Durkin, Michael K.; Horley, Ray; Varnham, Malcolm P.; Nilsson, Johan; Jeong, Yoonchan

2004-06-01

High Power Fiber Lasers (HPFLs) and High Power Fiber Amplifiers (HPFAs) promise a number of benefits in terms of their high optical efficiency, degree of integration, beam quality, reliability, spatial compactness and thermal management. These benefits are driving the rapid adoption of HPFLs in an increasingly wide range of applications and power levels ranging from a few Watts, in for example analytical applications, to high-power >1kW materials processing (machining and welding) applications. This paper describes SPI"s innovative technologies, HPFL products and their performance capabilities. The paper highlights key aspects of the design basis and provides an overview of the applications space in both the industrial and aerospace domains. Single-fiber CW lasers delivering 1kW output power at 1080nm have been demonstrated and are being commercialized for aerospace and industrial applications with wall-plug efficiencies in the range 20 to 25%, and with beam parameter products in the range 0.5 to 100 mm.mrad (corresponding to M2 = 1.5 to 300) tailored to application requirements. At power levels in the 1 - 200 W range, SPI"s proprietary cladding-pumping technology, GTWaveTM, has been employed to produce completely fiber-integrated systems using single-emitter broad-stripe multimode pump diodes. This modular construction enables an agile and flexible approach to the configuration of a range of fiber laser / amplifier systems for operation in the 1080nm and 1550nm wavelength ranges. Reliability modeling is applied to determine Systems martins such that performance specifications are robustly met throughout the designed product lifetime. An extensive Qualification and Reliability-proving programme is underway to qualify the technology building blocks that are utilized for the fiber laser cavity, pump modules, pump-driver systems and thermo-mechanical management. In addition to the CW products, pulsed fiber lasers with pulse energies exceeding 1mJ with peak pulse powers of up to 50kW have been developed and are being commercialized. In all cases reducing the total "cost of ownership" for customers and end users is our primary objective.

46. (Credit LSU) High service pumping room, c1904. The # ...

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

46. (Credit LSU) High service pumping room, c1904. The # 1 Worthington horizontal, triple expansion, high service engine is in the background. The pump whose steam end is in the foreground is a Blake compound, duplex horizontal engine, installed c1904. The engine in the center of the illustration is one of the original 1887 Blake high service engines (compound, duplex). It was shortly after removed. (From: Shreveport Progressive League, Shreveport of To-Day, September 1904, p. 47) - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

A solar-pumped Nd:YAG laser in the high collection efficiency regime

NASA Astrophysics Data System (ADS)

Lando, Mordechai; Kagan, Jacob; Linyekin, Boris; Dobrusin, Vadim

2003-07-01

Solar-pumped lasers can be used for space and terrestrial applications. We report on solar side-pumped Nd:YAG laser experiments, which included comprehensive beam quality measurements and demonstrated record collection efficiency and day long operation. A 6.75 m 2 segmented primary mirror was mounted on a commercial two-axis positioner and focused the solar radiation towards a stationary non-imaging-optics secondary concentrator, which illuminated a Nd:YAG laser rod. Solar side-pumped laser experiments were conducted in both the low and the high pumping density regimes. The low density system was composed of a 89 × 98-mm 2 aperture two-dimensional compound parabolic concentrator (CPC) and a 10-mm diameter 130-mm long Nd:YAG laser rod. The laser emitted up to 46 W and operated continuously for 5 h. The high density system was composed of a three-dimensional CPC with 98 mm entrance diameter and 24 mm exit diameter, followed by a two-dimensional CPC with a rectangular 24 × 33 mm 2 aperture. It pumped a 6-mm diameter 72 mm long Nd:YAG laser rod, which emitted up to 45 W. The results constitute a record collection efficiency of 6.7 W/m 2 of primary mirror. We compare the current results to previous solar side-pumped laser experiments, including experiments at higher pumping density but with low collection efficiency. Finally, we present a scaled up design for a 400 W laser pumped by a solar collection area of 60 m 2, incorporating simultaneously high collection efficiency and high pumping density.

18. Electrically driven pumps in Armory Street Pump House. Pumps ...

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

18. Electrically driven pumps in Armory Street Pump House. Pumps in background formerly drew water from the clear well. They went out of service when use of the beds was discontinued. Pumps in the foreground provide high pressure water to Hamden. - Lake Whitney Water Filtration Plant, Armory Street Pumphouse, North side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

Ultrahigh-speed Si-integrated on-chip laser with tailored dynamic characteristics

NASA Astrophysics Data System (ADS)

Park, Gyeong Cheol; Xue, Weiqi; Piels, Molly; Zibar, Darko; Mørk, Jesper; Semenova, Elizaveta; Chung, Il-Sug

2016-12-01

For on-chip interconnects, an ideal light source should have an ultralow energy consumption per bandwidth (operating en-ergy) as well as sufficient output power for error-free detection. Nanocavity lasers have been considered the most ideal for smaller operating energy. However, they have a challenge in obtaining a sufficient output power. Here, as an alternative, we propose an ultrahigh-speed microcavity laser structure, based on a vertical cavity with a high-contrast grating (HCG) mirror for transverse magnetic (TM) polarisation. By using the TM HCG, a very small mode volume and an un-pumped compact optical feedback structure can be realised, which together tailor the frequency response function for achieving a very high speed at low injection currents. Furthermore, light can be emitted laterally into a Si waveguide. From an 1.54-μm optically-pumped laser, a 3-dB frequency of 27 GHz was obtained at a pumping level corresponding to sub-mA. Using measured 3-dB frequen-cies and calculated equivalent currents, the modulation current efficiency factor (MCEF) is estimated to be 42.1 GHz/mA1/2, which is superior among microcavity lasers. This shows a high potential for a very high speed at low injection currents or avery small heat generation at high bitrates, which are highly desirable for both on-chip and off-chip applications.

Lead (Pb) contamination of self-supply groundwater systems in coastal Madagascar and predictions of blood lead levels in exposed children.

PubMed

Akers, D Brad; MacCarthy, Michael F; Cunningham, Jeffrey A; Annis, Jonathan; Mihelcic, James R

2015-03-03

Thousands of households in coastal Madagascar rely on locally manufactured pitcher-pump systems to provide water for drinking, cooking, and household use. These pumps typically include components made from lead (Pb). In this study, concentrations of Pb in water were monitored at 18 household pitcher pumps in the city of Tamatave over three sampling campaigns. Concentrations of Pb frequently exceeded the World Health Organization's provisional guideline for drinking water of 10 μg/L. Under first-draw conditions (i.e., after a pump had been inactive for 1 h), 67% of samples analyzed were in excess of 10 μg/L Pb, with a median concentration of 13 μg/L. However, flushing the pump systems before collecting water resulted in a statistically significant (p < 0.0001) decrease in Pb concentrations: 35% of samples collected after flushing exceeded 10 μg/L, with a median concentration of 9 μg/L. Based on measured Pb concentrations, a biokinetic model estimates that anywhere from 15% to 70% of children living in households with pitcher pumps may be at risk for elevated blood lead levels (>5 μg/dL). Measured Pb concentrations in water were not correlated at statistically significant levels with pump-system age, well depth, system manufacturer, or season of sample collection; only the contact time (i.e., flushed or first-draw condition) was observed to correlate significantly with Pb concentrations. In two of the 18 systems, Pb valve weights were replaced with iron, which decreased the observed Pb concentrations in the water by 57-89% in one pump and by 89-96% in the other. Both systems produced samples exclusively below 10 μg/L after substitution. Therefore, relatively straightforward operational changes on the part of the pump-system manufacturers and pump users might reduce Pb exposure, thereby helping to ensure the continued sustainability of pitcher pumps in Madagascar.

Multipass pumped Nd-based thin-disk lasers: continuous-wave laser operation at 1.06 and 0.9 {mu}m with intracavity frequency doubling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavel, Nicolaie; Luenstedt, Kai; Petermann, Klaus

2007-12-01

The laser performances of the 1.06 {mu}m 4F3/2 --> 4I11/2 four-level transition and of the 0.9 {mu}m 4F3/2 --> I9/24 quasi-three-level transition were investigated using multipass pumped Nd-based media in thin-disk geometry. When pumping at 0.81 {mu}m into the 4F5/2 level, continuous-wave laser operation was obtained with powers in excess of 10 W at 1.06 {mu}m, in the multiwatt region at 0.91 {mu}m in Nd:YVO4 and Nd:GdVO4, and at 0.95 {mu}m in Nd:YAG. Intracavity frequency-doubled Nd:YVO4 thin-disk lasers with output powers of 6.4 W at 532 nm and of 1.6 W at 457 nm were realized at this pumping wavelength.more » The pumping at 0.88 {mu}m, which is directed into the 4F3/2 emitting level, was also employed, and Nd:YVO4 and Nd:GdVO4 thin-disk lasers with {approx}9 W output power at 1.06 {mu}m and visible laser radiation at 0.53 {mu}m with output power in excess of 4 W were realized. Frequency-doubled Nd:vanadate thin-disk lasers with deep blue emission at 0.46 {mu}m were obtained under pumping directly into the 4F3/2 emitting level.« less

24. INTERIOR VIEW OF SUBTERRANEAN LEVEL OF PUMP HOUSE. No. ...

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

24. INTERIOR VIEW OF SUBTERRANEAN LEVEL OF PUMP HOUSE. No. 1, FLOODED AT THE TIME OF THE SURVEY. Jet Lowe, Photographer, 1989. - U.S. Steel Homestead Works, Auxiliary Buildings & Shops, Along Monongahela River, Homestead, Allegheny County, PA

46 CFR 154.1010 - Electrical equipment in gas-dangerous space or zone.

Code of Federal Regulations, 2012 CFR

2012-10-01

.... (c) A submerged cargo pump motor may be in a cargo tank if: (1) Low liquid level, motor current, or pump discharge pressure automatically shuts down power to the pump motor if the pump loses suction; (2) There is an audible and visual alarm at the cargo control station that actuates if the motor shuts down...

46 CFR 154.1010 - Electrical equipment in gas-dangerous space or zone.

Code of Federal Regulations, 2014 CFR

2014-10-01

.... (c) A submerged cargo pump motor may be in a cargo tank if: (1) Low liquid level, motor current, or pump discharge pressure automatically shuts down power to the pump motor if the pump loses suction; (2) There is an audible and visual alarm at the cargo control station that actuates if the motor shuts down...

The Hydraulic Ram (Or Impulse) Pump

ERIC Educational Resources Information Center

Mills, Allan

2014-01-01

The hydraulic impulse pump utilizes a fraction of the momentum of a flowing stream to lift a small portion of that water to a higher level. There it may be accumulated in an elevated cistern to provide sufficient water for several families, for the pump works 24 h a day with no additional source of energy. The operation of the pump is described,…

1.5-μm high-average power laser amplifier using a Er,Yb:glass planar waveguide for coherent Doppler lidar

NASA Astrophysics Data System (ADS)

Sakimura, Takeshi; Watanabe, Yojiro; Ando, Toshiyuki; Kameyama, Shumpei; Asaka, Kimio; Tanaka, Hisamichi; Yanagisawa, Takayuki; Hirano, Yoshihito; Inokuchi, Hamaki

2012-11-01

We have developed a 1.5-μm eye-safe wavelength high average power laser amplifier using an Er,Yb:glass planar waveguide for coherent Doppler LIDAR. Large cooling surface of the planar waveguide enabled high average power pumping for Er,Yb:glass which has low thermal fracture limit. Nonlinear effects are suppressed by the large beam size which is designed by the waveguide thickness and the beam width of the planar direction. Multi-bounce optical path configuration and high-intensity pumping provide high-gain and high-efficient operation using three-level laser material. With pulsed operation, the maximum pulse energy of 1.9 mJ was achieved at the repetition rate of 4 kHz. Output average power of the amplified signal was 7.6W with the amplified gain of more than 20dB. This amplifier is suitable for coherent Doppler LIDAR to enhance the measurable range.

RF rectifiers for EM power harvesting in a Deep Brain Stimulating device.

PubMed

Hosain, Md Kamal; Kouzani, Abbas Z; Tye, Susannah; Kaynak, Akif; Berk, Michael

2015-03-01

A passive deep brain stimulation (DBS) device can be equipped with a rectenna, consisting of an antenna and a rectifier, to harvest energy from electromagnetic fields for its operation. This paper presents optimization of radio frequency rectifier circuits for wireless energy harvesting in a passive head-mountable DBS device. The aim is to achieve a compact size, high conversion efficiency, and high output voltage rectifier. Four different rectifiers based on the Delon doubler, Greinacher voltage tripler, Delon voltage quadrupler, and 2-stage charge pumped architectures are designed, simulated, fabricated, and evaluated. The design and simulation are conducted using Agilent Genesys at operating frequency of 915 MHz. A dielectric substrate of FR-4 with thickness of 1.6 mm, and surface mount devices (SMD) components are used to fabricate the designed rectifiers. The performance of the fabricated rectifiers is evaluated using a 915 MHz radio frequency (RF) energy source. The maximum measured conversion efficiency of the Delon doubler, Greinacher tripler, Delon quadrupler, and 2-stage charge pumped rectifiers are 78, 75, 73, and 76 % at -5 dBm input power and for load resistances of 5-15 kΩ. The conversion efficiency of the rectifiers decreases significantly with the increase in the input power level. The Delon doubler rectifier provides the highest efficiency at both -5 and 5 dBm input power levels, whereas the Delon quadrupler rectifier gives the lowest efficiency for the same inputs. By considering both efficiency and DC output voltage, the charge pump rectifier outperforms the other three rectifiers. Accordingly, the optimised 2-stage charge pumped rectifier is used together with an antenna to harvest energy in our DBS device.

Burst mode pumping: A new mechanism of drinking in mosquitoes

DOE PAGES

Kikuchi, Kenji; Stremler, Mark A.; Chatterjee, Souvick; ...

2018-03-20

Mosquitoes transport liquid foods into the body using two muscular pumps in the head. In normal drinking, these pumps reciprocate in a stereotyped pattern of oscillation, with a high frequency but small stroke volume. Do mosquitoes modulate their neuromotor programs for pumping to produce different drinking modes? More broadly, what are the mechanical consequences of a two-pump system in insects? To address these questions, we used synchrotron x-ray imaging and fluid mechanical modeling to investigate drinking performance in mosquitoes. X-ray imaging of the pumps during drinking revealed two modes of pumping: continuous reciprocation with multiple small strokes, and a newlymore » discovered ‘burst mode’ involving a single, large-volume stroke. Results from modeling demonstrate that burst mode pumping creates a very large pressure drop and high volume flow rate, but requires a massive increase in power, suggesting that continuous pumping is more economical for drinking. Modeling also demonstrates that, from one mode of pumping to the other, the mechanical role of the individual pumps changes. Furthermore, these results suggest that the advantage of a two-pump system in insects lies in its flexibility, enabling the animal to pump efficiently or powerfully as demanded by environmental considerations.« less

Burst mode pumping: A new mechanism of drinking in mosquitoes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kikuchi, Kenji; Stremler, Mark A.; Chatterjee, Souvick

Mosquitoes transport liquid foods into the body using two muscular pumps in the head. In normal drinking, these pumps reciprocate in a stereotyped pattern of oscillation, with a high frequency but small stroke volume. Do mosquitoes modulate their neuromotor programs for pumping to produce different drinking modes? More broadly, what are the mechanical consequences of a two-pump system in insects? To address these questions, we used synchrotron x-ray imaging and fluid mechanical modeling to investigate drinking performance in mosquitoes. X-ray imaging of the pumps during drinking revealed two modes of pumping: continuous reciprocation with multiple small strokes, and a newlymore » discovered ‘burst mode’ involving a single, large-volume stroke. Results from modeling demonstrate that burst mode pumping creates a very large pressure drop and high volume flow rate, but requires a massive increase in power, suggesting that continuous pumping is more economical for drinking. Modeling also demonstrates that, from one mode of pumping to the other, the mechanical role of the individual pumps changes. Furthermore, these results suggest that the advantage of a two-pump system in insects lies in its flexibility, enabling the animal to pump efficiently or powerfully as demanded by environmental considerations.« less

Hyperfine Quantum Beat Spectroscopy of the Cs 8p level with Pulsed Pump-Probe Technique

NASA Astrophysics Data System (ADS)

Bayram, Burcin; Popov, Oleg; Kelly, Stephen; Boyle, Patrick; Salsman, Andrew

2013-05-01

Quantum beats arising from the hyperfine interaction were measured in a three-level excitation (lambda) scheme: pump for the 6s2S1 / 2 --> 8p2P3 / 2 and stimulated emission pump (probe) for the 8p2P3 / 2 --> 5d2D5 / 2 transitions of atomic cesium. In the technique, pump laser instantaneously excites the hot atomic vapor and creates anisotropy in the 8p2P3 / 2 level, and probe laser comes after some time delay. Delaying the probe time allows us to map out the motion of the polarized atoms like a stroboscope. According to the observed evolution of the hyperfine structure dependent parameters, e.g. alignment and atomic polarization, by delaying the arrival time of the stimulated emission pump laser (SEP), precise values of the magnetic dipole and electric quadrupole coefficients are obtained with an improved precision over previous results. The usefulness of the PUMP-SEP excitation scheme for the polarization hyperfine quantum beat measurements without complications from the Doppler effect will also be discussed. The financial support of the Research Corporation under the Grant number CC7133 and MiamiUniversity, College of the Arts and Sciences are acknowledged.

Near-Infrared Laser Pumped Intersubband THz Laser Gain in InGaAs-AlAsSb-InP Quantum Wells

NASA Technical Reports Server (NTRS)

Liu, An-Sheng; Ning, Cun-Zheng

1999-01-01

We investigate the possibility of using InGaAs-AlAsSb-InP coupled quantum wells to generate THz radiation by means of intersubband optical pumping. We show that large conduction band offsets of these quantum wells make it possible to use conventional near-infrared diode lasers around 1.55 micron as pump sources. Taking into account the pump-probe coherent interaction and the optical nonlinearity for the pump field, we calculate the THz gain of the quantum well structure. We show that resonant Raman scattering enhances the THz gain at low and moderate optical pumping levels. When the pump intensity is strong, the THz gain is reduced by pump-induced population redistribution and pump-probe coherent interactions.

Electrokinetic high pressure hydraulic system

DOEpatents

Paul, Phillip H.; Rakestraw, David J.; Arnold, Don W.; Hencken, Kenneth R.; Schoeniger, Joseph S.; Neyer, David W.

2001-01-01

An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based systems. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing valves, for controlling fluid flow rate, and manipulating fluid flow generally and in capillary-based systems (Microsystems), in particular. The compact nature of the inventive high pressure hydraulic pump provides the ability to construct a micro-scale or capillary-based HPLC system that fulfills the desire for small sample quantity, low solvent consumption, improved efficiency, the ability to run samples in parallel, and field portability. Control of pressure and solvent flow rate is achieved by controlling the voltage applied to an electrokinetic pump.

Electrokinetic high pressure hydraulic system

DOEpatents

Paul, Phillip H.; Rakestraw, David J.; Arnold, Don W.; Hencken, Kenneth R.; Schoeniger, Joseph S.; Neyer, David W.

2003-06-03

An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based system. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing valves, for controlling fluid flow rate, and manipulating fluid flow generally and in capillary-based systems (microsystems), in particular. The compact nature of the inventive high pressure hydraulic pump provides the ability to construct a micro-scale or capillary-based HPLC system that fulfills the desire for small sample quantity, low solvent consumption, improved efficiency, the ability to run samples in parallel, and field portability. Control of pressure and solvent flow rate is achieved by controlling the voltage applied to an electrokinetic pump.

Advanced Photonic Sensors Enabled by Semiconductor Bonding

DTIC Science & Technology

2010-05-31

a dry scroll backing pump to maintain the high differential pressure between the UV gun and the sample/analysis chamber. We also replaced the...semiconductor materials in an ultra-high vacuum (UHV) environment where the properties of the interface can be controlled with atomic-level precision. Such...year research program, we designed and constructed a unique system capable of fusion bonding two wafers in an ultra-high vacuum environment. This system

Downwell pump reliability: Geothermal experience update: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, P.F.

1988-01-01

Geothermal resources with temperatures between 250/sup 0/ and 360/sup 0/F (121/sup 0/C and 182/sup 0/C) are prime candidates for binary-cycle power generation, and constitute about 80% of the power-capable resources in the United States. The successful exploitation of these resources requires reliable high-capacity downwell brine production pumps, but earlier experience showed that high-capacity, high-temperature geothermal production pumps had many problems which resulted in a mean time-to-failure (MTTF) of less than 1000 h. However, steady progress has been made since 1981, and a large body of experience has been acquired by three geothermal binary plants. This survey of high-temperature geothermal downwellmore » pump users and manufacturers updates a prior survey (AP-3572) completed in early 1983. This survey traces the development of lineshaft pump technology from the late 1970s to the present (mid-1987), detailing the advances in design, materials selection, and operating practices. Case histories of 72 lineshaft pumps installed at three geothermal binary plants since late 1981 are documented, including some detailed cause of failure reports. In the recent past, pump lives in excess of 7000 h have become common, but a high continuing rate of premature failures resulted in a mean time-to-failure (MTTF) of about 5000 h. Based on recent advances which appear likely to eliminate most premature failures, the estimated near-term MTTF will be on the order of 8000 h. The survey found almost no development of high-temperature geothermal electric submersible pumps (ESP's) or close-coupled downwell hydraulic turbopumps, and concluded that considerable development and demonstration will be needed before these technologies are able to compete with existing high-temperature geothermal lineshaft pump technology. 36 refs., 10 figs., 25 tabs.« less

Improvement in intra-aortic balloon pumping and evaluation of its efficacy by electrode methods of control.

PubMed

Ioseliani, G D; Chilaia, S M

1983-02-01

A basically new design for the reversing balloon pump has been proposed for increasing the efficacy of intra-aortic balloon pumping (IABP). The device not only causes a significant increase in discharge, but also permits control of the central and peripheral circulation within the desired limits owing to back-and-forth movements (like a piston) of the balloon pump. Standard one- and two-chamber balloon pumps were compared. In addition to traditional hemodynamic and biochemical indexes, the efficacy of IABP was assessed based on electrode monitor control of PO2 and pH in the myocardium, peripheral tissues, and circulating blood. Based on 54 experiments on dogs, it was found that IABP with reversing balloon pumps in synchronous pulsation resulted in survival of 69% of the cases; PO2 and pH levels in the myocardium, tissues, and blood in the coronary sinus were close to normal, and coronary blood flow and peripheral circulation were increased. With standard one-chamber balloon pumps, the survival rate did not exceed 33.4%; PO2 and pH in the peripheral tissues reached critical levels.

21. VIEW TO NORTHWEST, ENGINE/PUMP HOUSE EXTENSION, HIGH PRESSURE PISTON ...

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

21. VIEW TO NORTHWEST, ENGINE/PUMP HOUSE EXTENSION, HIGH PRESSURE PISTON OF STEAM ENGINE NO. 4; CONTROL PANEL MOUNTED ON THE ENGINE; FLOOR VALVES CONTROL THE STEAM. - Deer Island Pumping Station, Boston, Suffolk County, MA

Effect of laser cavity parameters on saturation of light – current characteristics of high-power pulsed lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veselov, D A; Pikhtin, N A; Lyutetskiy, A V

2015-07-31

We report an experimental study of power characteristics of semiconductor lasers based on MOVPE-grown asymmetric separate-confinement heterostructures with a broadened waveguide as functions of cavity length, stripe contact width and mirror reflectivities. It is shown that at high current pump levels, the variation of the cavity parameters of a semiconductor laser (width, length and mirror reflectivities) influences the light – current (L – I) characteristic saturation and maximum optical power by affecting such laser characteristics, as the current density and the optical output loss. A model is elaborated and an optical power of semiconductor lasers is calculated by taking intomore » account the dependence of the internal optical loss on pump current density and concentration distribution of charge carriers and photons along the cavity axis of the cavity. It is found that only introduction of the dependence of the internal optical loss on pump current density to the calculation model provides a good agreement between experimental and calculated L – I characteristics for all scenarios of variations in the laser cavity parameters. (lasers)« less

Advancements in high-power diode laser stacks for defense applications

NASA Astrophysics Data System (ADS)

Pandey, Rajiv; Merchen, David; Stapleton, Dean; Patterson, Steve; Kissel, Heiko; Fassbender, Wilhlem; Biesenbach, Jens

2012-06-01

This paper reports on the latest advancements in vertical high-power diode laser stacks using micro-channel coolers, which deliver the most compact footprint, power scalability and highest power/bar of any diode laser package. We present electro-optical (E-O) data on water-cooled stacks with wavelengths ranging from 7xx nm to 9xx nm and power levels of up to 5.8kW, delivered @ 200W/bar, CW mode, and a power-conversion efficiency of >60%, with both-axis collimation on a bar-to-bar pitch of 1.78mm. Also, presented is E-O data on a compact, conductively cooled, hardsoldered, stack package based on conventional CuW and AlN materials, with bar-to-bar pitch of 1.8mm, delivering average power/bar >15W operating up to 25% duty cycle, 10ms pulses @ 45C. The water-cooled stacks can be used as pump-sources for diode-pumped alkali lasers (DPALs) or for more traditional diode-pumped solid-state lasers (DPSSL). which are power/brightness scaled for directed energy weapons applications and the conductively-cooled stacks as illuminators.

Highly Efficient Nd:yag Lasers for Free-space Optical Communications

NASA Technical Reports Server (NTRS)

Sipes, D. L., Jr.

1985-01-01

A highly efficient Nd:YAG laser end-pumped by semiconductor lasers as a possible free-space optical communications source is discussed. Because this concept affords high pumping densities, a long absorption length, and excellent mode-matching characteristics, it is estimated that electrical-to-optical efficiencies greater than 5% could be achieved. Several engineering aspects such as resonator size and configuration, pump collecting optics, and thermal effects are also discussed. Finally, possible methods for combining laser-diode pumps to achieve higher output powers are illustrated.

Electrokinetic high pressure hydraulic system

DOEpatents

Paul, Phillip H.; Rakestraw, David J.

2000-01-01

A compact high pressure hydraulic pump having no moving mechanical parts for converting electric potential to hydraulic force. The electrokinetic pump, which can generate hydraulic pressures greater than 2500 psi, can be employed to compress a fluid, either liquid or gas, and manipulate fluid flow. The pump is particularly useful for capillary-base systems. By combining the electrokinetic pump with a housing having chambers separated by a flexible member, fluid flow, including high pressure fluids, is controlled by the application of an electric potential, that can vary with time.

Excitation of the {sup 229m}Th nuclear isomer via resonance conversion in ionized atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karpeshin, F. F., E-mail: fkarpeshin@gmail.com; Trzhaskovskaya, M. B.

2015-09-15

Pressing problems concerning the optical pumping of the 7.6-eV {sup 229m}Th nuclear isomer, which is a candidate for a new nuclear optical reference point for frequencies, are examined. Physics behind the mechanism of the two-photon optical pumping of the isomer is considered. It is shown that, irrespective of the pumping scheme, a dominant contribution comes, in accord with what was proven earlier for the 3.5-eV isomer, from the resonance 8s–7s transition. Details of an optimum experimental scheme are discussed. It is shown that, after isomer excitation, the atom involved remains with a high probability in an excited state at anmore » energy of about 0.5 eV rather than in the ground state, the required energy of the two photons being equal to the energy of the nuclear level plus the energy of the lowest 7s state of the atom. The estimated pumping time is about 1.5 s in the case where the field strength of each laser is 1 V/cm.« less

Excitation of the 229 m Th nuclear isomer via resonance conversion in ionized atoms

NASA Astrophysics Data System (ADS)

Karpeshin, F. F.; Trzhaskovskaya, M. B.

2015-09-01

Pressing problems concerning the optical pumping of the 7.6-eV 229 m Th nuclear isomer, which is a candidate for a new nuclear optical reference point for frequencies, are examined. Physics behind the mechanism of the two-photon optical pumping of the isomer is considered. It is shown that, irrespective of the pumping scheme, a dominant contribution comes, in accord with what was proven earlier for the 3.5-eV isomer, from the resonance 8 s-7 s transition. Details of an optimum experimental scheme are discussed. It is shown that, after isomer excitation, the atom involved remains with a high probability in an excited state at an energy of about 0.5 eV rather than in the ground state, the required energy of the two photons being equal to the energy of the nuclear level plus the energy of the lowest 7 s state of the atom. The estimated pumping time is about 1.5 s in the case where the field strength of each laser is 1 V/cm.

Pumps for microfluidic cell culture.

PubMed

Byun, Chang Kyu; Abi-Samra, Kameel; Cho, Yoon-Kyoung; Takayama, Shuichi

2014-02-01

In comparison to traditional in vitro cell culture in Petri dishes or well plates, cell culture in microfluidic-based devices enables better control over chemical and physical environments, higher levels of experimental automation, and a reduction in experimental materials. Over the past decade, the advantages associated with cell culturing in microfluidic-based platforms have garnered significant interest and have led to a plethora of studies for high throughput cell assays, organs-on-a-chip applications, temporal signaling studies, and cell sorting. A clear concern for performing cell culture in microfluidic-based devices is deciding on a technique to deliver and pump media to cells that are encased in a microfluidic device. In this review, we summarize recent advances in pumping techniques for microfluidic cell culture and discuss their advantages and possible drawbacks. The ultimate goal of our review is to distill the large body of information available related to pumps for microfluidic cell culture in an effort to assist current and potential users of microfluidic-based devices for advanced in vitro cellular studies. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impact of left ventricular assist device speed adjustment on exercise tolerance and markers of wall stress.

PubMed

Hayward, Christopher S; Salamonsen, Robert; Keogh, Anne M; Woodard, John; Ayre, Peter; Prichard, Roslyn; Kotlyar, Eugene; Macdonald, Peter S; Jansz, Paul; Spratt, Phillip

2015-09-01

Left ventricular assist devices are crucial in rehabilitation of patients with end-stage heart failure. Whether cardiopulmonary function is enhanced with higher pump output is unknown. 10 patients (aged 39±16 years, mean±SD) underwent monitored adjustment of pump speed to determine minimum safe low speed and maximum safe high speed at rest. Patients were then randomized to these speed settings and underwent three 6-minute walk tests (6MWT) and symptom-limited cardiopulmonary stress tests (CPX) on separate days. Pump speed settings (low, normal and high) resulted in significantly different resting pump flows of 4.43±0.6, 5.03±0.94, and 5.72±1.2 l/min (P<.001). There was a significant enhancement of pump flows (greater at higher speed settings) with exercise (P<0.05). Increased pump speed was associated with a trend to increased 6MWT distance (P=.10); and CPX exercise time (p=.27). Maximum workload achieved and peak oxygen consumption were significantly different comparing low to high pump speed settings only (P<.05). N-terminal-pro-B-type natriuretic peptide release was significantly reduced at higher pump speed with exercise (P<.01). We have found that alteration of pump speed setting resulted in significant variation in estimated pump flow. The high-speed setting was associated with lower natriuretic hormone release consistent with lower myocardial wall stress. This did not, however, improve exercise tolerance.

Modulation of ouabain binding and potassium pump fluxes by cellular sodium and potassium in human and sheep erythrocytes.

PubMed Central

Joiner, C H; Lauf, P K

1978-01-01

1. Erythrocytes were treated with nystatin to alter internal Na (Nai) and K (Ki) composition. Although the rates of K pumping and [3H]ouabain binding were altered dramatically, the relationship between glycoside binding and K pump inhibition was unaffected. 2. Human cells with high Nai and low Ki exhibited an increased rate of ouabain binding as compared to high Ki, low Nai cells; this paralleled the stimulated K pump activity of high Nai cells. 3. At constant Ki, increasing internal Na stimulated K pump and ouabain binding rates concomitantly. 4. At low Nai, increasing Ki inhibited both K pumping and ouabain binding. However, at high Nai, increasing Ki from 4 to 44 mM stimulated the rate of glycoside binding, parallel to its effect of increasing the rate of active K influx. 5. Anti-L, an isoantibody to low K (LK) sheep red cells, increased the rate of ouabain binding via its stimulation of K pump turnover. Since the latter effect is the result of affinity changes at the internal cation activation site(s) of the pump (Lauf, Rasmusen, Hoffman, Dunham, Cook, Parmelee & Tosteson, 1970), the antibody's effect on ouabain binding reflected the positive correlation between the rates of K pump turnover and glycoside binding. 6. These data provide the first evidence in intact cells for the occurrence of a Nai-induced conformational change in the Na/K pump during its normal operational cycle. PMID:722574

High power tube solid-state laser with zigzag propagation of pump and laser beam

NASA Astrophysics Data System (ADS)

Savich, Michael

2015-02-01

A novel resonator and pumping design with zigzag propagation of pumping and laser beams permits to design an improved tube Solid State Laser (SSL), solving the problem of short absorption path to produce a high power laser beam (100 - 1000kW). The novel design provides an amplifier module and laser oscillator. The tube-shaped SSL includes a gain element fiber-optically coupled to a pumping source. The fiber optic coupling facilitates light entry at compound Brewster's angle of incidence into the laser gain element and uses internal reflection to follow a "zigzag" path in a generally spiral direction along the length of the tube. Optics are arranged for zigzag propagation of the laser beam, while the cryogenic cooling system is traditional. The novel method of lasing uses advantages of cylindrical geometry to reach the high volume of gain medium with compactness and structural rigidity, attain high pump density and uniformity, and reach a low threshold without excessive increase of the temperature of the crystal. The design minimizes thermal lensing and stress effects, and provides high gain amplification, high power extraction from lasing medium, high pumping and lasing efficiency and a high beam quality.

High power resonant pumping of Tm-doped fiber amplifiers in core- and cladding-pumped configurations.

PubMed

Creeden, Daniel; Johnson, Benjamin R; Rines, Glen A; Setzler, Scott D

2014-11-17

We have demonstrated ultra-high efficiency amplification in Tm-doped fiber with both core- and cladding-pumped configurations using a resonant tandem-pumping approach. These Tm-doped fiber amplifiers are pumped in-band with a 1908 nm Tm-doped fiber laser and operate at 1993 nm with >90% slope efficiency. In a core-pumped configuration, we have achieved 92.1% slope efficiency and 88.4% optical efficiency at 41 W output power. In a cladding-pumped configuration, we have achieved 123.1 W of output power with 90.4% optical efficiency and a 91.6% slope efficiency. We believe these are the highest optical efficiencies achieved in a Tm-doped fiber amplifier operating in the 2-micron spectral region.

Demand thrust pumped propulsion with automatic warm gas valving

NASA Astrophysics Data System (ADS)

Whitehead, J. C.

1992-06-01

Operation of a thrust-on-demand, monopropellant rocket propulsion system which uses lightweight low-pressure tankage, free-piston pumps, and a small high-pressure thrust chamber, is explained. The pump intake-exhaust valves use warm gas pneumatic signals to ensure that two reciprocating pumps are alternately pressurized, with overlap during switchover to permit uninterrupted propellant flow. Experiments demonstrate that the miniature pumps operate at any speed depending on downstream demand, and can deliver nearly their own mass in hydrazine per second, at 7 MPa (1000 psi). The valves, which use the alternating layers of metal and graphite to mitigate the effects of differential thermal expansion, have been warm-gas tested for thousands of cycles. For biopropellant operation, a pair of reciprocating oxidizer pumps would be slaved to the fuel pumps' pneumatic oscillator, to provide for pulsed or continuous demand-driven flow of both liquids. Mass ratios and thrust-to-weight ratios of demand-thrust pumped propulsion systems compare quite favorably to those of pressure-fed and turbo-pumped systems. Due to the relatively high densities of storable propellants, liquid mass fractions greater than 0.95 are attainable with these novel pumps, with thrust/weight ratios above 10. The high performance potential of small propulsion systems which use reciprocating pumps suggests that this technology can significantly increase the capability of many types of small spacecraft.

Side-pumping combiner for high-power fiber laser based on tandem pumping

NASA Astrophysics Data System (ADS)

Gu, Yanran; Lei, Chengmin; Liu, Jun; Li, Ruixian; Liu, Le; Xiao, Hu; Chen, Zilun

2017-11-01

We investigate a (2+1)×1 side-pumping combiner numerically and experimentally for high-power fiber laser based on tandem pumping for the first time. The influence of taper ratio and launch mode on the 1018-nm pump coupling efficiency and the leakage power into the coating of the signal fiber (LPC) is analyzed numerically. A side-pumping combiner is developed successfully by tapered-fused splicing technique based on the numerical analysis, consisting of two pump fibers (220/242 μm, NA=0.22) and a signal fiber (40/400 μm, NA=0.06/0.46). The total 1018-nm pump efficiency of the combiner is 98.1%, and the signal light insertion loss is <3%. The results show that, compared with laser diodes pumping, the combiner appears to have a better LPC performance and power handling capability when using 1018-nm fiber as the pump light. Meanwhile, an all-fiber MOPA laser based on tandem pumping with 1080-nm output of 2533 W and the slope efficiency of 82.8% is achieved based on the home-made combiner.

Representations and evolutionary operators for the scheduling of pump operations in water distribution networks.

PubMed

López-Ibáñez, Manuel; Prasad, T Devi; Paechter, Ben

2011-01-01

Reducing the energy consumption of water distribution networks has never had more significance. The greatest energy savings can be obtained by carefully scheduling the operations of pumps. Schedules can be defined either implicitly, in terms of other elements of the network such as tank levels; or explicitly, by specifying the time during which each pump is on/off. The traditional representation of explicit schedules is a string of binary values with each bit representing pump on/off status during a particular time interval. In this paper, we formally define and analyze two new explicit representations based on time-controlled triggers, where the maximum number of pump switches is established beforehand and the schedule may contain fewer than the maximum number of switches. In these representations, a pump schedule is divided into a series of integers with each integer representing the number of hours for which a pump is active/inactive. This reduces the number of potential schedules compared to the binary representation, and allows the algorithm to operate on the feasible region of the search space. We propose evolutionary operators for these two new representations. The new representations and their corresponding operations are compared with the two most-used representations in pump scheduling, namely, binary representation and level-controlled triggers. A detailed statistical analysis of the results indicates which parameters have the greatest effect on the performance of evolutionary algorithms. The empirical results show that an evolutionary algorithm using the proposed representations is an improvement over the results obtained by a recent state of the art hybrid genetic algorithm for pump scheduling using level-controlled triggers.

Ultra high vacuum pumping system and high sensitivity helium leak detector

DOEpatents

Myneni, Ganapati Rao

1997-01-01

An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10.sup.-13 atm cc s.sup.-1. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces backstreaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium.

Optimal Elevation and Configuration of Hanford's Double-Shell Tank Waste Mixer Pumps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onishi, Yasuo; Yokuda, Satoru T.; Majumder, Catherine A.

The objective of this study was to compare the mixing performance of the Lawrence pump, which has injection nozzles at the top, with an alternative pump that has injection nozzles at the bottom, and to determine the optimal elevation for the alternative pump. Sixteen cases were evaluated: two sludge thicknesses at eight levels. A two-step evaluation approach was used: Step 1 to evaluate all 16 cases with the non-rotating mixer pump model and Step 2 to further evaluate four of those cases with the more realistic rotating mixer pump model. The TEMPEST code was used.

Feasibility of solar-pumped dye lasers

NASA Technical Reports Server (NTRS)

Lee, Ja H.; Kim, Kyung C.; Kim, Kyong H.

1987-01-01

Dye laser gains were measured at various pump-beam irradiances on a dye cell in order to evaluate the feasibility of solar pumping. Rhodamine 6G dye was considered as a candidate for the solar-pumped laser because of its high utilization of the solar spectrum and high quantum efficiency. Measurements show that a solar concentration of 20,000 is required to reach the threshold of the dye.

Managing evaporation for more robust microscale assays. Part 2. Characterization of convection and diffusion for cell biology.

PubMed

Berthier, Erwin; Warrick, Jay; Yu, Hongmeiy; Beebe, David J

2008-06-01

Cell based microassays allow the screening of a multitude of culture conditions in parallel, which can be used for various applications from drug screening to fundamental cell biology research. Tubeless microfluidic devices based on passive pumping are a step towards accessible high throughput microassays, however they are vulnerable to evaporation. In addition to volume loss, evaporation can lead to the generation of small flows. Here, we focus on issues of convection and diffusion for cell culture in microchannels and particularly the transport of soluble factors secreted by cells. We find that even for humidity levels as high as 95%, convection in a passive pumping channel can significantly alter distributions of these factors and that appropriate system design can prevent convection.

Compact self-Q-switched Tm:YLF laser at 1.91 μm

NASA Astrophysics Data System (ADS)

Zhang, B.; Li, L.; He, C. J.; Tian, F. J.; Yang, X. T.; Cui, J. H.; Zhang, J. Z.; Sun, W. M.

2018-03-01

We report self-Q-switching operation in a diode-pumped Tm:YLF bulk laser by exploiting saturable re-absorption under the quasi-three-level regime. Robust self-Q-switched pulse output at 1.91 μm in fundamental mode is demonstrated experimentally with 1.5 at.% doped Tm:YLF crystal. At maximum absorbed pump power of 4.5 W, the average output power and pulse energy are obtained as high as 610 mW and 29 μJ, respectively, with the corresponding slope efficiency of 22%. Pulse repetition rate is tunable in the range of 3-21 kHz with changing the pump power. The dynamics of self-Q-switching of Tm:YLF laser are discussed with the help of a rate equation model showing good agreement with the experiment. The compact self-Q-switched laser near 2 μm has potential application in laser radar systems for accurate wind velocity measurements.

High pressure liquid gas pump

NASA Technical Reports Server (NTRS)

Acres, R. L.

1972-01-01

Design and development of two types of pumps for handling liquefied gases are discussed. One pump uses mechanical valve shift and other uses pneumatic valve shift. Illustrations of pumps are provided and detailed description of operation is included.

Robust modeling and performance analysis of high-power diode side-pumped solid-state laser systems.

PubMed

Kashef, Tamer; Ghoniemy, Samy; Mokhtar, Ayman

2015-12-20

In this paper, we present an enhanced high-power extrinsic diode side-pumped solid-state laser (DPSSL) model to accurately predict the dynamic operations and pump distribution under different practical conditions. We introduce a new implementation technique for the proposed model that provides a compelling incentive for the performance assessment and enhancement of high-power diode side-pumped Nd:YAG lasers using cooperative agents and by relying on the MATLAB, GLAD, and Zemax ray tracing software packages. A large-signal laser model that includes thermal effects and a modified laser gain formulation and incorporates the geometrical pump distribution for three radially arranged arrays of laser diodes is presented. The design of a customized prototype diode side-pumped high-power laser head fabricated for the purpose of testing is discussed. A detailed comparative experimental and simulation study of the dynamic operation and the beam characteristics that are used to verify the accuracy of the proposed model for analyzing the performance of high-power DPSSLs under different conditions are discussed. The simulated and measured results of power, pump distribution, beam shape, and slope efficiency are shown under different conditions and for a specific case, where the targeted output power is 140 W, while the input pumping power is 400 W. The 95% output coupler reflectivity showed good agreement with the slope efficiency, which is approximately 35%; this assures the robustness of the proposed model to accurately predict the design parameters of practical, high-power DPSSLs.

Effects of pumping strategies on pesticide concentration of a drinking water well

NASA Astrophysics Data System (ADS)

Aisopou, A.; Bjerg, P. L.; Binning, P. J.; Albrechtsen, H.

2011-12-01

Groundwater is an important source of drinking water production in many countries including Denmark. This requires high quality groundwater that meets the standards of the European Water Framework Directive. Yet as a result of agricultural activitity, deposition and previous handling, pesticides are frequently found in groundwater and can raise a substantial problem for ground water abstraction. The concentration of this contamination may vary between different layers. The heterogeneity of the subsurface geology and the depth of the drinking water well's screen are important parameters that affect the resulting contamination of the abstracted groundwater. The pesticide concentration in wells may also be affected by the pumping strategy because pumping can alter the structure of the flow field, the flowpath of water going to the well and subsequently the age of water at the well. The purpose of this study was to examine numerically the effects of pumping on pesticide contamination of drinking water wells using a reactive transport model in a hypothetical aquifer system resembling a typical Danish well field. The application history of the pesticides is crucial. This can be taken into account by assessing the effects of pumping on water age distribution along the well. Three compounds with different application histories were considered: an old banned pesticide MCPP (Mecoprop) which is mobile and relatively persistent in deeper aquifers, and a highly applied, biodegradable and strongly sorbing pesticide glyphosate, and its degradation product AMPA. A steady state flow field was first computed. A well field was then introduced and different pumping regimes were applied for a period of 180 years; a low-rate pumping, a high-rate pumping and a varying pumping regime. A constant application rate at the surface was assumed for the application period of each pesticide. The pre-abstraction age distribution of the water in the system was first estimated using a steady-state flow and transport simulation. These water ages were then used as the initial conditions for the transient simulations. The results of the simulations showed that the range of water ages contributing to the well increased during pumping and was substantially affected by the pumping rate. High pesticide concentrations were persistent in the well 40 to 100 years after they were banned, due to the high residence times in the aquifer. Large changes in simulated pesticides concentrations at the well occurred during pumping. The pesticide concentration reaching the well was affected by the pumping regime and the pesticide application history and properties. A higher pumping rate induced a higher pesticide concentration peak at the well of shorter duration, while a lower pumping rate induced a lower concentration peak of longer duration. The long term scenarios revealed that at high pumping rates MCPP would disappear 40 years after its application end year, while glyphosate concentrations increase and reach a plateau, which is highly dependent on the pumping rate. The findings of the study help understand the results of groundwater monitoring programmes and can be used for the quantitative evaluation of management and pumping strategies for the long-term supply of safe potable groundwater.

Simple systems for treating pumped, turbid water with flocculants and a geotextile dewatering bag.

PubMed

Kang, Jihoon; McLaughlin, Richard A

2016-11-01

Pumping sediment-laden water from excavations is often necessary on construction sites. This water is often treated by pumping it through geotextile dewatering bags. The bags are not designed to filter the fine sediments that create high turbidity, but dosing with a flocculant prior to the bag could result in greater turbidity control. This study compared two systems for introducing flocculant: passive dosing of commercial solid biopolymer (chitosan) and injection of dissolved polyacrylamide (PAM) in a length of corrugated pipe connected to the bag. The biopolymer system consisted of sequential porous socks containing a "charging agent" followed by chitosan in the corrugated pipe with two levels of dosing. The dissolved PAM was injected into turbid water at a flow-weighted concentration at 1 mg L(-1). For each treatment, sediment-laden turbid water in the range of 2000 to 3500 nephelometric turbidity units (NTU) was pumped into the upstream of corrugated pipe and samples were taken from pipe entrance, pipe exit, and dewatering bag exit. Without flocculant treatment, the dewatering bag reduced turbidity by 70% but the addition of flocculant increased the turbidity reduction up to 97% relative to influent. At the pipe exit, the low-dose biopolymer was less effective in reducing turbidity (37%) but it was equally effective as the high-dose biopolymer or PAM injection after the bag. Our results suggest that a relatively simple treatment with flocculants, either passively or actively, can be very effective in reducing turbidity for pumped water on construction sites. Copyright © 2016 Elsevier Ltd. All rights reserved.

Femtosecond Cr:LiSAF and Cr:LiCAF lasers pumped by tapered diode lasers.

PubMed

Demirbas, Umit; Schmalz, Michael; Sumpf, Bernd; Erbert, Götz; Petrich, Gale S; Kolodziejski, Leslie A; Fujimoto, James G; Kärtner, Franz X; Leitenstorfer, Alfred

2011-10-10

We report compact, low-cost and efficient Cr:Colquiriite lasers that are pumped by high brightness tapered laser diodes. The tapered laser diodes provided 1 to 1.2 W of output power around 675 nm, at an electrical-to-optical conversion efficiency of about 30%. Using a single tapered diode laser as the pump source, we have demonstrated output powers of 500 mW and 410 mW together with slope efficiencies of 47% and 41% from continuous wave (cw) Cr:LiSAF and Cr:LiCAF lasers, respectively. In cw mode-locked operation, sub-100-fs pulse trains with average power between 200 mW and 250 mW were obtained at repetition rates around 100 MHz. Upon pumping the Cr:Colquiriite lasers with two tapered laser diodes (one from each side of the crystal), we have observed scaling of cw powers to 850 mW in Cr:LiSAF and to 650 mW in Cr:LiCAF. From the double side pumped Cr:LiCAF laser, we have also obtained ~220 fs long pulses with 5.4 nJ of pulse energy at 77 MHz repetition rate. These are the highest energy levels reported from Cr:Colquiriite so far at these repetition rates. Our findings indicate that tapered diodes in the red spectral region are likely to become the standard pump source for Cr:Colquiriite lasers in the near future. Moreover, the simplified pumping scheme might facilitate efficient commercialization of Cr:Colquiriite systems, bearing the potential to significantly boost applications of cw and femtosecond lasers in this spectral region (750-1000 nm).

Energy dashboard for real-time evaluation of a heat pump assisted solar thermal system

NASA Astrophysics Data System (ADS)

Lotz, David Allen

The emergence of net-zero energy buildings, buildings that generate at least as much energy as they consume, has lead to greater use of renewable energy sources such as solar thermal energy. One example is a heat pump assisted solar thermal system, which uses solar thermal collectors with an electrical heat pump backup to supply space heating and domestic hot water. The complexity of such a system can be somewhat problematic for monitoring and maintaining a high level of performance. Therefore, an energy dashboard was developed to provide comprehensive and user friendly performance metrics for a solar heat pump system. Once developed, the energy dashboard was tested over a two-week period in order to determine the functionality of the dashboard program as well as the performance of the heating system itself. The results showed the importance of a user friendly display and how each metric could be used to better maintain and evaluate an energy system. In particular, Energy Factor (EF), which is the ratio of output energy (collected energy) to input energy (consumed energy), was a key metric for summarizing the performance of the heating system. Furthermore, the average EF of the solar heat pump system was 2.29, indicating an efficiency significantly higher than traditional electrical heating systems.

Development of a nonazeotropic heat pump for crew hygiene water heating

NASA Technical Reports Server (NTRS)

Walker, David H.; Deming, Glenn I.

1991-01-01

A heat pump system is currently under development to produce hot water for crew hygiene on future manned space missions. The heat pump uses waste heat sources and a nonazeotropic working fluid in a highly efficient cycle. The potential benefits include a reduction in peak power draw from 2 to 5 kW for electric cartridge heaters to just more than 100 W for the heat pump. As part of the heat pump development project, a unique high efficiency compressor was developed to maintain lubrication in a zero-gravity environment.

Face pumping of thin, solid-state slab lasers with laser diodes.

PubMed

Faulstich, A; Baker, H J; Hall, D R

1996-04-15

A new technique for face pumping of slab lasers uses transfer of light from 10 quasi-cw laser diode bars through a slotted mirror into a rectangular, highly ref lective pump chamber, giving efficient multipass pumping of a thin Nd:glass slab laser. A slope efficiency of 28% and a maximum pulse energy of 65 mJ have been obtained, and gain and loss measurements with thickness t = 0.45-1.04 mm have confirmed the 1/t scaling of gain in thin slabs and the high efficiency of pump light transfer.

Photoexcitation of lasers and chemical reactions for NASA missions: A theoretical study. [optical pumping in high pressure gas

NASA Technical Reports Server (NTRS)

Javan, A.; Guerra, M.

1981-01-01

The possibility of obtaining CW laser oscillation by optical pumping in the infrared at an elevated gas pressure is reviewed. A specific example utilizing a mixture of CO and NO gases is included. The gas pressures considered are in excess of several atmospheres. Laser frequency tuning over a broad region becomes possible at such elevated gas pressures due to collisional broadening of the amplifying transitions. The prior-rate and surprisal analysis are applied to obtain detailed VV and VT rates for CO and NO molecules and the transfer rates in a CO-NO gas mixture. The analysis is capable of giving temperature dependence of the rate constants. Computer estimates of the rates are presented for vibrational levels up to v = 50. The results show that in the high-lying vibrational states the VV transfer rates with Delta nu = 2 become appreciable.

Diode Pumped Alkaline Laser System: A High Powered, Low SWaP Directed Energy Option for Ballistic Missile Defense High-Level Summary - April 2017

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wisoff, P. J.

The Diode-Pumped Alkali Laser (DPAL) system is an R&D effort funded by the Missile Defense Agency (MDA) underway at Lawrence Livermore National Laboratory (LLNL). MDA has described the characteristics needed for a Boost Phase directed energy (DE) weapon to work against ICBM-class threat missiles. In terms of the platform, the mission will require a high altitude Unmanned Aerial Vehicle (UAV) that can fly in the “quiet” stratosphere and display long endurance – i.e., days on station. In terms of the laser, MDA needs a high power, low size and weight laser that could be carried by such a platform andmore » deliver lethal energy to an ICBM-class threat missile from hundreds of kilometers away. While both the military and industry are pursuing Directed Energy for tactical applications, MDA’s objectives pose a significantly greater challenge than other current efforts in terms of the power needed from the laser, the low size and weight required, and the range, speed, and size of the threat missiles. To that end, MDA is funding two R&D efforts to assess the feasibility of a high power (MWclass) and low SWaP (size, weight and power) laser: a fiber combining laser (FCL) project at MIT’s Lincoln Laboratory, and LLNL’s Diode-Pumped Alkali Laser (DPAL) system.« less

Contribution of variable-speed pump hydro storage for power system dynamic performance

NASA Astrophysics Data System (ADS)

Silva, B.; Moreira, C.

2017-04-01

This paper presents the study of variable-speed Pump Storage Powerplant (PSP) in the Portuguese power system. It evaluates the progressive integration in three major locations and compares the power system performance following a severe fault event with consequent disconnection of non-Fault Ride-through (FRT) compliant Wind Farms (WF). To achieve such objective, a frequency responsive model was developed in PSS/E and was further used to substitute existing fixed-speed PSP. The results allow identifying a clear enhancement on the power system performance by the presence of frequency responsive variable-speed PSP, especially for the scenario presented, with high level of renewables integration.

Practical method for transversely measuring the spin polarization of optically pumped alkali atoms

NASA Astrophysics Data System (ADS)

Ding, Zhichao; Yuan, Jie; Long, Xingwu

2018-06-01

A practical method to measure the spin polarization of optically pumped alkali atoms is demonstrated. In order to realize transverse measurement, the transverse spin component of spin-polarized alkali atoms is created by a rotating exciting magnetic field, and detected using the optical rotation of a near-resonant probe beam for realizing a high detection sensitivity. The dependency of the optical rotation on the spin polarization of 133Cs atoms is derived theoretically and verified experimentally. By changing the direction of the rotating magnetic field, we realize the transverse measurement of the spin polarization of 133Cs atoms in either ground-state hyperfine level.

Development of trivalent ytterbium doped fluorapatites for diode-pumped laser applications

NASA Astrophysics Data System (ADS)

Bayramian, Andrew James

2000-11-01

A major motivator of this work is the Mercury Project, a one kilowatt diode-pumped solid-state laser system under development at Lawrence Livermore National Laboratory (LLNL), which incorporates ytterbium doped strontium fluorapatite, Sr5(PO4)3F (S-FAP), as the amplifier gain medium. The primary focus of this thesis is a full understanding of the properties of this material, which is necessary for proper design and modeling of the system. Ytterbium-doped fluorapatites were investigated at LLNL prior to this work and found to be ideal candidate materials for high-power amplifier systems providing high absorption and emission cross sections, long radiative lifetimes, and high efficiency. A family of barium substituted S-FAP crystals was grown in an effort to modify the pump and emission bandwidths for application to broadband diode pumping and short pulse generation. Crystals of Yb 3+:Srs5-xBax(PO4) 3F where x < 1 showed homogeneous lines offering 8.4 nm (1.8X enhancement) of absorption bandwidth and 6.9 nm (1.4X enhancement) of emission bandwidth. The gain saturation fluence of Yb:S-FAP was measured to be 3.2 J/cm 2 with homogeneous extraction using a pump-probe experiment where the probe laser was a high intensity Q-switched master oscillator power amplifier system. The crystal quality of Czochralski grown Yb:S-FAP boules, which is effected by defects such as cracking, cloudiness, bubble core, slip dislocations, and anomalous absorption, was investigated interferometrically and quantified by means of Power Spectral Density (PSD) plots. Stimulated Raman Scattering (SRS) losses were evaluated by first measuring the SRS gain coefficient to be 1.3 cm/GW, then modeling the losses in the Mercury amplifier system. Countermeasures including the addition of bandwidth to the extraction beam and wedging of amplifier surfaces are shown to reduce the SRS losses allowing efficient laser gain extraction at higher intensities. Finally, an efficient Q-switched Yb:S-FAP oscillator was developed which operates three-level at 985 nm with a 21% slope efficiency. Frequency conversion of the 985 nm light to the 2nd harmonic at 492.5 nm was achieved with a 31% conversion efficiency. A diode pumped, doubled Yb:S-FAP laser at 492.5 nm would make possible a compact, efficient, high-power blue laser source.

A randomized study comparing blood glucose control and risk of severe hypoglycemia achieved by non-programmable versus programmable external insulin pumps.

PubMed

Catargi, B; Breilh, D; Gin, H; Rigalleau, V; Saux, M C; Roger, P; Tabarin, A

2001-06-01

To compare a non-programmable and a programmable insulin external pump using regular insulin on glycemic stability, the risk of severe hypoglycemia and metabolic control in type 1 diabetic patients. Ten type 1 diabetic patients were involved in a randomized, crossover study comparing two periods of 3 months with continuous subcutaneous insulin infusion (CSII) either with a non-programmable insulin pump or a programmable insulin pump. Comparisons were made among mean blood glucose values before and after meals, at bedtime and at 2: 00 a.m.; the risk of severe hypoglycemia assessed by the low blood glucose index (LBGI); and HbA1c. Mean average blood glucose (BG) measurements were significantly lower with the programmable in comparison with the non-programmable insulin pump (respectively 157+/-78 vs. 165+/-79, p=0.034). While postprandial values for BG were not different between the two pumps, the use of the programmable pump resulted in a significant decrease in mean preprandial BG levels (140+/-68 vs. 150+/-73 mg/dl p=0.039). Conversely mean BG level was lower at 2 a.m. with the non-prgrammable pump (125+/-81 vs. 134 +/-93 mg/dl, p=0.02) but with a higher incidence of hypoglycemia. Mean LBGI was comparable with the two pumps (3.1+/-8.6 vs. 2.8+/-6.9, p=0.1). There was a 0.2% decrease in HbA1c during the programmable pump period that did not reach statistical significance (p=0.37). The present study suggests that programmable external insulin pumps, although more complex and more expensive than non-programmable insulin pumps, significantly reduce fasting glycemia during the day without increasing the risk of severe hypoglycemia and are safer during the night.

Use of cardiopulmonary pump support during coronary artery bypass grafting in the high-risk: a meta-analysis.

PubMed

Yousif, A; Addison, D; Lakkis, N; Rosengart, T; Virani, S S; Birnbaum, Y; Alam, M

2018-05-01

Data from randomized trials evaluating the efficacy of on- versus off-pump coronary artery bypass grafting remain inconclusive, particularly in high-risk populations. The aim of this study is to compare the outcomes associated with on- versus off-pump coronary artery bypass grafting among high-risk patients. We performed a meta-analysis of randomized control trials comparing on- versus off-pump coronary artery bypass grafting, focusing on high-risk populations. Studies focusing on "high-risk" features: European System of Cardiac Operative Risk Evaluation (EuroSCORE) ≥ 5, age > 70 years, preexisting renal insufficiency, history of stroke(s), and the presence of left ventricular dysfunction were included. MEDLINE, Scopus, and Embase were searched for all publications between January 1, 2000 and August 1, 2016, using the following terms: on-pump, off-pump, coronary artery bypass, high-risk, left ventricular dysfunction, elderly, aged, and renal insufficiency. Endpoints included cardiovascular and all-cause mortality, non-fatal myocardial infarction, stroke, need for revascularization, renal failure, and length of hospital stay. Nine studies incorporating 11,374 patients with a mean age of 70 years were selected. There was no statistical difference in cardiovascular mortality, all-cause mortality, non-fatal myocardial infarction, and renal failure between the two groups. There was a decrease in further revascularization at 1 year with on-pump (OR 0.67 (0.50-0.89)). However, there was an increase in length of hospital stay by 2.24 days (p = 0.03) among the on-pump group with no difference in stroke (OR 1.34 (1.00-1.80)). On-pump is associated with a decreased risk of additional revascularization by 1 year. However, this appears to be a cost of longer hospitalization.

Maximizing fluid delivered by bubble-free electroosmotic pump with optimum pulse voltage waveform.

PubMed

Tawfik, Mena E; Diez, Francisco J

2017-03-01

In generating high electroosmotic (EO) flows for use in microfluidic pumps, a limiting factor is faradaic reactions that are more pronounced at high electric fields. These reactions lead to bubble generation at the electrodes and pump efficiency reduction. The onset of gas generation for high current density EO pumping depends on many parameters including applied voltage, working fluid, and pulse duration. The onset of gas generation can be delayed and optimized for maximum volume pumped in the minimum time possible. This has been achieved through the use of a novel numerical model that predicts the onset of gas generation during EO pumping using an optimized pulse voltage waveform. This method allows applying current densities higher than previously reported. Optimal pulse voltage waveforms are calculated based on the previous theories for different current densities and electrolyte molarity. The electroosmotic pump performance is investigated by experimentally measuring the fluid volume displaced and flow rate. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theoretical and experimental analysis of a multiphase screw pump, handling gas-liquid mixtures with very high gas volume fractions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raebiger, K.; Faculty of Advanced Technology, University of Glamorgan, Pontypridd, Wales; Maksoud, T.M.A.

In the investigation of the pumping behaviour of multiphase screw pumps, handling gas-liquid mixtures with very high gas volume fractions, theoretical and experimental analyses were performed. A new theoretical screw pump model was developed, which calculates the time-dependent conditions inside the several chambers of a screw pump as well as the exchange of mass and energy between these chambers. By means of the performed experimental analysis, the screw pump model was verified, especially at very high gas volume fractions from 90% to 99%. The experiments, which were conducted with the reference fluids water and air, can be divided mainly intomore » the determination of the steady state pumping behaviour on the one hand and into the analysis of selected transient operating conditions on the other hand, whereas the visualisation of the leakage flows through the circumferential gaps was rounded off the experimental analysis. (author)« less

Characterization of Defects in Scaled Mis Dielectrics with Variable Frequency Charge Pumping

NASA Astrophysics Data System (ADS)

Paulsen, Ronald Eugene

1995-01-01

Historically, the interface trap has been extensively investigated to determine the effects on device performance. Recently, much attention has been paid to trapping in near-interface oxide traps. Performance of high precision analog circuitry is affected by charge trapping in near-interface oxide traps which produces hysteresis, charge redistribution errors, and dielectric relaxation effects. In addition, the performance of low power digital circuitry, with reduced noise margins, may be drastically affected by the threshold voltage shifts associated with charge trapping in near -interface oxide traps. Since near-interface oxide traps may substantially alter the performance of devices, complete characterization of these defects is necessary. In this dissertation a new characterization technique, variable frequency charge pumping, is introduced which allows charge trapped at the interface to be distinguished from the charge trapped within the oxide. The new experimental technique is an extension of the charge pumping technique to low frequencies such that tunneling may occur from interface traps to near-interface oxide traps. A generalized charge pumping model, based on Shockley-Read-Hall statistics and trap-to-trap tunneling theory, has been developed which allows a more complete characterization of near-interface oxide traps. A pair of coupled differential equations governing the rate of change of occupied interface and near-interface oxide traps have been developed. Due to the experimental conditions in the charge pumping technique the equations may be decoupled, leading to an equation governing the rate of change of occupied interface traps and an equation governing the rate of change of occcupied near-interface oxide traps. Solving the interface trap equation and applying non-steady state charge dynamics leads to an interface trap component of the charge pumping current. In addition, solution to the near-interface oxide trap equation leads to an additional oxide trap component to the charge pumping current. Numerical simulations have been performed to support the analytical development of the generalized charge pumping model. By varying the frequency of the applied charge pumping waveform and monitoring the charge recombined per cycle, the contributions from interface traps may be separated from the contributions of the near-interface oxide traps. The generalized charge pumping model allows characterization of the density and spatial distribution of near-interface oxide traps from this variable frequency charge pumping technique. Characterization of interface and near-interface oxide trap generation has been performed on devices exposed to ionizing radiation, hot electron injection, and high -field/Fowler-Nordheim stressing. Finally, using SONOS nonvolatile memory devices, a framework has been established for experimentally determining not only the spatial distribution of near-interface oxide traps, but also the energetic distribution. An experimental approach, based on tri-level charge pumping, is discussed which allows the energetic distribution of near-interface oxide traps to be determined.

Reviews of a Diode-Pumped Alkali Laser (DPAL): a potential high powered light source

NASA Astrophysics Data System (ADS)

Cai, He; Wang, You; Han, Juhong; An, Guofei; Zhang, Wei; Xue, Liangping; Wang, Hongyuan; Zhou, Jie; Gao, Ming; Jiang, Zhigang

2015-03-01

Diode pumped alkali vapor lasers (DPALs) were first developed by in W. F. Krupke at the beginning of the 21th century. In the recent years, DPALs have been rapidly developed because of their high Stokes efficiency, good beam quality, compact size and near-infrared emission wavelengths. The Stokes efficiency of a DPAL can achieve a miraculous level as high as 95.3% for cesium (Cs), 98.1% for rubidium (Rb), and 99.6% for potassium (K), respectively. The thermal effect of a DPAL is theoretically smaller than that of a normal diode-pumped solid-state laser (DPSSL). Additionally, generated heat of a DPAL can be removed by circulating the gases inside a sealed system. Therefore, the thermal management would be relatively simple for realization of a high-powered DPAL. In the meantime, DPALs combine the advantages of both DPSSLs and normal gas lasers but evade the disadvantages of them. Generally, the collisionally broadened cross sections of both the D1 and the D2 lines for a DPAL are much larger than those for the most conventional solid-state, fiber and gas lasers. Thus, DPALs provide an outstanding potentiality for realization of high-powered laser systems. It has been shown that a DPAL is now becoming one of the most promising candidates for simultaneously achieving good beam quality and high output power. With a lot of marvelous merits, a DPAL becomes one of the most hopeful high-powered laser sources of next generation.

Optimising the efficiency of pulsed diode pumped Yb:YAG laser amplifiers for ns pulse generation.

PubMed

Ertel, K; Banerjee, S; Mason, P D; Phillips, P J; Siebold, M; Hernandez-Gomez, C; Collier, J C

2011-12-19

We present a numerical model of a pulsed, diode-pumped Yb:YAG laser amplifier for the generation of high energy ns-pulses. This model is used to explore how optical-to-optical efficiency depends on factors such as pump duration, pump spectrum, pump intensity, doping concentration, and operating temperature. We put special emphasis on finding ways to achieve high efficiency within the practical limitations imposed by real-world laser systems, such as limited pump brightness and limited damage fluence. We show that a particularly advantageous way of improving efficiency within those constraints is operation at cryogenic temperature. Based on the numerical findings we present a concept for a scalable amplifier based on an end-pumped, cryogenic, gas-cooled multi-slab architecture.

Mechanical pumps for superfluid helium transfer in space

NASA Technical Reports Server (NTRS)

Izenson, M. G.; Swift, W. L.

1988-01-01

Two alternate mechanical pump concepts have been identified for the transfer of superfluid helium in space. Both pumps provide flow at sufficient head and have operating characteristics suitable for the Space Infrared Telescope Facility (SIRTF) refill mission. One pump operates at a relatively low speed and utilizes mechanical roller bearings, while the other operates at a higher rotational speed using either electromagnetic or tilting pad gas-dynamic bearings. The use of gas bearings requires transfer of normal helium so that the gas pressure within the pump casing is high enough to operate the bearings. The operating characteristics of both pumps are predicted, the dimensions are estimated and major technology issues are identified. The major issues for each pump design are cavitation performance and bearing development. Roller bearings require quantified reliability for operation in space while electromagnetic bearings require basic development as well as a complex control system. The low speed pump has significantly poorer hydraulic efficiency than the high speed pump.

LMFBR with booster pump in pumping loop

DOEpatents

Rubinstein, H.J.

1975-10-14

A loop coolant circulation system is described for a liquid metal fast breeder reactor (LMFBR) utilizing a low head, high specific speed booster pump in the hot leg of the coolant loop with the main pump located in the cold leg of the loop, thereby providing the advantages of operating the main pump in the hot leg with the reliability of cold leg pump operation.

Micromachined evaporators for AMTEC cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izenson, M.G.; Crowley, C.J.

1996-12-31

To achieve high cell efficiency and reliability, the capillary pumping system for Alkali Metal Thermal to Electric Conversion (AMTEC) must have three key characteristics: (1) very small pores to achieve a high capillary pumping head, (2) high permeability for the flow of liquid sodium to minimize internal losses, and (3) be made from a material that is exceptionally stable at high temperatures in a sodium environment. The authors have developed micromachining techniques to manufacture high performance evaporators for AMTEC cells. The evaporators have been fabricated from stainless steel, molybdenum, and a niobium alloy (Nb-1Zr). The regular, micromachined structure leads tomore » very high capillary pumping head with high permeability for liquid flow. Data from tests performed with common fluids at room temperature characterize the capillary pumping head and permeability of these structures. Three micromachined evaporators have been built into AMTEC cells and operated at temperatures up to 1,100 K. Results from these tests confirm the excellent pumping capabilities of the micromachined evaporators.« less

Earth Resources Stewardship at Department of Defense Installations

DTIC Science & Technology

1994-03-01

Roberts, Kevin Morrison, and Carlos Latorre, USM. Mr. J. D. Lashlee (GL) contributed to the sections on remote sensing imageky, mobility, and geographic...nearby observation wells. The test measurements are: static water level before pumping is started, pump rate, and dynamic waer levels measured at

Preliminary simulation of chloride transport in the Equus Beds aquifer and simulated effects of well pumping and artificial recharge on groundwater flow and chloride transport near the city of Wichita, Kansas, 1990 through 2008

USGS Publications Warehouse

Klager, Brian J.; Kelly, Brian P.; Ziegler, Andrew C.

2014-01-01

The Equus Beds aquifer in south-central Kansas is a primary water-supply source for the city of Wichita. Water-level declines because of groundwater pumping for municipal and irrigation needs as well as sporadic drought conditions have caused concern about the adequacy of the Equus Beds aquifer as a future water supply for Wichita. In March 2006, the city of Wichita began construction of the Equus Beds Aquifer Storage and Recovery project, a plan to artificially recharge the aquifer with excess water from the Little Arkansas River. Artificial recharge will raise groundwater levels, increase storage volume in the aquifer, and deter or slow down a plume of chloride brine approaching the Wichita well field from the Burrton, Kansas area caused by oil production activities in the 1930s. Another source of high chloride water to the aquifer is the Arkansas River. This study was prepared in cooperation with the city of Wichita as part of the Equus Beds Aquifer Storage and Recovery project. Chloride transport in the Equus Beds aquifer was simulated between the Arkansas and Little Arkansas Rivers near the Wichita well field. Chloride transport was simulated for the Equus Beds aquifer using SEAWAT, a computer program that combines the groundwater-flow model MODFLOW-2000 and the solute-transport model MT3DMS. The chloride-transport model was used to simulate the period from 1990 through 2008 and the effects of five well pumping scenarios and one artificial recharge scenario. The chloride distribution in the aquifer for the beginning of 1990 was interpolated from groundwater samples from around that time, and the chloride concentrations in rivers for the study period were interpolated from surface water samples. Five well-pumping scenarios and one artificial-recharge scenario were assessed for their effects on simulated chloride transport and water levels in and around the Wichita well field. The scenarios were: (1) existing 1990 through 2008 pumping conditions, to serve as a baseline scenario for comparison with the hypothetical scenarios; (2) no pumping in the model area, to demonstrate the chloride movement without the influence of well pumping; (3) double municipal pumping from the Wichita well field with existing irrigation pumping; (4) existing municipal pumping with no irrigation pumping in the model area; (5) double municipal pumping in the Wichita well field and no irrigation pumping in the model area; and (6) increasing artificial recharge to the Phase 1 Artificial Storage and Recovery project sites by 2,300 acre-feet per year. The effects of the hypothetical pumping and artificial recharge scenarios on simulated chloride transport were measured by comparing the rate of movement of the 250-milligrams-per-liter-chloride front for each hypothetical scenario with the baseline scenario at the Arkansas River area near the southern part of the Wichita well field and the Burrton plume area. The scenarios that increased the rate of movement the most compared to the baseline scenario of existing pumping between the Arkansas River and the southern boundary of the well field were those that doubled the city of Wichita’s pumping from the well field (scenarios 3 and 5), increasing the rate of movement by 50 to 150 feet per year, with the highest rate increases in the shallow layer and the lowest rate increases in the deepest layer. The no pumping and no irrigation pumping scenarios (2 and 4) slowed the rate of movement in this area by 150 to 210 feet per year and 40 to 70 feet per year, respectively. In the double Wichita pumping scenario (3), the rate of movement in the shallow layer of the Burrton area decreased by about 50 feet per year. Simulated chloride rate of movement in the deeper layers of the Burrton area was decreased in the no pumping and no irrigation scenarios (2 and 4) by 80 to 120 feet per year and 50 feet per year, respectively, and increased in the scenarios that double Wichita’s pumping (3 and 5) from the well field by zero to 130 feet per year, with the largest increases in the deepest layer. In the increased Phase 1 artificial recharge scenario (6), the rate of chloride movement in the Burrton area increased in the shallow layer by about 30 feet per year, and decreased in the middle and deepest layer by about 10 and 60 feet per year, respectively. Comparisons of the rate of movement of the simulated 250-milligrams-per-liter-chloride front in the hypothetical scenarios to the baseline scenario indicated that, in general, increases to pumping in the well field area increased the rate of simulated chloride movement toward the well field area by as much as 150 feet per year. Reductions in pumping slowed the advance of chloride toward the well field by as much as 210 feet per year, although reductions did not stop the movement of chloride toward the well field, including when pumping rates were eliminated. If pumping is completely discontinued, the rate of chloride movement is about 500 to 600 feet per year in the area between the Arkansas River and the southern part of the Wichita well field, and 70 to 500 feet per year in the area near Burrton with the highest rate of movement in the shallow aquifer layer. The averages of simulated water-levels in index monitoring wells in the Wichita well field at the end of 2008 were calculated for each scenario. Compared to the baseline scenario, the average simulated water level was 5.05 feet higher for the no pumping scenario, 4.72 feet lower for the double Wichita pumping with existing irrigation scenario, 2.49 feet higher for the no irrigation pumping with existing Wichita pumping scenario, 1.53 feet lower for the double Wichita pumping with no irrigation scenario, and 0.48 feet higher for the increased Phase 1 artificial recharge scenario. The groundwater flow was simulated with a preexisting groundwater-flow model, which was not altered to calibrate the solute-transport model to observed chloride-concentration data. Therefore, some areas in the model had poor fit between simulated chloride concentrations and observed chloride concentrations, including the area between Arkansas River and the southern part of the Wichita well field, and the Hollow-Nikkel area about 6 miles north of Burrton. Compared to the interpreted location of the 250-milligrams per liter-chloride front based on data collected in 2011, in the Arkansas River area the simulated 250-milligrams per liter-chloride front moved from the river toward the well field about twice the rate of the actual 250-milligrams per liter-chloride front in the shallow layer and about four times the rate of the actual 250-milligrams per liter-chloride front in the deep layer. Future groundwater-flow and chloride-transport modeling efforts may achieve better agreement between observed and simulated chloride concentrations in these areas by taking the chloride-transport model fit into account when adjusting parameters such as hydraulic conductivity, riverbed conductance, and effective porosity during calibration. Results of the hypothetical scenarios simulated indicate that the Burrton chloride plume will continue moving toward the well field regardless of pumping in the area and that one alternative may be to increase pumping from within the plume area to reverse the groundwater-flow gradients and remove the plume. Additionally, the results of modeling these scenarios indicate that eastward movement of the Burrton plume could be slowed by the additional artificial recharge at the Phase 1 sites and that decreasing pumping along the Arkansas River or increasing water levels could retard the movement of chloride and may prevent further encroachment into the southern part of the well field area.

High Energy, Single-Mode, All-Solid-State and Tunable UV Laser Transmitter

NASA Technical Reports Server (NTRS)

Prasad, Narasimha S.; Singh, Upendra N.; Hovis, FLoyd

2007-01-01

A high energy, single mode, all solid-state Nd:YAG laser primarily for pumping an UV converter is developed. Greater than 1 J/pulse at 50 HZ PRF and pulse widths around 22 ns have been demonstrated. Higher energy, greater efficiency may be possible. Refinements are known and practical to implement. Technology Demonstration of a highly efficient, high-pulse-energy, single mode UV wavelength generation using flash lamp pumped laser has been achieved. Greater than 90% pump depletion is observed. 190 mJ extra-cavity SFG; IR to UV efficiency > 21% (> 27% for 1 mJ seed). 160 mJ intra-cavity SFG; IR to UV efficiency up to 24% Fluence < 1 J/sq cm for most beams. The pump beam quality of the Nd:YAG pump laser is being refined to match or exceed the above UV converter results. Currently the Nd:YAG pump laser development is a technology demonstration. System can be engineered for compact packaging.

Mid-infrared 1  W hollow-core fiber gas laser source.

PubMed

Xu, Mengrong; Yu, Fei; Knight, Jonathan

2017-10-15

We report the characteristics of a 1 W hollow-core fiber gas laser emitting CW in the mid-IR. Our system is based on an acetylene-filled hollow-core optical fiber guiding with low losses at both the pump and laser wavelengths and operating in the single-pass amplified spontaneous emission regime. Through systematic characterization of the pump absorption and output power dependence on gas pressure, fiber length, and pump intensity, we determine that the reduction of pump absorption at high pump flux and the degradation of gain performance at high gas pressure necessitate the use of increased gain fiber length for efficient lasing at higher powers. Low fiber attenuation is therefore key to efficient high-power laser operation. We demonstrate 1.1 W output power at a 3.1 μm wavelength by using a high-power erbium-doped fiber amplifier pump in a single-pass configuration, approximately 400 times higher CW output power than in the ring cavity previously reported.

History of the membrane (pump) theory of the living cell from its beginning in mid-19th century to its disproof 45 years ago--though still taught worldwide today as established truth.

PubMed

Ling, Gilbert

2007-01-01

The concept that the basic unit of all life, the cell, is a membrane-enclosed soup of (free) water, (free) K+ (and native) proteins is called the membrane theory. A careful examination of past records shows that this theory has no author in the true sense of the word. Rather, it grew mostly out of some mistaken ideas made by Theodor Schwann in his Cell Theory. (This is not to deny that there is a membrane theory with an authentic author but this authored membrane theory came later and is much more narrowly focussed and accordingly can at best be regarded as an offshoot of the broader and older membrane theory without an author.) However, there is no ambiguity on the demise of the membrane theory, which occurred more than 60 years ago, when a flood of converging evidence showed that the asymmetrical distribution of K+ and Na+ observed in virtually all living cells is not the result of the presence of a membrane barrier that permits some solutes like water and K+ to move in and out of the cell, while barring--absolutely and permanently--the passage of other solutes like Na+. To keep the membrane theory afloat, submicroscopic pumps were installed across the cell membrane to maintain, for example, the level of Na+ in the cell low and the level of K+ high by the ceaseless pumping activities at the expense of metabolic energy. Forty-five year ago this version of the membrane theory was also experimentally disproved. In spite of all these overwhelming evidence against the membrane-pump theory, it still is being taught as verified truth in all high-school and biology textbooks known to us today. Meanwhile, almost unnoticed, a new unifying theory of the living cell, called the association-induction hypothesis came into being some 40 years ago. Also little noticed was the fact that it has received extensive confirmation worldwide and has shown an ability to provide self-consistent interpretations of most if not all known experimental observations that are contradicting the membrane-pump theory as well as other observations that seem to support the membrane pump theory.

Ultra high vacuum pumping system and high sensitivity helium leak detector

DOEpatents

Myneni, G.R.

1997-12-30

An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10{sup {minus}13} atm cc/s. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces back streaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium. 2 figs.

Advancements in high-power high-brightness laser bars and single emitters for pumping and direct diode application

NASA Astrophysics Data System (ADS)

An, Haiyan; Jiang, Ching-Long J.; Xiong, Yihan; Zhang, Qiang; Inyang, Aloysius; Felder, Jason; Lewin, Alexander; Roff, Robert; Heinemann, Stefan; Schmidt, Berthold; Treusch, Georg

2015-03-01

We have continuously optimized high fill factor bar and packaging design to increase power and efficiency for thin disc laser system pump application. On the other hand, low fill factor bars packaged on the same direct copper bonded (DCB) cooling platform are used to build multi-kilowatt direct diode laser systems. We have also optimized the single emitter designs for fiber laser pump applications. In this paper, we will give an overview of our recent advances in high power high brightness laser bars and single emitters for pumping and direct diode application. We will present 300W bar development results for our next generation thin disk laser pump source. We will also show recent improvements on slow axis beam quality of low fill factor bar and its application on performance improvement of 4-5 kW TruDiode laser system with BPP of 30 mm*mrad from a 600 μm fiber. Performance and reliability results of single emitter for multiemitter fiber laser pump source will be presented as well.

Effect of Pumping on Groundwater Levels: A Case Study

NASA Astrophysics Data System (ADS)

Sindhu, G.; Vijayachandran, Lekshmi

2018-03-01

Groundwater is a major source for drinking and domestic purposes. Nowadays, extensive pumping has become a major issue of concern since pumping has led to rapid decline in the groundwater table, thus imposing landward gradient, leading to saline water intrusion especially in coastal areas. Groundwater pumping has seen its utmost effect on coastal aquifer systems, where the sea-ward gradient gets disturbed due to anthropogenic influences. Hence, a groundwater flow modelling of an aquifer system is essential for understanding the various hydro-geologic conditions, which can be used to study the responses of the aquifer system with regard to various pumping scenarios. Besides, a model helps to predict the water levels for the future period with respect to changing environment. In this study, a finite element groundwater flow model of a coastal aquifer system at Aakulam, Trivandrum district is developed, calibrated and simulated using the software Finite Element subsurface Flow system (FEFLOW 6.2).This simulated model is then used to predict the groundwater levels for a future 5 year period during pre monsoon and post monsoon season.

Effect of Pumping on Groundwater Levels: A Case Study

NASA Astrophysics Data System (ADS)

Sindhu, G.; Vijayachandran, Lekshmi

2018-06-01

Groundwater is a major source for drinking and domestic purposes. Nowadays, extensive pumping has become a major issue of concern since pumping has led to rapid decline in the groundwater table, thus imposing landward gradient, leading to saline water intrusion especially in coastal areas. Groundwater pumping has seen its utmost effect on coastal aquifer systems, where the sea-ward gradient gets disturbed due to anthropogenic influences. Hence, a groundwater flow modelling of an aquifer system is essential for understanding the various hydro-geologic conditions, which can be used to study the responses of the aquifer system with regard to various pumping scenarios. Besides, a model helps to predict the water levels for the future period with respect to changing environment. In this study, a finite element groundwater flow model of a coastal aquifer system at Aakulam, Trivandrum district is developed, calibrated and simulated using the software Finite Element subsurface Flow system (FEFLOW 6.2).This simulated model is then used to predict the groundwater levels for a future 5 year period during pre monsoon and post monsoon season.

Active locking and entanglement in type II optical parametric oscillators

NASA Astrophysics Data System (ADS)

Ruiz-Rivas, Joaquín; de Valcárcel, Germán J.; Navarrete-Benlloch, Carlos

2018-02-01

Type II optical parametric oscillators are amongst the highest-quality sources of quantum-correlated light. In particular, when pumped above threshold, such devices generate a pair of bright orthogonally-polarized beams with strong continuous-variable entanglement. However, these sources are of limited practical use, because the entangled beams emerge with different frequencies and a diffusing phase difference. It has been proven that the use of an internal wave-plate coupling the modes with orthogonal polarization is capable of locking the frequencies of the emerging beams to half the pump frequency, as well as reducing the phase-difference diffusion, at the expense of reducing the entanglement levels. In this work we characterize theoretically an alternative locking mechanism: the injection of a laser at half the pump frequency. Apart from being less invasive, this method should allow for an easier real-time experimental control. We show that such an injection is capable of generating the desired phase locking between the emerging beams, while still allowing for large levels of entanglement. Moreover, we find an additional region of the parameter space (at relatively large injections) where a mode with well defined polarization is in a highly amplitude-squeezed state.

Development (design and systematization) of HMS Group pump ranges

NASA Astrophysics Data System (ADS)

Tverdokhleb, I.; Yamburenko, V.

2017-08-01

The article reveals the need for pump range charts development for different applications and describes main principles used by HMS Group. Some modern approaches to pump selection are reviewed and highlighted the need for pump compliance with international standards and modern customer requirements. Even though pump design types are similar for different applications they need adjustment to specific requirements, which gets manufacturers develop their particular design for each pump range. Having wide pump ranges for different applications enables to create pump selection software, facilitating manufacturers to prepare high quality quotations in shortest time.

Electromagnetic Pumps for Liquid Metal-Fed Electric Thrusters

NASA Technical Reports Server (NTRS)

Polzin, Kurt A.; Markusic, Thomas E.

2007-01-01

Prototype designs of two separate pumps for use in electric propulsion systems with liquid lithium and bismuth propellants are presented. Both pumps are required to operate at elevated temperatures, and the lithium pump must additionally withstand the corrosive nature of the propellant. Compatibility of the pump materials and seals with lithium and bismuth were demonstrated through proof-of-concept experiments followed by post-experiment visual inspections. The pressure rise produced by the bismuth pump was found to be linear with input current and ranged from 0-9 kPa for corresponding input current levels of 0-30 A, showing good quantitative agreement with theoretical analysis.

Efficient blue emission of ytterbium-doped Sr5(PO4)3F under quasi-three-level intracavity pumping

NASA Astrophysics Data System (ADS)

Yang, Y.; Cao, G. H.

2012-02-01

We report an Yb:Sr5(PO4)3F (Yb:S-FAP) laser emitting at 985 nm intracavity pumped by a 912 nm diode-pumped Nd:GdVO4 laser. A 808 nm diode laser is used to pump the Nd:GdVO4 crystal emitting at 912 nm, and the Yb:S-FAP laser emitting at 985 nm intracavity pumped at 912 nm. With incident pump power of 17.5 W, intracavity second harmonic generation has been demonstrated with a power of 131 mW at 492.5 nm by using a LBO nonlinear crystal.

Fan and pump noise control

NASA Technical Reports Server (NTRS)

Misoda, J.; Magliozzi, B.

1973-01-01

The development is described of improved, low noise level fan and pump concepts for the space shuttle. In addition, a set of noise design criteria for small fans and pumps was derived. The concepts and criteria were created by obtaining Apollo hardware test data to correlate and modify existing noise estimating procedures. A set of space shuttle selection criteria was used to determine preliminary fan and pump concepts. These concepts were tested and modified to obtain noise sources and characteristics which yield the design criteria and quiet, efficient space shuttle fan and pump concepts.

Towards Terawatt Sub-Cycle Long-Wave Infrared Pulses via Chirped Optical Parametric Amplification and Indirect Pulse Shaping

PubMed Central

Yin, Yanchun; Chew, Andrew; Ren, Xiaoming; Li, Jie; Wang, Yang; Wu, Yi; Chang, Zenghu

2017-01-01

We present an approach for both efficient generation and amplification of 4–12 μm pulses by tailoring the phase matching of the nonlinear crystal Zinc Germanium Phosphide (ZGP) in a narrowband-pumped optical parametric chirped pulse amplifier (OPCPA) and a broadband-pumped dual-chirped optical parametric amplifier (DC-OPA), respectively. Preliminary experimental results are obtained for generating 1.8–4.2 μm super broadband spectra, which can be used to seed both the signal of the OPCPA and the pump of the DC-OPA. The theoretical pump-to-idler conversion efficiency reaches 27% in the DC-OPA pumped by a chirped broadband Cr2+:ZnSe/ZnS laser, enabling the generation of  Terawatt-level 4–12 μm pulses with an available large-aperture ZGP. Furthermore, the 4–12 μm idler pulses can be compressed to sub-cycle pulses by compensating the tailored positive chirp of the idler pulses using the bulk compressor NaCl, and by indirectly controlling the higher-order idler phase through tuning the signal (2.4–4.0 μm) phase with a commercially available acousto-optic programmable dispersive filter (AOPDF). A similar approach is also described for generating high-energy 4–12 μm sub-cycle pulses via OPCPA pumped by a 2 μm Ho:YLF laser. PMID:28367966

Cavitating vortices in the guide vanes region related to the pump-turbine pumping mode rotating stall

NASA Astrophysics Data System (ADS)

Ješe, U.; Skotak, A.; Mikulašek, J.

2017-04-01

Reversible pump-turbines used in Pumped Storage Power Plants are among the most cost-efficient solutions for storing and recovering large amount of energy in short time. Presented paper is focused on the pump-turbine pumping mode part-load instabilities, among them the rotating stall and the cavitating vortex in the distributor region. Rotating stall can be described as a periodic occurrence and decay of the recirculation zones in the distributor with its own rotational characteristics frequency. Unstable behaviour can result in high radial forces, high pressure fluctuations and local velocity fluctuations that can in some cases lead into the occurrence of the cavitating vortex in the distributor region, even though the distributor is located in the high pressure region. Computationally demanding calculations have been performed using commercial CFD code. Analysed results have been compared to the experimental data obtained in the ČKD Blansko Engineering hydraulic laboratory.

Theoretical investigation of output features of a diode-pumped rubidium vapor laser

NASA Astrophysics Data System (ADS)

Wang, You; Cai, He; Zhang, Wei; Xue, Liangping; Wang, Hongyuan; Han, Juhong

2014-02-01

In the recent years, diode-pumped alkali lasers (DPALs) have been paid many attentions because of their excellent performances. In fact, the characteristics of a DPAL strongly depend on the physical features of buffer gases. In this report, we selected a diode-pumped rubidium vapor laser (DPRVL), which is an important type among three common DPALs, to investigate how the characteristics of a DPRVL are affected by different conditions. The results signify that the population ratio of two excitation energy-levels are close to that corresponding to thermal equilibrium as the pressure of buffer gases and the temperature of a vapor cell become higher. It has been found that quenching of the upper levels cannot be simply ignored especially for the case of weak pump. The conclusions are thought to be helpful for the configuration design of an end-pumped DPAL.

Historic water-level changes and pumpage from the principal aquifers of the Memphis area, Tennessee: 1886-1975

USGS Publications Warehouse

Criner, James H.; Parks, William Scott

1976-01-01

Pumpage from the Fort Pillow Sand ("1,400-foot" sand) began in 1924 and increased at a yearly rate of about 0.6 Mgal/d (2.3 Ml/d) until 1942. From 1943 to 1962, pumpage averaged about 11.5 Mgal/d (43.5 Ml/d), then was reduced as MLGW (Memphis Light, Gas and Water Division) discontinued wells that became unserviceable. MLGW ceased pumping from the aquifer in 1974, and pumpage from the remaining industrial wells in Shelby County in 1975 was 4.4 Mgal/d (16.6 Ml/d). Water levels in the Fort Pillow Sand generally have risen since 1963. Water l evels in the aquifers in the Memphis area fluctuate inversely with changes in pumping. Analysis of observation-well and pumpage data indicates that local water levels can be altered by changing the pumping rates or by varying the areal distribution of pumping.

Use of a plastic insulin dosage guide to correct blood glucose levels out of the target range and for carbohydrate counting in subjects with type 1 diabetes.

PubMed

Kaufman, F R; Halvorson, M; Carpenter, S

1999-08-01

To improve glycemic control, a hand-held plastic Insulin Dosage Guide was developed to correct blood glucose levels outside of the target range. Protocol 1: Some 40 children (mean age 10.6+/-4.6 years) were randomly assigned for 3 months to use a written-on-paper algorithm or the Insulin Dosage Guide to correct abnormal blood glucose levels. Mean HbA1c and blood glucose levels and time to teach insulin dosage correction were compared. Protocol 2: The Insulin Dosage Guide was used by 83 subjects (mean age 11.4+/-4.3 years) for 1 year, and mean HbA1c levels, blood glucose levels, and number of consecutive high blood glucose values taken before and after the year were compared. Protocol 3: Some 20 patients (mean age 10.1+/-3.7 years) using rapid-acting insulin and 64 patients (mean age 15.9+/-3.6 years) using an insulin pump and rapid-acting insulin used the Insulin Dosage Guide and had mean blood glucose levels, HbA1c, and percentage of blood glucose levels outside of the target range determined. Protocol 1: There was a significant reduction in mean HbA1c (P = 0.04) and blood glucose levels (P = 0.05) and in the time needed to teach how to correct blood glucose values using the Insulin Dosage Guide compared with the paper algorithm. Protocol 2: There was a decrease in mean HbA1c levels (P = 0.0001) and a decrease in the mean number of consecutive blood glucose levels (P = 0.001) over the 1-year time period. Protocol 3: With rapid-acting insulin, there was a significant increase in the percentage of blood glucose levels within the target range (1 month, P = 0.04; at 3 months, P = 0.03). With the insulin pump, there was a high rate (90%) of blood glucose levels in the target range during pump initiation when the Insulin Dosage Guide was used. This inexpensive hand-held plastic card, which is portable and easy to use, may help patients improve glycemia and successfully manage diabetes.

RECCAS - REmoval of Cytokines during CArdiac Surgery: study protocol for a randomised controlled trial.

PubMed

Baumann, Andreas; Buchwald, Dirk; Annecke, Thorsten; Hellmich, Martin; Zahn, Peter K; Hohn, Andreas

2016-03-12

On-pump cardiac surgery triggers a significant postoperative systemic inflammatory response, sometimes resulting in multiple-organ dysfunction associated with poor clinical outcome. Extracorporeal cytokine elimination with a novel haemoadsorption (HA) device (CytoSorb®) promises to attenuate inflammatory response. This study primarily assesses the efficacy of intraoperative HA during cardiopulmonary bypass (CPB) to reduce the proinflammatory cytokine burden during and after on-pump cardiac surgery, and secondarily, we aim to evaluate effects on postoperative organ dysfunction and outcomes in patients at high risk. This will be a single-centre randomised, two-arm, patient-blinded trial of intraoperative HA in patients undergoing on-pump cardiac surgery. Subjects will be allocated to receive either CPB with intraoperative HA or standard CPB without HA. The primary outcome is the difference in mean interleukin 6 (IL-6) serum levels between the two study groups on admission to the intensive care unit. A total number of 40 subjects was calculated as necessary to detect a clinically relevant 30 % reduction in postoperative IL-6 levels. Secondary objectives evaluate effects of HA on markers of inflammation up to 48 hours postoperatively, damage to the endothelial glycocalyx and effects on clinical scores and parameters of postoperative organ dysfunction and outcomes. In this pilot trial we try to assess whether intraoperative HA with CytoSorb® can relevantly reduce postoperative IL-6 levels in patients undergoing on-pump cardiac surgery. Differences in secondary outcome variables between the study groups may give rise to further studies and may lead to a better understanding of the mechanisms of haemoadsorption. German Clinical Trials Register number DRKS00007928 (Date of registration 3 Aug 2015).

Reexamining the Hypoglycemia Fear Survey for Parents of Young Children in a Sample of Children Using Insulin Pumps.

PubMed

Patton, Susana R; Noser, Amy E; Clements, Mark A; Dolan, Lawrence M; Powers, Scott W

2017-02-01

We update the psychometric properties of the Hypoglycemia Fear Survey-Parents of Young Children (HFS-PYC), a 26-item measure of parents' hypoglycemia fear for young children using an insulin pump. We combined three similar datasets for the analyses. The data analyzed included parents' responses to the HFS-PYC and a demographic form. For a subset of children (n = 91), we also analyzed self-monitoring of blood glucose data. We used confirmatory factor analysis (CFA) to confirm the measure's original factor structure. Additional analyses examined reliability and validity of a revised HFS-PYC for parents of young children using pumps. We analyzed data from 116 parents (93% mothers). Mean child age and HbA1c were 5.2 ± 1.3 years and 8.2% ± 1.1%, respectively. CFA identified a 22-item two-factor solution (χ 2 (208, n = 116) = 368.688, P < 0.001, root mean square error of approximation = 0.08, comparative fit index = 0.94, and Tucker-Lewis index = 0.93) with factors corresponding to the original subscales: worry and behavior. The revised subscales demonstrated at least adequate internal consistency (Cronbach's alpha >0.65). Correlations revealed significant negative associations between current HFS-PYC worry scores and children's mean daily blood glucose and percent of very high glucose levels per day, suggesting less fear among parents of young children with elevated glycemic levels. In addition, there was a positive association with the percent of glucose levels in target, suggesting greater hypoglycemia fear among parents of children who have better control. Results provide preliminary evidence for the reliability and validity of a reduced 22-item HFS-PYC for parents of children using insulin pumps.

Turbopump options for nuclear thermal rockets

NASA Astrophysics Data System (ADS)

Bissell, W. R.; Gunn, S. V.

1992-07-01

Several turbopump options for delivering liquid nitrogen to nuclear thermal rocket (NTR) engines were evaluated and compared. Axial and centrifugal flow pumps were optimized, with and without boost pumps, utilizing current design criteria within the latest turbopump technology limits. Two possible NTR design points were used, a modest pump pressure rise of 1,743 psia and a relatively higher pump pressure rise of 4,480 psia. Both engines utilized the expander cycle to maximize engine performance for the long duration mission. Pump suction performance was evaluated. Turbopumps with conventional cavitating inducers were compared with zero NPSH (saturated liquid in the tanks) pumps over a range of tank saturation pressures, with and without boost pumps. Results indicate that zero NSPH pumps at high tank vapor pressures, 60 psia, are very similar to those with the finite NPSHs. At low vapor pressures efficiencies fall and turbine pressure ratios increase leading to decreased engine chamber pressures and or increased pump pressure discharges and attendant high-pressure component weights. It may be concluded that zero tank NSPH capabilities can be obtained with little penalty to the engine systems but boost pumps are needed if tank vapor pressure drops below 30 psia. Axial pumps have slight advantages in weight and chamber pressure capability while centrifugal pumps have a greater operating range.

Experimental analysis of the flow pattern of a pump turbine model in pump mode

NASA Astrophysics Data System (ADS)

Guggenberger, Mark; Senn, Florian; Jaberg, Helmut; Gehrer, Arno; Sallaberger, Manfred; Widmer, Christian

2016-11-01

Reversible pump turbines are the only means to store primary energy in an highly efficient way. Within a short time their operation can be switched between the different operational regimes thus enhancing the stabilization of the electric grid. These qualities in combination with the operation even at off-design conditions offer a high flexibility to the energy market. However, pump turbines pass through operational regimes where their behaviour becomes unstable. One of these effects occurs when the flowrate is decreased continuously down to a minimum. This point is the physical limitation of the pump operation and is very difficult to predict properly by numerical design without a model test. The purpose of the present study is to identify the fluid mechanical phenomena leading to the occurrence of instabilities of pump turbines in pump mode. A reduced scale model of a ANDRITZ pump turbine was installed on a 4-quadrant test rig for the experimental investigation of unstable conditions in pump mode. The performed measurements are based on the IEC60193-standard. Characteristic measurements at a single guide vane opening were carried out to get a detailed insight into the instabilities in pump mode. The interaction between runner and guide vane was analysed by Particle Image Velocimetry. Furthermore, high-speed visualizations of the suction side part load flow and the suction recirculation were performed. Like never before the flow pattern in the draft tube cone became visible with the help of a high-speed camera by intentionally caused cavitation effects which allow a qualitative view on the flow pattern in the draft tube cone. Suction recirculation is observed in form of single vortices separating from each runner blade and stretching into the draft tube against the main flow direction. To find an explanation for the flow phenomena responsible for the appearance of the unstable head curve also characteristic velocity distributions on the pressure side were combined with high-speed visualizations on the suction side of the pump turbine model. The results enhance the comprehension of the physical background leading to the instability and improve the numerical predictability of the instability in pump mode.

High-Capacity, Portable Firefighting Pump

NASA Technical Reports Server (NTRS)

Burns, Ralph A.

1988-01-01

Report describes an evaluation of firefighting module that delivers water at 5,000 gal/min (320 L/s). Is compact, self-contained, portable water pump. Besides firefighting, module used for flood control, pumping water into large vessels, and pump water from sinking ships.

Solar powered blackbody-pumped lasers

NASA Astrophysics Data System (ADS)

Christiansen, Walter H.; Sirota, J. M.

1991-02-01

A concept for a solar-powered laser is presented which utilizes an intermediate blackbody cavity to provide a uniform optical pumping environment for the lasant, typically CO or CO2 or possibly a solid state laser medium. High power cw blackbody- pumped lasers with efficiencies on the order of 20 percent or more are feasible. The physical basis of this idea is reviewed. Small scale experiments using a high temperature oven as the optical pump have been carried out with gas laser mixtures. Detailed calculations showing a potential efficiency of 35 percent for blackbody pumped Nd:YAG system are discussed.

Laser dye DCM: CW, synchronously pumped, cavity pumped and single-frequency performance

NASA Astrophysics Data System (ADS)

Marason, E. G.

1981-04-01

Laser dye DCM exhibits a tuning range of 605 to 725 nm with a lasing efficiency as high as 34% when pumped by the 488 nm line of the argon ion laser, placing it among the most efficient and broadly tunable dyes known. Performance of the dye is characterized for four laser systems: 1) continuous wave, 2) synchronously pumped (SP), 3) cavity dumped synchrompously pumped (SPCD) and 4) single-frequency ring dye laser. Pulse peak powers were as high as 520 W and 2.8 kW for SP and SPCD systems respectively.

Radiance limits of ceramic phosphors under high excitation fluxes

NASA Astrophysics Data System (ADS)

Lenef, Alan; Kelso, John; Zheng, Yi; Tchoul, Maxim

2013-09-01

Ceramic phosphors, excited by high radiance pump sources, offer considerable potential for high radiance conversion. Interestingly, thermodynamic arguments suggest that the radiance of the luminescent spot can even exceed that of the incoming light source. In practice, however, thermal quenching and (non-thermal) optical saturation limit the maximum attainable radiance of the luminescent source. We present experimental data for Ce:YAG and Ce:GdYAG ceramics in which these limits have been investigated. High excitation fluxes are achieved using laser pumping. Optical pumping intensities exceeding 100W/mm2 have been shown to produce only modest efficiency depreciation at low overall pump powers because of the short Ce3+ lifetime, although additional limitations exist. When pump powers are higher, heat-transfer bottlenecks within the ceramic and heat-sink interfaces limit maximum pump intensities. We find that surface temperatures of these laser-pumped ceramics can reach well over 150°C, causing thermal-quenching losses. We also find that in some cases, the loss of quantum efficiency with increasing temperature can cause a thermal run-away effect, resulting in a rapid loss in converted light, possibly over-heating the sample or surrounding structures. While one can still obtain radiances on the order of many W/mm2/sr, temperature quenching effects ultimately limit converted light radiance. Finally, we use the diffusion-approximation radiation transport models and rate equation models to simulate some of these nonlinear optical pumping and heating effects in high-scattering ceramics.

Prevalence of Insulin Pump Therapy and Its Association with Measures of Glycemic Control: Results from the Canadian Study of Longevity in Type 1 Diabetes.

PubMed

Boulet, Geneviève; Halpern, Elise M; Lovblom, Leif E; Weisman, Alanna; Bai, Johnny-Wei; Eldelekli, Devrim; Keenan, Hillary A; Brent, Michael H; Paul, Narinder; Bril, Vera; Cherney, David Z I; Perkins, Bruce A

2016-05-01

We aimed to determine cross-sectional insulin pump prevalence and factors associated with measures of glycemic control as a secondary analysis in a long-standing type 1 diabetes mellitus (T1DM) national cohort. Canadian participants with ≥50 years of T1DM (n = 305) were administered a comprehensive mail-based questionnaire including acquisition of contemporaneous laboratory results. Factors associated with pump use, glycosylated hemoglobin (HbA1c), and hypoglycemia were analyzed by regression. The 305 participants had a median age of 65 [interquartile range, 59, 71] years, median diabetes duration of 54 [51, 59] years, and mean HbA1c level of 7.5 ± 1.1%. Prevalence of pump use was 44% (133/305), with median duration of use 8 [4, 13] years. Compared with the non-pump subgroup, the pump subgroup had numerically lower but similar HbA1c levels (7.4 ± 0.9% vs. 7.6 ± 1.2%; P = 0.22) and reported greater numbers of minor hypoglycemia events (6.5 vs. 5.1 events/patient·month; P = 0.004) and fewer severe hypoglycemia events (0.5 vs. 1.3 events/patient·year; P = 0.02) in the past year. More frequent daily glucose tests and more frequent minor hypoglycemia events-but not pump therapy or its prescription parameters-were independently associated with lower HbA1c level in multivariable regression. However, use of insulin pump and habitual use of continuous glucose monitoring (≥1 week/month) were each independently associated with lower risk of severe hypoglycemia (risk ratio = 0.50 [P < 0.0001] and 0.30 [P = 0.001], respectively). Insulin pump and continuous glucose monitoring technologies were associated with lower risk of severe hypoglycemia, while frequent daily glucose testing was associated with lower HbA1c level. These findings imply that basic self-management skill and technology play complementary roles in glycemic control among older adults with long-standing T1DM.

High-efficiency ytterbium-free erbium-doped all-glass double cladding silicate glass fiber for resonantly-pumped fiber lasers.

PubMed

Qiang, Zexuan; Geng, Jihong; Luo, Tao; Zhang, Jun; Jiang, Shibin

2014-02-01

A highly efficient ytterbium-free erbium-doped silicate glass fiber has been developed for high-power fiber laser applications at an eye-safe wavelength near 1.55 μm. Our preliminary experiments show that high laser efficiency can be obtained from a relatively short length of the gain fiber when resonantly pumped at 1535 nm in both core- and cladding-pumping configurations. With a core-pumping configuration as high as 75%, optical-to-optical efficiency and 4 W output power were obtained at 1560 nm from a 1 m long gain fiber. When using a cladding-pumping configuration, approximately 13 W output power with 67.7% slope efficiency was demonstrated from a piece of 2 m long fiber. The lengths of silicate-based gain fiber are much shorter than their silica-based counterparts used in other experiments, which is significantly important for high-power narrow-band and/or pulsed laser applications.

264 W output power at 1585 nm in Er-Yb codoped fiber laser using in-band pumping.

PubMed

Jebali, M A; Maran, J-N; LaRochelle, S

2014-07-01

We demonstrate a high-power cladding-pumped Er-Yb codoped fiber laser with 74% efficiency. A pump-limited output power of 264 W is obtained using in-band pumping at 1535 nm. We compare the efficiency of 1480 and 1535 nm pumping through numerical simulations and experimental measurements.

Preliminary Design of Critical Function Monitoring System of PGSFR

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2015-07-01

A PGSFR (Prototype Gen-IV Sodium-cooled Fast Reactor) is under development at Korea Atomic Energy Research Institute. A critical function monitoring system of the PGSFR is preliminarily studied. The functions of CFMS are to display critical plant variables related to the safety of the plant during normal and accident conditions and guide the operators corrective actions to keep the plant in a safe condition and mitigate the consequences of accidents. The minimal critical functions of the PGSFR are composed of reactivity control, reactor core cooling, reactor coolant system integrity, primary heat transfer system(PHTS) heat removal, sodium water reaction mitigation, radiation controlmore » and containment conditions. The variables and alarm legs of each critical function of the PGSFR are as follows; - Reactivity control: The variables of reactivity control function are power range neutron flux instrumentation, intermediate range neutron flux instrumentation, source range neutron flux instrumentation, and control rod bottom contacts. The alarm leg to display the reactivity controls consists of status of control drop malfunction, high post trip power and thermal reactivity addition. - Reactor core cooling: The variables are PHTS sodium level, hot pool temperature of PHTS, subassembly exit temperature, cold pool temperature of the PHTS, PHTS pump current, and PHTS pump breaker status. The alarm leg consists of high core delta temperature, low sodium level of the PHTS, high subassembly exit temperature, and low PHTS pump load. - Reactor coolant system integrity: The variables are PHTS sodium level, cover gas pressure, and safeguard vessel sodium level. The alarm leg is composed of low sodium level of PHTS, high cover gas pressure and high sodium level of the safety guard vessel. - PHTS heat removal: The variables are PHTS sodium level, hot pool temperature of PHTS, core exit temperature, cold pool temperature of the PHTS, flow rate of passive residual heat removal system, flow rate of active residual heat removal system, and temperatures of air heat exchanger temperature of residual heat removal systems. The alarm legs are composed of two legs of a 'passive residual heat removal system not cooling' and 'active residual heat removal system not cooling'. - Sodium water reaction mitigation: The variables are intermediate heat transfer system(IHTS) pressure, pressure and temperature and level of sodium dump tank, the status of rupture disk, hydrogen concentration in IHTS and direct variable of sodium-water-reaction measure. The alarm leg consists of high IHTS pressure, the status of sodium water reaction mitigation system and the indication of direct measure. - Radiation control: The variables are radiation of PHTS, radiation of IHTS, and radiation of containment purge. The alarm leg is composed of high radiation of PHTS and IHTS, and containment purge system. - Containment condition: The variables are containment pressure, containment isolation status, and sodium fire. The alarm leg consists of high containment pressure, status of containment isolation and status of sodium fire. (authors)« less

Operation of a high-gradient superconducting radio-frequency cavity with a non-evaporable getter pump

DOE PAGES

Ciovati, G.; Geng, R.; Lushtak, Y.; ...

2016-10-28

The use of non-evaporable getter (NEG) pumps in particle accelerators has increased significantly over the past few years because of their large pumping speed, particularly for hydrogen, compared to the size of the pump. A concern about using such pumps in superconducting radio-frequency (SRF) accelerators is the possibility of shedding particulates which could then migrate into the SRF cavities and produce field emission, therefore degrading the cavity performance. One option to mitigate such issue is to use sintered getter materials which intrinsically offer superior mechanical and particle retention properties. In this article we present the results from cryogenic RF testsmore » of a high-gradient SRF cavity after being evacuated several times with an NEG pump equipped with sintered getter disks and placed in close proximity to the cavity. Here, the results showed that the cavity performance was not affected by the pump up to the quench gradient of 34 MV/m. As a result of this study, two such NEG pumps have been installed next to a cryomodule in the CEBAF accelerator to maintain ultra-high vacuum in the SRF cryomodule and two adjacent warm girder sections.« less

Design and properties of high-power highly-coherent single-frequency VECSEL emitting in the near- to mid-IR for photonic applications

NASA Astrophysics Data System (ADS)

Garnache, A.; Laurain, A.; Myara, M.; Sellahi, M.; Cerutti, L.; Perez, J. P.; Michon, A.; Beaudoin, G.; Sagnes, I.; Cermak, P.; Romanini, D.

2017-11-01

We demonstrate high power (multiwatt) low noise single frequency operation of tunable compact verical-external- cavity surface-emitting-lasers exhibiting a low divergence high beam quality, of great interest for photonics applications. The quantum-well based lasers are operating in CW at RT at 1μm and 2.3μm exploiting GaAs and Sb technologies. For heat management purpose the VECSEL membranes were bonded on a SiC substrate. Both high power diode pumping (using GaAs commercial diode) at large incidence angle and electrical pumping are developed. The design and physical properties of the coherent wave are presented. We took advantage of thermal lens-based stability to develop a short (0.5-5mm) external cavity without any intracavity filter. We measured a low divergence circular TEM00 beam (M2 = 1.2) close to diffraction limit, with a linear light polarization (> 30 dB). The side mode suppression ratio is > 45 dB. The free running laser linewidth is 37 kHz limited by pump induced thermal fluctuations. Thanks to this high-Q external cavity approach, the frequency noise is low and the dynamics is in the relaxation-oscillation-free regime, exhibiting low intensity noise (< 0.1%), with a cutoff frequency ∽ 41MHz above which the shot noise level is reached. The key parameters limiting the laser power and coherence will be discussed. These design/properties can be extended to other wavelengths.

Rotating and positive-displacement pumps for low-thrust rocket engines. Volume 1: Pump Evaluation and design. [of centrifugal pumps

NASA Technical Reports Server (NTRS)

Macgregor, C.; Csomor, A.

1974-01-01

Rotating and positive displacement pumps of various types were studied for pumping liquid fluorine for low-thrust, high-performance rocket engines. Included in the analysis were: centrifugal, pitot, Barske, Tesla, drag, gear, vane, axial piston, radial piston, diaphragm, and helirotor pump concepts. The centrifugal pump and the gear pump were selected and these were carried through detailed design and fabrication. Mechanical difficulties were encountered with the gear pump during the preliminary tests in Freon-12. Further testing and development was therefore limited to the centrifugal pump. Tests on the centrifugal pump were conducted in Freon-12 to determine the hydrodynamic performance and in liquid fluorine to demonstrate chemical compatibility.

Postprandial lymphatic pump function after a high-fat meal: a characterization of contractility, flow, and viscosity

PubMed Central

Kassis, Timothy; Yarlagadda, Sri Charan; Kohan, Alison B.; Tso, Patrick; Breedveld, Victor

2016-01-01

Dietary lipids are transported from the intestine through contractile lymphatics. Chronic lipid loads can adversely affect lymphatic function. However, the acute lymphatic pump response in the mesentery to a postprandial lipid meal has gone unexplored. In this study, we used the rat mesenteric collecting vessel as an in vivo model to quantify the effect of lipoproteins on vessel function. Lipid load was continuously monitored by using the intensity of a fluorescent fatty-acid analog, which we infused along with a fat emulsion through a duodenal cannula. The vessel contractility was simultaneously quantified. We demonstrated for the first time that collecting lymphatic vessels respond to an acute lipid load by reducing pump function. High lipid levels decreased contraction frequency and amplitude. We also showed a strong tonic response through a reduction in the end-diastolic and systolic diameters. We further characterized the changes in flow rate and viscosity and showed that both increase postprandially. In addition, shear-mediated Ca2+ signaling in lymphatic endothelial cells differed when cultured with lipoproteins. Together these results show that the in vivo response could be both shear and lipid mediated and provide the first evidence that high postprandial lipid has an immediate negative effect on lymphatic function even in the acute setting. PMID:26968208

A mathematical model of the pancreatic duct cell generating high bicarbonate concentrations in pancreatic juice.

PubMed

Whitcomb, David C; Ermentrout, G Bard

2004-08-01

To develop a simple, physiologically based mathematical model of pancreatic duct cell secretion using experimentally derived parameters that generates pancreatic fluid bicarbonate concentrations of >140 mM after CFTR activation. A new mathematical model was developed simulating a duct cell within a proximal pancreatic duct and included a sodium-2-bicarbonate cotransporter (NBC) and sodium-potassium pump (NaK pump) on a chloride-impermeable basolateral membrane, CFTR on the luminal membrane with 0.2 to 1 bicarbonate to chloride permeability ratio. Chloride-bicarbonate antiporters (Cl/HCO3 AP) were added or subtracted from the basolateral (APb) and luminal (APl) membranes. The model was integrated over time using XPPAUT. This model predicts robust, NaK pump-dependent bicarbonate secretion with opening of the CFTR, generates and maintains pancreatic fluid secretion with bicarbonate concentrations >140 mM, and returns to basal levels with CFTR closure. Limiting CFTR permeability to bicarbonate, as seen in some CFTR mutations, markedly inhibited pancreatic bicarbonate and fluid secretion. A simple CFTR-dependent duct cell model can explain active, high-volume, high-concentration bicarbonate secretion in pancreatic juice that reproduces the experimental findings. This model may also provide insight into why CFTR mutations that predominantly affect bicarbonate permeability predispose to pancreatic dysfunction in humans.

Salinity Tolerance of Two Potato Cultivars (Solanum tuberosum) Correlates With Differences in Vacuolar Transport Activity

PubMed Central

Jaarsma, Rinse; de Boer, Albertus H.

2018-01-01

Potato is an important cultivated crop species and since it is moderately salt sensitive there is a need to develop more salt tolerant cultivars. A high activity of Na+ transport across the tonoplast in exchange for H+ is essential to reduce Na+ toxicity. The proton motive force (PMF) generated by the V-H+-ATPase and the V-H+-PPase energizes the Na+(K+)/H+ antiport. We compared the activity, gene expression, and protein levels of the vacuolar proton pumps and the Na+/H+ antiporters in two potato cultivars (Solanum tuberosum) contrasting in their salt tolerance (cv. Desiree; tolerant and Mozart; sensitive) grown at 0 and 60 mM NaCl. Tonoplast-enriched vesicles were used to study the pump activity and protein levels of the V-H+-ATPase and the V-H+-PPase and the activity of the Na+/H+ antiporter. Although salt stress reduced the V-H+-ATPase and the V-H+-PPase activity in both cultivars, the decline in H+ pump activity was more severe in the salt-sensitive cultivar Mozart. After salt treatment, protein amounts of the vacuolar H+ pumps decreased in Mozart but remained unchanged in the cultivar Desiree. Decreased protein amounts of the V-H+-PPase found in Mozart may explain the reduced V-H+-PPase activity found for Mozart after salt stress. Under non-stress conditions, protein amounts of V-H+-PPase were equal in both cultivars while the V-H+-PPase activity was already twice as high and remained higher after salt treatment in the cultivar Desiree as compared to Mozart. This cultivar-dependent V-H+-PPase activity may explain the higher salt tolerance of Desiree. Moreover, combined with reduced vacuolar H+ pump activity, Mozart showed a lower Na+/H+ exchange activity and the Km for Na+ is at least twofold lower in tonoplast vesicles from Desiree, what suggests that NHXs from Desiree have a higher affinity for Na+ as compared to Mozart. From these results, we conclude that the higher capacity in combination with the higher affinity for Na+ uptake can be an important factor to explain the differences in salt tolerance of these two potato cultivars. PMID:29922314

Salinity Tolerance of Two Potato Cultivars (Solanum tuberosum) Correlates With Differences in Vacuolar Transport Activity.

PubMed

Jaarsma, Rinse; de Boer, Albertus H

2018-01-01

Potato is an important cultivated crop species and since it is moderately salt sensitive there is a need to develop more salt tolerant cultivars. A high activity of Na + transport across the tonoplast in exchange for H + is essential to reduce Na + toxicity. The proton motive force (PMF) generated by the V-H + -ATPase and the V-H + -PPase energizes the Na + (K + )/H + antiport. We compared the activity, gene expression, and protein levels of the vacuolar proton pumps and the Na + /H + antiporters in two potato cultivars ( Solanum tuberosum ) contrasting in their salt tolerance (cv. Desiree; tolerant and Mozart; sensitive) grown at 0 and 60 mM NaCl. Tonoplast-enriched vesicles were used to study the pump activity and protein levels of the V-H + -ATPase and the V-H + -PPase and the activity of the Na + /H + antiporter. Although salt stress reduced the V-H + -ATPase and the V-H + -PPase activity in both cultivars, the decline in H + pump activity was more severe in the salt-sensitive cultivar Mozart. After salt treatment, protein amounts of the vacuolar H + pumps decreased in Mozart but remained unchanged in the cultivar Desiree. Decreased protein amounts of the V-H + -PPase found in Mozart may explain the reduced V-H + -PPase activity found for Mozart after salt stress. Under non-stress conditions, protein amounts of V-H + -PPase were equal in both cultivars while the V-H + -PPase activity was already twice as high and remained higher after salt treatment in the cultivar Desiree as compared to Mozart. This cultivar-dependent V-H + -PPase activity may explain the higher salt tolerance of Desiree. Moreover, combined with reduced vacuolar H + pump activity, Mozart showed a lower Na + /H + exchange activity and the K m for Na + is at least twofold lower in tonoplast vesicles from Desiree, what suggests that NHXs from Desiree have a higher affinity for Na + as compared to Mozart. From these results, we conclude that the higher capacity in combination with the higher affinity for Na + uptake can be an important factor to explain the differences in salt tolerance of these two potato cultivars.

Lasing in strongly scattering dielectric microstructures

NASA Astrophysics Data System (ADS)

Florescu, Lucia

In the first part of this thesis, a detailed analysis of lasing in random multiple-light-scattering media with gain is presented. Random laser emission is analyzed using a time-dependent diffusion model for light propagating in the medium containing active atoms. We demonstrate the effects of scatterers to narrow the emission spectral linewidth and to shorten the emitted pulse duration at a specific threshold pump intensity. This threshold pump intensity decreases with scatterer density and excitation spot diameter, in excellent agreement with experimental results. The coherence properties of the random laser are studied using a generalized master equation. The random laser medium is treated as a collection of low quality-factor cavities, coupled by random photon diffusion. Laser-like coherence, on average, is demonstrated above a specific pumping threshold. We demonstrate that with stronger scattering, the pumping threshold for the transition from chaotic to isotropic coherent light emission decreases and enhanced optical coherence for the emitted light is achieved above threshold. The second part of this thesis presents a study of lasing in photonic crystals (PCs). The emission from an incoherently pumped atomic system in interaction with the electro-magnetic reservoir of a PC is analyzed using a set of generalized semiclassical Maxwell-Bloch equations. We demonstrate that the photonic band edge facilitates the enhancement of stimulated emission and the reduction of internal losses, leading to an important lowering of the laser threshold. In addition, an increase of the laser output at a photonic band edge is demonstrated. We next develop a detailed quantum theory of a coherently pumped two-level atom in a photonic band gap material, coupled to both a multi-mode wave-guide channel and a high-quality micro-cavity embedded within the PC. The cavity field characteristics are highly distinct from that of a corresponding high-Q cavity in ordinary vacuum. We demonstrate enhanced, inversionless, and nearly coherent light generation when the photon density of states (DOS) jump between the Mollow spectral components of atomic resonance fluorescence is large. In the case of a vanishing photon DOS on the lower Mollow sideband and no dipolar dephasing, the emitted photon statistics is Poissonian and the cavity field exhibits quadrature coherence.

Coupling of methylmercury uptake with respiration and water pumping in freshwater tilapia Oreochromis niloticus.

PubMed

Wang, Rui; Wong, Ming-Hung; Wang, Wen-Xiong

2011-09-01

The relationships among the uptake of toxic methylmercury (MeHg) and two important fish physiological processes-respiration and water pumping--in the Nile tilapia (Oreochromis niloticus) were explored in the present study. Coupled radiotracer and respirometric techniques were applied to measure simultaneously the uptake rates of MeHg, water, and oxygen under various environmental conditions (temperature, dissolved oxygen level, and water flow). A higher temperature enhanced MeHg influx and the oxygen consumption rate but had no effect on the water uptake, indicating the influence of metabolism on MeHg uptake. The fish showed a high tolerance to hypoxia, and the oxygen consumption rate was not affected until the dissolved oxygen concentration decreased to extremely low levels (below 1 mg/L). The MeHg and water uptake rates increased simultaneously as the dissolved oxygen level decreased, suggesting the coupling of water flux and MeHg uptake. The influence of fish swimming performance on MeHg uptake was also investigated for the first time. Rapidly swimming fish showed significantly higher uptake rates of MeHg, water, and oxygen, confirming the coupling relationships among respiration, water pumping, and metal uptake. Moreover, these results support that MeHg uptake is a rate-limiting process involving energy. Our study demonstrates the importance of physiological processes in understanding mercury bioaccumulation in fluctuating aquatic environments. Copyright © 2011 SETAC.

Factors affecting the distribution of hydrocarbon contaminants and hydrogeochemical parameters in a shallow sand aquifer

NASA Astrophysics Data System (ADS)

Lee, Jin-Yong; Cheon, Jeong-Yong; Lee, Kang-Kun; Lee, Seok-Young; Lee, Min-Hyo

2001-07-01

The distributions of hydrocarbon contaminants and hydrogeochemical parameters were investigated in a shallow sand aquifer highly contaminated with petroleum hydrocarbons leaked from solvent storage tanks. For these purposes, a variety of field investigations and studies were performed, which included installation of over 100 groundwater monitoring wells and piezometers at various depths, soil logging and analyses during well and piezometer installation, chemical analysis of groundwater, pump tests, and slug tests. Continuous water level monitoring at three selected wells using automatic data-logger and manual measuring at other wells were also conducted. Based on analyses of the various investigations and tests, a number of factors were identified to explain the distribution of the hydrocarbon contaminants and hydrogeochemical parameters. These factors include indigenous biodegradation, hydrostratigraphy, preliminary pump-and-treat remedy, recharge by rainfall, and subsequent water level fluctuation. The permeable sandy layer, in which the mean water table elevation is maintained, provided a dominant pathway for contaminant transport. The preliminary pump-and-treat action accelerated the movement of the hydrocarbon contaminants and affected the redox evolution pattern. Seasonal recharge by rain, together with indigenous biodegradation, played an important role in the natural attenuation of the petroleum hydrocarbons via mixing/dilution and biodegradation. The water level fluctuations redistributed the hydrocarbon contaminants by partitioning them into the soil and groundwater. The identified factors are not independent but closely inter-correlated.

Optimized Biasing of Pump Laser Diodes in a Highly Reliable Metrology Source for Long-Duration Space Missions

NASA Technical Reports Server (NTRS)

Poberezhskiy, Ilya Y; Chang, Daniel H.; Erlig, Herman

2011-01-01

Optical metrology system reliability during a prolonged space mission is often limited by the reliability of pump laser diodes. We developed a metrology laser pump module architecture that meets NASA SIM Lite instrument optical power and reliability requirements by combining the outputs of multiple single-mode pump diodes in a low-loss, high port count fiber coupler. We describe Monte-Carlo simulations used to calculate the reliability of the laser pump module and introduce a combined laser farm aging parameter that serves as a load-sharing optimization metric. Employing these tools, we select pump module architecture, operating conditions, biasing approach and perform parameter sensitivity studies to investigate the robustness of the obtained solution.

High pumping-power fiber combiner for double-cladding fiber lasers and amplifiers

NASA Astrophysics Data System (ADS)

Zheng, Jinkun; Zhao, Wei; Zhao, Baoyin; Li, Zhe; Chang, Chang; Li, Gang; Gao, Qi; Ju, Pei; Gao, Wei; She, Shengfei; Wu, Peng; Hou, Chaoqi; Li, Weinan

2018-03-01

A high pumping-power fiber combiner for backward pumping configurations is fabricated and demonstrated by manufacturing process refinement. The pump power handling capability of every pump fiber can extend to 600 W, corresponding to the average pump coupling efficiency of 94.83%. Totally, 2.67-kW output power with the beam quality factor M2 of 1.41 was obtained, using this combiner in the fiber amplifier experimental setup. In addition, the temperature of the splicing region was less than 50.0°C in the designed combiner under the action of circulating cooling water. The experimental results prove that the designed combiner is a promising integrated all-fiber device for multikilowatt continuous-wave fiber laser with excellent beam quality.

Clad-pumped Er-nanoparticle-doped fiber laser (Conference Presentation)

NASA Astrophysics Data System (ADS)

Baker, Colin C.; Friebele, E. Joseph; Rhonehouse, Daniel L.; Marcheschi, Barbara A.; Peele, John R.; Kim, Woohong; Sanghera, Jasbinder S.; Zhang, Jun; Chen, Youming; Pattnaik, Radha K.; Dubinskii, Mark

2017-03-01

Erbium-doped fiber lasers are attractive for directed energy weapons applications because they operate in a wavelength region that is both eye-safer and a window of high atmospheric transmission. For these applications a clad-pumped design is desirable, but the Er absorption must be high because of the areal dilution of the doped core vs. the pump cladding. High Er concentrations typically lead to Er ion clustering, resulting in quenching and upconversion. Nanoparticle (NP) doping of the core overcomes these problems by physically surrounding the Er ions with a cage of Al and O in the NP, which keeps them separated to minimize excited state energy transfer. A significant issue is obtaining high Er concentrations without the NP agglomeration that degrades the optical properties of the fiber core. We have developed the process for synthesizing stable Er-NP suspension which have been used to fabricate EDFs with Er concentrations >90 dB/m at 1532 nm. Matched clad fibers have been evaluated in a core-pumped MOPA with pump and signal wavelengths of 1475 and 1560 nm, respectively, and efficiencies of 72% with respect to absorbed pump have been obtained. We have fabricated both NP- and solution-doped double clad fibers, which have been measured in a clad-pumped laser testbed using a 1532 nm pump. The 1595 nm laser efficiency of the NP-doped fiber was 47.7%, which is high enough for what is believed to be the first laser experiment with the cladding pumped, NP-doped fiber. Further improvements are likely with a shaped cladding and new low-index polymer coatings with lower absorption in the 1500 - 1600 nm range.

Low-cost, high-performance nonevaporable getter pumps using nonevaporable getter pills

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kodama, Hiraku; Ohno, Shinya; Tanaka, Masatoshi

Nonevaporable getter (NEG) pumps are widely used for maintaining a clean ultrahigh vacuum (UHV) of ≤10{sup −8 }Pa because of their high pumping speeds for hydrogen (H{sub 2}) and active gases in the UHV region. In addition, they are oil free, evaporation free, sputtering free, sublimation free, magnetic field free, vibration free, economical, compact, lightweight, and energy saving. In the present paper, the authors report a new NEG pump which is composed of commercial 60 NEG pills (ϕ10 × 3 mm; 70 wt. % Zr, 24.6 wt. % V, and 5.4 wt. % Fe), titanium parts, a DN 40 conflat flange, and a tantalum heater.more » The NEG pills are vertically and radially aligned around the heater to maximize the effective area for pumping. After activation at 400 °C for 30 min, the pumping speeds of the NEG pump were measured with the orifice method. Pumping speeds of 140–130, 200–140, 190–130, and 35–17 l/s were estimated for H{sub 2}, CO, CO{sub 2}, and N{sub 2} gasses, respectively, in a pumped-quantity range of 0.01–0.1 Pa l. Since the NEG pump is composed of a heating unit and a NEG module, the pumping speeds can be improved by increasing the number of NEG modules. These NEG pumps are favorable alternatives to sputtering ion pumps or titanium sublimation pumps.« less

Exploring Ultrafast Structural Dynamics for Energetic Enhancement or Disruption

DTIC Science & Technology

2016-03-01

it. In a pump -push/ dump probe experiment, a secondary laser pulse (push/ dump ) is used after the initial perturbation due to the pump pulse. The...increased. The pump -push/ dump probe technique is a difficult experiment that requires a highly stable laser source. Ultrafast pump -probe experiments...decomposition of solids. Journal of Applied Physics. 2001;89:4156–4166. 17. Kee TW. Femtosecond pump -push-probe and pump - dump -probe spectroscopy of

Pump Thrombosis following HeartMate II Left Ventricular Assist Device Implantation in a Patient with Aspirin and Plavix Resistance.

PubMed

Ghodsizad, Ali; Badiye, A; Zeriouh, M; Pae, W; Koerner, M M; Loebe, M

2016-12-14

Despite advances in pump technology, thromboembolic events and pump thrombosis are potentially life-threatening complications in patients with continuous flow ventricular assist devices. Here we describe a patient with pump thrombosis following LVAD HeartMate II implantation presenting with Aspirin and Plavix resistance and signs of acute hemolysis as manifested by high LDH, changing pump power, pulse index and reduced pump flows.

KrF laser pumping by electron beam discharge

NASA Astrophysics Data System (ADS)

Bonnet, J.; Fournier, G.; Pigache, D.

1981-09-01

The pumping of excimer lasers used in nuclear fusion and isotope separation is considered. Homogeneous ionization with an electron beam permitted discharge pumping of a KrF laser with a discharge-energy/beam-energy ratio 5. This high value is obtained to the detriment of an energy density and an efficiency which are about half the best values obtained under other conditions. This result does not modify a recent conclusion indicating that an electron beam controlled discharge has no significant advantage over a pure electron beam as regards pumping high energy KrF lasers at high repetition rate.

Engine with hydraulic fuel injection and ABS circuit using a single high pressure pump

DOEpatents

Bartley, Bradley E.; Blass, James R.; Gibson, Dennis H.

2001-01-01

An engine system comprises a hydraulically actuated fuel injection system and an ABS circuit connected via a fluid flow passage that provides hydraulic fluid to both the fuel injection system and to the ABS circuit. The hydraulically actuated system includes a high pressure pump. The fluid control passage is in fluid communication with an outlet from the high pressure pump.

Design and Specification of Low Pressure Sewer Systems for Recreation Areas.

DTIC Science & Technology

1985-02-01

holding tank receives wastewater Iflows by gravity. Level scitsors act ivate the grinder pump operation pump at preset levels. Emergency 40 overf low aid...above the septic 0 Lank floor, the septic tank should be secured against flotation . Test in. 70. Septir t.ank s shouldt Ihe wat’rtight and must be...8217 , pump i rig je,j , aind powt, r cost . Annual power cost can he estimated using the fo I I owi rig express ion: APC =ae PC (4) whe -e 0 APIC annual

TANK 26 EVAPORATOR FEED PUMP TRANSFER ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tamburello, D; Si Lee, S; Richard Dimenna, R

2008-09-30

The transfer of liquid salt solution from Tank 26 to an evaporator is to be accomplished by activating the evaporator feed pump, located approximately 72 inches above the sludge layer, while simultaneously turning on the downcomer. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics methods to determine the amount of entrained sludge solids pumped out of the tank to the evaporator with the downcomer turned on. The analysis results showed that, for the maximummore » and minimum supernate levels in Tank 26 (252.5 and 72 inches above the sludge layer, respectively), the evaporator feed pump will entrain between 0.05 and 0.1 wt% sludge solids weight fraction into the eductor, respectively. Lower tank liquid levels, with respect to the sludge layer, result in higher amounts of sludge entrainment due to the increased velocity of the plunging jets from the downcomer and evaporator feed pump bypass as well as decreased dissipation depth.« less

Pump and probe spectroscopy with continuous wave quantum cascade lasers.

PubMed

Kirkbride, James M R; Causier, Sarah K; Dalton, Andrew R; Weidmann, Damien; Ritchie, Grant A D

2014-02-07

This paper details infra-red pump and probe studies on nitric oxide conducted with two continuous wave quantum cascade lasers both operating around 5 μm. The pump laser prepares a velocity selected population in a chosen rotational quantum state of the v = 1 level which is subsequently probed using a second laser tuned to a rotational transition within the v = 2 ← v = 1 hot band. The rapid frequency scan of the probe (with respect to the molecular collision rate) in combination with the velocity selective pumping allows observation of marked rapid passage signatures in the transient absorption profiles from the polarized vibrationally excited sample. These coherent transient signals are influenced by the underlying hyperfine structure of the pump and probe transitions, the sample pressure, and the coherent properties of the lasers. Pulsed pump and probe studies show that the transient absorption signals decay within 1 μs at 50 mTorr total pressure, reflecting both the polarization and population dephasing times of the vibrationally excited sample. The experimental observations are supported by simulation based upon solving the optical Bloch equations for a two level system.

Low-Cost, Rugged High-Vacuum System

NASA Technical Reports Server (NTRS)

Sorensen, Paul; Kline-Schoder, Robert

2012-01-01

A need exists for miniaturized, rugged, low-cost high-vacuum systems. Recent advances in sensor technology have led to the development of very small mass spectrometer detectors as well as other analytical instruments such as scanning electron microscopes. However, the vacuum systems to support these sensors remain large, heavy, and power-hungry. To meet this need, a miniaturized vacuum system was developed based on a very small, rugged, and inexpensive-to-manufacture molecular drag pump (MDP). The MDP is enabled by a miniature, very-high-speed (200,000 rpm), rugged, low-power, brushless DC motor optimized for wide temperature operation and long life. The key advantages of the pump are reduced cost and improved ruggedness compared to other mechanical hig-hvacuum pumps. The machining of the rotor and stators is very simple compared to that necessary to fabricate rotor and stator blades for other pump designs. Also, the symmetry of the rotor is such that dynamic balancing of the rotor will likely not be necessary. Finally, the number of parts in the unit is cut by nearly a factor of three over competing designs. The new pump forms the heart of a complete vacuum system optimized to support analytical instruments in terrestrial applications and on spacecraft and planetary landers. The MDP achieves high vacuum coupled to a ruggedized diaphragm rough pump. Instead of the relatively complicated rotor and stator blades used in turbomolecular pumps, the rotor in the MDP consists of a simple, smooth cylinder of aluminum. This will turn at approximately 200,000 rpm inside an outer stator housing. The pump stator comprises a cylindrical aluminum housing with one or more specially designed grooves that serve as flow channels. To minimize the length of the pump, the gas is forced down the flow channels of the outer stator to the base of the pump. The gas is then turned and pulled toward the top through a second set of channels cut into an inner stator housing that surrounds the motor. The compressed gas then flows down channels in the motor housing to the exhaust port of the pump. The exhaust port of the pump is connected to a commercially available diaphragm or scroll pump.

Theoretical model predictions and experimental results for a wavelength switchable Tm:YAG laser.

PubMed

Niu, Yanxiong; Wang, Caili; Liu, Wenwen; Niu, Haisha; Xu, Bing; Man, Da

2014-07-01

We present a theoretical model study of a quasi-three-level laser with particular attention given to the Tm:YAG laser. The oscillating conditions of this laser were theoretically analyzed from the point of the pump threshold while taking into account reabsorption loss. The laser oscillation at 2.02 μm with large stimulated emission sections was suppressed by selecting the appropriate coating for the cavity mirrors, then an efficient laser-diode side-pumped continuous-wave Tm:YAG crystal laser operating at 2.07 μm was realized. Experiments with the Tm:YAG laser confirmed the accuracy of the model, and the model was able to accurately predict that the high Stark sub-level within the H3₆ ground state manifold has a low laser threshold and long laser wavelength, which was achieved by decreasing the transmission of the output coupler.

Skeletal myopathy in juvenile barramundi, Lates calcarifer (Bloch), cultured in potassium-deficient saline groundwater.

PubMed

Partridge, G J; Creeper, J

2004-09-01

Saline groundwater is being pumped from a number of locations in rural Western Australia to prevent secondary salinity impacting farmland, rural infrastructure and areas with high conservation value. Aquaculture may offset the costs of groundwater pumping, and the suitability of groundwater for finfish aquaculture is being assessed through bioassays. There are marked spatial variations in the ionic composition of saline ground water in Western Australia and this paper describes two bioassays investigating a saline, potassium-deficient water source that resulted in mortalities in juvenile barramundi, Lates calcarifer (Bloch). Histopathological examination revealed severe degeneration and necrosis of skeletal muscles, marked hyperplasia of branchial chloride cells and renal tubular necrosis. Clinical chemistry findings included hypernatraemia and hyperchloridaemia of the blood plasma and lowered muscle potassium levels. It is concluded that the principal cause of death was skeletal myopathy induced by low water potassium levels.

The effect of electromagnetically induced transparency in a potassium nanocell

NASA Astrophysics Data System (ADS)

Sargsyan, A.; Amiryan, A.; Leroy, C.; Vartanyan, T. A.; Sarkisyan, D.

2017-07-01

The effect of electromagnetically induced transparency (EIT) has been experimentally implemented for the first time for the (4 S 1/2-4 P 1/2-4 S 1/2) Λ-system of potassium atom levels in a nanocell with a 770-nm-thick column of atomic vapor. It is shown that, at such a small thickness of the vapor column, the EIT resonance can be observed only when the coupling-laser frequency is in exact resonance with the frequency of the corresponding atomic transition. The EIT resonance disappears even if the coupling-laser frequency differs slightly (by 50 MHz) from that of the corresponding atomic transition, which is due to the high thermal velocity of K atoms. The EIT resonance and related velocity selective optical pumping resonances caused by optical pumping (formed by the coupling) can be simultaneously recorded because of the small ( 462 MHz) hyperfine splitting of the lower 4 S 1/2 level.

Large size crystalline vs. co-sintered ceramic Yb(3+):YAG disk performance in diode pumped amplifiers.

PubMed

Albach, Daniel; Chanteloup, Jean-Christophe

2015-01-12

A comprehensive experimental benchmarking of Yb(3+):YAG crystalline and co-sintered ceramic disks of similar thickness and doping level is presented in the context of high average power laser amplifier operation. Comparison is performed considering gain, depolarization and wave front deformation quantitative measurements and analysis.

Diabetes Mellitus and the Insulin Pump: What Teachers Need to Know

ERIC Educational Resources Information Center

Obringer, S. John; Coffey, Kenneth

2006-01-01

Diabetes is a condition where high amounts of glucose are found in the bloodstream due to impaired secretion of insulin. The hormone insulin was discovered by two physicians, Fredrick Banting and James Mcleod in 1921. Individuals with severe diabetes typically controlled their glucose level with multiple daily injections of insulin. Recently the…

Controlled induced recharge tests at Kalamazoo, Michigan

USGS Publications Warehouse

Deutsch, Morris

1962-01-01

This article discusses the results of a controlled field testing program, which indicated that definite hydraulic and other advantages may be gained from induced recharging as practiced at Kalamazoo, Michigan. Results include the following: water levels and artesian pressures can be maintained at high stages, the results are lower pumping lifts and substantial reductions in the amount of power used for pumping; the high water levels permit increased rates of withdrawal during periods of peak demand; encroachment of poor quality water from other aquifers is minimized; the surface water induced into the aquifer is filtered naturally through great thicknesses of earth materials; natural underground storage is used to conserve and protect water, which otherwise would flow largely to waste; and, significant supplemental benefits, including flood control, have been derived. The tests demonstrated that it is possible to manipulate the regimen of a complex hydrologic system for definite hydraulic benefits with predictable results. Furthermore with current methods, quantitative evaluations may be made of the effects of induced recharge. The results of the tests, therefore, are applicable in other areas of similar hydrogeologic environments.

Fabrication of micro metallic valve and pump

NASA Astrophysics Data System (ADS)

Yang, Ming; Kabasawa, Yasunari; Ito, Kuniyoshi

2010-03-01

Fabrication of micro devices by using micro metal forming was proposed by the authors. We developed a desktop servo-press machine with precise tooling system. Precise press forming processes including micro forging and micro joining has been carried out in a progressive die. In this study, micro metallic valve and pump were fabricated by using the precise press forming. The components are made of sheet metals, and assembled in to a unit in the progressive die. A micro check-valve with a diameter of 3mm and a length of 3.2mm was fabricated, and the property of flow resistance was evaluated. The results show that the check valve has high property of leakage proof. Since the valve is a unit parts with dimensions of several millimeters, it has advantage to be adapted to various pump design. Here, two kinds of micro pumps with the check-valves were fabricated. One is diaphragm pump actuated by vibration of the diaphragm, and another is tube-shaped pump actuated by resonation. The flow quantities of the pumps were evaluated and the results show that both of the pumps have high pumping performance.

Engineering the Implementation of Pumped Hydro Energy Storage in the Arizona Power Grid

NASA Astrophysics Data System (ADS)

Dixon, William Jesse J.

This thesis addresses the issue of making an economic case for bulk energy storage in the Arizona bulk power system. Pumped hydro energy storage (PHES) is used in this study. Bulk energy storage has often been suggested for large scale electric power systems in order to levelize load (store energy when it is inexpensive [energy demand is low] and discharge energy when it is expensive [energy demand is high]). It also has the potential to provide opportunities to avoid transmission and generation expansion, and provide for generation reserve margins. As the level of renewable energy resources increases, the uncertainty and variability of wind and solar resources may be improved by bulk energy storage technologies. For this study, the MATLab software platform is used, a mathematical based modeling language, optimization solvers (specifically Gurobi), and a power flow solver (PowerWorld) are used to simulate an economic dispatch problem that includes energy storage and transmission losses. A program is created which utilizes quadratic programming to analyze various cases using a 2010 summer peak load from the Arizona portion of the Western Electricity Coordinating Council (WECC) system. Actual data from industry are used in this test bed. In this thesis, the full capabilities of Gurobi are not utilized (e.g., integer variables, binary variables). However, the formulation shown here does create a platform such that future, more sophisticated modeling may readily be incorporated. The developed software is used to assess the Arizona test bed with a low level of energy storage to study how the storage power limit effects several optimization outputs such as the system wide operating costs. Large levels of energy storage are then added to see how high level energy storage affects peak shaving, load factor, and other system applications. Finally, various constraint relaxations are made to analyze why the applications tested eventually approach a constant value. This research illustrates the use of energy storage which helps minimize the system wide generator operating cost by "shaving" energy off of the peak demand. The thesis builds on the work of another recent researcher with the objectives of strengthening the assumptions used, checking the solutions obtained, utilizing higher level simulation languages to affirm results, and expanding the results and conclusions. One important point not fully discussed in the present thesis is the impact of efficiency in the pumped hydro cycle. The efficiency of the cycle for modern units is estimated at higher than 90%. Inclusion of pumped hydro losses is relegated to future work.

Inhibitors of Proton Pumping

PubMed Central

Bisson, Mary A.

1986-01-01

Reported inhibitors of the Characean plasmalemma proton pump were tested for their ability to inhibit the passive H+ conductance which develops in Chara corallina Klein ex Willd. at high pH. Diethylstilbestrol inhibits the proton pump and the passive H+ conductance with about the same time course, at concentrations that have no effect on cytoplasmic streaming. N-Ethylmaleimide, a sulfhydryl reagent which is small and relatively nonpolar, also inhibits both pumping and passive conductance of H+. However, it also inhibits cytoplasmic streaming with about the same time course, and therefore could not be considered a specific ATPase inhibitor. p-Chloromercuribenzene sulfonate (PCMBS), a sulfhydryl reagent which is large and charged and hence less able to penetrate the membrane, does not inhibit pumping or conductance at low concentration. At high concentration, PCMBS sometimes inhibits pumping without affecting H+ conductance, but since streaming is also inhibited, the effect on the pump cannot be said to be specific. 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide, a water soluble carbodiimide, weakly inhibits both pump and conductance, apparently specifically. PMID:16664807

Improvement of pump tubes for gas guns and shock tube drivers

NASA Technical Reports Server (NTRS)

Bogdanoff, D. W.

1990-01-01

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

Effect of laser speckle on light from laser diode-pumped phosphor-converted light sources.

PubMed

Aquino, Felipe; Jadwisienczak, Wojciech M; Rahman, Faiz

2017-01-10

Laser diode (LD) pumped white light sources are being developed as an alternative to light-emitting diode-pumped sources for high efficiency and/or high brightness applications. While several performance metrics of laser-pumped phosphor-converted light sources have been investigated, the effect of laser speckle has not been sufficiently explored. This paper describes our experimental studies on how laser speckle affects the behavior of light from laser-excited phosphor lamps. A single LD pumping a phosphor plate was the geometry explored in this work. Overall, our findings are that the down-converted light did not exhibit any speckle, whereas speckle was present in the residual pump light but much reduced from that in direct laser light. Furthermore, a thicker coating of small-grained phosphors served to effectively reduce speckle through static pump light diffusion in the phosphor coating. Our investigations showed that speckle is not of concern in illumination from LD-pumped phosphor-converted light sources.

A survey of instabilities within centrifugal pumps and concepts for improving the flow range of pumps in rocket engines

NASA Technical Reports Server (NTRS)

Veres, Joseph P.

1992-01-01

Design features and concepts that have primary influence on the stable operating flow range of propellant-feed centrifugal turbopumps in a rocket engine are discussed. One of the throttling limitations of a pump-fed rocket engine is the stable operating range of the pump. Several varieties of pump hydraulic instabilities are mentioned. Some pump design criteria are summarized and a qualitative correlation of key parameters to pump stall and surge are referenced. Some of the design criteria were taken from the literature on high pressure ratio centrifugal compressors. Therefore, these have yet to be validated for extending the stable operating flow range of high-head pumps. Casing treatment devices, dynamic fluid-damping plenums, backflow-stabilizing vanes and flow-reinjection techniques are summarized. A planned program was undertaken at LeRC to validate these concepts. Technologies developed by this program will be available for the design of turbopumps for advanced space rocket engines for use by NASA in future space missions where throttling is essential.

Deep Throttle Turbopump Technology Design Concepts

NASA Technical Reports Server (NTRS)

Guinzburg, Adiel; Williams, Morgan; Ferguson, Tom; Garcia, Roberto (Technical Monitor)

2002-01-01

The objective of this project is to increase the throttling range of turbopumps from 30 to 120% of the design value, while maintaining high performance levels. Details are given on wide flow range issues, H-Q characteristics, stall characteristics, energy levels, pressure fluctuations at impeller exit, WFR impeller characteristics, commercial diffuser pumps, slotted or tandem vanes, leading edge characteristics, leading edge models, throat models, diffusion passage models, computational fluid dynamics (CFD) methodologies, and CFD flow cases.

High brightness fiber laser pump sources based on single emitters and multiple single emitters

NASA Astrophysics Data System (ADS)

Scheller, Torsten; Wagner, Lars; Wolf, Jürgen; Bonati, Guido; Dörfel, Falk; Gabler, Thomas

2008-02-01

Driven by the potential of the fiber laser market, the development of high brightness pump sources has been pushed during the last years. The main approaches to reach the targets of this market had been the direct coupling of single emitters (SE) on the one hand and the beam shaping of bars and stacks on the other hand, which often causes higher cost per watt. Meanwhile the power of single emitters with 100μm emitter size for direct coupling increased dramatically, which also pushed a new generation of wide stripe emitters or multi emitters (ME) of up to 1000μm emitter size respectively "minibars" with apertures of 3 to 5mm. The advantage of this emitter type compared to traditional bars is it's scalability to power levels of 40W to 60W combined with a small aperture which gives advantages when coupling into a fiber. We show concepts using this multiple single emitters for fiber coupled systems of 25W up to 40W out of a 100μm fiber NA 0.22 with a reasonable optical efficiency. Taking into account a further efficiency optimization and an increase in power of these devices in the near future, the EUR/W ratio pushed by the fiber laser manufacturer will further decrease. Results will be shown as well for higher power pump sources. Additional state of the art tapered fiber bundles for photonic crystal fibers are used to combine 7 (19) pump sources to output powers of 100W (370W) out of a 130μm (250μm) fiber NA 0.6 with nominal 20W per port. Improving those TFB's in the near future and utilizing 40W per pump leg, an output power of even 750W out of 250μm fiber NA 0.6 will be possible. Combined Counter- and Co-Propagated pumping of the fiber will then lead to the first 1kW fiber laser oscillator.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bamberger, Judith A.; Enderlin, Carl W.

Million-gallon double-shell tanks at Hanford are used to store transuranic, high-level, and low-level radioactive wastes. These wastes consist of a large volume of salt-laden solution covering a smaller volume of settled sludge primarily containing metal hydroxides. These wastes will be retrieved and processed into immobile waste forms suitable for permanent disposal. Retrieval is an important step in implementing these disposal scenarios. The retrieval concept evaluated is to use submerged dual-nozzle jet mixer pumps with horizontally oriented nozzles located near the tank floor that produce horizontal jets of fluid to mobilize the settled solids. The mixer pumps are oscillated through 180more » about a vertical axis so the high velocity fluid jets sweep across the floor of the tank. After the solids are mobilized, the pumps will continue to operate at a reduced flow rate producing lower velocity jets sufficient to maintain the particles in a uniform suspension (concentration uniformity). Several types of waste and tank configurations exist at Hanford. The jet mixer pump systems and operating conditions required to mobilize sludge and maintain slurry uniformity will be a function of the waste type and tank configuration. The focus of this work was to conduct a 1/12-scale experiment to develop an analytical model to relate slurry uniformity to tank and mixer pump configurations, operating conditions, and sludge properties. This experimental study evaluated concentration uniformity in a 1/12-scale experiment varying the Reynolds number (Re), Froude number (Fr), and gravitational settling parameter (Gs) space. Simulant physical properties were chosen to obtain the required Re and Gs where Re and Gs were varied by adjusting the kinematic viscosity and mean particle diameter, respectively. Test conditions were achieved by scaling the jet nozzle exit velocity in a 75-in. diameter tank using a mock-up of a centrally located dual-opposed jet mixer pump located just above the tank floor. Concentration measurements at sampling locations throughout the tank were used to assess the degree of uniformity achieved during each test. Concentration data was obtained using a real time in-situ ultrasonic attenuation probe and post-test analysis of discrete batch samples. The undissolved solids concentration at these locations was analyzed to determine whether the tank contents were uniform (≤ ±10% variation about mean) or nonuniform (> ±10% variation about mean) in concentration. Concentration inhomogeneity was modeled as a function of dimensionless parameters. The parameters that best describe the maximum solids volume fraction that can be suspended were found to be 1) the Fr based on nozzle average discharge velocity and tank contents level and 2) the dimensionless particle size based on nozzle diameter. The dependence on the jet Re does not appear to be statistically significant.« less

Stress Introduction Rate Alters the Benefit of AcrAB-TolC Efflux Pumps.

PubMed

Langevin, Ariel M; Dunlop, Mary J

2018-01-01

Stress tolerance studies are typically conducted in an all-or-none fashion. However, in realistic settings-such as in clinical or metabolic engineering applications-cells may encounter stresses at different rates. Therefore, how cells tolerate stress may depend on its rate of appearance. To address this, we studied how the rate of stress introduction affects bacterial stress tolerance by focusing on a key stress response mechanism. Efflux pumps, such as AcrAB-TolC of Escherichia coli , are membrane transporters well known for the ability to export a wide variety of substrates, including antibiotics, signaling molecules, and biofuels. Although efflux pumps improve stress tolerance, pump overexpression can result in a substantial fitness cost to the cells. We hypothesized that the ideal pump expression level would involve a rate-dependent trade-off between the benefit of pumps and the cost of their expression. To test this, we evaluated the benefit of the AcrAB-TolC pump under different rates of stress introduction, including a step, a fast ramp, and a gradual ramp. Using two chemically diverse stresses, the antibiotic chloramphenicol and the jet biofuel precursor pinene, we assessed the benefit provided by the pumps. A mathematical model describing these effects predicted the benefit as a function of the rate of stress introduction. Our findings demonstrate that as the rate of introduction is lowered, stress response mechanisms provide a disproportionate benefit to pump-containing strains, allowing cells to survive beyond the original inhibitory concentrations. IMPORTANCE Efflux pumps are ubiquitous in nature and provide stress tolerance in the cells of species ranging from bacteria to mammals. Understanding how pumps provide tolerance has far-reaching implications for diverse fields, from medicine to biotechnology. Here, we investigated how the rate of stressor appearance impacts tolerance. We focused on two distinct substrates of AcrAB-TolC efflux pumps, the antibiotic chloramphenicol and the biofuel precursor pinene. Interestingly, tolerance is highly dependent on the rate of stress introduction. Therefore, it is important to consider not only the total quantity of a stressor but also the rate at which it is applied. The implications of this work are significant because environments are rarely static; antibiotic concentrations change during dosing, and metabolic engineering processes change with time. Copyright © 2017 American Society for Microbiology.

Comparative study of myocardial high energy phosphate substrate content in slow and fast growing chicken and in chickens with heart failure and ascites.

PubMed

Olkowski, A A; Nain, S; Wojnarowicz, C; Laarveld, B; Alcorn, J; Ling, B B

2007-09-01

In order to explain the biochemical mechanisms associated with deteriorating heart function in broiler chickens, this study compared myocardial high energy phosphate substrates in leghorns, feed restricted (Broilers-Res) broilers, ad libitum fed broilers (Broilers-AL), and in broilers that developed heart failure and ascites. The profile of adenine nucleotide content in the heart tissue did not differ between leghorns and Broilers-Res, but there were significant differences among Broilers-Res, Broilers-AL, and broilers with ascites. During intensive growth periods, leghorns and Broilers-Res showed increasing trends in heart ATP levels, whereas in fast growing broilers the heart ATP declined (p<0.021). ATP:ADP and ATP:CrP ratios increased with age in both leghorn and Broilers-Res, declined in fast growing broilers, and were the lowest in broilers that developed heart failure. The changes in heart high energy phosphate profile in broilers suggest that the energy demand of the heart during a rapid growth phase may exceed the bird's metabolic capacity to supply adequate levels of high energy phosphate substrate. The insufficiency of energy substrate likely contributes to the declining heart rate. In some individuals this may lead to impaired heart pump function, and in more severe cases may progress to heart pump failure.

High efficiency laser-pumped emerald lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lai, S.T.

1987-09-25

Highly efficient laser operation has been achieved in emerald. In a quasi-cw laser-pumped emerald laser, 64% output slope efficiency has been measured at 768 nm, corresponding to a laser quantum yield of 76%. An output power of 1.6 W was reached at 3.6 W of pump power at 647.1 nm from a krypton laser, and was pump power limited. The emerald laser has a tuning range of 720 to 842 nm. The round trip loss excluding the excited state absorption (ESA) is 0.4%/cm. These results indicate the high laser efficiency and the high optical quality of the emerald attainable inmore » the present laser.« less

Volume Bragg grating narrowed high-power and highly efficient cladding-pumped Raman fiber laser.

PubMed

Liu, Jun; Yao, Weichao; Zhao, Chujun; Shen, Deyuan; Fan, Dianyuan

2014-12-10

High-power and highly efficient operation of a single-mode cladding-pumped Raman fiber laser with narrow lasing bandwidth is demonstrated. The spectral narrowing was realized by an external cavity containing a volume Bragg grating with a center wavelength of 1658 nm. A maximum output power of 10.4 W at 1658.3 nm with a spectral linewidth (FWHM) of ∼0.1  nm was obtained for the launched pump power of 18.4 W, corresponding to a slope efficiency of 109% with respect to the launched pump power. Lasing characteristics of free-running operation are also evaluated and discussed.

High energy, widely tunable Si-prism-array coupled terahertz-wave parametric oscillator with a deformed pump and optimal crystal location for angle tuning.

PubMed

Zhang, Ruiliang; Qu, Yanchen; Zhao, Weijiang; Chen, Zhenlei

2017-03-20

A high energy, widely tunable Si-prism-array coupled terahertz-wave parametric oscillator (TPO) has been demonstrated by using a deformed pump. The deformed pump is cut from a beam spot of 2 mm in diameter by a 1-mm-wide slit. In comparison with a small pump spot (1-mm diameter), the THz-wave coupling area for the deformed pump is increased without limitation to the low-frequency end of the tuning range. Besides, the crystal location is specially designed to eliminate the alteration of the output position of the pump during angle tuning, so the initially adjusted nearest pumped region to the THz-wave exit surface is maintained throughout the tuning range. The tuning range is 0.58-2.5 THz for the deformed pump, while its low frequency end is limited at approximately 1.2 THz for the undeformed pump with 2 mm diameter. The highest THz-wave output of 2 μJ, which is 2.25 times as large as that from the pump of 1 mm in diameter, is obtained at 1.15 THz under 38 mJ (300  MW/cm²) pumping. The energy conversion efficiency is 5.3×10^-5.

Measured Performance of a Low Temperature Air Source Heat Pump

DOE Office of Scientific and Technical Information (OSTI.GOV)

R.K. Johnson

2013-09-01

A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor “boosted heat pump” technology. The Low Temperature Heat Pump system operates with four increasing levels of capacity (heat output) as the outdoor temperature drops.

How NaCl raises blood pressure: a new paradigm for the pathogenesis of salt-dependent hypertension

PubMed Central

Leenen, Frans H. H.; Chen, Ling; Golovina, Vera A.; Hamlyn, John M.; Pallone, Thomas L.; Van Huysse, James W.; Zhang, Jin; Wier, W. Gil

2012-01-01

Excess dietary salt is a major cause of hypertension. Nevertheless, the specific mechanisms by which salt increases arterial constriction and peripheral vascular resistance, and thereby raises blood pressure (BP), are poorly understood. Here we summarize recent evidence that defines specific molecular links between Na+ and the elevated vascular resistance that directly produces high BP. In this new paradigm, high dietary salt raises cerebrospinal fluid [Na+]. This leads, via the Na+-sensing circumventricular organs of the brain, to increased sympathetic nerve activity (SNA), a major trigger of vasoconstriction. Plasma levels of endogenous ouabain (EO), the Na+ pump ligand, also become elevated. Remarkably, high cerebrospinal fluid [Na+]-evoked, locally secreted (hypothalamic) EO participates in a pathway that mediates the sustained increase in SNA. This hypothalamic signaling chain includes aldosterone, epithelial Na+ channels, EO, ouabain-sensitive α2 Na+ pumps, and angiotensin II (ANG II). The EO increases (e.g.) hypothalamic ANG-II type-1 receptor and NADPH oxidase and decreases neuronal nitric oxide synthase protein expression. The aldosterone-epithelial Na+ channel-EO-α2 Na+ pump-ANG-II pathway modulates the activity of brain cardiovascular control centers that regulate the BP set point and induce sustained changes in SNA. In the periphery, the EO secreted by the adrenal cortex directly enhances vasoconstriction via an EO-α2 Na+ pump-Na+/Ca2+ exchanger-Ca2+ signaling pathway. Circulating EO also activates an EO-α2 Na+ pump-Src kinase signaling cascade. This increases the expression of the Na+/Ca2+ exchanger-transient receptor potential cation channel Ca2+ signaling pathway in arterial smooth muscle but decreases the expression of endothelial vasodilator mechanisms. Additionally, EO is a growth factor and may directly participate in the arterial structural remodeling and lumen narrowing that is frequently observed in established hypertension. These several central and peripheral mechanisms are coordinated, in part by EO, to effect and maintain the salt-induced elevation of BP. PMID:22058154

Effect of proton pump inhibitors on markers of risk for high-grade dysplasia and oesophageal cancer in Barrett's oesophagus.

PubMed

Hillman, L C; Chiragakis, L; Shadbolt, B; Kaye, G L; Clarke, A C

2008-02-15

It has been shown that the presence on diagnosis of endoscopic macroscopic markers indicates a high-risk group for Barrett's oesophagus. To determine whether proton pump inhibitor therapy prior to diagnosis of Barrett's oesophagus influences markers for risk development of subsequent high-grade dysplasia/adenocarcinoma. A review of all patients with Barrett's oesophagus entering a surveillance programme was undertaken. Five hundred and two patients diagnosed with Barrett's oesophagus were assessed on diagnosis for endoscopic macroscopic markers or low-grade dysplasia. Subsequent development of high-grade dysplasia/adenocarcinoma was documented. The relationship between the initiation of proton pump inhibitor therapy prior to the diagnosis of BE and the presence of macroscopic markers or low-grade dysplasia at entry was determined. Fourteen patients developed high-grade dysplasia/adenocarcinoma during surveillance. Patients who entered without prior proton pump inhibitor therapy were 3.4 times (95% CI: 1.98-5.85) more likely to have a macroscopic marker or low-grade dysplasia than those patients already on a proton pump inhibitor. Use of proton pump inhibitor therapy prior to diagnosis of Barrett's oesophagus significantly reduced the presence of markers used to stratify patient risk. Widespread use of proton pump inhibitors will confound surveillance strategies for patients with Barrett's oesophagus based on entry characteristics but is justified because of the lower risk of neoplastic progression.

High-efficient Nd:YAG microchip laser for optical surface scanning

NASA Astrophysics Data System (ADS)

Šulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

2017-12-01

A CW operating, compact, high-power, high-efficient diode pumped 1064nm laser, based on Nd:YAG active medium, was developed for optical surface scanning and mapping applications. To enhance the output beam quality, laser stability, and compactness, a microchip configuration was used. In this arrangement the resonator mirrors were deposited directly on to the laser crystal faces. The Nd-doping concentration was 1 at.% Nd/Y. The Nd:YAG crystal was 5mm long. The laser resonator without pumping radiation recuperation was investigated {the output coupler was transparent for pumping radiation. For the generated laser radiation the output coupler reflectivity was 95%@1064 nm. The diameter of the samples was 5 mm. For the laser pumping two arrangements were investigated. Firstly, a fibre coupled laser diode operating at wavelength 808nm was used in CW mode. The 400 ¹m fiber was delivering up to 14W of pump power amplitude to the microchip laser. The maximum CW output power of 7.2W @ 1064nm in close to TEM00 beam was obtained for incident pumping power 13.7W @ 808 nm. The differential efficiency in respect to the incident pump power reached 56 %. Secondly, a single-emitter, 1W laser diode operating at 808nm was used for Nd:YAG microchip pumping. The laser pumping was directly coupled into the microchip laser using free-space lens optics. Slope efficiency up to 70% was obtained in stable, high-quality, 1064nm laser beam with CW power up to 350mW. The system was successfully used for scanning of super-Gaussian laser mirrors reflectivity profile.

Geohydrology of the Souris River Valley in the vicinity of Minot, North Dakota

USGS Publications Warehouse

Pettyjohn, Wayne A.

1967-01-01

The Minot area is in the north-central part of North Dakota and includes part of the Souris River valley. The region is covered by glacial drift of late Wisconsin age except in small areas where the Fort Union Formation of Tertiary age crops out. Thickness of the drift is controlled by the topography of the bedrock. In places the drift is more than 450 feet thick, but it averages about 100 feet thick.Water from the Fort Union Formation is soft and is of sodium bicarbonate type that is undesirable for many uses. Wells in the formation produce only a few gallons per minute.Six glacial aquifers were studied in the report area, but detailed work was limited to the Minot aquifer. The Sundre buried-channel and the lower Souris aquifers contain large quantities of bard water of good chemical quality, but little is known of their hydraulic characteristics owing to lack of development. The North Hill and South Hill aquifers generally provide small quantities of hard water that may be high in iron and sodium. The northwest buried-channel aquifer has a high content of iron and chloride. Locally as much as 1,000 gallons per minute may be pumped from it.The Minot aquifer is a thick deposit of sand and gravel confined to the Souris River valley. The water level has declined more than 70 feet since the first municipal well began pumping in 1916. In .some places the water level in the aquifer declined more than 20 feet during 1961-1963. The rapid decline in water level indicates that a serious water shortage may arise in the near future unless counter measures are taken to prevent it.The Minot aquifer is under both artesian and water-table conditions. In places the transmissibility exceeds 250,000 gallons per day per foot. In 1963, 13 municipal wells pump'ed an average of nearly 4 million gallons per day from the aquifer. Some wells produce as much as 1,000 gallons per minute. The Minot aquifer receives most of its recharge from the buried glaciofiuvial deposits and from the Souris River. Natural recharge probably average about 3 million gallons per day. About 56,000 acre-feet of water available to wells was in storage in 1963.Artificial recharge could be used to counteract the rapid decline in water levels. Several feasible artificial recharge sites are in the western part of Minot, where highly permeable sand and gravel crop out.

Model Refinement and Simulation of Groundwater Flow in Clinton, Eaton, and Ingham Counties, Michigan

USGS Publications Warehouse

Luukkonen, Carol L.

2010-01-01

A groundwater-flow model that was constructed in 1996 of the Saginaw aquifer was refined to better represent the regional hydrologic system in the Tri-County region, which consists of Clinton, Eaton, and Ingham Counties, Michigan. With increasing demand for groundwater, the need to manage withdrawals from the Saginaw aquifer has become more important, and the 1996 model could not adequately address issues of water quality and quantity. An updated model was needed to better address potential effects of drought, locally high water demands, reduction of recharge by impervious surfaces, and issues affecting water quality, such as contaminant sources, on water resources and the selection of pumping rates and locations. The refinement of the groundwater-flow model allows simulations to address these issues of water quantity and quality and provides communities with a tool that will enable them to better plan for expansion and protection of their groundwater-supply systems. Model refinement included representation of the system under steady-state and transient conditions, adjustments to the estimated regional groundwater-recharge rates to account for both temporal and spatial differences, adjustments to the representation and hydraulic characteristics of the glacial deposits and Saginaw Formation, and updates to groundwater-withdrawal rates to reflect changes from the early 1900s to 2005. Simulations included steady-state conditions (in which stresses remained constant and changes in storage were not included) and transient conditions (in which stresses changed in annual and monthly time scales and changes in storage within the system were included). These simulations included investigation of the potential effects of reduced recharge due to impervious areas or to low-rainfall/drought conditions, delineation of contributing areas with recent pumping rates, and optimization of pumping subject to various quantity and quality constraints. Simulation results indicate potential declines in water levels in both the upper glacial aquifer and the upper sandstone bedrock aquifer under steady-state and transient conditions when recharge was reduced by 20 and 50 percent in urban areas. Transient simulations were done to investigate reduced recharge due to low rainfall and increased pumping to meet anticipated future demand with 24 months (2 years) of modified recharge or modified recharge and pumping rates. During these two simulation years, monthly recharge rates were reduced by about 30 percent, and monthly withdrawal rates for Lansing area production wells were increased by 15 percent. The reduction in the amount of water available to recharge the groundwater system affects the upper model layers representing the glacial aquifers more than the deeper bedrock layers. However, with a reduction in recharge and an increase in withdrawals from the bedrock aquifer, water levels in the bedrock layers are affected more than those in the glacial layers. Differences in water levels between simulations with reduced recharge and reduced recharge with increased pumping are greatest in the Lansing area and least away from pumping centers, as expected. Additionally, the increases in pumping rates had minimal effect on most simulated streamflows. Additional simulations included updating the estimated 10-year wellhead-contributing areas for selected Lansing-area wells under 2006-7 pumping conditions. Optimization of groundwater withdrawals with a water-resource management model was done to determine withdrawal rates while minimizing operational costs and to determine withdrawal locations to achieve additional capacity while meeting specified head constraints. In these optimization scenarios, the desired groundwater withdrawals are achieved by simulating managed wells (where pumping rates can be optimized) and unmanaged wells (where pumping rates are not optimized) and by using various combinations of existing and proposed well locations.

Stimulated emission pumping spectroscopy of the [X](1)A' state of CHF.

PubMed

Mukarakate, Calvin; Tao, Chong; Jordan, Christopher D; Polik, William F; Reid, Scott A

2008-01-24

We have recorded stimulated emission pumping (SEP) spectra of the A1A' ' 1A' system of CHF, which reveal rich detail concerning the rovibronic structure of the 1A' state up to approximately 7000 cm-1 above the vibrationless level. Using several intermediate A1A' ' state levels, we obtained rotationally resolved spectra for 16 of the 33 levels observed in our previous single vibronic level (SVL) emission study (Fan et al., J. Chem. Phys. 2005, 123, 014314), in addition to one new level. An anharmonic effective Hamiltonian model poorly reproduces the term energies even with the improved set of data because of the extensive interactions among levels in a given polyad (p) having combinations of nu1, nu2, nu3, which satisfy the relationship p = 2nu1 + nu2 + nu3. However, the precise A rotational constants determined from the SEP data were invaluable in clarifying the assignments for these strongly perturbed levels, and the data are well reproduced using a multiresonance effective Hamiltonian model. The derived vibrational parameters are in good agreement with high level ab initio calculations. The experimental frequencies were combined with those of CDF to derive a harmonic force field and average (rz,r(z)e) structures for the ground state.

Continuous cryopump with a device for regenerating the cryosurface

DOEpatents

Foster, C.A.

1988-02-16

A high throughput continuous cryopump is provided. The cryopump incorporates an improved method for regenerating the cryopumping surface while the pump is in continuous operation. The regeneration of the cryopumping surface does not thermally cycle the pump, and to this end a small chamber connected to a secondary pumping source serves to contain and exhaust frost removed from the cryopumping surface during such regeneration. The frost is exhausted at a rate substantially independent of the speed of the cryopump which enhances the capability of the pump to achieve a high compression ratio and allow the pump to operate continuously while the cryopumping surface is being regenerated. 8 figs.

High power operation of cladding pumped holmium-doped silica fibre lasers.

PubMed

Hemming, Alexander; Bennetts, Shayne; Simakov, Nikita; Davidson, Alan; Haub, John; Carter, Adrian

2013-02-25

We report the highest power operation of a resonantly cladding-pumped, holmium-doped silica fibre laser. The cladding pumped all-glass fibre utilises a fluorine doped glass layer to provide low loss cladding guidance of the 1.95 µm pump radiation. The operation of both single mode and large-mode area fibre lasers was demonstrated, with up to 140 W of output power achieved. A slope efficiency of 59% versus launched pump power was demonstrated. The free running emission was measured to be 2.12-2.15 µm demonstrating the potential of this architecture to address the long wavelength operation of silica based fibre lasers with high efficiency.

Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 3A: High pressure oxidizer turbo-pump preburner pump housing stress analysis report

NASA Technical Reports Server (NTRS)

Shannon, Robert V., Jr.

1989-01-01

The model generation and structural analysis performed for the High Pressure Oxidizer Turbopump (HPOTP) preburner pump volute housing located on the main pump end of the HPOTP in the space shuttle main engine are summarized. An ANSYS finite element model of the volute housing was built and executed. A static structural analysis was performed on the Engineering Analysis and Data System (EADS) Cray-XMP supercomputer

LOX/LH2 vane pump for auxiliary propulsion systems

NASA Technical Reports Server (NTRS)

Hemminger, J. A.; Ulbricht, T. E.

1985-01-01

Positive displacement pumps offer potential efficiency advantages over centrifugal pumps for future low thrust space missions. Low flow rate applications, such as space station auxiliary propulsion or dedicated low thrust orbiter transfer vehicles, are typical of missions where low flow and high head rise challenge centrifugal pumps. The positive displacement vane pump for pumping of LOX and LH2 is investigated. This effort has included: (1) a testing program in which pump performance was investigated for differing pump clearances and for differing pump materials while pumping LN2, LOX, and LH2; and (2) an analysis effort, in which a comprehensive pump performance analysis computer code was developed and exercised. An overview of the theoretical framework of the performance analysis computer code is presented, along with a summary of analysis results. Experimental results are presented for pump operating in liquid nitrogen. Included are data on the effects on pump performance of pump clearance, speed, and pressure rise. Pump suction performance is also presented.

Vacuum space charge effects in sub-picosecond soft X-ray photoemission on a molecular adsorbate layer

DOE PAGES

Dell'Angela, M.; Anniyev, T.; Beye, M.; ...

2015-03-01

Vacuum space charge-induced kinetic energy shifts of O 1s and Ru 3d core levels in femtosecond soft X-ray photoemission spectra (PES) have been studied at a free electron laser (FEL) for an oxygen layer on Ru(0001). We fully reproduced the measurements by simulating the in-vacuum expansion of the photoelectrons and demonstrate the space charge contribution of the high-order harmonics in the FEL beam. Employing the same analysis for 400 nm pump-X-ray probe PES, we can disentangle the delay dependent Ru 3d energy shifts into effects induced by space charge and by lattice heating from the femtosecond pump pulse.

Solar-pumped electronic-to-vibrational energy transfer lasers

NASA Technical Reports Server (NTRS)

Harries, W. L.; Wilson, J. W.

1981-01-01

The possibility of using solar-pumped lasers as solar energy converters is examined. The absorbing media considered are halogens or halogen compounds, which are dissociated to yield excited atoms, which then hand over energy to a molecular lasing medium. Estimates of the temperature effects for a Br2-CO2-He system with He as the cooling gas are given. High temperatures can cause the lower energy levels of the CO2 laser transition to be filled. The inverted populations are calculated and lasing should be possible. However, the efficiency is less than 0.001. Examination of other halogen-molecular lasant combinations (where the rate coefficients are known) indicate efficiencies in all cases of less than 0.005.

Experimental investigations of argon and xenon ion sources

NASA Technical Reports Server (NTRS)

Kaufman, H. R.

1975-01-01

The multipole thruster was used to investigate the use of argon and xenon propellants as possible alternatives to the electric thruster propellants of mercury and cesium. The multipole approach was used because of its general high performance level. The design employed, using flat and cylindrical rolled sections of sheet metal, was selected for ease of fabrication, design, assembly, and modification. All testing was conducted in a vacuum facility and the pumping was accomplished by a 0.8 m diffusion pump together with liquid nitrogen cooled liner. Minimum discharge losses were in the 200-250 ev. ion range for both argon and xenon. Flatness parameters were typically in the 0.70-0.75 range.

Vacuum space charge effects in sub-picosecond soft X-ray photoemission on a molecular adsorbate layer.

PubMed

Dell'Angela, M; Anniyev, T; Beye, M; Coffee, R; Föhlisch, A; Gladh, J; Kaya, S; Katayama, T; Krupin, O; Nilsson, A; Nordlund, D; Schlotter, W F; Sellberg, J A; Sorgenfrei, F; Turner, J J; Öström, H; Ogasawara, H; Wolf, M; Wurth, W

2015-03-01

Vacuum space charge induced kinetic energy shifts of O 1s and Ru 3d core levels in femtosecond soft X-ray photoemission spectra (PES) have been studied at a free electron laser (FEL) for an oxygen layer on Ru(0001). We fully reproduced the measurements by simulating the in-vacuum expansion of the photoelectrons and demonstrate the space charge contribution of the high-order harmonics in the FEL beam. Employing the same analysis for 400 nm pump-X-ray probe PES, we can disentangle the delay dependent Ru 3d energy shifts into effects induced by space charge and by lattice heating from the femtosecond pump pulse.

Temporal Behavior of the Pump Pulses, Residual Pump Pulses, and THz Pulses for D2O Gas Pumped by a TEA CO2 Laser

NASA Astrophysics Data System (ADS)

Geng, Lijie; Zhang, Zhifeng; Zhai, Yusheng; Su, Yuling; Zhou, Fanghua; Qu, Yanchen; Zhao, Weijiang

2016-08-01

Temporal behavior of the pump pulses, residual pump pulses, and THz pulses for optically pumped D2O gas molecules was investigated by using a tunable TEA CO2 laser as the pumping source. The pulse profiles of pump laser pulses, residual pump pulses, and the THz output pulses were measured, simultaneously, at several different gas pressures. For THz pulse, the pulse delay between the THz pulse and the pump pulse was observed and the delay time was observed to increase from 40 to 70 ns with an increase in gas pressure from 500 to 1700 Pa. Both THz pulse broadening and compression were observed, and the pulse broadening effect transformed to the compression effect with increasing the gas pressure. For the residual pump pulse, the full width at half maximum (FWHM) of the main pulse decreased with increasing gas pressure, and the main pulse disappeared at high gas pressures. The secondary pulses were observed at high gas pressure, and the time intervals of about 518 and 435 ns were observed between the THz output pulse and the secondary residual pump pulse at the pressure of 1400 Pa and 1700 Pa, from which the vibrational relaxation time constants of about 5.45 and 5.55 μs Torr were obtained.

76 FR 68661 - Airworthiness Directives; Turbomeca S.A. Arriel 2B and 2B1 Turboshaft Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-07

... high- pressure (HP) pump shaft on HP/LP pump hydro-mechanical metering units (HMUs) that do not...-mechanical metering unit (HMU) LP fuel pump impeller and the HP fuel pump shaft, since AD 2010-03-06 (75 FR...

Management of diabetes mellitus: is the pump mightier than the pen?

PubMed

Pickup, John C

2012-02-28

Continuous subcutaneous insulin infusion (CSII, or insulin pump therapy) reduces HbA1c levels and hypoglycaemia in patients with type 1 diabetes mellitus (T1DM) compared with multiple daily insulin injections (MDI). The greatest reduction in HbA(1c) levels with CSII occurs in patients with the worst glycaemic control; therefore, the most appropriate and cost-effective use of CSII in adults with T1DM is in those who have continued, elevated HbA(1c) levels or disabling hypoglycaemic episodes with MDI (including the use of long-acting insulin analogues and structured patient education). The disadvantages of CSII include higher costs than MDI and the risk of ketosis in the event of pump failure. In children with T1DM, CSII may be used when MDI is considered impractical or inappropriate. Pumps are not generally recommended for patients with type 2 diabetes mellitus but may improve control in some subgroups. A new generation of smaller insulin infusion pumps with an integrated cannula, called patch pumps, could improve uptake of CSII in general. The important clinical question is not whether CSII is more efficacious than MDI in general adult T1DM, but whether CSII further improves glycaemic control when this control continues to be poor with MDI, and evidence exists that in most cases it does.

Ground-water system, estimation of aquifer hydraulic properties, and effects of pumping on ground-water flow in Triassic sedimentary rocks in and near Lansdale, Pennsylvania

USGS Publications Warehouse

Senior, Lisa A.; Goode, Daniel J.

1999-01-01

Ground water in Triassic-age sedimentary fractured-rock aquifers in the area of Lansdale, Pa., is used as drinking water and for industrial supply. In 1979, ground water in the Lansdale area was found to be contaminated with trichloroethylene, tetrachloroethylene, and other man-made organic compounds, and in 1989, the area was placed on the U.S. Environmental Protection Agency's (USEPA) National Priority List as the North Penn Area 6 site. To assist the USEPA in the hydrogeological assessment of the site, the U.S. Geological Survey began a study in 1995 to describe the ground-water system and to determine the effects of changes in the well pumping patterns on the direction of ground-water flow in the Lansdale area. This determination is based on hydrologic and geophysical data collected from 1995-98 and on results of the simulation of the regional ground-water-flow system by use of a numerical model.Correlation of natural-gamma logs indicate that the sedimentary rock beds strike generally northeast and dip at angles less than 30 degrees to the northwest. The ground-water system is confined or semi-confined, even at shallow depths; depth to bedrock commonly is less than 20 feet (6 meters); and depth to water commonly is about 15 to 60 feet (5 to 18 meters) below land surface. Single-well, aquifer-interval-isolation (packer) tests indicate that vertical permeability of the sedimentary rocks is low. Multiple-well aquifer tests indicate that the system is heterogeneous and that flow appears primarily in discrete zones parallel to bedding. Preferred horizontal flow along strike was not observed in the aquifer tests for wells open to the pumped interval. Water levels in wells that are open to the pumped interval, as projected along the dipping stratigraphy, are drawn down more than water levels in wells that do not intersect the pumped interval. A regional potentiometric map based on measured water levels indicates that ground water flows from Lansdale towards discharge areas in three drainages, the Wissahickon, Towamencin, and Neshaminy Creeks.Ground-water flow was simulated for different pumping patterns representing past and current conditions. The three-dimensional numerical flow model (MODFLOW) was automatically calibrated by use of a parameter estimation program (MODFLOWP). Steady-state conditions were assumed for the calibration period of 1996. Model calibration indicates that estimated recharge is 8.2 inches (208 millimeters) and the regional anisotropy ratio for the sedimentary-rock aquifer is about 11 to 1, with permeability greatest along strike. The regional anisotropy is caused by up- and down-dip termination of high-permeability bed-oriented features, which were not explicitly simulated in the regional-scale model. The calibrated flow model was used to compare flow directions and capture zones in Lansdale for conditions corresponding to relatively high pumping rates in 1994 and to lower pumping rates in 1997. Comparison of the 1994 and 1997 simulations indicates that wells pumped at the lower 1997 rates captured less ground water from known sites of contamination than wells pumped at the 1994 rates. Ground-water flow rates away from Lansdale increased as pumpage decreased in 1997.A preliminary evaluation of the relation between ground-water chemistry and conditions favorable for the degradation of chlorinated solvents was based on measurements of dissolved-oxygen concentration and other chemical constituents in water samples from 92 wells. About 18 percent of the samples contained less than or equal to 5 milligrams per liter dissolved oxygen, a concentration that indicates reducing conditions favorable for degradation of chlorinated solvents.

Geothermal down well pumping system

NASA Technical Reports Server (NTRS)

Matthews, H. B.; Mcbee, W. D.

1974-01-01

A key technical problem in the exploitation of hot water geothermal energy resources is down-well pumping to inhibit mineral precipitation, improve thermal efficiency, and enhance flow. A novel approach to this problem involves the use of a small fraction of the thermal energy of the well water to boil and super-heat a clean feedwater flow in a down-hole exchanger adjacent to the pump. This steam powers a high-speed turbine-driven pump. The exhaust steam is brought to the surface through an exhaust pipe, condensed, and recirculated. A small fraction of the high-pressure clean feedwater is diverted to lubricate the turbine pump bearings and prevent leakage of brine into the turbine-pump unit. A project demonstrating the feasibility of this approach by means of both laboratory and down-well tests is discussed.

Numerical simulation of ground-water flow in lower Satus Creek Basin, Yakima Indian Reservation, Washington

USGS Publications Warehouse

Prych, E.A.

1983-01-01

A multilayer numerical model of steady-state ground-water flow in lower Satus Creek basin was constructed, calibrated using time-averaged data, and used to estimate the long-term effects of proposed irrigation-water management plans on ground-water levels in the area. Model computations showed that irrigation of new lands in the Satus uplands would raise ground-water levels in lower Satus Creek basin and thereby increase the size of the waterlogged areas. The model also demonstrated that pumping water from wells, reducing the amount of irrigation water used in the lowlands, and stopping leakage from Satus No. 2 and 3 Pump Canals were all effective methods to alleviate present waterlogging in some parts of the basin and to counteract some of the anticipated ground-water-level rises that would be caused by irrigating the uplands. The proposed changes in water use affected model-computed ground-water levels most in the eastern part of the basin between Satus No. 2 and No. 3 Pump Canals. The effects on ground-water levels in the western part of the basin between Satus Creek and Satus No. 2 Pump Canal were smaller. (USGS)

High efficiency and good beam quality of electro-optic, cavity-dumped and double-end pumped Nd:YLF laser

NASA Astrophysics Data System (ADS)

Tang, X. X.; Fan, Z. W.; Qiu, J. S.; Lian, F. Q.; Zhang, X. L.

2012-06-01

In this paper, we describe a Nd:YLF laser based on high-speed RTP electro-optical cavity dumping technique. Two home-made 150 W fiber pump modules are used from both sides to pump Nd:YLF crystal. Coupling systems are the key elements in end-pumped solid-state lasers, the aberrations of which greatly affect the efficiency of the lasers. In order to get high efficient and good quality laser output, the optical software ZEMAX is used to design a four-piece coupling system. When the pumped energy is 32 mJ at the repetition rate of 1 Hz, the output energy is 6.5 mJ with 2.5 ns pulse width. When the pumped energy is 13.1 W at the repetition rate of 200 Hz, the output energy is 2.2 W with small M 2 factor where M {/x 2} is 1.04, and M {/y 2} is 1.05, and the light-light conversion efficiency is up to 16.8%.

Pump absorption in coiled and twisted double-clad hexagonal fiber: effect of launching conditions and core location

NASA Astrophysics Data System (ADS)

Dalidet, Romain; Peterka, Pavel; Doya, Valérie; Aubrecht, Jan; Koška, Pavel

2018-02-01

Ever extending applications of fiber lasers require energy efficient, high-power, small footprint and reliable fiber lasers and laser wavelength versatility. To meet these demands, next generation of active fibers for high-power fiber lasers is coming out that will eventually offer tailored spectroscopic properties, high robustness and reduced cooling requirements and improved efficiency through tailored pump absorption. We report on numerical modelling of the efficiency of the pump absorption in double clad active fibers with hexagonal shape of the inner cladding cross section and rare-earth-doped core. We analyze both the effect of different radii of the spool on which the fiber is coiled and different fiber twisting rates. Two different launching conditions were investigated: the Gaussian input pump beam and a speckle pattern that mimics the output of the pump laser diode pigtail. We have found that by asymmetric position of the rare-earth-doped core we can significantly improve the pump absorption.

Comparative analysis of heat pump and biomass boiler for small detached house heating

NASA Astrophysics Data System (ADS)

Olkowski, Tomasz; Lipiński, Seweryn; Olędzka, Aneta

2017-10-01

The purpose of the work is to answer the question - which of the two selected heat sources is more economically beneficial for small detached house: heat pump or biomass boiler fuelled with wood-pellets? The comparative analysis of these sources was carried out to discuss the issue. First, cost of both, equipment and operation of selected heat systems were analysed. Additionally, CO2 emission levels associated with these heat systems were determined. The comparative analysis of the costs of both considered heat systems showed that equipment cost of heat pump system is considerably bigger than the cost of biomass boiler system. The comparison of annual operation costs showed that heat pump operation cost is slightly lower than operation cost of biomass boiler. The analysis of above results shows that lower operation cost of heat pump in comparison with biomass boiler cost lets qualify heat pump as more economically justified only after 38 years of work. For both analysed devices, CO2 emission levels were determined. The considerations take into account the fact that heat pump consumes electricity. It is mostly generated through combustion of coal in Poland. The results show that in Poland biomass boiler can be described as not only more economically justified system but also as considerably more ecological.

A blackbody radiation-pumped CO2 laser experiment

NASA Technical Reports Server (NTRS)

Christiansen, W. H.; Insuik, R. J.; Deyoung, R. J.

1982-01-01

Thermal radiation from a high temperature oven was used as an optical pump to achieve lasing from CO2 mixtures. Laser output as a function of blackbody temperature and gas conditions is described. This achievement represents the first blackbody cavity pumped laser and has potential for solar pumping.

High power (2+1) ×1 taper-fused all-fiber side-pumped combiner

NASA Astrophysics Data System (ADS)

Wu, Juan; Ma, Yi; Yan, Hong

2018-03-01

A novel design and fabrication method of a (2+1) ×1 taper-fused all-fiber side-pumped combiner is reported. The pump coupling efficiency of this pump combiner was studied theoretically and experimentally. The measurement results indicated that the coupling efficiency of the pump light is 96.5%, the signal-to-pump isolation reaches 31dB, and the signal loss of the combiner is 0.19dB. A backward-pumped fiber laser system was established by using this (2+1) ×1 side-pumped combiner directly, achieving a signal laser output of 1007W with M2=1.33.

Hundred-watt-level high power random distributed feedback Raman fiber laser at 1150 nm and its application in mid-infrared laser generation.

PubMed

Zhang, Hanwei; Zhou, Pu; Wang, Xiong; Du, Xueyuan; Xiao, Hu; Xu, Xiaojun

2015-06-29

Two kinds of hundred-watt-level random distributed feedback Raman fiber have been demonstrated. The optical efficiency can reach to as high as 84.8%. The reported power and efficiency of the random laser is the highest one as we know. We have also demonstrated that the developed random laser can be further used to pump a Ho-doped fiber laser for mid-infrared laser generation. Finally, 23 W 2050 nm laser is achieved. The presented laser can obtain high power output efficiently and conveniently and opens a new direction for high power laser sources at designed wavelength.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Podoskin, A. A., E-mail: podoskin@mail.ioffe.ru; Shashkin, I. S.; Slipchenko, S. O.

A model describing the operation of a completely optical cell, based on the competition of lasing of Fabry-Perot cavity modes and the high-Q closed mode in high-power semiconductor lasers is proposed. Based on rate equations, the conditions of lasing switching between Fabry-Perot modes for ground and excited lasing levels and the closed mode are considered in the case of increasing internal optical loss under conditions of high current pump levels. The optical-cell operation conditions in the mode of a high-power laser radiation switch (reversible mode-structure switching) and in the mode of a memory cell with bistable irreversible lasing switching betweenmore » mode structures with various Q-factors are considered.« less

Multistage quantum absorption heat pumps.

PubMed

Correa, Luis A

2014-04-01

It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these devices scales with their size, we design generalized N-dimensional ideal heat pumps by merging N-2 elementary three-level stages. We set them to operate in the absorption chiller mode between given hot and cold baths and study their maximum achievable cooling power and the corresponding efficiency as a function of N. While the efficiency at maximum power is roughly size-independent, the power itself slightly increases with the dimension, quickly saturating to a constant. Thus, interestingly, scaling up autonomous quantum heat pumps does not render a significant enhancement beyond the optimal double-stage configuration.

OPCPA front end and contrast optimization for the OMEGA EP kilojoule, picosecond laser

DOE PAGES

Dorrer, C.; Consentino, A.; Irwin, D.; ...

2015-09-01

OMEGA EP is a large-scale laser system that combines optical parametric amplification and solid-state laser amplification on two beamlines to deliver high-intensity, high-energy optical pulses. The temporal contrast of the output pulse is limited by the front-end parametric fluorescence and other features that are specific to parametric amplification. The impact of the two-crystal parametric preamplifier, pump-intensity noise, and pump-signal timing is experimentally studied. The implementation of a parametric amplifier pumped by a short pump pulse before stretching, further amplification, and recompression to enhance the temporal contrast of the high-energy short pulse is described.

Simulation of Laser Induced Thermal Damage in Nd:YVO4 Crystals

NASA Astrophysics Data System (ADS)

Nagi, Richie

Neodymium-doped yttrium orthovanadate (Nd:YVO4) is a commonly used gain medium in Diode Pumped Solid State (DPSS) lasers, but high heat loading of Nd:YVO4 at high pump powers (≥ 5 W) leads to thermal distortions and crystal fracture, which limits the utility of Nd:YVO 4 for high power applications. In this thesis, a Nd:YVO4 crystal suffered thermal damage during experiments for investigating the optical gain characteristics of the crystal. This thesis examines the thermal damage mechanisms in detail. Principally, laser induced melting, as well as laser induced thermal stress fracture were studied, all in the absence of stimulated emission in the crystal. The optical system for coupling the pump laser light into the crystal was first simulated in Zemax, an optical design software, and the simulations were then compared to the experimental coupling efficiency results, which were found to be in agreement. The simulations for the laser coupling system were then used in conjunction with LASCAD, a finite element analysis software, to obtain the temperatures inside the crystal, as a function of optical power coupled into the crystal. The temperature simulations were then compared to the experimental results, which were in excellent agreement, and the temperature simulations were then generalized to other crystal geometries and Nd doping levels. Zemax and LASCAD were also used to simulate the thermal stress in the crystal as a function of the coupled optical power, and the simulations were compared to experiments, both of which were found to be in agreement. The thermal stress simulations were then generalized to different crystal geometries and Nd doping levels as well.

Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 3B: High pressure fuel turbo-pump preburner pump bearing assembly analysis

NASA Technical Reports Server (NTRS)

Power, Gloria B.; Violett, Rebeca S.

1989-01-01

The analysis performed on the High Pressure Oxidizer Turbopump (HPOTP) preburner pump bearing assembly located on the Space Shuttle Main Engine (SSME) is summarized. An ANSYS finite element model for the inlet assembly was built and executed. Thermal and static analyses were performed.

POTENTIAL IMPACT OF BLENDING RESIDUAL SOLIDS FROM TANKS 18/19 MOUNDS WITH TANK 7 OPERATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eibling, R; Erich Hansen, E; Bradley Pickenheim, B

2007-03-29

High level waste tanks 18F and 19F have residual mounds of waste which may require removal before the tanks can be closed. Conventional slurry pump technology, previously used for waste removal and tank cleaning, has been incapable of removing theses mounds from tanks 18F and 19F. A mechanical cleaning method has been identified that is potentially capable of removing and transferring the mound material to tank 7F for incorporation in a sludge batch for eventual disposal in high level waste glass by the Defense Waste Processing Facility. The Savannah River National Laboratory has been requested to evaluate whether the materialmore » transferred from tanks 18F/19F by the mechanical cleaning technology can later be suspended in Tank 7F by conventional slurry pumps after mixing with high level waste sludge. The proposed mechanical cleaning process for removing the waste mounds from tanks 18 and 19 may utilize a high pressure water jet-eductor that creates a vacuum to mobilize solids. The high pressure jet is also used to transport the suspended solids. The jet-eductor system will be mounted on a mechanical crawler for movement around the bottom of tanks 18 and 19. Based on physical chemical property testing of the jet-eductor system processed IE-95 zeolite and size-reduced IE-95 zeolite, the following conclusions were made: (1) The jet-eductor system processed zeolite has a mean and median particle size (volume basis) of 115.4 and 43.3 microns in water. Preferential settling of these large particles is likely. (2) The jet-eductor system processed zeolite rapidly generates settled solid yield stresses in excess of 11,000 Pascals in caustic supernates and will not be easily retrieved from Tank 7 with the existing slurry pump technology. (3) Settled size-reduced IE-95 zeolite (less than 38 microns) in caustic supernate does not generate yield stresses in excess of 600 Pascals in less than 30 days. (4) Preferential settling of size-reduced zeolite is a function of the amount of sludge and the level of dilution for the mixture. (5) Blending the size-reduced zeolite into larger quantities of sludge can reduce the amount of preferential settling. (6) Periodic dilution or resuspension due to sludge washing or other mixing requirements will increase the chances of preferential settling of the zeolite solids. (7) Mixtures of Purex sludge and size-reduced zeolite did not produce yield stresses greater than 200 Pascals for settling times less than thirty days. Most of the sludge-zeolite blends did not exceed 50 Pascals. These mixtures should be removable by current pump technology if sufficient velocities can be obtained. (8) The settling rate of the sludge-zeolite mixtures is a function of the ionic strength (or supernate density) and the zeolite- sludge mixing ratio. (9) Simulant tests indicate that leaching of Si may be an issue for the processed Tank 19 mound material. (10) Floating zeolite fines observed in water for the jet-eductor system and size-reduced zeolite were not observed when the size-reduced zeolite was blended with caustic solutions, indicating that the caustic solutions cause the fines to agglomerate. Based on the test programs described in this report, the potential for successfully removing Tank 18/19 mound material from Tank 7 with the current slurry pump technology requires the reduction of the particle size of the Tank 18/19 mound material.« less

UHF front-end feeding RFID-based body sensor networks by exploiting the reader signal

NASA Astrophysics Data System (ADS)

Pasca, M.; Colella, R.; Catarinucci, L.; Tarricone, L.; D'Amico, S.; Baschirotto, A.

2016-05-01

This paper presents an integrated, high-sensitivity UHF radio frequency identification (RFID) power management circuit for body sensor network applications. The circuit consists of a two-stage RF-DC Dickson's rectifier followed by an integrated five-stage DC-DC Pelliconi's charge pump driven by an ultralow start-up voltage LC oscillator. The DC-DC charge pump interposed between the RF-DC rectifier and the output load provides the RF to load isolation avoiding losses due to the diodes reverse saturation current. The RF-DC rectifier has been realized on FR4 substrate, while the charge pump and the oscillator have been realized in 180 nm complementary metal oxide semiconductor (CMOS) technology. Outdoor measurements demonstrate the ability of the power management circuit to provide 400 mV output voltage at 14 m distance from the UHF reader, in correspondence of -25 dBm input signal power. As demonstrated in the literature, such output voltage level is suitable to supply body sensor network nodes.

Multi-photon microscopy with a low-cost and highly efficient Cr:LiCAF laser

PubMed Central

Sakadić, Sava; Demirbas, Umit; Mempel, Thorsten R.; Moore, Anna; Ruvinskaya, Svetlana; Boas, David A.; Sennaroglu, Alphan; Kartner, Franz X.; Fujimoto, James G.

2009-01-01

Multi-photon microscopy (MPM) is a powerful tool for biomedical imaging, enabling molecular contrast and integrated structural and functional imaging on the cellular and subcellular level. However, the cost and complexity of femtosecond laser sources that are required in MPM are significant hurdles to widespread adoption of this important imaging modality. In this work, we describe femtosecond diode pumped Cr:LiCAF laser technology as a low cost alternative to femtosecond Ti:Sapphire lasers for MPM. Using single mode pump diodes which cost only $150 each, a diode pumped Cr:LiCAF laser generates ~70-fs duration, 1.8-nJ pulses at ~800 nm wavelengths, with a repetition rate of 100 MHz and average output power of 180 mW. Representative examples of MPM imaging in neuroscience, immunology, endocrinology and cancer research using Cr:LiCAF laser technology are presented. These studies demonstrate the potential of this laser source for use in a broad range of MPM applications. PMID:19065223

Bose-Einstein condensation of spin wave quanta at room temperature.

PubMed

Dzyapko, O; Demidov, V E; Melkov, G A; Demokritov, S O

2011-09-28

Spin waves are delocalized excitations of magnetic media that mainly determine their magnetic dynamics and thermodynamics at temperatures far below the critical one. The quantum-mechanical counterparts of spin waves are magnons, which can be considered as a gas of weakly interacting bosonic quasi-particles. Here, we discuss the room-temperature kinetics and thermodynamics of the magnon gas in yttrium iron garnet films driven by parametric microwave pumping. We show that for high enough pumping powers, the thermalization of the driven gas results in a quasi-equilibrium state described by Bose-Einstein statistics with a non-zero chemical potential. Further increases of the pumping power cause a Bose-Einstein condensation documented by an observation of the magnon accumulation at the lowest energy level. Using the sensitivity of the Brillouin light scattering spectroscopy to the degree of coherence of the scattering magnons, we confirm the spontaneous emergence of coherence of the magnons accumulated at the bottom of the spectrum, occurring if their density exceeds a critical value.

Theoretical evaluation of a continues-wave Ho3+:BaY2F8 laser with mid-infrared emission

NASA Astrophysics Data System (ADS)

Rong, Kepeng; Cai, He; An, Guofei; Han, Juhong; Yu, Hang; Wang, Shunyan; Yu, Qiang; Wu, Peng; Zhang, Wei; Wang, Hongyuan; Wang, You

2018-01-01

In this paper, we build a theoretical model to study a continues-wave (CW) Ho3+:BaY2F8 laser by considering both energy transfer up-conversion (ETU) and cross relaxation (CR) processes. The influences of the pump power, reflectance of an output coupler (OC), and crystal length on the output features are systematically analyzed for an end-pumped configuration, respectively. We also investigate how the processes of ETU and CR in the energy-level system affect the output of a Ho3+:BaY2F8 laser by use of the kinetic evaluation. The simulation results show that the optical-to-optical efficiency can be promoted by adjusting the parameters such as the reflectance of an output coupler, crystal length, and pump power. It has been theoretically demonstrated that the threshold of a Ho3+:BaY2F8 laser is very high for the lasing operation in a CW mode.

Comparative study of DPAL and XPAL systems and selection principal of parameters

NASA Astrophysics Data System (ADS)

Huang, Wei; Tan, Rongqing; Li, Zhiyong; Han, Gaoce; Li, Hui

2016-10-01

A theoretical model based on common pump structure is proposed to analyze the laser output characteristics of DPAL (Diode pumped alkali vapor laser) and XPAL (Exciplex pumped alkali laser) in this paper. The model predicts that an optical-to-optical efficiency approaching 80% can be achieved for continuous-wave four- and five-XPAL systems with broadband pumping which is several times of pumped linewidth for DPAL. Operation parameters including pumped intensity, temperature, cell' s length, mixed gas concentration, pumped linewidth and output mirror reflectivity are analyzed for DPAL and XPAL systems basing on the kinetic model. The result shows a better performance in Cs-Ar XPAL laser with requirements of relatively high Ar concentration, high pumped intensity and high temperature. Comparatively, for Cs-DPAL laser, lower temperature and lower pumped intensity should be acquired. In addition, the predictions of selection principal of temperature and cell's length are also presented. The conception of the equivalent "alkali areal density" is proposed in this paper. It is defined as the product of the alkali density and cell's length. The result shows that the output characteristics of DPAL (or XPAL) system with the same alkali areal density but different temperatures turn out to be equal. It is the areal density that reflects the potential of DPAL or XPAL systems directly. A more detailed analysis of similar influences of cavity parameters with the same areal density is also presented. The detailed results of continuous-wave DPAL and XPAL performances as a function of pumped laser linewidth and mixed gas pressure are presented along with an analysis of influences of output coupler.

Factors Affecting Specific-Capacity Tests and their Application--A Study of Six Low-Yielding Wells in Fractured-Bedrock Aquifers in Pennsylvania

USGS Publications Warehouse

Risser, Dennis W.

2010-01-01

This report by the U.S. Geological Survey, prepared in cooperation with the Pennsylvania Department of Environmental Protection, Bureau of Mining and Reclamation, evaluates factors affecting the application of specific-capacity tests in six low-yielding water wells in areas of coal mining or quarrying in Pennsylvania. Factors such as pumping rate, duration of pumping, aquifer properties, wellbore storage, and turbulent flow were assessed by theoretical analysis and by completing multiple well tests, selected to be representative of low-yielding household-supply wells in areas of active coal mining or quarrying. All six wells were completed in fractured-bedrock aquifers--five in coal-bearing shale, siltstone, sandstone, limestone, and coal of Pennsylvanian and Permian age and one in limestone of Cambrian age. The wells were pumped 24 times during 2007-09 at rates from 0.57 to 14 gallons per minute during tests lasting from 22 to 240 minutes. Geophysical logging and video surveys also were completed to determine the depth, casing length, and location of water-yielding zones in each of the test wells, and seasonal water-level changes were measured during 2007-09 by continuous monitoring at each well. The tests indicated that specific-capacity values were reproducible within about ? 20 percent if the tests were completed at the same pumping rate and duration. A change in pumping duration, pumping rate, or saturated aquifer thickness can have a substantial effect on the comparability of repeated tests. The largest effect was caused by a change in aquifer thickness in well YO 1222 causing specific capacity from repeated tests to vary by a factor of about 50. An increase in the duration of pumping from 60 to 180 minutes caused as much as a 62 percent decrease in specific capacity. The effect of differing pumping rates on specific capacity depends on whether or not the larger rate causes the water level in the well to fall below a major water-yielding zone; when this decline happened at well CA 462, specific capacity was reduced by about 63 percent. Estimates of the maximum yield for low-yielding wells that are computed by multiplying the available drawdown by the specific-capacity value may contain large errors if the wells were pumped at low rates that do not cause much water-level drawdown. The estimates of yield are likely to be too large because the effects of lowering the water level in the well below water-yielding zones have not been incorporated. Better yield estimates can be made by the use of step-drawdown tests or by over-pumping at a rate large enough to dewater most of the wellbore. The maximum well yield, after overpumping, can be estimated from the rate of water-level recovery or by subtracting the incremental rate of change of borehole storage at the end of the test from the pumping rate.

Unshrouded Impeller Technology Development Status

NASA Technical Reports Server (NTRS)

Droege, Alan R.; Williams, Robert W.; Garcia, Roberto

2000-01-01

To increase payload and decrease the cost of future Reusable Launch Vehicles (RLVs), engineers at NASA/MSFC and Boeing, Rocketdyne are developing unshrouded impeller technology for application to rocket turbopumps. An unshrouded two-stage high-pressure fuel pump is being developed to meet the performance objectives of a three-stage shrouded pump. The new pump will have reduced manufacturing costs and pump weight. The lower pump weight will allow for increased payload.

Simulation of the ground-water flow system at Naval Submarine Base Bangor and vicinity, Kitsap County, Washington

USGS Publications Warehouse

Heeswijk, Marijke van; Smith, Daniel T.

2002-01-01

An evaluation of the interaction between ground-water flow on Naval Submarine Base Bangor and the regional-flow system shows that for selected alternatives of future ground-water pumping on and near the base, the risk is low that significant concentrations of on-base ground-water contamination will reach off-base public-supply wells and hypothetical wells southwest of the base. The risk is low even if worst-case conditions are considered ? no containment and remediation of on-base contamination. The evaluation also shows that future saltwater encroachment of aquifers below sea level may be possible, but this determination has considerable uncertainty associated with it. The potential effects on the ground-water flow system resulting from four hypothetical ground-water pumping alternatives were considered, including no change in 1995 pumping rates, doubling the rates, and 2020 rates estimated from population projections with two different pumping distributions. All but a continuation of 1995 pumping rates demonstrate the possibility of future saltwater encroachment in the Sea-level aquifer on Naval Submarine Base Bangor. The amount of time it would take for encroachment to occur is unknown. For all pumping alternatives, future saltwater encroachment in the Sea-level aquifer also may be possible along Puget Sound east and southeast of the base. Future saltwater encroachment in the Deep aquifer also may be possible throughout large parts of the study area. Projections of saltwater encroachment are least certain outside the boundaries of Naval Submarine Base Bangor. The potential effects of the ground-water pumping alternatives were evaluated by simulating the ground-water flow system with a three-dimensional uniform-density ground-water flow model. The model was calibrated by trial-and-error by minimizing differences between simulated and measured or estimated variables. These included water levels from prior to January 17, 1977 (termed 'predevelopment'), water-level drawdowns since predevelopment until April 15, 1995, ground-water discharge to streams in water year 1995, and residence times of ground water in different parts of the flow system that were estimated in a separate but related study. Large amounts of ground water were pumped from 1977 through 1980 from the Sea-level aquifer on Naval Submarine Base Bangor to enable the construction of an off-shore drydock. Records of the flow-system responses to the applied stresses were used to help calibrate the model. Errors in the calibrated model were significant. The poor agreement between simulated and measured values could be improved by making many local changes to hydraulic parameters but these changes were not supported by other data. Model errors may have resulted in errors in the simulated effects of ground-water pumping alternatives.

High-Reliability Pump Module for Non-Planar Ring Oscillator Laser

NASA Technical Reports Server (NTRS)

Liu, Duncan T.; Qiu, Yueming; Wilson, Daniel W.; Dubovitsky, Serge; Forouhar, Siamak

2007-01-01

We propose and have demonstrated a prototype high-reliability pump module for pumping a Non-Planar Ring Oscillator (NPRO) laser suitable for space missions. The pump module consists of multiple fiber-coupled single-mode laser diodes and a fiber array micro-lens array based fiber combiner. The reported Single-Mode laser diode combiner laser pump module (LPM) provides a higher normalized brightness at the combined beam than multimode laser diode based LPMs. A higher brightness from the pump source is essential for efficient NPRO laser pumping and leads to higher reliability because higher efficiency requires a lower operating power for the laser diodes, which in turn increases the reliability and lifetime of the laser diodes. Single-mode laser diodes with Fiber Bragg Grating (FBG) stabilized wavelength permit the pump module to be operated without a thermal electric cooler (TEC) and this further improves the overall reliability of the pump module. The single-mode laser diode LPM is scalable in terms of the number of pump diodes and is capable of combining hundreds of fiber-coupled laser diodes. In the proof-of-concept demonstration, an e-beam written diffractive micro lens array, a custom fiber array, commercial 808nm single mode laser diodes, and a custom NPRO laser head are used. The reliability of the proposed LPM is discussed.

Efforts to Improve Efficiency of Extraction Well Operation at the Fernald Preserve, Harrison, Ohio – 16177

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glassmeyer, Cathy; Hooten, Gwen; Hertel, Bill

The Fernald Preserve, a former uranium processing facility that produced high-purity uranium metal products during the Cold War, is located in southwest Ohio. The facility became a US Department of Energy Office of Legacy Management (LM) site in November 2006, following completion of the Comprehensive Environmental Response, Compensation, and Liability Act environmental remediation and site restoration (with the exception of groundwater). When the site was turned over to LM, approximately 76.5 ha of the Great Miami Aquifer remained contaminated with uranium above the final remediation level of 30 μg/L. Here, uranium contamination is being removed from groundwater in the Greatmore » Miami Aquifer through a pump-and-treat operation, which is predicted to continue until 2033. Twenty extraction wells pump about 30 million liters per day. Operation of the system is impacted by iron in the groundwater that promotes iron fouling of the well pumps, motors, and screens. The design of the well field evolved over 21 years and reflected a conservative system that could respond to a wide range of pumping conditions. For instance, some of the extraction wells were sized with pumps and motors that would allow the well to pump up to 1890 L/min (500 gpm) if warranted. The added flexibility, though, came at the cost of operational efficiency. We describe the efforts that have been taken by LM since the Fernald site was transferred to LM to mitigate the operational impacts from the iron fouling aquifer conditions and improve the efficiency of the well-field operation. Variable-frequency drives were installed at six wells to replace flow control valves. Several wells with oversized pumps and motors were changed from 24-hour per day operation to 8-hour per day operation to allow the pumps to operate closer to their design flow rates. Pumps and motors were “right-sized” at many wells to improve pumping efficiency. The process used to rehabilitate (or clean) well screens was improved, and a process was developed to clean pumps without having to pull them from the well. To reduce pressure drops, improvements were also made to the configuration of the discharge piping. A new control system was installed for each well to allow local control and local tracking of energy used. The amount of energy used daily compared to number of gallons pumped provides a method to assess pump performance and determine when action is necessary to restore well pump efficiency. Additionally, the metrics being employed to help quantify well-field efficiency improvements are described, and the benefits achieved by proactively managing the pump-and-treat operation are presented.« less

Continuous cryopump with a device for regenerating the cryosurface

DOEpatents

Foster, Christopher A.

1988-01-01

A high throughput continuous cryopump is provided. The cryopump (10) incorporates an improved method for regenerating the cryopumping surface (22) while the pump is in continuous operation. The regeneration of the cryopumping surface (22) does not thermally cycle the pump, and to this end a small chamber (91) connected to a secondary pumping source (60) serves to contain and exhaust frost removed from the cryopumping surface (22) during such regeneration. The frost is exhausted at a rate substantially independent of the speed of the cryopump which enhances the capability of the pump to achieve a high compression ratio and allow the pump to operate continuously while the cryopumping surface is being regenerated.

On the feasibility of closed-loop control of intra-aortic balloon pumping

NASA Technical Reports Server (NTRS)

Clark, J. W., Jr.; Bourland, H. M.; Kane, G. R.

1973-01-01

A closed-loop control scheme for the control of intra-aortic balloon pumping has been developed and tested in dog experiments. A performance index reflecting the general objectives of balloon-assist pumping is developed and a modified steepest ascent control algorithm is utilized for the selection of a proper operating point for the balloon during its pumping cycle. This paper attempts to indicate the feasibility of closed-loop control of balloon pumping, and particularly its flexibility in achieving both diastolic augmentation of mean aortic pressure and control of the level of end-diastolic pressure (EDP) an important factor in reducing heart work.

Three-dimensional wide-field pump-probe structured illumination microscopy

PubMed Central

Kim, Yang-Hyo; So, Peter T.C.

2017-01-01

We propose a new structured illumination scheme for achieving depth resolved wide-field pump-probe microscopy with sub-diffraction limit resolution. By acquiring coherent pump-probe images using a set of 3D structured light illumination patterns, a 3D super-resolution pump-probe image can be reconstructed. We derive the theoretical framework to describe the coherent image formation and reconstruction scheme for this structured illumination pump-probe imaging system and carry out numerical simulations to investigate its imaging performance. The results demonstrate a lateral resolution improvement by a factor of three and providing 0.5 µm level axial optical sectioning. PMID:28380860

46 CFR 182.520 - Bilge pumps.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Highly resistant to salt water, petroleum oil, heat, and vibration. (g) If a fixed hand pump is used to... 46 Shipping 7 2010-10-01 2010-10-01 false Bilge pumps. 182.520 Section 182.520 Shipping COAST...) MACHINERY INSTALLATION Bilge and Ballast Systems § 182.520 Bilge pumps. (a) A vessel must be provided with...

Contamination of successive samples in portable pumping systems

Treesearch

Robert B. Thomas; Rand E. Eads

1983-01-01

Automatic discrete sample pumping systems used to monitor water quality should deliver to storage all materials pumped in a given cycle. If they do not, successive samples will be contaminated, a severe problem with highly variable suspended sediment concentrations in small streams. The cross-contamination characteristics of two small commonly used portable pumping...

Uncooled pump combiners for fiber laser and amplifier systems

NASA Astrophysics Data System (ADS)

Bansal, L.; Sienkowski, R.; Neale, C.; Mann, J.; Headley, C.

2018-02-01

In this work we demonstrate a high transmission pump combiner that can operate uncooled at a maximum power of 400W for a continuous duration of 100hrs. The 7x1 pump combiner has seven 105/125 μm diameter 0.22 NA input pump fibers and a 247 μm diameter and 0.22 NA glass clad output fiber. The combiner has a high, 99%, pump transmission efficiency. These devices withstand without failure, a series of environmental stress tests, namely Thermal Cycling (-40 to 85ºC) and Damp Humidity (85ºC/85RH). These tests are conducted to uncover any latent defects in the device structure. The combiner's also survive an elevated temperature of 75ºC at a power of 365W for duration of 5hrs, without any noticeable change in pump transmission.

Three stage vacuum system for ultralow temperature installation

NASA Astrophysics Data System (ADS)

Das, N. K.; Pradhan, J.; Naser, Md Z. A.; Mandal, B. Ch; Roy, A.; Kumar, P.; Mallik, C.; Bhandari, R. K.

2012-11-01

We use a three stage vacuum system for developing a dilution fridge at VECC, Kolkata. We aim at achieving a cooling power of 20μW at 100mK for various experiments especially in the field of condensed matter and nuclear physics. The system is essentially composed of four segments-bath cryostat, vacuum system, dilution insert and 3He circulation circuit. Requirement of vacuum system at different stages are different. The vacuum system for cryostat and for internal vacuum chamber located within the helium bath is a common turbo molecular pump backed by scroll pump as to maintain a vacuum ~10-6mbar. For bringing down the temperature of the helium evaporator, we use a high throughput Roots pump backed by a dry pump. The pumping system for 3He distillation chamber (still) requires a high pumping speed, so a turbo drag pump backed by a scroll pump has been installed. As the fridge use precious 3He gas for operation, the entire system has been made to be absolutely leak proof with respect to the 3He gas.

FMR-driven spin pumping in Y3Fe5O12-based structures

NASA Astrophysics Data System (ADS)

Yang, Fengyuan; Hammel, P. Chris

2018-06-01

Ferromagnetic resonance driven spin pumping, a topic of steadily increasing interest since its emergence over two decades ago, remains one of the most exciting research fields in condensed matter physics. Among the many materials that have been explored for spin pumping, yttrium iron garnet (YIG) is one of the most extensively studied because of its exceptionally low magnetic damping and insulating nature. There is a great amount of literature in the spin pumping and related research fields, too broad for this review to cover. In this Topical Review, we focus on the YIG-based spin pumping results carried out by our groups, including: the mechanism and technical details of our off-axis sputtering technique for the growth of single-crystalline YIG epitaxial films with a high degree ordering, experimental evidence for the high quality of the YIG films, spin pumping results from YIG into various transition metals and their heterostructures, dynamic spin transport in YIG/antiferromagnet hybrid structures, intralayer spin pumping by localized spin wave modes confined by a micromagnetic probe, dynamic spin coupling between YIG and nitrogen-vacancy centers in diamond, parametric spin pumping from high-wavevector spin waves in YIG, and localized spin wave mode behavior in broadly tunable spatially complex magnetic configurations. These results build on the power and versatility of YIG spin pumping to improve our understanding of spin dynamics, spin currents, spin Hall physics, spin–orbit coupling, dynamic magnetic coupling, and the relationship between these phenomena in a broad range of materials, geometries, and settings.

Threshold kinetics of a solar-simulator-pumped iodine laser

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Lee, Y.; Weaver, W. R.; Humes, D. H.; Lee, J. H.

1984-01-01

A model of the chemical kinetics of the n-C3F7I solar-simulator-pumped iodine laser is utilized to study the major kinetic processes associated with the threshold behavior of this experimental system. Excited-state diffusion to the cell wall is the dominant limiting factor below 5 torr. Excited-state diffusion to the cell wall is the dominant limiting factor below 5 torr. Excited-state recombination with the alkyl radical and quenching by the parent gas control threshold at higher pressures. Treatment of the hyperfine splitting and uncertainty in the pressure broadening are important factors in fixing the threshold level. In spite of scatter in the experimental data caused by instabilities in the simulator high-pressure high-pressure arc, reasonable agreement is achieved between the model and experiment. Model parameters arrived at are within the uncertainty range of values found in the literature.

Aviation-fuel lubricity evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1988-07-01

Fuel-system components have experienced problems with the slipperiness or lubricity of the fuel back to the early 1960's. As a consequence of the level of refinement necessary for the PWA 523 fuel (now designated MIL-T-38219 grade JP-7) to obtain its high-temperature stability, many of the polar compounds contributing to lubricity had been removed, resulting in abnormal hydraulic fuel-pump wear. A lubricity-enhancing compound was developed (PWA 536) to eliminate the wear problem. High-pressure piston-type fuel pumps were one of the first parts of the engine fuel system to exhibit problems related to fuel properties. One early problem manifested itself as corrosionmore » of silver-plated slipper pads and was related to carryover of residual-chlorides fuel. Fuel controls were another part of the engine fuel system susceptible to fuel properties. Lack of lubricity agents caused fuel control sliding servo valves to stick.« less

Meta-Modeling-Based Groundwater Remediation Optimization under Flexibility in Environmental Standard.

PubMed

He, Li; Xu, Zongda; Fan, Xing; Li, Jing; Lu, Hongwei

2017-05-01

  This study develops a meta-modeling based mathematical programming approach with flexibility in environmental standards. It integrates numerical simulation, meta-modeling analysis, and fuzzy programming within a general framework. A set of models between remediation strategies and remediation performance can well guarantee the mitigation in computational efforts in the simulation and optimization process. In order to prevent the occurrence of over-optimistic and pessimistic optimization strategies, a high satisfaction level resulting from the implementation of a flexible standard can indicate the degree to which the environmental standard is satisfied. The proposed approach is applied to a naphthalene-contaminated site in China. Results show that a longer remediation period corresponds to a lower total pumping rate and a stringent risk standard implies a high total pumping rate. The wells located near or in the down-gradient direction to the contaminant sources have the most significant efficiency among all of remediation schemes.

Impact of input FBG reflectivity and forward pump power on RIN transfer in ultralong Raman laser amplifiers.

PubMed

Rizzelli, Giuseppe; Iqbal, Md Asif; Gallazzi, Francesca; Rosa, Paweł; Tan, Mingming; Ania-Castañón, Juan Diego; Krzczanowicz, Lukasz; Corredera, Pedro; Phillips, Ian; Forysiak, Wladek; Harper, Paul

2016-12-12

Relative intensity noise transfer from the pump to the signal in 2nd-order ultra-long Raman laser amplifiers for telecommunications is characterized numerically and experimentally. Our results showcase the need for careful adjustment of the front FBG reflectivity and the relative contribution of forward pump power, and their impact on performance. Finally, our analysis is verified through a 10 × 30 GBaud DP-QPSK transmission experiment, showing a large Q factor penalty associated with the combination of high forward pumping and high reflectivities.

Method for a microfluidic weaklink device

DOEpatents

Shepodd, Timothy J [Livermore, CA; Duncan, Matthew P [Augusta, GA

2009-12-01

The present invention relates to an electrokinetic (EK) pump capable of creating high pressures electroosmotically, and capable of retaining high pressures. Both pressure creation and retention are accomplished without the need for moving parts. The EK pump uses a polymerizable fluid that creates the pressure-retaining seal within the EK pump when polymerization is initiated, typically by exposure to UV radiation. Weaklink devices are advantageously constructed including such a pressure-retaining EK pump since, among other advantages, the response of the weaklink device relies on predictable and reliable chemical polymerization reactions.

Canned pump having a high inertia flywheel

DOEpatents

Veronesi, Luciano; Raimondi, ALbert A.

1989-01-01

A canned pump is described which includes a motor, impeller, shaft, and high inertia flywheel mounted within a hermetically sealed casing. The flywheel comprises a heavy metal disk made preferably of a uranium alloy with a stainless steel shell sealably enclosing the heavy metal. The outside surfaces of the stainless steel comprise thrust runners and a journal for mating with, respectively, thrust bearing shoes and radial bearing segments. The bearings prevent vibration of the pump and, simultaneously, minimize power losses normally associated with the flywheel resulting from frictionally pumping surrounding fluid.

Canned pump having a high inertia flywheel

DOEpatents

Veronesi, L.; Raimondi, A.A.

1989-12-12

A canned pump is described which includes a motor, impeller, shaft, and high inertia flywheel mounted within a hermetically sealed casing. The flywheel comprises a heavy metal disk made preferably of a uranium alloy with a stainless steel shell sealably enclosing the heavy metal. The outside surfaces of the stainless steel comprise thrust runners and a journal for mating with, respectively, thrust bearing shoes and radial bearing segments. The bearings prevent vibration of the pump and, simultaneously, minimize power losses normally associated with the flywheel resulting from frictionally pumping surrounding fluid. 5 figs.