Evaporation on/in Capillary Structures of High Heat Flux Two-Phase Devices

NASA Technical Reports Server (NTRS)

Faghri, Amir; Khrustalev, Dmitry

1996-01-01

Two-phase devices (heat pipes, capillary pumped loops, loop heat pipes, and evaporators) have become recognized as key elements in thermal control systems of space platforms. Capillary and porous structures are necessary and widely used in these devices, especially in high heat flux and zero-g applications, to provide fluid transport and enhanced heat transfer during vaporization and condensation. However, some unexpected critical phenomena, such as dryout in long heat pipe evaporators and high thermal resistance of loop heat pipe evaporators with high heat fluxes, are possible and have been encountered in the use of two-phase devices in the low gravity environment. Therefore, a detailed fundamental investigation is proposed to better understand the fluid behavior in capillary-porous structures during vaporization at high heat fluxes. The present paper addresses some theoretical aspects of this investigation.

Design and Testing of a Cryogenic Capillary Pumped Loop Flight Experiment

NASA Technical Reports Server (NTRS)

Bugby, David C.; Kroliczek, Edward J.; Ku, Jentung; Swanson, Ted; Tomlinson, B. J.; Davis, Thomas M.; Baumann, Jane; Cullimore, Brent

1998-01-01

This paper details the flight configuration and pre-flight performance test results of the fifth generation cryogenic capillary pumped loop (CCPL-5). This device will fly on STS-95 in October 1998 as part of the CRYOTSU Flight Experiment. This flight represents the first in-space demonstration of a CCPL, a miniaturized two-phase fluid circulator for thermally linking cryogenic cooling sources to remote cryogenic components. CCPL-5 utilizes N2 as the working fluid and has a practical operating range of 75-110 K. Test results indicate that CCPL-5, which weighs about 200 grams, can transport over 10 W of cooling a distance of 0.25 m (or more) with less than a 5 K temperature drop.

Thermal Vacuum Testing of a Helium Loop Heat Pipe for Large Area Cryocooling

NASA Technical Reports Server (NTRS)

Ku, Jentung; Robinson, Franklin

2016-01-01

Future NASA space telescopes and exploration missions require cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks. One device that can potentially be used to provide closed-loop cryocooling is the cryogenic loop heat pipe (CLHP). A CLHP has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A helium CLHP has been tested extensively in a thermal vacuum chamber using a cryocooler as the heat sink to characterize its transient and steady performance and to verify its ability to cool large areas or components in the 3 degrees Kelvin temperature range. The helium CLHP thermal performance test included cool-down from the ambient temperature, startup, capillary limit, heat removal capability, rapid power changes, and long duration steady state operation. The helium CLHP demonstrated robust operation under steady state and transient conditions. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully by simply applying power to both the capillary pump and the evaporator plate without pre-conditioning. It could adapt to a rapid heat load change and quickly reach a new steady state. Heat removal between 10 megawatts and 140 megawatts was demonstrated, yielding a power turn down ratio of 14. When the CLHP capillary limit was exceeded, the loop could resume its normal function by reducing the power to the capillary pump. Steady state operations up to 17 hours at several heat loads were demonstrated. The ability of the helium CLHP to cool large areas was therefore successfully verified.

Capillary-Driven Heat Transfer Experiment: Keeping It Cool in Space

NASA Technical Reports Server (NTRS)

Lekan, Jack F.; Allen, Jeffrey S.

1998-01-01

Capillary-pumped loops (CPL's) are devices that are used to transport heat from one location to another--specifically to transfer heat away from something. In low-gravity applications, such as satellites (and possibly the International Space Station), CPL's are used to transfer heat from electrical devices to space radiators. This is accomplished by evaporating one liquid surface on the hot side of the CPL and condensing the vapor produced onto another liquid surface on the cold side. Capillary action, the phenomenon that causes paper towels to absorb spilled liquids, is used to "pump" the liquid back to the evaporating liquid surface (hot side) to complete the "loop." CPL's require no power to operate and can transfer heat over distances as large as 30 ft or more. Their reliance upon evaporation and condensation to transfer heat makes them much more economical in terms of weight than conventional heat transfer systems. Unfortunately, they have proven to be unreliable in space operations, and the explanation for this unreliability has been elusive. The Capillary-Driven Heat Transfer (CHT) experiment is investigating the fundamental fluid physics phenomena thought to be responsible for the failure of CPL's in low-gravity operations. If the failure mechanism can be identified, then appropriate design modifications can be developed to make capillary phase-change heat-transport devices a more viable option in space applications. CHT was conducted onboard the Space Shuttle Columbia during the first Microgravity Science Laboratory (MSL-1) mission, STS-94, which flew from July 1 to 17, 1997. The CHT glovebox investigation, which was conceived by Dr. Kevin Hallinan and Jeffrey Allen of the University of Dayton, focused on studying the dynamics associated with the heating and cooling at the evaporating meniscus within a capillary phase-change device in a low-gravity environment. The CHT experimental hardware was designed by a small team of engineers from Aerospace Design & Fabrication (ADF), the NASA Lewis Research Center, and the University of Dayton. The hardware consisted of two experiment modules that each contained an instrumented test loop (idealized capillary-pumped loop), a base unit for power conversion and backlighting, a display unit with 15 LED's (light-emitting diodes) to display temperatures, pressure, heater power, and time, a control unit to select heaters and heater settings, a cooling fan, and associated cables.

Polymeric heat pipe wick

NASA Technical Reports Server (NTRS)

Seidenberg, Benjamin

1988-01-01

A wick for use in a capillary loop pump heat pipe is described. The wick material is an essentially uniformly porous, permeable, open-cell, polyethylene thermoplastic foam having an ultrahigh average molecular weight of from approximately 1 to 5 million, and an average pore size of about 10 to 12 microns. A representative material having these characteristics is POREX UF, which has an average molecular weight of about 3 million. This material is fully compatible with the FREONs and anhydrous ammonia and allows for the use of these very efficient working fluids in capillary loops.

Testing of a Helium Loop Heat Pipe for Large Area Cryocooling

NASA Technical Reports Server (NTRS)

Ku, Jentung; Robinson, Franklin

2016-01-01

Future NASA space telescopes and exploration missions require cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks. One device that can potentially be used to provide closed-loop cryocooling is the cryogenic loop heat pipe (CLHP). A CLHP has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A helium CLHP has been tested extensively in a thermal vacuum chamber using a cryocooler as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components in the 3K temperature range. A copper plate with attached electrical heaters was used to simulate the heat source, and heat was collected by the CLHP evaporator and transferred to the cryocooler for ultimate heat rejection. The helium CLHP thermal performance test included cool-down from the ambient temperature, startup, capillary limit, heat removal capability, rapid power changes, and long duration steady state operation. The helium CLHP demonstrated robust operation under steady state and transient conditions. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully without pre-conditioning by simply applying power to both the capillary pump and the evaporator plate. It could adapt to rapid changes in the heat load, and reach a new steady state very quickly. Heat removal between 10mW and 140mW was demonstrated, yielding a power turn down ratio of 14. When the CLHP capillary limit was exceeded, the loop could resume its normal function by reducing the power to the capillary pump. Steady state operations up to 17 hours at several heat loads were demonstrated. The ability of the helium CLHP to cool large areas was therefore successfully verified.

Testing of a Helium Loop Heat Pipe for Large Area Cryocooling

NASA Technical Reports Server (NTRS)

Ku, Jentung; Robinson, Franklin Lee

2015-01-01

Future NASA space telescopes and exploration missions require cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks. One device that can potentially be used to provide closed-loop cryocooling is the cryogenic loop heat pipe (CLHP). A CLHP has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A helium CLHP has been tested extensively in a thermal vacuum chamber using a cryocooler as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components in the 3K temperature range. A copper plate with attached electrical heters was used to simulate the heat source, and heat was collected by the CLHP evaporator and transferred to the cryocooler for ultimate heat rejection. The helium CLHP thermal performance test included cool-down from the ambient temperature, startup, capillary limit, heat removal capability, rapid power changes, and long duration steady state operation. The helium CLHP demonstrated robust operation under steady state and transient conditions. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully without pre-conditioning by simply applying power to both the capillary pump and the evaporator plate. It could adapt to rapid changes in the heat load, and reach a new steady state very quickly. Heat removal between 10mW and 140mW was demonstrated, yielding a power turn down ratio of 14. When the CLHP capillary limit was exceeded, the loop could resume its normal function by reducing the power to the capillary pump. Steady state operations up to 17 hours at several heat loads were demonstrated. The ability of the helium CLHP to cool large areas was therefore successfully verified.

Mathematical Modeling of Loop Heat Pipes with Multiple Capillary Pumps and Multiple Condensers. Part 1; Stead State Stimulations

NASA Technical Reports Server (NTRS)

Hoang, Triem T.; OConnell, Tamara; Ku, Jentung

2004-01-01

Loop Heat Pipes (LHPs) have proven themselves as reliable and robust heat transport devices for spacecraft thermal control systems. So far, the LHPs in earth-orbit satellites perform very well as expected. Conventional LHPs usually consist of a single capillary pump for heat acquisition and a single condenser for heat rejection. Multiple pump/multiple condenser LHPs have shown to function very well in ground testing. Nevertheless, the test results of a dual pump/condenser LHP also revealed that the dual LHP behaved in a complicated manner due to the interaction between the pumps and condensers. Thus it is redundant to say that more research is needed before they are ready for 0-g deployment. One research area that perhaps compels immediate attention is the analytical modeling of LHPs, particularly the transient phenomena. Modeling a single pump/single condenser LHP is difficult enough. Only a handful of computer codes are available for both steady state and transient simulations of conventional LHPs. No previous effort was made to develop an analytical model (or even a complete theory) to predict the operational behavior of the multiple pump/multiple condenser LHP systems. The current research project offered a basic theory of the multiple pump/multiple condenser LHP operation. From it, a computer code was developed to predict the LHP saturation temperature in accordance with the system operating and environmental conditions.

Ceramic heat pipe wick

NASA Technical Reports Server (NTRS)

Seidenberg, Benjamin (Inventor); Swanson, Theodore (Inventor)

1989-01-01

A wick for use in a capillary loop pump heat pipe is disclosed. The wick material is an essentially uniformly porous, permeable, open-cell, silicon dioxide/aluminum oxide inorganic ceramic foam having a silica fiber ratio, by weight, of about 78 to 22, respectively, a density of 6 lbs/cu ft, and an average pore size of less than 5 microns. A representative material having these characteristics is Lockheed Missile and Space Company, Inc.'s HTP 6-22. This material is fully compatible with the freons and anhydrous ammonia and allows for the use of these very efficient working fluids, and others, in capillary loops.

Investigation of thermal-fluid mechanical characteristics of the Capillary Pump Loop

NASA Technical Reports Server (NTRS)

Kiper, Ali M.

1991-01-01

The main purpose is the experimental and analytical study of behavior of the Capillary Pump Loop (CPL) heat pipe system during the transient mode of operating by applying a step heat pulse to one or more evaporators. Prediction of the CPL behavior when subjected to pulse heat loading requires further study before the transient response of CPL system can be fully understood. The following tasks are discussed: (1) exploratory testing of a CPL heat pipe for transient operational conditions which could generate the type of oscillatory inlet temperature behavior observed in an earlier testing of NASA/GSFC CPL-2 heat pipe system; (2) analytical investigation of the CPL inlet section temperature oscillations; (3) design, construction and testing of a bench-top CPL test system for study of the CPL transient operation; and (4) transient analysis of a CPL heat pipe by applying a step power input to the evaporators.

Flight Test Results for the HST Orbital Systems Test (HOST) Capillary Pump Loop Cooling System

NASA Technical Reports Server (NTRS)

Buchko, M.; Kaylor, M.; Kroliczek, E.; Ottenstein, L.

1999-01-01

The Near Infrared Camera and Multi Object Spectrometer (NICMOS) was installed in the Hubble Space Telescope (MST) in February 1997. Shortly thereafter, the instrument experienced a thermal short in its solid nitrogen dewar system which will significantly shorten the instrument's useful life. A reverse Brayton cycle mechanical refrigerator will be installed during the Third Servicing Mission (SM3) to provide cooling for the instrument, and thereby extend its operations. A Capillary Pump Loop (CPL) and radiator system was designed, built and tested to remove up to 500 watts of heat from the mechanical cryocooler and its associated electronics. The HST Orbital Systems Test (HOST) platform was flown on the Space Shuttle Discovery (STS-95) as a flight demonstration of the cryocooler system, CPL control electronics, and the CPL/Radiator. This paper will present the flight test results and thermal performance of the CPL system in detail.

A bi-directional two-phase/two-phase heat exchanger

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura

1993-01-01

This paper describes the design and test of a heat exchanger that transfers heat from one two-phase thermal loop to another with very small drops in temperature and pressure. The heat exchanger condenses the vapor in one loop while evaporating the liquid in the other without mixing of the condensing and evaporating fluids. The heat exchanger is bidirectional in that it can transfer heat in reverse, condensing on the normally evaporating side and vice versa. It is fully compatible with capillary pumped loops and mechanically pumped loops. Test results verified that performance of the heat exchanger met the design requirements. It demonstrated a heat transfer rate of 6800 watts in the normal mode of operation and 1000 watts in the reverse mode with temperature drops of less than 5 C between two thermal loops.

The Phillips Laboratory capillary pumped loop test facility

NASA Astrophysics Data System (ADS)

Gluck, Donald F.; Kaylor, Marc C.

1996-03-01

An ammonia capillary pumped loop (CPL) test facility has been designed, fabricated, subject to acceptance tests, and assembled at Phillips Laboratory. Its intent is to support a wide range of Air Force programs, bringing CPL technology to flight readiness for operational systems. The facility provides a high degree of modularity and flexibility with several heating and cooling options, and capability for elevation (+/- 15 in.), tilt (+/-60°) and transport length variation. It has a 182 by 44 by 84 inch envelope, an expected heat load capability of 2500 W, and a temperature range of 0 to 50 °C. The evaporator section has two plates with four capillary pumps (CPs) each, with a starter pump on one plate. The CPs are 5/8 in., with TAG aluminum 6063-T6 casing and UHMW polyethylene wicks. The active lengths are 15 and 30 inch with both 10 and 15 micron wicks. The individual CPs have thermal and hydraulic isolation capability, and are removable. The transport section consists of stainless steel lines in a serpentine configuration, a 216 in3 free volume reservoir, and a mechanical pump. The vapor transport line contains a capillary device (which can be bypassed) for vapor blockage during startup. The condenser consists of two separately valved, parallel cold plates each with a downstream noncondensible gas trap. Cooling of up to 1500 W at -50 °C is provided by an FTS Systems chiller using Flourinert FC-72. An enclosure/exhaust system is provided for safety and emergency venting of ammonia. An ammonia charge station performs or supports the functions of proof pressure, flushing with ammonia, purging with gaseous nitrogen, evacuation of all or part of the CPL to 20 microns, and charging. Instrumentation consists of over 116 thermocouples, five of which are internal; one absolute and six differential pressure transducers; eleven watt transducers, and a reservoir load cell. The data acquisition system consists of a temperature scanner, Bernoulli drive, and two Macintosh computers using LabView software. Data scanning and storage as rapid as once every three seconds for thermocouples and once per 0.6 seconds for transducers is supported.

Thermal management system technology development for space station applications

NASA Technical Reports Server (NTRS)

Rankin, J. G.; Marshall, P. F.

1983-01-01

A short discussion of the history to date of the NASA thermal management system technology development program is presented, and the current status of several ongoing studies and hardware demonstration tasks is reported. One element of technology that is required for long-life, high-power orbital platforms/stations that is being developed is heat rejection and a space-constructable radiator system. Aspects of this project include high-efficiency fin concepts, a heat pipe quick-disconnect device, high-capacity heat pipes, and an alternate interface heat exchanger design. In the area of heat acquisition and transport, developments in a pumped two-phase transport loop, a capillary pumped transport loop using the concept of thermal utility are reported. An example of a thermal management system concept is provided.

Thermal management of high power space based systems

NASA Technical Reports Server (NTRS)

Hwangbo, H.; Mcever, W. S.

1985-01-01

Conventional techniques of using a portion of the spacecraft skin for radiation of waste heat will be inadequate for high powered payloads (50 to 100 kWe) due to the lack of sufficient area. A Shuttle type system using a pumped single phase fluid loop could be scaled up to higher power but this type of system would require excessive pump power and weight. A pumped two-phase heat transfer loop has a much lower pumping requirement due to the higher latent heat of vaporization of the fluid in comparison to the sensible heat it can absorb through a temperature change. Concepts for an evaporator and a condenser for a pumped two-phase system are described. The condenser uses capillary grooves and a separate pumped condensate return line to achieve high heat transfer coefficients and stable operation due to the separation of the vapor and liquid flows. The cold plate evaporator uses wicks to contain the liquid and transport it to the heated surface. It can also function as a condenser for warming components. Control concepts for the cold plate are discussed. Concepts for deployment or erection of large space radiators are also considered.

Thermal Technology Development Activities at the Goddard Space Flight Center - 2001

NASA Technical Reports Server (NTRS)

Butler, Dan

2002-01-01

This presentation provides an overview of thermal technology development activities carried out at NASA's Goddard Space Flight Center during 2001. Specific topics covered include: two-phase systems (heat pipes, capillary pumped loops, vapor compression systems and phase change materials), variable emittance systems, advanced coatings, high conductivity materials and electrohydrodynamic (EHD) thermal coatings. The application of these activities to specific space missions is also discussed.

Thermal control systems for low-temperature heat rejection on a lunar base

NASA Technical Reports Server (NTRS)

Sridhar, K. R.; Gottmann, Matthias

1992-01-01

In this report, Rankine-cycle heat pumps and absorption heat pumps (ammonia-water and lithium bromide-water) have been analyzed and optimized for a lunar base cooling load of 100 kW. For the Rankine cycle, a search of several commonly used commercial refrigerants provided R11 and R717 as possible working fluids. Hence, the Rankine-cycle analysis has been performed for both R11 and R717. Two different configurations were considered for the system--one in which the heat pump is directly connected to the rejection loop and another in which a heat exchanger connects the heat pump to the rejection loop. For a marginal increase in mass, the decoupling of the rejection loop and the radiator from the heat pump provides greater reliability of the system and better control. Hence, the decoupled system is the configuration of choice. The optimal TCS mass for a 100 kW cooling load at 270 K was 5940 kg at a radiator temperature of 362 K. R11 was the working fluid in the heat pump, and R717 was the transport fluid in the rejection loop. Two TCS's based on an absorption-cycle heat pump were considered, one with an ammonia-water mixture and the other with a lithium bromide-water mixture as the working fluid. A complete cycle analysis was performed for these systems. The system components were approximated as heat exchangers with no internal pressure drop for the mass estimate. This simple approach underpredicts the mass of the systems, but is a good 'optimistic' first approximation to the TCS mass in the absence of reliable component mass data. The mass estimates of the two systems reveal that, in spite of this optimistic estimate, the absorption heat pumps are not competitive with the Rankine-cycle heat pumps. Future work at the systems level will involve similar analyses for the Brayton- and Stirling-cycle heat pumps. The analyses will also consider the operation of the pump under partial-load conditions. On the component level, a capillary evaporator will be designed, built, and tested in order to investigate its suitability in lunar base TCS and microgravity two-phase applications.

Two-phase/two-phase heat exchanger analysis

NASA Technical Reports Server (NTRS)

Kim, Rhyn H.

1992-01-01

A capillary pumped loop (CPL) system with a condenser linked to a double two-phase heat exchanger is analyzed numerically to simulate the performance of the system from different starting conditions to a steady state condition based on a simplified model. Results of the investigation are compared with those of similar apparatus available in the Space Station applications of the CPL system with a double two-phase heat exchanger.

Micro-Columnated Loop Heat Pipe: The Future of Electronic Substrates

NASA Astrophysics Data System (ADS)

Dhillon, Navdeep Singh

The modern world is run by semiconductor-based electronic systems. Due to continuous improvements in semiconductor device fabrication, there is a clear trend in the market towards the development of electronic devices and components that not only deliver enhanced computing power, but are also more compact. Thermal management has emerged as the primary challenge in this scenario where heat flux dissipation of electronic chips is increasing exponentially, but conventional cooling solutions such as conduction and convection are no longer feasible. To keep device junction temperatures within the safe operating limit, there is an urgent requirement for ultra-high-conductivity thermal substrates that not only absorb and transport large heat fluxes, but can also provide localized cooling to thermal hotspots. This dissertation describes the design, modeling, and fabrication of a phase change-based, planar, ultra-thin, passive thermal transport system that is inspired by the concept of loop heat pipes and capillary pumped loops. Fabricated on silicon and Pyrex wafers using microfabrication techniques, the micro-columnated loop heat pipe (muCLHP) can be integrated directly with densely packed or multiply-stacked electronic substrates, to provide localized high-heat-flux thermal management. The muCLHP employs a dual-scale coherent porous silicon(CPS)-based micro-columnated wicking structure, where the primary CPS wick provides large capillary forces for fluid transport, while a secondary surface-wick maximizes the rate of thin-film evaporation. To overcome the wick thickness limitation encountered in conventional loop heat pipes, strategies based on MEMS surface micromachining techniques were developed to reduce parasitic heat flow from the evaporator to the compensation chamber of the device. Finite element analysis was used to confirm this reduction in a planar evaporator design, thus enabling the generation of a large motive temperature head for continuous device operation. To predict the overall heat carrying capacity of the muCLHP in the capillary pumping limit, an analytical model was developed to account for a steady state pressure balance in the device flow loop. Based on this model, a design optimization study, employing monotonicity analysis and numerical optimization techniques, was undertaken. It was found that an optimized muCLHP device can absorb heat fluxes as large as 1293 W/cm2 when water is used as a working fluid. A finite volume method-based numerical model was also developed to compute the rates of thin-film evaporation from the patterned surface of the secondary wick. The numerical results indicated that, by properly optimizing the dual-scale wick topology, allowable evaporative heat fluxes can be made commensurate with the heat flux performance predicted by the capillary pumping limit. The latter part of the dissertation deals with the fabrication, packaging, and experimental testing of several in-plane-wicking micro loop heat pipe (muLHP) prototypes. These devices were fabricated on silicon and Pyrex substrates and closely resemble the muCLHP design philosophy, with the exception that the CPS wick is substituted with an easier to fabricate in-plane wick. A novel thermal-flux method was developed for the degassing and fluid charging of the muLHP prototypes. Experiments were conducted to study the process of evaporation and dynamics of the liquid and vapor phases in the device flow loop. Using these results, the overall device and individual component topologies critical to the operation of the two-phase flow loop were identified. A continuous two-phase device flow loop was demonstrated for applied evaporator heat fluxes as high as 41 W/cm2. The performance of these devices, currently found to be limited by the motive temperature head requirement, can be significantly improved by implementing the parasitic heat flow-reduction strategies developed in this work. The 3-D thin-film evaporation model, when integrated into the overall device modeling framework, will enable a design optimization of the micro-columnated wick for further device performance enhancements.

Gravity Effect on Capillary Limit in a Miniature Loop Heat Pipe with Multiple Evaporators and Multiple Condensers

NASA Technical Reports Server (NTRS)

Nagano, Hosei; Ku, Jentung

2007-01-01

This paper describes the gravity effect on heat transport characteristics in a minia6re loop heat pipe with multiple evaporators and multiple condensers. Tests were conducted in three different orientations: horizontal, 45deg tilt, and vertical. The gravity affected the loop's natural operating temperature, the maximum heat transport capability, and the thermal conductance. In the case that temperatures of compensation chambers were actively controlled, the required control heater power was also dependent on the test configuration. In the vertical configuration, the secondary wick was not able to pump the liquid from the CC to the evaporator against the gravity. Thus the loop could operate stably or display some peculiar behaviors depending on the initial liquid distribution between the evaporator and the CC. Because such an initial condition was not known prior to the test, the subsequent loop performance was unpredictable.

Comments on the Operation of Capillary Pumped Loop Devices in Low Gravity

NASA Technical Reports Server (NTRS)

Hallinan, K. P.; Allen, J. S.

1999-01-01

The operation of Capillary Pumped Loops (CPL's) in low gravity has generally been unable to match ground-based performance. The reason for this poorer performance has been elusive. In order to investigate the behavior of a CPL in low-gravity, an idealized, glass CPL experiment was constructed. This experiment, known as the Capillary-driven Heat Transfer (CHT) experiment, was flown on board the Space Shuttle Columbia in July 1997 during the Microgravity Science Laboratory mission. During the conduct of the CHT experiment an unexpected failure mode was observed. This failure mode was a result of liquid collecting and then eventually bridging the vapor return line. With the vapor return line blocked, the condensate was unable to return to the evaporator and dry-out subsequently followed. The mechanism for this collection and bridging has been associated with long wavelength instabilities of the liquid film forming in the vapor return line. Analysis has shown that vapor line blockage in present generation CPL devices is inevitable. Additionally, previous low-gravity CPL tests have reported the presence of relatively low frequency pressure oscillations during erratic system performance. Analysis reveals that these pressure oscillations are in part a result of long wavelength instabilities present in the evaporator pores, which likewise lead to liquid bridging and vapor entrapment in the porous media. Subsequent evaporation to the trapped vapor increases the vapor pressure. Eventually the vapor pressure causes ejection of the bridged liquid. Recoil stresses depress the meniscus, the vapor pressure rapidly increases, and the heated surface cools. The process then repeats with regularity.

Light propagation in the micro-size capillary injected by high temperature liquid

NASA Astrophysics Data System (ADS)

Li, Yan-jun; Li, Edward; Xiao, Hai

2016-11-01

The high temperature liquid is injected into the micro-size capillary and its light propagation behavior is investigated. We focus on two different liquid pumping methods. The first method can pump the high temperature liquid tin into the micro-size capillary by using a high pressure difference system. After pumping, a single mode fiber (SMF) connected with the optical carrier based microwave interferometry (OCMI) system is used to measure different liquid tin levels in the micro-size capillary. The second method can pump the room temperature engine oil into the capillary by using a syringe pump. This method can avoid the air bubbles when the liquids are pumped into the capillary.

Thermal Control and Enhancement of Heat Transport Capacity of Two-Phase Loops With Electrohydrodynamic Conduction Pumping

NASA Technical Reports Server (NTRS)

Seyed-Yagoobi, J.; Didion, J.; Ochterbeck, J. M.; Allen, J.

2000-01-01

There are three kinds of electrohydrodynamics (EHD) pumping based on Coulomb force: induction pumping, ion-drag pumping, and pure conduction pumping. EHD induction pumping relies on the generation of induced charges. This charge induction in the presence of an electric field takes place due to a non-uniformity in the electrical conductivity of the fluid which can be caused by a non-uniform temperature distribution and/or an inhomogeneity of the fluid (e.g. a two-phase fluid). Therefore, induction pumping cannot be utilized in an isothermal homogeneous liquid. In order to generate Coulomb force, a space charge must be generated. There are two main mechanisms for generating a space charge in an isothermal liquid. The first one is associated with the ion injection at a metal/liquid interface and the related pumping is referred to as ion-drag pumping. Ion-drag pumping is not desirable because it can deteriorate the electrical properties of the working fluid. The second space charge generation mechanism is associated with the heterocharge layers of finite thickness in the vicinity of the electrodes. Heterocharge layers result from dissociation of the neutral electrolytic species and recombination of the generated ions. This type of pumping is referred to as pure conduction pumping. This project investigates the EHD pumping through pure conduction phenomenon. Very limited work has been conducted in this field and the majority of the published papers in this area have mistakenly assumed that the electrostriction force was responsible for the net flow generated in an isothermal liquid. The main motivation behind this study is to investigate an EHD conduction pump for a two-phase loop to be operated in the microgravity environment. The pump is installed in the liquid return passage (isothermal liquid) from the condenser section to the evaporator section. Unique high voltage and ground electrodes have been designed that generate sufficient pressure heads with very low electric power requirements making the EHD conduction pumping attractive to applications such as two-phase systems (e.g. capillary pumped loops and heat pipes). Currently, the EHD conduction pump performance is being tested on a two-phase loop under various operating conditions in the laboratory environment. The simple non-mechanical and lightweight design of the EHD pump combined with the rapid control of performance by varying the applied electric field, low power consumption, and reliability offer significant advantages over other pumping mechanisms; particularly in reduced gravity applications.

An Investigation Into: I) Active Flow Control for Cold-Start Performance Enhancement of a Pump-Assisted, Capillary-Driven, Two-Phase Cooling Loop II) Surface Tension of n-Pentanol + Water, a Self-Rewetting Working Fluid, From 25 °C to 85 °C

NASA Astrophysics Data System (ADS)

Bejarano, Roberto Villa

Cold-start performance enhancement of a pump-assisted, capillary-driven, two-phase cooling loop was attained using proportional integral and fuzzy logic controls to manage the boiling condition inside the evaporator. The surface tension of aqueous solutions of n-Pentanol, a self-rewetting fluid, was also investigated for enhancing heat transfer performance of capillary driven (passive) thermal devices was also studied. A proportional-integral control algorithm was used to regulate the boiling condition (from pool boiling to thin-film boiling) and backpressure in the evaporator during cold-start and low heat input conditions. Active flow control improved the thermal resistance at low heat inputs by 50% compared to the baseline (constant flow rate) case, while realizing a total pumping power savings of 56%. Temperature overshoot at start-up was mitigated combining fuzzy-logic with a proportional-integral controller. A constant evaporator surface temperature of 60°C with a variation of +/-8°C during start-up was attained with evaporator thermal resistances as low as 0.10 cm2--K/W. The surface tension of aqueous solutions of n-Pentanol, a self-rewetting working fluid, as a function of concentration and temperature were also investigated. Self-rewetting working fluids are promising in two-phase heat transfer applications because they have the ability to passively drive additional working fluid towards the heated surface; thereby increasing the dryout limitations of the thermal device. Very little data is available in literature regarding the surface tension of these fluids due to the complexity involved in fluid handling, heating, and experimentation. Careful experiments were performed to investigate the surface tension of n-Pentanol + water. The concentration and temperature range investigated were from 0.25%wt. to1.8%wt and 25°C to 85°C, respectively.

Performance demonstration of hydrogen advanced loop heat pipe for 20-30K cryocooling of far infrared sensors

NASA Astrophysics Data System (ADS)

Hoang, Triem T.; O'Connell, Tamara A.; Ku, Jentung; Butler, C. D.; Swanson, Theodore D.

2005-08-01

The James Webb Space Telescope (JWST) program have identified the need for cryogenic cooling transport devices that (i) provide robust/reliable thermal management for Infrared (IR) sensors/detectors in the temperature range of 20-30K, (ii) minimize vibration effects of mechanical cryocoolers on the instruments, (iii) reduce spatial temperature gradients in cryogenic components, and (iv) afford long continuous service life of the telescope. Passive two-phase capillary cooling technologies such as heat pipes, Loop Heat Pipes (LHPs), and Capillary pumped Loops (CPLs) have proven themselves capable of performing necessary thermal control functions for room temperature applications. They have no mechanical moving part to wear out or to introduce unwanted vibration to the instruments and, hence, are reliable and maintenancefree. However, utilizing these capillary devices for cryogenic cooling still remains a challenge because of difficulties involving the system start-up and operation in a warm environment. An advanced concept of LHP using Hydrogen as the working fluid was recently developed to demonstrate the cryocooling transport capabilities in the temperature range of 20-30K. A full-size demonstration test loop - appropriately called H2-ALHP_2 - was constructed and performance tested extensively in a thermal vacuum chamber. It was designed specifically to manage "heat parasitics" from a warm surrounding, enabling it to start up from an initially supercritical state and operate without requiring a rigid heat shield. Like room temperature LHPs, the H2-ALHP transport lines were made of small-diameter stainless steel tubing that are flexible enough to isolate the cryocooler-induced vibration from the IR instruments. In addition, focus of the H2-ALHP research and development effort was also placed on the system weight saving for space-based applications.

Capillary pumping independent of the liquid surface energy and viscosity

NASA Astrophysics Data System (ADS)

Guo, Weijin; Hansson, Jonas; van der Wijngaart, Wouter

2018-03-01

Capillary pumping is an attractive means of liquid actuation because it is a passive mechanism, i.e., it does not rely on an external energy supply during operation. The capillary flow rate generally depends on the liquid sample viscosity and surface energy. This poses a problem for capillary-driven systems that rely on a predictable flow rate and for which the sample viscosity or surface energy are not precisely known. Here, we introduce the capillary pumping of sample liquids with a flow rate that is constant in time and independent of the sample viscosity and sample surface energy. These features are enabled by a design in which a well-characterized pump liquid is capillarily imbibed into the downstream section of the pump and thereby pulls the unknown sample liquid into the upstream pump section. The downstream pump geometry is designed to exert a Laplace pressure and fluidic resistance that are substantially larger than those exerted by the upstream pump geometry on the sample liquid. Hence, the influence of the unknown sample liquid on the flow rate is negligible. We experimentally tested pumps of the new design with a variety of sample liquids, including water, different samples of whole blood, different samples of urine, isopropanol, mineral oil, and glycerol. The capillary filling speeds of these liquids vary by more than a factor 1000 when imbibed to a standard constant cross-section glass capillary. In our new pump design, 20 filling tests involving these liquid samples with vastly different properties resulted in a constant volumetric flow rate in the range of 20.96-24.76 μL/min. We expect this novel capillary design to have immediate applications in lab-on-a-chip systems and diagnostic devices.

Small capillary pumped AMTEC systems

NASA Astrophysics Data System (ADS)

Hunt, Thomas K.; Sievers, Robert K.; Butkiewicz, David A.; Pantolin, Jan E.; Ivanenok, Joseph F.

1993-01-01

Alkali Metal Thermoelectric Converter (AMTEC) systems offer significant potential advantages for space power. Recent experiments have shown that electromagnetic pumps can operate with a negative priming head and so may be suitable for space applications in microgravity (Hunt et al. 1992). Capillary pumped cells offer an alternative approach to microgravity compatibility. We have designed, built, and operated capillary pumped AMTEC cells in various orientations with respect to gravity in order to provide a presumptive demonstration of zero-G capability (Sievers et al. 1992). We report lifetime and performance data for these capillary pumped AMTEC cells. Progress on other issues relating to space flight testing of AMTEC systems is also discussed.

Capillary Limit in a Loop Heat Pipe with Dual Evaporators

NASA Technical Reports Server (NTRS)

Ku, Jentung; Birur, Gajanana; Obenschain, Arthur F. (Technical Monitor)

2002-01-01

This paper describes a study on the capillary limit of a loop heat pipe (LHP) with two evaporators and two condensers. Both theoretical analysis and experimental investigation are conducted. Tests include heat load to one evaporator only, even heat loads to both evaporators and uneven heat load to both evaporators. Results show that after the capillary limit is exceeded, vapor will penetrate through the wick of the weaker evaporator and the compensation chamber (CC) of that evaporator will control the loop operating temperature regardless of which CC has been in control prior to the event Because the evaporator can tolerate vapor bubbles, the loop may continue to work and reach a new steady state at a higher operating temperature. The loop may even function with a modest increase in the heat load past the capillary limit With a heat load to only one evaporator, the capillary limit can be identified by rapid increases in the operating temperature and in the temperature difference between the evaporator and the CC. However, it is more difficult to tell when the capillary limit is exceeded if heat loads are applied to both evaporators. In all cases, the loop can recover by reducing the heat load to the loop.

The NICMOS Cooling SYSTEM-5 Years of Successful On-Orbit Operation

NASA Astrophysics Data System (ADS)

Swift, W. L.; Dolan, F. X.; Zagarola, M. V.

2008-03-01

The NICMOS Cooling System consists of a closed-loop turbo-Brayton cryocooler coupled with a cryogenic circulator that provides refrigeration to the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST). The cryocooler heat is rejected to space through a capillary pumped loop connected to radiators mounted on the side of the telescope. The system was deployed and integrated with NICMOS by astronauts during STS-109 (Space Shuttle Columbia) in March 2002. It has operated nearly continuously without performance degradation since that time, maintaining NICMOS detectors at a constant temperature of 77 K. Miniature, high-speed turbomachines are used in the cryocooler and the circulator loop to provide vibration-free, long-life operation. A small centrifugal compressor and miniature turboalternator are key elements of the closed loop cryocooler. A miniature cryogenic centrifugal circulator in a separate pressurized neon loop transports heat from the NICMOS instrument to the cryocooler interface heat exchanger. This paper describes the development of the system, key operational features, ground and orbital tests prior to its deployment, and operational results during its five-year operational history on orbit.

Nailfold capillary patterns in healthy subjects: a real issue in capillaroscopy.

PubMed

Ingegnoli, Francesca; Gualtierotti, Roberta; Lubatti, Chiara; Bertolazzi, Chiara; Gutierrez, Marwin; Boracchi, Patrizia; Fornili, Marco; De Angelis, Rossella

2013-11-01

Nailfold capillaroscopy has been extensively applied in a broad spectrum of pathologic conditions, but very few data have been published in healthy individuals. The aim of this study was to describe the nailfold capillary findings on a large series of healthy subjects using the video-capillaroscopy technique. Nailfold capillaries were studied based on their morphology, dimensions and density. Then, to evaluate jointly the association between different capillary findings in groups of subjects which were homogeneous for their characteristics, cluster analysis was performed. The results (median) of capillary measurements were as follows: loop length 207μm, external diameter 39μm, internal diameter 17μm, apical diameter 17μm, and intercapillary distance 143μm. Based on the cluster analysis three major "normal" morphologic capillaroscopic patterns were depicted: 1) the "normal" pattern mainly with 2 to 5 U-shaped loops/mm and ≤2 tortuous loops/mm; 2) the "perfect normal" pattern with ≥5 U-shaped loops/mm and 3) the "unusual normal" with at least 1 meandering or bushy loop, or at least 1 microhemorrhage, or with >4 crossed loops/mm. Regarding the loop measurements, the majority of subjects had a median of 7capillaries/mm with a median length of 198μm. © 2013 Elsevier Inc. All rights reserved.

Cooperative suction by vertical capillary array pump for controlling flow profiles of microfluidic sensor chips.

PubMed

Horiuchi, Tsutomu; Hayashi, Katsuyoshi; Seyama, Michiko; Inoue, Suzuyo; Tamechika, Emi

2012-10-18

A passive pump consisting of integrated vertical capillaries has been developed for a microfluidic chip as an useful component with an excellent flow volume and flow rate. A fluidic chip built into a passive pump was used by connecting the bottoms of all the capillaries to a top surface consisting of a thin layer channel in the microfluidic chip where the thin layer channel depth was smaller than the capillary radius. As a result the vertical capillaries drew fluid cooperatively rather than independently, thus exerting the maximum suction efficiency at every instance. This meant that a flow rate was realized that exhibited little variation and without any external power or operation. A microfluidic chip built into this passive pump had the ability to achieve a quasi-steady rather than a rapidly decreasing flow rate, which is a universal flow characteristic in an ordinary capillary.

NASA Goddard Space Flight Center Cooperative Enterprise

NASA Technical Reports Server (NTRS)

Fredley, Joseph E.; Lysak, Daniel B.

2004-01-01

The viability of a Capillary Heat Pump (CHP) concept using a Loop Heat Pipe evaporator and an eductor in a closed loop to reject heat at a higher temperature than it is acquired at with the goal of reducing spacecraft radiator area is examined. Eductor inefficiency resulting from the mixing of high velocity motive flow with low velocity suction flow may preclude spacecraft radiator area savings. The utility of a CHP for thermal management may be limited to those missions where system mass is of secondary concern compared to system reliability, or where a heat pump is required to accommodate relatively high thermal rejection temperatures. Shearography techniques for nondestructive inspection and evaluation were examined for two unique applications. Shearography is shown to give good results in evaluating the quality of bonds holding lead tiles to the SWIFT spacecraft BAT gamma ray mask. Also, a novel technique was developed allowing specular objects to be inspected using shearography to evaluate bonding between the skin and core of a specular surface honeycomb structure. Large-scale bond failures are readily identified.

Evaporation of binary mixtures in microgravity

NASA Technical Reports Server (NTRS)

Girgis, Morris; Matta, Nabil; Kolli, Kiran; Brown, Leon; Chubb, Kevin

1995-01-01

The motivation of this research is to obtain a better understanding of phase-change heat transfer within single and binary liquid meniscii, both in 1-g and 0-g environments. During phase 1 and part of phase 2, in a glass test cell with an inclined heated plate, 1-6 experiments on pentane with additions of decane up to 3% were conducted to determine the optimum concentration that will exhibit the maximum heat transfer and stability. During phase 2 emphasis was given to explore fundamental research issues and to ultimately develop a reliable capillary pumped loop (CPL) device for low gravity. In related experimental work, it was found that thermocapillary stresses near the contract line could result in a degraded wettability which ultimately could explain the observed failure of CPL devices in zero-gravity environment. Therefore, the current experimental effort investigates the effect of adding binary constituents in improving the thermocapillary characteristics near the contact line within the loop configuration. Achievements during second phase include: (1) Further enhancement of Central State University's Microgravity Laboratory by adding or improving upon capabilities of photography, video imaging, fluid visualization, and general experimental testing capabilities; (2) Experimental results for the inclined plate cell; (3) Modeling effort with a detailed scaling analysis; (4) Additional testing with a tube loop configuration to extend experimental work by Dickens, et al.; (5) Fabrication of a capillary loop to be tested using binary fluid (pentane/decane). The device that has been recently completed will be set up horizontally so that the effect of gravity on the performance is negligible. Testing will cover a wide range of parameters such as decane/pentane concentration, heat input value, heat input location (below or above meniscus), and loop temperature.

Overview of Loop Heat Pipe Operation

NASA Technical Reports Server (NTRS)

Ku, Jentung

1999-01-01

Loop heat pipes (LHP's) are two-phase heat transfer devices that utilize the evaporation and condensation of a working fluid to transfer heat, and the capillary forces developed in the porous wicks to circulate the fluid. The LHP was first developed in the former Soviet Union in the early 1980s, about the same time that the capillary pumped loop (CPL) was developed in the United States. The LHP is known for its high pumping capability and robust operation mainly due to the use of fine-pored metal wicks and an integral evaporator/hydro-accumulator design. The LHP technology is rapidly gaining acceptance in aerospace community. It is the baseline design for thermal control of several spacecraft, including NASA's GLAS and Chemistry, ESA's ATLID, CNES' STENTOR, RKA's OBZOR, and several commercial satellites. Numerous LHP papers have been published since the mid-1980's. Most papers presented test results and discussions on certain specific aspects of the LHP operation. LHP's and CPL's show many similarities in their operating principles and performance characteristics. However, they also display significant differences in many aspects of their operation. Some of the LHP behaviors may seem strange or mysterious, even to experienced CPL practitioners. The main purpose of this paper is to present a systematic description of the operating principles and thermal-hydraulic behaviors of LHP'S. LHP operating principles will be given first, followed by a description of the thermal-hydraulics involved in LHP operation. Operating characteristics and important parameters affecting the LHP operation will then be described in detail. Peculiar behaviors of the LHP, including temperature hysteresis and temperature overshoot during start-up, will be explained. For simplicity, most discussions will focus upon LHP's with a single evaporator and a single condenser, but devices with multiple evaporators and condensers will also be discussed. Similarities and differences between LHP's and CPL's will be addressed throughout the paper whenever appropriate.

Capillary Pumped Heat Transfer (CHT) Experiment

NASA Technical Reports Server (NTRS)

Hallinan, Kevin P.; Allen, J. S.

1998-01-01

The operation of Capillary Pumped Loops (CPL's) in low gravity has generally been unable to match ground-based performance. The reason for this poorer performance has been elusive. In order to investigate the behavior of a CPL in low-gravity, an idealized, glass CPL experiment was constructed. This experiment, known as the Capillary-driven Heat Transfer (CHT) experiment, was flown on board the Space Shuttle Columbia in July 1997 during the Microgravity Science Laboratory mission. During the conduct of the CHT experiment an unexpected failure mode was observed. This failure mode was a result of liquid collecting and then eventually bridging the vapor return line. With the vapor return line blocked, the condensate was unable to return to the evaporator and dry-out subsequently followed. The mechanism for this collection and bridging has been associated with long wavelength instabilities of the liquid film forming in the vapor return line. Analysis has shown that vapor line blockage in present generation CPL devices is inevitable. Additionally, previous low-gravity CPL tests have reported the presence of relatively low frequency pressure oscillations during erratic system performance. Analysis reveals that these pressure oscillations are in part a result of long wavelength instabilities present in the evaporator pores, which likewise lead to liquid bridging and vapor entrapment in the porous media. Subsequent evaporation to the trapped vapor increases the vapor pressure. Eventually the vapor pressure causes ejection of the bridged liquid. Recoil stresses depress the meniscus, the vapor pressure rapidly increases, and the heated surface cools. The process then repeats with regularity.

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.

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

Ground Source Heat Pumps vs. Conventional HVAC: A Comparison of Economic and Environmental Costs

DTIC Science & Technology

2009-03-26

of systems are surface water heat pumps (SWHPs), ground water heat pumps (GWHPs), and ground coupled heat pumps ( GCHPs ) (Kavanaugh & Rafferty, 1997...Kavanaugh & Rafferty, 1997). Ground Coupled Heat Pumps (Closed-Loop Ground Source Heat Pumps) GCHPs , otherwise known as closed-loop GSHPs, are the...Significant confusion has arisen through the use of GCHP and closed-loop GSHP terminology. Closed-loop GSHP is the preferred nomenclature for this

Investigation of Capillary Limit in a Loop Heat Pipe

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura; Rogers, Paul; Cheung, Kwok; Obenschain, Arthur F. (Technical Monitor)

2001-01-01

This paper presets an experimental study on the capillary limit of a loop heat pipe (LHP) at low powers. The slow thermal response of the loop at low powers made it possible to observe interactions among various components after the capillary limit was exceeded. The capillary limit at low powers was achieved by imposing additional pressure drops on the vapor line through the use of a metering valve. A differential pressure transducer was also used to measure the pressure drop across the evaporator and the compensation chamber (CC). Test results show that when the capillary limit is exceeded, vapor will penetrate the primary wick, resulting in a partial dry-out of the evaporator and a rapid increase of the CC temperature. Because the evaporator can tolerate vapor bubbles, the LHP will continue to function and may reach a new steady state at the higher temperature. Thus, the LHP will exhibit a graceful degradation in performance rather than a complete failure. Moreover, the loop can recover from a partial dry-out by reducing the heat load without a re-start.

Performing Isoelectric Focusing and Simultaneous Fractionation of Proteins on A Rotary Valve Followed by Sodium Dodecyl – Polyacrylamide Gel Electrophoresis

PubMed Central

Wang, Wei; Lu, Joann J.; Gu, Congying; Zhou, Lei; Liu, Shaorong

2013-01-01

In this technical note, we design and fabricate a novel rotary valve and demonstrate its feasibility for performing isoelectric focusing and simultaneous fractionation of proteins, followed by sodium dodecyl – polyacrylamide gel electrophoresis. The valve has two positions. In one position, the valve routes a series of capillary loops together into a single capillary tube where capillary isoelectric focusing (CIEF) is performed. By switching the valve to another position, the CIEF-resolved proteins in all capillary loops are isolated simultaneously, and samples in the loops are removed and collected in vials. After the collected samples are briefly processed, they are separated via sodium dodecyl – polyacrylamide gel electrophoresis (SDS-PAGE, the 2nd-D separation) on either a capillary gel electrophoresis instrument or a slab-gel system. The detailed valve configuration is illustrated, and the experimental conditions and operation protocols are discussed. PMID:23819755

An improved loopless mounting method for cryocrystallography

NASA Astrophysics Data System (ADS)

Qi, Jian-Xun; Jiang, Fan

2010-01-01

Based on a recent loopless mounting method, a simplified loopless and bufferless crystal mounting method is developed for macromolecular crystallography. This simplified crystal mounting system is composed of the following components: a home-made glass capillary, a brass seat for holding the glass capillary, a flow regulator, and a vacuum pump for evacuation. Compared with the currently prevalent loop mounting method, this simplified method has almost the same mounting procedure and thus is compatible with the current automated crystal mounting system. The advantages of this method include higher signal-to-noise ratio, more accurate measurement, more rapid flash cooling, less x-ray absorption and thus less radiation damage to the crystal. This method can be extended to the flash-freeing of a crystal without or with soaking it in a lower concentration of cryoprotectant, thus it may be the best option for data collection in the absence of suitable cryoprotectant. Therefore, it is suggested that this mounting method should be further improved and extensively applied to cryocrystallographic experiments.

Triggering vacuum capillaries for pneumatic pumping and metering liquids in point-of-care immunoassays.

PubMed

Weng, Kuo-Yao; Chou, Nien-Jen; Cheng, Jya-Wei

2008-07-01

An innovative vacuum capillary pneumatic actuation concept that can be used for point-of-care testing has been investigated. The vacuum glass capillaries are encapsulated within a laminated pouch and incorporated into the fluidic card. Vacuum glass capillaries broken by external force such as finger pressure, generate the pneumatic forces to induce liquid flow in the fluidic system. The sizes of vacuum capillary play a vital role in the pumping and metering functions of the system. The luteinizing hormone (LH) chromatographic immunoassay performances in the fluidic cards show consistency comparable to that obtained by manual micropipetting. The vacuum capillary pneumatic actuation will be applied in other complex handling step bioassays and lab-on-a-chip devices.

Development Specification for the Portable Life Support System (PLSS) Thermal Loop Pump

NASA Technical Reports Server (NTRS)

Anchondo, Ian; Campbell, Colin

2017-01-01

The AEMU Thermal Loop Pump Development Specification establishes the requirements for design, performance, and testing of the Water Pump as part of the Thermal System of the Advanced Portable Life Support System (PLSS). It is envisioned that the Thermal Loop Pump is a positive displacement pump that provides a repeatable volume of flow against a given range of back-pressures provided by the various applications. The intention is to operate the pump at a fixed speed for the given application. The primary system is made up of two identical and redundant pumps of which only one is in operation at given time. The Auxiliary Loop Pump is an identical pump design to the primary pumps but is operated at half the flow rate. Inlet positive pressure to the pumps is provided by the upstream Flexible Supply Assembly (FSA-431 and FSA-531) which are physically located inside the suit volume and pressurized by suit pressure. An integrated relief valve, placed in parallel to the pump's inlet and outlet protects the pump and loop from over-pressurization. An integrated course filter is placed upstream of the pump's inlet to provide filtration and prevent potential debris from damaging the pump.

GAS eleven node thermal model (GEM)

NASA Technical Reports Server (NTRS)

Butler, Dan

1988-01-01

The Eleven Node Thermal Model (GEM) of the Get Away Special (GAS) container was originally developed based on the results of thermal tests of the GAS container. The model was then used in the thermal analysis and design of several NASA/GSFC GAS experiments, including the Flight Verification Payload, the Ultraviolet Experiment, and the Capillary Pumped Loop. The model description details the five cu ft container both with and without an insulated end cap. Mass specific heat values are also given so that transient analyses can be performed. A sample problem for each configuration is included as well so that GEM users can verify their computations. The model can be run on most personal computers with a thermal analyzer solution routine.

Enhanced Microchip Electrophoresis Separations Combined with Electrochemical Detection Utilizing a Capillary Embedded in Polystyrene.

PubMed

Mehl, Benjamin T; Martin, R Scott

2018-01-07

The ability to use microchip-based electrophoresis for fast, high-throughput separations provides researchers with a tool for close-to real time analysis of biological systems. While PDMS-based electrophoresis devices are popular, the separation efficiency is often an issue due to the hydrophobic nature of PDMS. In this study, a hybrid microfluidic capillary device was fabricated to utilize the positive features of PDMS along with the electrophoretic performance of fused silica. A capillary loop was embedded in a polystyrene base that can be coupled with PDMS microchannels at minimal dead volume interconnects. A method for cleaning out the capillaries after a wet-polishing step was devised through the use of 3D printed syringe attachment. By comparing the separation efficiency of fluorescein and CBI-glycine with both a PDMS-based serpentine device and the embedded capillary loop device, it was shown that the embedded capillary loop device maintained higher theoretical plates for both analytes. A Pd decoupler with a carbon or Pt detection electrode were embedded along with the loop allowing integration of the electrophoretic separation with electrochemical detection. A series of catecholamines were separated to show the ability to resolve similar analytes and detect redox active species. The release of dopamine and norepinephrine from PC 12 cells was also analyzed showing the compatibility of these improved microchip separations with high ionic cell buffers associated with cell culture.

Chemical micro-sensor

DOEpatents

Ruggiero, Anthony J.

2005-05-03

An integrated optical capillary electrophoresis system for analyzing an analyte. A modulated optical pump beam impinges on an capillary containing the analyte/buffer solution which is separated by electrophoresis. The thermally-induced change in the index of refraction of light in said electrophoresis capillary is monitored using an integrated micro-interferometer. The interferometer includes a first interferometer arm intersecting the electrophoresis capillary proximate the excitation beam and a second, reference interferometer arm. Changes in index of refraction in the analyte measured by interrogating the interferometer state using white light interferometry and a phase-generated carrier demodulation technique. Background thermo-optical activity in the buffer solution is cancelled by splitting the pump beam and exciting pure buffer solution in a second section of capillary where it crosses the reference arm of the interferometer.

Day and Night Closed-Loop Control Using the Integrated Medtronic Hybrid Closed-Loop System in Type 1 Diabetes at Diabetes Camp.

PubMed

Ly, Trang T; Roy, Anirban; Grosman, Benyamin; Shin, John; Campbell, Alex; Monirabbasi, Salman; Liang, Bradley; von Eyben, Rie; Shanmugham, Satya; Clinton, Paula; Buckingham, Bruce A

2015-07-01

To evaluate the feasibility and efficacy of a fully integrated hybrid closed-loop (HCL) system (Medtronic MiniMed Inc., Northridge, CA), in day and night closed-loop control in subjects with type 1 diabetes, both in an inpatient setting and during 6 days at diabetes camp. The Medtronic MiniMed HCL system consists of a fourth generation (4S) glucose sensor, a sensor transmitter, and an insulin pump using a modified proportional-integral-derivative (PID) insulin feedback algorithm with safety constraints. Eight subjects were studied over 48 h in an inpatient setting. This was followed by a study of 21 subjects for 6 days at diabetes camp, randomized to either the closed-loop control group using the HCL system or to the group using the Medtronic MiniMed 530G with threshold suspend (control group). The overall mean sensor glucose percent time in range 70-180 mg/dL was similar between the groups (73.1% vs. 69.9%, control vs. HCL, respectively) (P = 0.580). Meter glucose values between 70 and 180 mg/dL were also similar between the groups (73.6% vs. 63.2%, control vs. HCL, respectively) (P = 0.086). The mean absolute relative difference of the 4S sensor was 10.8 ± 10.2%, when compared with plasma glucose values in the inpatient setting, and 12.6 ± 11.0% compared with capillary Bayer CONTOUR NEXT LINK glucose meter values during 6 days at camp. In the first clinical study of this fully integrated system using an investigational PID algorithm, the system did not demonstrate improved glucose control compared with sensor-augmented pump therapy alone. The system demonstrated good connectivity and improved sensor performance. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Confocal laser-scanning microscopy of capillaries in normal and psoriatic skin

NASA Astrophysics Data System (ADS)

Archid, Rami; Patzelt, Alexa; Lange-Asschenfeldt, Bernhard; Ahmad, Sufian S.; Ulrich, Martina; Stockfleth, Eggert; Philipp, Sandra; Sterry, Wolfram; Lademann, Juergen

2012-10-01

An important and most likely active role in the pathogenesis of psoriasis has been attributed to changes in cutaneous blood vessels. The purpose of this study was to use confocal laser-scanning microscopy (CLSM) to investigate dermal capillaries in psoriatic and normal skin. The structures of the capillary loops in 5 healthy participants were compared with those in affected skin of 13 psoriasis patients. The diameters of the capillaries and papillae were measured for each group with CLSM. All investigated psoriasis patients showed elongated, widened, and tortuous microvessels in the papillary dermis, whereas all healthy controls showed a single capillary loop in each dermal papilla. The capillaries of the papillary loop and the dermal papilla were significantly enlarged in the psoriatic skin lesions (diameters 24.39±2.34 and 146.46±28.52 μm, respectively) in comparison to healthy skin (diameters 9.53±1.8 and 69.48±17.16 μm, respectively) (P<0.001). CLSM appears to represent a promising noninvasive technique for evaluating dermal capillaries in patients with psoriasis. The diameter of the vessels could be seen as a well-quantifiable indicator for the state of psoriatic skin. CLSM could be useful for therapeutic monitoring to delay possible recurrences.

Heat pipe with embedded wick structure

DOEpatents

Adkins, Douglas Ray; Shen, David S.; Tuck, Melanie R.; Palmer, David W.; Grafe, V. Gerald

1998-01-01

A heat pipe has an embedded wick structure that maximizes capillary pumping capability. Heat from attached devices such as integrated circuits evaporates working fluid in the heat pipe. The vapor cools and condenses on a heat dissipation surface. The condensate collects in the wick structure, where capillary pumping returns the fluid to high heat areas.

Heat pipe with embedded wick structure

DOEpatents

Adkins, D.R.; Shen, D.S.; Tuck, M.R.; Palmer, D.W.; Grafe, V.G.

1998-06-23

A heat pipe has an embedded wick structure that maximizes capillary pumping capability. Heat from attached devices such as integrated circuits evaporates working fluid in the heat pipe. The vapor cools and condenses on a heat dissipation surface. The condensate collects in the wick structure, where capillary pumping returns the fluid to high heat areas. 7 figs.

Heat pipe with embedded wick structure

DOEpatents

Adkins, Douglas Ray; Shen, David S.; Tuck, Melanie R.; Palmer, David W.; Grafe, V. Gerald

1999-01-01

A heat pipe has an embedded wick structure that maximizes capillary pumping capability. Heat from attached devices such as integrated circuits evaporates working fluid in the heat pipe. The vapor cools and condenses on a heat dissipation surface. The condensate collects in the wick structure, where capillary pumping returns the fluid to high heat areas.

Kinking and Torsion Can Significantly Improve the Efficiency of Valveless Pumping in Periodically Compressed Tubular Conduits. Implications for Understanding of the Form-Function Relationship of Embryonic Heart Tubes.

PubMed

Hiermeier, Florian; Männer, Jörg

2017-11-19

Valveless pumping phenomena (peristalsis, Liebau-effect) can generate unidirectional fluid flow in periodically compressed tubular conduits. Early embryonic hearts are tubular conduits acting as valveless pumps. It is unclear whether such hearts work as peristaltic or Liebau-effect pumps. During the initial phase of its pumping activity, the originally straight embryonic heart is subjected to deforming forces that produce bending, twisting, kinking, and coiling. This deformation process is called cardiac looping. Its function is traditionally seen as generating a configuration needed for establishment of correct alignments of pulmonary and systemic flow pathways in the mature heart of lung-breathing vertebrates. This idea conflicts with the fact that cardiac looping occurs in all vertebrates, including gill-breathing fishes. We speculate that looping morphogenesis may improve the efficiency of valveless pumping. To test the physical plausibility of this hypothesis, we analyzed the pumping performance of a Liebau-effect pump in straight and looped (kinked) configurations. Compared to the straight configuration, the looped configuration significantly improved the pumping performance of our pump. This shows that looping can improve the efficiency of valveless pumping driven by the Liebau-effect. Further studies are needed to clarify whether this finding may have implications for understanding of the form-function relationship of embryonic hearts.

Kinking and Torsion Can Significantly Improve the Efficiency of Valveless Pumping in Periodically Compressed Tubular Conduits. Implications for Understanding of the Form-Function Relationship of Embryonic Heart Tubes

PubMed Central

Hiermeier, Florian; Männer, Jörg

2017-01-01

Valveless pumping phenomena (peristalsis, Liebau-effect) can generate unidirectional fluid flow in periodically compressed tubular conduits. Early embryonic hearts are tubular conduits acting as valveless pumps. It is unclear whether such hearts work as peristaltic or Liebau-effect pumps. During the initial phase of its pumping activity, the originally straight embryonic heart is subjected to deforming forces that produce bending, twisting, kinking, and coiling. This deformation process is called cardiac looping. Its function is traditionally seen as generating a configuration needed for establishment of correct alignments of pulmonary and systemic flow pathways in the mature heart of lung-breathing vertebrates. This idea conflicts with the fact that cardiac looping occurs in all vertebrates, including gill-breathing fishes. We speculate that looping morphogenesis may improve the efficiency of valveless pumping. To test the physical plausibility of this hypothesis, we analyzed the pumping performance of a Liebau-effect pump in straight and looped (kinked) configurations. Compared to the straight configuration, the looped configuration significantly improved the pumping performance of our pump. This shows that looping can improve the efficiency of valveless pumping driven by the Liebau-effect. Further studies are needed to clarify whether this finding may have implications for understanding of the form-function relationship of embryonic hearts. PMID:29367548

Nailfold capillaroscopy abnormalities correlate with cutaneous and visceral involvement in systemic sclerosis patients.

PubMed

Sato, Lucy T; Kayser, Cristiane; Andrade, Luís E C

2009-01-01

The aim of this study was to correlate quantitative and semiquantitative nailfold capillaroscopy (NFC) parameters with the extent of cutaneous and visceral involvement in systemic sclerosis (SSc) patients. The presence of clinical and serological alterations was evaluated retrospectively and correlated with NFC findings (number of capillary loops/mm, vascular deletion score and number of enlarged and giant capillary loops). For evaluation of disease extension five manifestations were analyzed: finger pad lesions, skin involvement, esophageal involvement, interstitial lung disease, and pulmonary hypertension. There were 105 NFC examinations in 92 patients, 13 of whom were evaluated at two different time points. Patients with diffuse cutaneous SSc had a higher vascular deletion score than patients with limited cutaneous SSc, sine scleroderma SSc, and overlap syndrome (1.67+/-0.91 vs 0.99+/-0.82; p=0.0005). Modified Rodnan's skin score correlated positively with capillary deletion, evaluated by the vascular deletion score and the number of capillary loops/mm (p<0.001 and p=0.012; respectively). Patients with three or more involved tracts presented lower number of capillary loops/mm (8.00+/-1.69 vs 9.23+/-1.31 capillary loops/mm; p=0.025) and a higher vascular deletion score (1.41+/-0.95 vs 0.73+/-0.76; p=0.027) when compared to patients with less than three affected tracts. Vascular deletion score was significantly higher in patients with anti-Scl-70 antibodies that in patients without anti-Scl-70 antibodies (p=0.02). NFC abnormalities correlated positively with the diffuse form of SSc, the degree of cutaneous involvement, the number of affected tracts, and the presence of anti-Scl-70 antibodies.

Scanning mass spectrometry with integrated constant distance positioning

NASA Astrophysics Data System (ADS)

Li, Nan; Eckhard, Kathrin; Aßmann, Jens; Hagen, Volker; Otto, Horst; Chen, Xingxing; Schuhmann, Wolfgang; Muhler, Martin

2006-08-01

Scanning mass spectrometry is of growing importance for the characterization of catalytically active surfaces. The instrument presented here is capable of measuring catalytic activity spatially resolved by means of two concentric capillaries. The outer one is used for cofeeding reactants such as ethene and hydrogen to the sample surface, whereas the inner one is pumping off the product mixture as inlet to a quadrupole mass spectrometer. Three-dimensional measurements under stagnant-point flow conditions become possible based on a home-built capillary positioning unit. Step-motor driven positioning stages exhibiting a minimum step width of 2.5μm̸half step are used for the x, y positioning, and the step motor in z direction has a resolution of 1μm̸half step. The system is additionally equipped with a feedback loop for following the topography of the sample throughout scanning. Hence, the obtained catalytic data are unimpaired by signal changes caused by the morphology of the investigated structure. For distance control the argon ion current is used originating from externally fed argon diffusing into the confined space between the accurately positioned capillaries and the sample surface. A well-defined microchannel flow field with 400μm wide channels and 200μm wide mounds was chosen to evaluate the developed method. The catalytic activity of a Pt catalyst deposited on glassy carbon was successfully visualized in constant probe to sample distance. Simultaneously, the topography of the sample was recorded derived from the z positioning of the capillaries.

Miniature Heat Transport System for Nanosatellite Technology

NASA Technical Reports Server (NTRS)

Douglas, Donya M,

1999-01-01

The scientific understanding of key physical processes between the Sun and the Earth require simultaneous measurements from many vantage points in space. Nano-satellite technologies will enable a class of constellation missions for the NASA Space Science Sun-Earth Connections. This recent emphasis on the implementation of smaller satellites leads to a requirement for development of smaller subsystems in several areas. Key technologies under development include: advanced miniaturized chemical propulsion; miniaturized sensors; highly integrated, compact electronics; autonomous onboard and ground operations; miniatures low power tracking techniques for orbit determination; onboard RF communications capable of transmitting data to the ground from far distances; lightweight efficient solar array panels; lightweight, high output battery cells; lightweight yet strong composite materials for the nano-spacecraft and deployer-ship structures. These newer smaller systems may have higher power densities and higher thermal transport requirements than seen on previous small satellites. Furthermore, the small satellites may also have a requirement to maintain thermal control through extended earth shadows, possibly up to 8 hours long. Older thermal control technology, such as heaters, thermostats, and heat pipes, may not be sufficient to meet the requirements of these new systems. Conversely, a miniature two-phase heat transport system (Mini-HTS) such as a Capillary Pumped Loop (CPL) or Loop Heat Pipe (LBP) is a viable alternative. A Mini-HTS can provide fine temperature control, thermal diode action, and a highly efficient means of heat transfer. The Mini-HTS would have power capabilities in the range of tens of watts or less and provide thermal control over typical spacecraft ranges. The Mini-HTS would allow the internal portion of the spacecraft to be thermally isolated from the external radiator, thus protecting the internal components from extreme cold temperatures during an eclipse. The Mini-HTS would transport the beat from these components to a radiator during their operational modes, and it would be shutdown during non-operational or eclipse modes. Shutdown of the Mini-HTS would be accomplished with small heaters and has been successfully demonstrated on numerous occasions, both in the lab and on flight experiments. Efforts are now underway to miniaturize two-phase heat transport systems for the Nanosatellite project, with potential application to other small satellite programs. 'ne goal of this project is to design, build, and test miniature heat transport systems (MHTS) that would demonstrate the feasibility of a small Capillary Pumped Loop (CPL) or Loop Heat Pipe (LBP).

Miniaturised medium pressure capillary liquid chromatography system with flexible open platform design using off-the-shelf microfluidic components.

PubMed

Li, Yan; Dvořák, Miloš; Nesterenko, Pavel N; Stanley, Roger; Nuchtavorn, Nantana; Krčmová, Lenka Kujovská; Aufartová, Jana; Macka, Mirek

2015-10-08

Trends towards portable analytical instrumentation of the last decades have not been equally reflected in developments of portable liquid chromatography (LC) instrumentation for rapid on-site measurements. A miniaturised medium pressure capillary LC (MPLC) system with gradient elution capability has been designed based on a flexible modular microfluidic system using primarily off-the-shelf low cost components to ensure wide accessibility to other analysts. The microfluidic platform was assembled on a breadboard and contained microsyringe pumps and switch valves, complemented with an injection valve and on-capillary detectors, all controlled by a PC. Four miniaturised microsyringe pumps, with 5, 20 and 100 μL syringe volume options, formed the basis of the pumping system. Two pairs of pumps were used for each mobile phase to create gradient elution capability. The two microsyringe pumps in each pairs were linked by two electrically operated microfluidic switching valves and both pairs of pumps were connected through a zero void volume cross-connector, thus providing a low hold-up volume for gradient formation. Sample was injected by a 20 nL nano-LC sampling valve, directly connected to a 18 cm long 100 μm i.d. Chromolith CapRod RP-18 monolithic capillary column. On-capillary LED-based UV-vis photometric detection was conducted through a piece of equal diameter fused silica capillary connected after the column. The performance of the portable LC system was evaluated theoretically and experimentally, including the maximum operating pressure, gradient mixing performance, and the performance of the detectors. The 5 μL microsyringe pump offered the best performance, with typical maximum operating pressures up to 11.4 ± 0.4 MPa (water) and gradient pumping repeatability of between 4 and 9% for gradients between 0.10% s(-1) and 0.33% s(-1). Test analytes of charged and uncharged dyes and pharmaceuticals of varying hydrophobicity showed typical RSD values of 0.7-1.4% and 3.3-4.8% in isocratic mode and 1.2-4.6% and 3.2-6.4% in gradient mode, respectively for retention time and peak area repeatability. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Two-phase/two-phase heat exchanger simulation analysis

NASA Technical Reports Server (NTRS)

Kim, Rhyn H.

1992-01-01

The capillary pumped loop (CPL) system is one of the most desirable devices to dissipate heat energy in the radiation environment of the Space Station providing a relatively easy control of the temperature. A condenser, a component of the CPL system, is linked with a buffer evaporator in the form of an annulus section of a double tube heat exchanger arrangement: the concentric core of the double tube is the condenser; the annulus section is used as a buffer between the conditioned space and the radiation surrounding but works as an evaporator. A CPL system with this type of condenser is modeled to simulate its function numerically. Preliminary results for temperature variations of the system are shown and more investigations are suggested for further improvement.

78 FR 58535 - Hydropower Regulatory Efficiency Act of 2013; Supplemental Notice of Workshop

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-24

... license for hydropower development at non-powered dams and closed-loop pumped storage projects in... for licensing hydropower development at non-powered dams and closed-loop pumped storage projects... closed- loop pumped storage) affect the steps included in a two-year process? 3.9 Should there be a...

Excimer lasers

NASA Technical Reports Server (NTRS)

Palmer, A. J.; Hess, L. D.; Stephens, R. R.

1976-01-01

A theoretical and experimental investigation into the possibility of achieving CW discharge pumped excimer laser oscillation is reported. Detailed theoretical modeling of capillary discharge pumping of the XeF and KXe and K2 excimer systems was carried out which predicted the required discharge parameters for reaching laser threshold on these systems. Capillary discharge pumping of the XeF excimer system was investigated experimentally. The experiments revealed a lower excimer level population density than predicted theoretically by about an order of magnitude. The experiments also revealed a fluorine consumption problem in the discharge in agreement with theory.

Differentiation between primary and secondary Raynaud's phenomenon: a prospective study comparing nailfold capillaroscopy using an ophthalmoscope or stereomicroscope

PubMed Central

Anders, H; Sigl, T; Schattenkirchner, M

2001-01-01

BACKGROUND—Nailfold capillary microscopy is a routine procedure in the investigation of patients with Raynaud's phenomenon (RP). As a standard method, nailfold capillary morphology is inspected with a stereomicroscope to look for capillary abnormalities such as giant loops, avascular areas, and bushy capillaries, which have all been found to be associated with certain connective tissue diseases.
AIM—To investigate prospectively whether nailfold capillary inspection using an ophthalmoscope is of equivalent diagnostic value to standard nailfold capillary microscopy.
METHOD—All the fingers of 26 patients with RP were examined in a blinded fashion and compared with the final diagnosis one month later.
RESULTS—All giant loops, large avascular areas, and bushy capillaries were identified by both methods. The correlation for moderate avascular areas and crossed capillaries was 0.93 and 0.955 respectively. The correlation for minor abnormalities that do not contribute to the differentiation between primary and secondary RP was 0.837 and 0.861 respectively. All patients were classified identically by the two methods.
CONCLUSION—For the evaluation of patients with RP, nailfold capillary morphology can reliably be assessed with an ophthalmoscope.

 PMID:11247874

78 FR 62322 - Hydropower Regulatory Efficiency Act of 2013; Notice of Rescheduled Two-Year Licensing Process...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-16

... at non-powered dams and closed-loop pumped storage projects in compliance with section 6 of the... process for licensing hydropower development at non-powered dams and closed-loop pumped storage projects...-powered dam versus closed- loop pumped storage) affect the steps included in a two-year process? 3.9...

Ring cavity for a Raman capillary waveguide amplifier

DOEpatents

Kurnit, N.A.

1981-01-27

A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

Ring cavity for a Raman capillary waveguide amplifir

DOEpatents

Kurnit, N.A.

1981-01-27

A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

Ring cavity for a raman capillary waveguide amplifier

DOEpatents

Kurnit, Norman A.

1983-07-19

A regenerative ring amplifier and regenerative ring oscillator which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO.sub.2 laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplifier Stokes signal is synchronous with the mode-locked spikes of the incoming CO.sub.2 laser pump signal.

Tutorial on Quantification of Differences between Single- and Two-Component Two-Phase Flow and Heat Transfer

NASA Astrophysics Data System (ADS)

Delil, A. A. M.

2003-01-01

Single-component two-phase systems are envisaged for aerospace thermal control applications: Mechanically Pumped Loops, Vapour Pressure Driven Loops, Capillary Pumped Loops and Loop Heat Pipes. Thermal control applications are foreseen in different gravity environments: Micro-g, reduced-g for Mars or Moon bases, 1-g during terrestrial testing, and hyper-g in rotating spacecraft, during combat aircraft manoeuvres and in systems for outer planets. In the evaporator, adiabatic line and condenser sections of such single-component two-phase systems, the fluid is a mixture of the working liquid (for example ammonia, carbon dioxide, ethanol, or other refrigerants, etc.) and its saturated vapour. Results of two-phase two-component flow and heat transfer research (pertaining to liquid-gas mixtures, e.g. water/air, or argon or helium) are often applied to support research on flow and heat transfer in two-phase single-component systems. The first part of the tutorial updates the contents of two earlier tutorials, discussing various aerospace-related two-phase flow and heat transfer research. It deals with the different pressure gradient constituents of the total pressure gradient, with flow regime mapping (including evaporating and condensing flow trajectories in the flow pattern maps), with adiabatic flow and flashing, and with thermal-gravitational scaling issues. The remaining part of the tutorial qualitatively and quantitatively determines the differences between single- and two-component systems: Two systems that physically look similar and close, but in essence are fully different. It was already elucidated earlier that, though there is a certain degree of commonality, the differences will be anything but negligible, in many cases. These differences (quantified by some examples) illustrates how careful one shall be in interpreting data resulting from two-phase two-component simulations or experiments, for the development of single-component two-phase thermal control systems for various gravity environments.

Diabetic microangiopathy in capillaroscopic examination of juveniles with diabetes type 1.

PubMed

Kaminska-Winciorek, Grażyna; Deja, Grażyna; Polańska, Joanna; Jarosz-Chobot, Przemysława

2012-01-30

The aim of this work was a quantitative and qualitative assessment of a selected part of the microcirculation in children with diabetes type 1 using videocapillaroscopy technique. The authors tested a group consisting of 145 children (70 boys, 75 girls) diagnosed and treated for diabetes type 1 in the Diabetic Clinic of GCZD in Katowice for at least one year. The study included history, clinical examination (including dermatological examination) and videocapillaroscopy. Capillaroscopy, a non-invasive, painless and easily repeatable test, was performed using videocapillaroscopy with digital storage of the obtained images. All nailfolds were examined in all children using videocapillaroscopy, and the obtained images were assessed quantitatively and qualitatively for changes in capillary loops in the tested children according to the defined diagnostic procedure. The analysis of capillaroscopic images described selected quantitative and qualitative characteristics. The conducted analysis showed an increase in the number of capillaries and their elongation, the presence of megacapillaries and Raynaud loops, which were accompanied by an intensive red background, indicating possible neoangiogenesis. The increase in the number of capillaries, disturbances in distribution of capillaries and the presence of abnormal capillaries were correlated with the longer duration of diabetes. Raynaud loops were more frequently found in the cases of increased mean values of HbA1c. Higher values of HbA1c influenced the capillaroscopic images, mainly the number of vessels, including Raynaud loops. Videocapillaroscopy technique could be a useful tool to detect the early changes of microangiopathy in children with diabetes type 1.

SU-E-QI-06: Design and Initial Validation of a Precise Capillary Phantom to Test Perfusion Systems

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

Wood, R; Iacobucci, G; Khobragade, P

2014-06-15

Purpose: To design a precise perfusion phantom mimicking capillaries of the brain vasculature which could be used to test various perfusion protocols and algorithms which generate perfusion maps. Methods: A perfusion phantom was designed in Solidworks and built using additive manufacturing. The phantom was an overall cylindrical shape of diameter and height 20mm and containing capillaries of 200μm or 300μm which were parallel and in contact making up the inside volume where flow was allowed. We created a flow loop using a peristaltic pump and contrast agent was injected manually. Digital Subtraction Angiographic images and low contrast images with conemore » beam CT were acquired after the contrast was injected. These images were analyzed by our own code in LabVIEW software and Time-Density Curve, MTT and TTP was calculated. Results: Perfused area was visible in the cone beam CT images; however, individual capillaries were not distinguishable. The Time-Density Curve acquired was accurate, sensitive and repeatable. The parameters MTT, and TTP offered by the phantom were very sensitive to slight changes in the TDC shape. Conclusion: We have created a robust calibrating model for evaluation of existing perfusion data analysis systems. This approach is extremely sensitive to changes in the flow due to the high temporal resolution and could be used as a golden standard to assist developers in calibrating and testing of imaging perfusion systems and software algorithms. Supported by NIH Grant: 2R01EB002873 and an equipment grant from Toshiba Medical Systems Corporation.« less

Ring cavity for a Raman capillary waveguide amplifier

DOEpatents

Kurnit, N.A.

1983-07-19

Disclosed is a regenerative ring amplifier and regenerative ring oscillator which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO[sub 2] laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplifier Stokes signal is synchronous with the mode-locked spikes of the incoming CO[sub 2] laser pump signal. 6 figs.

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.

Digital capillaroscopy as important tool for early diagnostics of arterial hypertension

NASA Astrophysics Data System (ADS)

Gurfinkel, Yu. I.; Sasonko, M. L.; Priezzhev, A. V.

2015-03-01

The study is aimed to determine the digital capillaroscopy possibilities in early diagnostics of an arterial hypertension. A total of 123 adult persons were examined in the study. The first group consisted of 40 patients with prehypertension (BP 130-139/85-89 mm Hg). The second group included 36 patients with 1-2 stage of hypertension (mean systolic BP 152.7±12 mm Hg). Patients in both groups did not receive regular drug therapy. The group of volunteers (n=47) included healthy adults without signs of cardiovascular pathology. The capillary circulation was examined on the nailbed using the optical digital capillaroscope developed by the company "AET", Russia. Diameters of the arterial and venous segments, perivascular zone size, capillary blood velocity, the degree of arterial loops narrowing and the density of the capillary network were estimated. In patients with arterial hypertension and even in patients with prehypertension remodeling and rarefaction of capillaries and the expressed narrowing their arterial loops were manifested. The results of the study revealed the presence of abnormalities of microcirculation parameters in patients of both groups. The capillaries density in both groups of patients was significantly lower than in healthy persons. The significant narrowing of arterial loops was revealed in patients with both arterial hypertension and prehypertension, in comparison with healthy volunteers. Capillary blood velocity did not differ significantly between healthy volunteers group and the group of prehypertensive patients. However in patients with hypertension this parameter was significantly lower in comparison with control group.

[The diagnostic significance of nailfold video-capillaroscopy in systemic sclerosis].

PubMed

Li, Lin-Guang; Zhang, Jiang-Lin; Liu, Xiu-Hua; Huang, Feng

2012-05-01

To observe nailfold capillary changes in a cohort of connective tissue disease (CTD) with Raynaud's phenomenon (RP) and to explore the diagnostic value of nailfold video-capillaroscopy (NVC) in systemic sclerosis (SSc). Sixty CTD patients with RP divided into SSc group (n = 36) and non-SSc group (n = 24) were referred to an experienced operator for NVC. The patients had decreased capillary loops in SSc group with the capillary diameter more enlarged in SSc group than non-SSc group. The number of patients in SSc group with giant capillaries was 14, while 3 in non-SSc group. There were 23 patients with haemorrhages in SSc group and 9 in non-SSc group. The number of patients with severe effusion was 15 in SSc group, while 2 in non-SSc group. By using the ROC curves, indexes with AUC at least 0.7 of the input capillary diameter, the output capillary diameter, the middle capillary diameter, blood color and effusion for the diagnostic cutoff points were 18.5 µm, 24.5 µm, 19.5µm, deep red and severe effusion. With at least 2 out of the top 3 indexes, the diagnostic sensitivity and specificity of SSc were higher. CTD Patients with RP of SSc have less capillary loops, more enlarged capillaries, more giant capillaries, more severe effusion and more haemorrhages than non-SSc patients. The characteristics of nailfold capillary changes in SSc patients with RP can be helpful for the diagnosis and the differential diagnosis of SSc.

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

Micro-Textured Black Silicon Wick for Silicon Heat Pipe Array

NASA Technical Reports Server (NTRS)

Yee, Karl Y.; Sunada, Eric T.; Ganapathi, Gani B.; Manohara, Harish; Homyk, Andrew; Prina, Mauro

2013-01-01

Planar, semiconductor heat arrays have been previously proposed and developed; however, this design makes use of a novel, microscale black silicon wick structure that provides increased capillary pumping pressure of the internal working fluid, resulting in increased effective thermal conductivity of the device, and also enables operation of the device in any orientation with respect to the gravity vector. In a heat pipe, the efficiency of thermal transfer from the case to the working fluid is directly proportional to the surface area of the wick in contact with the fluid. Also, the primary failure mechanism for heat pipes operating within the temperature range of interest is inadequate capillary pressure for the return of fluid from the condenser to the wick. This is also what makes the operation of heat pipes orientation-sensitive. Thus, the two primary requirements for a good wick design are a large surface area and high capillary pressure. Surface area can be maximized through nanomachined surface roughening. Capillary pressure is largely driven by the working fluid and wick structure. The proposed nanostructure wick has characteristic dimensions on the order of tens of microns, which promotes menisci of very small radii. This results in the possibility of enormous pumping potential due to the inverse proportionality with radius. Wetting, which also enhances capillary pumping, can be maximized through growth of an oxide layer or material deposition (e.g. TiO2) to create a superhydrophilic surface.

Impact of Heterogeneity on Vadose Zone Drainage During Pumping: Numerical Simulations of the Borden Aquifer

NASA Astrophysics Data System (ADS)

Bunn, M. I.; Jones, J.; Endres, A. L.

2009-05-01

Unconfined aquifers are in direct contact with the earth's surface; hence, they are an important focus in groundwater recharge and contaminant transport studies. While pumping tests have long been used to quantify aquifer properties, the contribution of drainage from the vadose zone during pumping has been the subject of debate for decades. In 2001, a highly detailed data set was collected during a seven-day pumping test in the unconfined aquifer at CFB Borden, Ontario (Bevan et al., 2005). The frequent observation of moisture content profiles during the test has initiated a closer examination of the vadose zone response to pumping. The moisture profiles collected during the test were obtained using a neutron probe. The neutron data depicts a capillary fringe thickness that increases with both proximity to the pumping well and duration of pumping. This capillary fringe extension results in delayed drainage that persists to the end of the seven-day test with the shape of the transition zone remaining constant (Bevan et al., 2005). Simulations of the pumping test were conducted using Hydrogeosphere (Therrien et al., 2006). Initial simulations were completed based on the conceptual model of a homogeneous and slightly anisotropic aquifer. The simulation results replicated the observed piezometric response, but were unable to produce any change in the thickness of the capillary fringe. It was hypothesized that the discrepancy between observations and simulation results may be the result of assumptions such as the homogeneity of the hydraulic conductivity field. In an effort to replicate this potential mechanism for the observed extension, the conceptual model was updated to better reflect the mildly heterogeneous hydraulic conductivity field of the Borden aquifer. Conductivity fields were generated using the statistical description of the Borden aquifer given by Sudicky (1986) with an adjusted mean log conductivity to better approximate the observed piezometric response. The inclusion of heterogeneity appears to have little effect on the hydraulic head drawdown, or the thickness of the capillary fringe. Heterogeneity does lead to delayed drainage in the drier portion of the vadose zone, where volumetric water content is less than 0.13 m3/m3. This effect is more pronounced with proximity to the pumping well, and is negligible at 15 m from the well. The amount of excess moisture in the vadose zone does not appear to be a function of pumping duration.

Fetal villosity and microvasculature of the bovine placentome in the second half of gestation

PubMed Central

LEISER, R.; KREBS, C.; KLISCH, K.; EBERT, B.; DANTZER, V.; SCHULER, G.; HOFFMANN, B.

1997-01-01

The architecture of the fetal villous tree and its vasculature in the bovine placentome were studied in the second half of gestation using both conventional histology and histology of ink-filled blood vessels. These were compared with corrosion casts of plastic fillings of the vasculature, prepared for scanning electron microscopy. This combination of morphological methods allows perception of the villous tree throughout gestation from broad-conical to tall-conical form where branch ramification occurs mainly at right angles to the stem. The stem villus typically contains a single central artery and several peripheral veins arranged in parallel. The proximal branches to the stem, the intermediate villi, contain a central arteriole and accompanying venules. The distal branches, the terminal villi, enclose capillary convolutions which consist of an afferent arterial capillary limb, capillary loops and efferent venous capillary limbs. Vascular interconnections exist within the terminal villi, as capillaries or venules between the capillary convolutions, serially bridging them in up to 5 places, and as capillary anastomoses between the capillary loops. Coiling and sinusoidal dilatations of these loops develop near the end of gestation. The intraplacentomal rearrangement of villous trees with progressive gestation and their morphological vascular adaptations are discussed in relation to placental function, including the ever increasing need for transplacental substance exchange. This adaptation allows the blood to traverse the shortest possible arterioarteriolar route to the periphery of the trees where exchange takes place. The need for an increasing blood flow stimulates capillary growth and at the same time optimises the blood flow reaching the placental barrier represented by the vessel cast surface. The capillaries also carry the blood back into the very voluminous system of venules and veins where back diffusion may occur. The total volume of terminal villi of bovine placentome, the ‘working part’ of villous trees, hence distinctly increases with respect to the stem and intermediate villi, the ‘supplying part’ of the villous tree. In morphological terms the efficiency of the bovine transplacental diffusional exchange is higher than in the closely related ‘co-ruminants’ sheep and goats and distinctly higher when compared with the human placenta. PMID:9449071

Mathematical model development and simulation of heat pump fruit dryer

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

Achariyaviriya, S.; Soponronnarit, S.; Terdyothin, A.

2000-01-01

A mathematical model of a heat pump fruit dryer was developed to study the performance of heat pump dryers. Using the moisture content of papaya glace drying, the refrigerant temperature at the evaporator and condenser and the performance, was verified. It was found that the simulated results using closed loop heat pump dryer were close to the experimental results. The criteria for evaluating the performance were specific moisture extraction rate and drying rate. The results showed that ambient conditions affected significantly on the performance of the open loop dryer and the partially closed loop dryer. Also, the fraction of evaporatormore » bypass air affected markedly the performance of all heat pump dryers. In addition, it was found that specific air flow rate and drying air temperature affected significantly the performance of all heat pump dryers.« less

Critical capillary channel flow

NASA Astrophysics Data System (ADS)

Grah, Aleksander; Klatte, Jörg; Dreyer, Michael E.

The main subject are numerical studies on capillary channel flow, based on results of the sounding rocket experiments TEXUS 41/42. The flow through a capillary channel is established by a gear pump at the outlet. The channel, consists of two parallel glass plates with a width of 25 mm, a gap of 10 mm and a length of 12 mm. The meniscus of a compensation tube maintains a constant system pressure. Steady and dynamic pressure effects in the system force the surfaces to bend inwards. A maximum flow rate is achieved when the free surface collapses and gas ingestion occurs at the outlet. This critical flow rate depends on the channel geometry, the flow regime and the liquid properties. The aim of the experiments is the determination of the free surface shape and to find the maximum flow rate. In order to study the unsteady liquid loop behaviour, a dimensionless transient model was developed. It is based on the unsteady Bernoulli equation, the unsteady continuity equation and geometrical conditions for the surface curvature and the flow cross-section. The pressure is related to the curvature of the free liquid surface by the dimensionless Gauss-Laplace equation with two principal radii. The experimental and evaluated contour data shows good agreement for a sequence of transient flow rate perturbations. The surface oscillation frequencies and amplitudes can be predicted with quite high accuracy. The dynamic of the pump is defined by the increase of the flow rate in a time period. To study the unsteady system behavior in the "worst case", we use a perturbations related to the natural frequency of the oscillating liquid. In the case of steady flow at maximum flow rate, when the "choking" effect occurs, the surfaces collapse and cause gas ingestion into the channel. This effect is related to the Speed Index. At the critical flow rate the Speed Index reaches the value Sca = 1, in analogy to the Mach Number. Unsteady choking does not necessarily cause surface collapse. We show, that temporarily Speed Index values exceeding One may be achieved for a perfectly stable supercritical dynamic flow. As a supercritical criterion for the dynamic free surface stability we define a Dynamic Index D considering the local capillary pressure and the convective pressure, which is a function of the local velocity. The Dynamic Index is below One for stable flow while D = 1 indicates surface collapse. This studies result in a stability diagram, which defines the limits of flow dynamics and the maximum unsteady flow rate. It may serve as a road map for open capillary channel flow control.

IN-PILE CORROSION TEST LOOPS FOR AQUEOUS HOMOGENEOUS REACTOR SOLUTIONS

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

Savage, H.C.; Jenks, G.H.; Bohlmann, E.G.

1960-12-21

An in-pile corrosion test loop is described which is used to study the effect of reactor radiation on the corrosion of materials of construction and the chemical stability of fuel solutions of interest to the Aqueous Homogeneous Reactor Program at ORNL. Aqueous solutions of uranyl sulfate are circulated in the loop by means of a 5-gpm canned-rotor pump, and the pump loop is designed for operation at temperatures to 300 ts C and pressures to 2000 psia while exposed to reactor radiation in beam-hole facilities of the LITR and ORR. Operation of the first loop in-pile was begun in Octobermore » 1954, and since that time 17 other in-pile loop experiments were completed. Design criteria of the pump loop and its associated auxiliary equipment and instrumentation are described. In-pile operating procedures, safety features, and operating experience are presented. A cost summary of the design, fabrication, and installation of the loop and experimental facillties is also included. (auth)« less

Feasibility study on an energy-saving desiccant wheel system with CO2 heat pump

NASA Astrophysics Data System (ADS)

Liu, Yefeng; Meng, Deren; Chen, Shen

2018-02-01

In traditional desiccant wheel, air regeneration process occurs inside an open loop, and lots of energy is consumed. In this paper, an energy-saving desiccant wheel system with CO2 heat pump and closed loop air regeneration is proposed. The general theory and features of the desiccant wheel are analysed. The main feature of the proposed system is that the air regeneration process occurs inside a closed loop, and a CO2 heat pump is utilized inside this loop for the air regeneration process as well as supplying cooling for the process air. The simulation results show that the proposed system can save significant energy.

Super energy saver heat pump with dynamic hybrid phase change material

DOEpatents

Ally, Moonis Raza [Oak Ridge, TN; Tomlinson, John Jager [Knoxville, TN; Rice, Clifford Keith [Clinton, TN

2010-07-20

A heat pump has a refrigerant loop, a compressor in fluid communication with the refrigerant loop, at least one indoor heat exchanger in fluid communication with the refrigerant loop, and at least one outdoor heat exchanger in fluid communication with the refrigerant loop. The at least one outdoor heat exchanger has a phase change material in thermal communication with the refrigerant loop and in fluid communication with an outdoor environment. Other systems, devices, and methods are described.

[Blood vessels of the epiphysis in comparative-anatomical aspect].

PubMed

Selin, Iu M

1977-05-01

The structure of the epiphysis and its inner blood vessels were studied in the representatives of nine orders of placental mammals and in man by means of injection of stained masses into the arteries and veins and subsequent preparation of histological sections. Not only form and topography of the organ differ in the representatives of different orders, but histological picture of the epiphysis is specific for each of them. In insectivores and chiroptera the loops of the inner three-dimensional capillary network are stretched along the longitudinal axis of the organ. In the epiphysis of carnivores, ungulata and monkey, the intraorganic vessels are situated in stromal trabeculae and the loops of the capillary network have polygonal shape. The intraepiphyseal vessels in man are arranged in peculiar baskets which envelope parenchymal lobules. The intraorganic veins beginning from the loops of the capillary network do not follow the arteries penetrating into the organ, but independently go to different surface parts of the organ where they flow into extraorganic veins.

A microfluidic circulatory system integrated with capillary-assisted pressure sensors.

PubMed

Chen, Yangfan; Chan, Ho Nam; Michael, Sean A; Shen, Yusheng; Chen, Yin; Tian, Qian; Huang, Lu; Wu, Hongkai

2017-02-14

The human circulatory system comprises a complex network of blood vessels interconnecting biologically relevant organs and a heart driving blood recirculation throughout this system. Recreating this system in vitro would act as a bridge between organ-on-a-chip and "body-on-a-chip" and advance the development of in vitro models. Here, we present a microfluidic circulatory system integrated with an on-chip pressure sensor to closely mimic human systemic circulation in vitro. A cardiac-like on-chip pumping system is incorporated in the device. It consists of four pumping units and passive check valves, which mimic the four heart chambers and heart valves, respectively. Each pumping unit is independently controlled with adjustable pressure and pump rate, enabling users to control the mimicked blood pressure and heartbeat rate within the device. A check valve is located downstream of each pumping unit to prevent backward leakage. Pulsatile and unidirectional flow can be generated to recirculate within the device by programming the four pumping units. We also report an on-chip capillary-assisted pressure sensor to monitor the pressure inside the device. One end of the capillary was placed in the measurement region, while the other end was sealed. Time-dependent pressure changes were measured by recording the movement of the liquid-gas interface in the capillary and calculating the pressure using the ideal gas law. The sensor covered the physiologically relevant blood pressure range found in humans (0-142.5 mmHg) and could respond to 0.2 s actuation time. With the aid of the sensor, the pressure inside the device could be adjusted to the desired range. As a proof of concept, human normal left ventricular and arterial pressure profiles were mimicked inside this device. Human umbilical vein endothelial cells (HUVECs) were cultured on chip and cells can respond to mechanical forces generated by arterial-like flow patterns.

Irradiation of orderly multiline spectra from linear plasma formed by vacuum discharge capillary

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Hayasi, Yasuomi; Germer, Rudolf; Ojima, Hidenori; Takayama, Kazuyoshi; Ido, Hideaki

2005-03-01

The fundamental experiments for measuring soft x-ray characteristics from the vacuum capillary are described. These experiments are primarily performed in order to generate intense soft x rays. The generator consists of a high-voltage power supply, a polarity-inversion ignitron pulse generator, a turbomolecular pump, and a radiation tube with a capillary. A high-voltage condenser of 200 nF in the pulse generator is charged up to 20 kV by the power supply, and the electric charges in the condenser are discharged to the capillary in the tube after closing the ignitron. During the discharge, weakly ionized plasma forms on the inner and outer sides of a capillary. In the present work, the pump evacuates air from the tube with a pressure of about 1 mPa, and a demountable capillary was developed in order to measure x-ray spectra according to changes in the capillary length. In this capillary, the anode (target) and cathode elements can be changed corresponding to the objectives. The capillary diameter is 2.0 mm, and the length is adjusted from 1 to 50 mm. When a capillary with aluminum anode and cathode electrodes was employed, both the cathode voltage and the discharge current almost displayed damped oscillations. The peak values of the voltage and current increased when the charging voltage was increased, and their maximum values were -11.5 kV and 4.7 kA, respectively. The x-ray durations observed by a 1.6 μm aluminum filter were less than 30 μs. In the spectrum measurement, we observed orderly multi-line spectra. The line photon energies seldom varied according to changes in the condenser charging voltage and to changes in the electrode element. The line number decreased with corresponding decreases in the capillary length.

Excimer lasers

NASA Technical Reports Server (NTRS)

Palmer, A. J.; Hess, L. D.; Stephens, R. R.; Pepper, D. M.

1977-01-01

The results of a two-year investigation into the possibility of developing continuous wave excimer lasers are reported. The program included the evaluation and selection of candidate molecular systems and discharge pumping techniques. The K Ar/K2 excimer dimer molecules and the xenon fluoride excimer molecule were selected for study; each used a transverse and capillary discharges pumping technique. Experimental and theoretical studies of each of the two discharge techniques applied to each of the two molecular systems are reported. Discharge stability and fluorine consumption were found to be the principle impediments to extending the XeF excimer laser into the continuous wave regime. Potassium vapor handling problems were the principal difficulty in achieving laser action on the K Ar/K2 system. Of the four molecular systems and pumping techniques explored, the capillary discharge pumped K Ar/K2 system appears to be the most likely candidate for demonstrating continuous wave excimer laser action primarily because of its predicted lower pumping threshold and a demonstrated discharge stability advantage.

Recovery Act: Cedarville School District Retrofit of Heating and Cooling Systems with Geothermal Heat Pumps and Ground Source Water Loops

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

Jarrell, Mark

Cedarville School District retrofitted the heating and cooling systems in three campus areas (High School, Middle School, and Upper Elementary School) with geothermal heat pumps and ground source water loops, as a demonstration project for the effective implementation of geothermal heat pump systems and other energy efficiency and air quality improvements.

Evaporation from a meniscus within a capillary tube in microgravity

NASA Technical Reports Server (NTRS)

Hallinan, K. P.

1993-01-01

The following represents a summary of progress made on the project 'Evaporation from a Capillary Meniscus in Microgravity' being conducted at the University of Dayton during the period 1 Dec. 1992 to 30 Nov. 1993. The efforts during this first year of the grant focused upon the following specific tasks: (1) application of a 3-D scattering particle image velocimetry technique to thin film velocity field measurement; (2) modeling the thermo-fluid behavior of the evaporating meniscus in 0-g within large diameter capillaries; (3) conceptualization of the space flight test cell (loop) configuration; (4) construction of prototypes of the test loop configuration; (5) conduct of experiments in 0-g in the 2.2 second drop tower at NASA-LeRC to study evaporation from a capillary meniscus within a square cuvette; and (6) investigation of the effect of vibrations on the stability of the meniscus. An overview of the work completed within these six task areas is presented.

Water-heating dehumidifier

DOEpatents

Tomlinson, John J.

2006-04-18

A water-heating dehumidifier includes a refrigerant loop including a compressor, at least one condenser, an expansion device and an evaporator including an evaporator fan. The condenser includes a water inlet and a water outlet for flowing water therethrough or proximate thereto, or is affixed to the tank or immersed into the tank to effect water heating without flowing water. The immersed condenser design includes a self-insulated capillary tube expansion device for simplicity and high efficiency. In a water heating mode air is drawn by the evaporator fan across the evaporator to produce cooled and dehumidified air and heat taken from the air is absorbed by the refrigerant at the evaporator and is pumped to the condenser, where water is heated. When the tank of water heater is full of hot water or a humidistat set point is reached, the water-heating dehumidifier can switch to run as a dehumidifier.

Method of Manufacturing Micro-Disperse Particles of Sodium Borohydride

DOEpatents

Kravitz, Stanley H.; Hecht, Andrew M.; Sylwester. Alan P.; Bell, Nelson S.

2008-09-23

A compact solid source of hydrogen gas, where the gas is generated by contacting water with micro-disperse particles of sodium borohydride in the presence of a catalyst, such as cobalt or ruthenium. The micro-disperse particles can have a substantially uniform diameter of 1-10 microns, and preferably about 3-5 microns. Ruthenium or cobalt catalytic nanoparticles can be incorporated in the micro-disperse particles of sodium borohydride, which allows a rapid and complete reaction to occur without the problems associated with caking and scaling of the surface by the reactant product sodium metaborate. A closed loop water management system can be used to recycle wastewater from a PEM fuel cell to supply water for reacting with the micro-disperse particles of sodium borohydride in a compact hydrogen gas generator. Capillary forces can wick water from a water reservoir into a packed bed of micro-disperse fuel particles, eliminating the need for using an active pump.

Method of generating hydrogen gas from sodium borohydride

DOEpatents

Kravitz, Stanley H.; Hecht, Andrew M.; Sylwester, Alan P.; Bell, Nelson S.

2007-12-11

A compact solid source of hydrogen gas, where the gas is generated by contacting water with micro-disperse particles of sodium borohydride in the presence of a catalyst, such as cobalt or ruthenium. The micro-disperse particles can have a substantially uniform diameter of 1-10 microns, and preferably about 3-5 microns. Ruthenium or cobalt catalytic nanoparticles can be incorporated in the micro-disperse particles of sodium borohydride, which allows a rapid and complete reaction to occur without the problems associated with caking and scaling of the surface by the reactant product sodium metaborate. A closed loop water management system can be used to recycle wastewater from a PEM fuel cell to supply water for reacting with the micro-disperse particles of sodium borohydride in a compact hydrogen gas generator. Capillary forces can wick water from a water reservoir into a packed bed of micro-disperse fuel particles, eliminating the need for using an active pump.

Compact solid source of hydrogen gas

DOEpatents

Kravitz, Stanley H.; Hecht, Andrew M.; Sylwester, Alan P.; Bell, Nelson S.

2004-06-08

A compact solid source of hydrogen gas, where the gas is generated by contacting water with micro-disperse particles of sodium borohydride in the presence of a catalyst, such as cobalt or ruthenium. The micro-disperse particles can have a substantially uniform diameter of 1-10 microns, and preferably about 3-5 microns. Ruthenium or cobalt catalytic nanoparticles can be incorporated in the micro-disperse particles of sodium borohydride, which allows a rapid and complete reaction to occur without the problems associated with caking and scaling of the surface by the reactant product sodium metaborate. A closed loop water management system can be used to recycle wastewater from a PEM fuel cell to supply water for reacting with the micro-disperse particles of sodium borohydride in a compact hydrogen gas generator. Capillary forces can wick water from a water reservoir into a packed bed of micro-disperse fuel particles, eliminating the need for using an active pump.

Effect of working fluids on thermal performance of closed loop pulsating heat pipe

NASA Astrophysics Data System (ADS)

Kolková, Zuzana; Malcho, Milan

2014-08-01

Improving the performance of electrical components needs higher heat removal from these systems. One of the solutions available is to use a sealed heat pipe with a throbbing filling, where development meets the current requirements for intensification of heat removal and elimination of moving parts cooling systems. Heat pipes operate using phase change working fluid, and it is evaporation and condensation. They have a meandering shape and are characterized by high intensity of heat transfer, high durability and reliability. Advantage of these tubes is that it is not necessary to create the internal capillary structure for transporting liquid and they need any pump to the working fluid circulation. They have a simple structure, low cost, high performance, and they can be used for various structural applications. The choice of working fluid volume and performance affects thermal performance. Distilled water, ethanol and acetone were used in the performance ranges 0-80%.

Development of a 45kpsi ultrahigh pressure liquid chromatography instrument for gradient separations of peptides using long microcapillary columns and sub-2μm particles.

PubMed

Grinias, Kaitlin M; Godinho, Justin M; Franklin, Edward G; Stobaugh, Jordan T; Jorgenson, James W

2016-10-21

Commercial chromatographic instrumentation for bottom-up proteomics is often inadequate to resolve the number of peptides in many samples. This has inspired a number of complex approaches to increase peak capacity, including various multidimensional approaches, and reliance on advancements in mass spectrometry. One-dimensional reversed phase separations are limited by the pressure capabilities of commercial instruments and prevent the realization of greater separation power in terms of speed and resolution inherent to smaller sorbents and ultrahigh pressure liquid chromatography. Many applications with complex samples could benefit from the increased separation performance of long capillary columns packed with sub-2μm sorbents. Here, we introduce a system that operates at a constant pressure and is capable of separations at pressures up to 45kpsi. The system consists of a commercially available capillary liquid chromatography instrument, for sample management and gradient creation, and is modified with a storage loop and isolated pneumatic amplifier pump for elevated separation pressure. The system's performance is assessed with a complex peptide mixture and a range of microcapillary columns packed with sub-2μm C18 particles. Copyright © 2016 Elsevier B.V. All rights reserved.

Automated fluid analysis apparatus and techniques

DOEpatents

Szecsody, James E.

2004-03-16

An automated device that couples a pair of differently sized sample loops with a syringe pump and a source of degassed water. A fluid sample is mounted at an inlet port and delivered to the sample loops. A selected sample from the sample loops is diluted in the syringe pump with the degassed water and fed to a flow through detector for analysis. The sample inlet is also directly connected to the syringe pump to selectively perform analysis without dilution. The device is airtight and used to detect oxygen-sensitive species, such as dithionite in groundwater following a remedial injection to treat soil contamination.

Glomerular Lesions in Proteinuric Miniature Schnauzer Dogs.

PubMed

Furrow, E; Lees, G E; Brown, C A; Cianciolo, R E

2017-05-01

Miniature Schnauzer dogs are predisposed to idiopathic hypertriglyerceridemia, which increases risk for diseases such as pancreatitis and gallbladder mucocele. Recently, elevated triglyceride concentrations have been associated with proteinuria in this breed, although it is difficult to determine which abnormality is primary. Retrospective review of renal tissue from 27 proteinuric Miniature Schnauzers revealed that 20 dogs had ultrastructural evidence of osmophilic globules consistent with lipid in glomerular tufts. Seven of these dogs had lipid thromboemboli in glomerular capillary loops that distorted their shape and compressed circulating erythrocytes. Triglyceride concentrations were reported in 6 of these 7 dogs, and all were hypertriglyceridemic. In addition, glomerular lipidosis (defined as accumulation of foam cells within peripheral capillary loops) was identified in a single dog. The remaining 12 dogs had smaller amounts of lipid that could only be identified ultrastructurally. Neither signalment data nor clinicopathologic parameters (serum albumin, serum creatinine, urine protein-to-creatinine ratio, and blood pressure) differed among the various types of lipid lesions. During the time course of this study, all dogs diagnosed with glomerular lipid thromboemboli were Miniature Schnauzers, underscoring the importance of recognizing these clear spaces within capillary loops as lipid.

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.

Numerical Analysis of Combined Well and Open-Closed Loops Geothermal (CWG) Systems

NASA Astrophysics Data System (ADS)

Park, Yu-Chul

2016-04-01

Open-loop geothermal heat pump (GHP) system and closed-loop heat pump systems have been used in Korea to reduce emission of greenhouse gases such as carbon dioxide (CO2). The GHP systems have the pros and cons, for example, the open-loop GHP system is good energy-efficient and the closed-loop GHP system requires minimum maintenance costs. The open-loop GHP system can be used practically only with large amount of groundwater supply. The closed-loop GHP system can be used with high costs of initial installation. The performance and efficiency of the GHP system depend on the characteristics of the GHP system itself in addition to the geologic conditions. To overcome the cons of open-loop or closed-loop GHP system, the combined well and open-closed loops geothermal (CWG) system was designed. The open-loop GHP system is surrounded with closed-loop GHP systems in the CWG system. The geothermal energy in closed-loop GHP systems is supplied by the groundwater pumped by the open-loop GHP system. In this study, 2 different types of the CWG systems (small aperture hybrid CWG system and large aperture CWG system) are estimated using numerical simulation models in the aspect of energy efficiency. This work was supported by the New & Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea. (No.20153030111120).

Physiological control of a rotary blood pump with selectable therapeutic options: control of pulsatility gradient.

PubMed

Arndt, Andreas; Nüsser, Peter; Graichen, Kurt; Müller, Johannes; Lampe, Bernhard

2008-10-01

A control strategy for rotary blood pumps meeting different user-selectable control objectives is proposed: maximum support with the highest feasible flow rate versus medium support with maximum ventricular washout and controlled opening of the aortic valve (AoV). A pulsatility index (PI) is calculated from the pressure difference, which is deduced from the axial thrust measured by the magnetic bearing of the pump. The gradient of PI with respect to pump speed (GPI) is estimated via online system identification. The outer loop of a cascaded controller regulates GPI to a reference value satisfying the selected control objective. The inner loop controls the PI to a reference value set by the outer loop. Adverse pumping states such as suction and regurgitation can be detected on the basis of the GPI estimates and corrected by the controller. A lumped-parameter computer model of the assisted circulation was used to simulate variations of ventricular contractility, pulmonary venous pressure, and aortic pressure. The performance of the outer control loop was demonstrated by transitions between the two control modes. Fast reaction of the inner loop was tested by stepwise reduction of venous return. For maximum support, a low PI was maintained without inducing ventricular collapse. For maximum washout, the pump worked at a high PI in the transition region between the opening and the permanently closed AoV. The cascaded control of GPI and PI is able to meet different control objectives and is worth testing in vitro and in vivo.

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.

Leak Mitigation in Mechanically Pumped Fluid Loops for Long Duration Space Missions

NASA Technical Reports Server (NTRS)

Miller, Jennifer R.; Birur, Gajanana; Bame, David; Mastropietro, A. J.; Bhandari, Pradeep; Lee, Darlene; Karlmann, Paul; Liu, Yuanming

2013-01-01

Mechanically pumped fluid loops (MPFLs) are increasingly considered for spacecraft thermal control. A concern for long duration space missions is the leak of fluid leading to performance degradation or potential loop failure. An understanding of leak rate through analysis, as well as destructive and non-destructive testing, provides a verifiable means to quantify leak rates. The system can be appropriately designed to maintain safe operating pressures and temperatures throughout the mission. Two MPFLs on the Mars Science Laboratory Spacecraft, launched November 26, 2011, maintain the temperature of sensitive electronics and science instruments within a -40 deg C to 50 deg C range during launch, cruise, and Mars surface operations. With over 100 meters of complex tubing, fittings, joints, flex lines, and pumps, the system must maintain a minimum pressure through all phases of the mission to provide appropriate performance. This paper describes the process of design, qualification, test, verification, and validation of the components and assemblies employed to minimize risks associated with excessive fluid leaks from pumped fluid loop systems.

Deletion of a unique loop in the mycobacterial F-ATP synthase γ subunit sheds light on its inhibitory role in ATP hydrolysis-driven H(+) pumping.

PubMed

Hotra, Adam; Suter, Manuel; Biuković, Goran; Ragunathan, Priya; Kundu, Subhashri; Dick, Thomas; Grüber, Gerhard

2016-05-01

The F1 FO -ATP synthase is one of the enzymes that is essential to meet the energy requirement of both the proliferating aerobic and hypoxic dormant stages of the life cycle of mycobacteria. Most F-ATP synthases consume ATP in the α3 :β3 headpiece to drive the γ subunit, which couples ATP cleavage with proton pumping in the c ring of FO via the bottom of the γ subunit. ATPase-driven H(+) pumping is latent in mycobacteria. The presence of a unique 14 amino acid residue loop of the mycobacterial γ subunit has been described and aligned in close vicinity to the c-ring loop Priya R et al. (2013) J Bioenerg Biomembr 45, 121-129 Here, we used inverted membrane vesicles (IMVs) of fast-growing Mycobacterium smegmatis and a variety of covalent and non-covalent inhibitors to characterize the ATP hydrolysis activity of the F-ATP synthase inside IMVs. These vesicles formed a platform to investigate the function of the unique mycobaterial γ loop by deleting the respective loop-encoding sequence (γ166-179 ) in the genome of M. smegmatis. ATP hydrolysis-driven H(+) pumping was observed in IMVs containing the Δγ166-179 mutant protein but not for IMVs containing the wild-type F-ATP synthase. In addition, when compared to the wild-type enzyme, IMVs containing the Δγ166-179 mutant protein showed increased ATP cleavage and lower levels of ATP synthesis, demonstrating that the loop affects ATPase activity, ATPase-driven H(+) pumping and ATP synthesis. These results further indicate that the loop may affect coupling of ATP hydrolysis and synthesis in a different mode. © 2016 Federation of European Biochemical Societies.

Electromagnetic liquid pistons for capillarity-based pumping.

PubMed

Malouin, Bernard A; Vogel, Michael J; Olles, Joseph D; Cheng, Lili; Hirsa, Amir H

2011-02-07

The small scales associated with lab-on-a-chip technologies lend themselves well to capillarity-dominated phenomena. We demonstrate a new capillarity-dominated system where two adjoining ferrofluid droplets can behave as an electronically-controlled oscillator or switch by an appropriate balance of magnetic, capillary, and inertial forces. Their oscillatory motion can be exploited to displace a surrounding liquid (akin to an axial piston pump), forming electromagnetic "liquid pistons." Such ferrofluid pistons can pump a precise volume of liquid via finely tunable amplitudes (cf. pump stroke) or resonant frequencies (cf. pump speed) with no solid moving parts for long-term operation without wear in a small device. Furthermore, the rapid propagation of electromagnetic fields and the favorable scaling of capillary forces with size permit micron sized devices with very fast operating speeds (∼kHz). The pumping dynamics and performance of these liquid pistons is explored, with experimental measurements showing good agreement with a spherical cap model. While these liquid pistons may find numerous applications in micro- and mesoscale fluidic devices (e.g., remotely activated drug delivery), here we demonstrate the use of these liquid pistons in capillarity-dominated systems for chip-level, fast-acting adaptive liquid lenses with nearly perfect spherical interfaces.

Scanning Electron Microscopic Structure of the Lingual Papillae of the Common Opossum (Didelphis marsupialis)

NASA Astrophysics Data System (ADS)

Okada, Shigenori; Schraufnagel, Dean E.

2005-08-01

The mammalian tongue has evolved for specialized functions in different species. The structure of its papillae tells about the animal's diet, habit, and taxonomy. The opossum has four kinds of lingual papillae (filiform, conical, fungiform, vallate). Scanning electron microscopy of the external features, connective tissue cores, and corrosion casts of the microvasculature show the filiform papillae have a spearhead-like main process and spiny accessory processes around the apical part of the main process. The shape and number of both processes depend on their position on the tongue. On the apex, the main processes have shovel-like capillary networks and the accessory processes have small conical networks. On the lingual radix, the processes have small capillary loops. In the patch region, conical papillae have capillaries arranged as a full sail curving posteriorly. The fungiform papillae are scattered among the filiform papillae and have capillary baskets beneath each taste bud. Giant fungiform papillae on the tongue tip are three to four times larger than the ones on the lingual body. Capillaries of giant papillae form a fan-shaped network. The opossum has three vallate papillae arranged in a triangle. Their tops have secondary capillary loops but not their lateral surfaces. Mucosal folds on the posterolateral border have irregular, fingerlike projections with cylindrical capillary networks. These findings and the structure of the rest of the masticatory apparatus suggest the lingual papillae of opossum have kept their ancestral carnivorous features but also developed the herbivore characteristics of other marsupials.

Scanning electron microscopic structure of the lingual papillae of the common opossum (Didelphis marsupialis).

PubMed

Okada, Shigenori; Schraufnagel, Dean E

2005-08-01

The mammalian tongue has evolved for specialized functions in different species. The structure of its papillae tells about the animal's diet, habit, and taxonomy. The opossum has four kinds of lingual papillae (filiform, conical, fungiform, vallate). Scanning electron microscopy of the external features, connective tissue cores, and corrosion casts of the microvasculature show the filiform papillae have a spearhead-like main process and spiny accessory processes around the apical part of the main process. The shape and number of both processes depend on their position on the tongue. On the apex, the main processes have shovel-like capillary networks and the accessory processes have small conical networks. On the lingual radix, the processes have small capillary loops. In the patch region, conical papillae have capillaries arranged as a full sail curving posteriorly. The fungiform papillae are scattered among the filiform papillae and have capillary baskets beneath each taste bud. Giant fungiform papillae on the tongue tip are three to four times larger than the ones on the lingual body. Capillaries of giant papillae form a fan-shaped network. The opossum has three vallate papillae arranged in a triangle. Their tops have secondary capillary loops but not their lateral surfaces. Mucosal folds on the posterolateral border have irregular, fingerlike projections with cylindrical capillary networks. These findings and the structure of the rest of the masticatory apparatus suggest the lingual papillae of opossum have kept their ancestral carnivorous features but also developed the herbivore characteristics of other marsupials.

A capital cost comparison of commercial ground-source heat pump systems

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

Rafferty, K.

1994-06-01

The purpose of the report is to compare capital costs associated with the three designs of ground source heat pumps. Specifically, the costs considered are those associated with the heat source/heat sink or ground source portion of the system. In order to standardize the heat rejection over the three designs, it was assumed that the heat pump loop would operate at a temperature range of 85{degree} (to the heat pumps) to 95{degree} (from the heat pumps) under peak conditions. The assumption of constant loop temperature conditions for all three permits an apples-to-apples comparison of the alternatives.

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

Anderson, J.L.; Jenkins, E.M.; Walthers, C.R.

Compound cryopumps have been added to the Tritium Systems Test Assembly (TSTA) integrated fusion fuel loop. Operations have been performed which closely simulate an actual fusion reactor pumping scenario. In addition, performance data have been taken that support the concept of using coconut charcoal as a sorbent at 4K for pumping helium. Later tests show that coconut charcoal may be used to co-pump D,T and He mixtures on a single 4K panel. Rotary spiral pumps have been used successfully in several applications at TSTA and have acquired more than 9000 hours of maintenance-free operation. Metal bellows pumps have been usedmore » to back the spiral pumps and have been relatively trouble free in loop operations. Bellows pumps also have more than 9000 hours of maintenance-free operation. 5 refs., 6 figs.« less

Analysis of pressure head-flow loops of pulsatile rotodynamic blood pumps.

PubMed

Jahren, Silje E; Ochsner, Gregor; Shu, Fangjun; Amacher, Raffael; Antaki, James F; Vandenberghe, Stijn

2014-04-01

The clinical importance of pulsatility is a recurring topic of debate in mechanical circulatory support. Lack of pulsatility has been identified as a possible factor responsible for adverse events and has also demonstrated a role in myocardial perfusion and cardiac recovery. A commonly used method for restoring pulsatility with rotodynamic blood pumps (RBPs) is to modulate the speed profile, synchronized to the cardiac cycle. This introduces additional parameters that influence the (un)loading of the heart, including the timing (phase shift) between the native cardiac cycle and the pump pulses, and the amplitude of speed modulation. In this study, the impact of these parameters upon the heart-RBP interaction was examined in terms of the pressure head-flow (HQ) diagram. The measurements were conducted using a rotodynamic Deltastream DP2 pump in a validated hybrid mock circulation with baroreflex function. The pump was operated with a sinusoidal speed profile, synchronized to the native cardiac cycle. The simulated ventriculo-aortic cannulation showed that the level of (un)loading and the shape of the HQ loops strongly depend on the phase shift. The HQ loops displayed characteristic shapes depending on the phase shift. Increased contribution of native contraction (increased ventricular stroke work [WS ]) resulted in a broadening of the loops. It was found that the previously described linear relationship between WS and the area of the HQ loop for constant pump speeds becomes a family of linear relationships, whose slope depends on the phase shift. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

Centaur propellant acquisition system study

NASA Technical Reports Server (NTRS)

Blatt, M. H.; Walter, M. D.

1975-01-01

A study was performed to determine the desirability of replacing the hydrogen peroxide settling system on the Centaur D-1S with a capillary acquisition system. A comprehensive screening was performed to select the most promising capillary device fluid acquisition, thermal conditioning, and fabrication techniques. Refillable start baskets and bypass feed start tanks were selected for detailed design. Critical analysis areas were settling and refilling, start sequence development with an initially dry boost pump, and cooling the fluid delivered to the boost pump in order to provide necessary net position suction head (NPSH). Design drawings were prepared for the start basket and start tank concepts for both LO2 and LH2 tanks. System comparisons indicated that the start baskets using wicking for thermal conditioning, and thermal subcooling for boost pump NPSH, are the most desirable systems for future development.

Centaur propellant acquisition system

NASA Technical Reports Server (NTRS)

Blatt, M. H.; Aydelott, J. C.

1975-01-01

The desirability of replacing the hydrogen peroxide settling system of the Centaur D-1S with a capillary acquisition system was evaluated. A comprehensive screening was performed to select the most promising capillary device fluid acquisition, thermal conditioning, and fabrication techniques. Refillable start baskets and bypass feed start tanks were selected for detailed design. Critical analysis areas were settling and refilling, start sequence development with an initially dry boost pump, and cooling the fluid delivered to the boost pump to provide the necessary net positive suction head (NPSH). Design drawings were prepared for start basket and start tank concepts for both the liquid oxygen and liquid hydrogen tanks. System comparisons indicated that the start baskets using wicking flow for thermal conditioning, and thermal subcooling for providing boost pump NPSH, are the most desirable systems for future Centaur acquisition system development.

Adaptable Single Active Loop Thermal Control System (TCS) for Future Space Missions

NASA Technical Reports Server (NTRS)

Mudawar, Issam; Lee, Seunghyun; Hasan, Mohammad

2015-01-01

This presentation will examine the development of a thermal control system (TCS) for future space missions utilizing a single active cooling loop. The system architecture enables the TCS to be reconfigured during the various mission phases to respond, not only to varying heat load, but to heat rejection temperature as well. The system will consist of an accumulator, pump, cold plates (evaporators), condenser radiator, and compressor, in addition to control, bypass and throttling valves. For cold environments, the heat will be rejected by radiation, during which the compressor will be bypassed, reducing the system to a simple pumped loop that, depending on heat load, can operate in either a single-phase liquid mode or two-phase mode. For warmer environments, the pump will be bypassed, enabling the TCS to operate as a heat pump. This presentation will focus on recent findings concerning two-phase flow regimes, pressure drop, and heat transfer coefficient trends in the cabin and avionics micro-channel heat exchangers when using the heat pump mode. Also discussed will be practical implications of using micro-channel evaporators for the heat pump.

Coupled dual loop absorption heat pump

DOEpatents

Sarkisian, Paul H.; Reimann, Robert C.; Biermann, Wendell J.

1985-01-01

A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.

International Space Station Active Thermal Control Sub-System On-Orbit Pump Performance and Reliability Using Liquid Ammonia as a Coolant

NASA Technical Reports Server (NTRS)

Morton, Richard D.; Jurick, Matthew; Roman, Ruben; Adamson, Gary; Bui, Chinh T.; Laliberte, Yvon J.

2011-01-01

The International Space Station (ISS) contains two Active Thermal Control Sub-systems (ATCS) that function by using a liquid ammonia cooling system collecting waste heat and rejecting it using radiators. These subsystems consist of a number of heat exchangers, cold plates, radiators, the Pump and Flow Control Subassembly (PFCS), and the Pump Module (PM), all of which are Orbital Replaceable Units (ORU's). The PFCS provides the motive force to circulate the ammonia coolant in the Photovoltaic Thermal Control Subsystem (PVTCS) and has been in operation since December, 2000. The Pump Module (PM) circulates liquid ammonia coolant within the External Active Thermal Control Subsystem (EATCS) cooling the ISS internal coolant (water) loops collecting waste heat and rejecting it through the ISS radiators. These PM loops have been in operation since December, 2006. This paper will discuss the original reliability analysis approach of the PFCS and Pump Module, comparing them against the current operational performance data for the ISS External Thermal Control Loops.

Glomerular Lesions in Proteinuric Miniature Schnauzer Dogs

PubMed Central

Furrow, E.; Lees, G. E.; Brown, C. A.; Cianciolo, R. E.

2017-01-01

Miniature Schnauzer dogs are predisposed to idiopathic hypertriglyerceridemia, which increases risk for diseases such as pancreatitis and gallbladder mucocele. Recently, elevated triglyceride concentrations have been associated with proteinuria in this breed, although it is difficult to determine which abnormality is primary. Retrospective review of renal tissue from 27 proteinuric Miniature Schnauzers revealed that 20 dogs had ultrastructural evidence of osmophilic globules consistent with lipid in glomerular tufts. Seven of these dogs had lipid thromboemboli in glomerular capillary loops that distorted their shape and compressed circulating erythrocytes. Triglyceride concentrations were reported in 6 of these 7 dogs, and all were hypertriglyceridemic. In addition, glomerular lipidosis (defined as accumulation of foam cells within peripheral capillary loops) was identified in a single dog. The remaining 12 dogs had smaller amounts of lipid that could only be identified ultrastructurally. Neither signalment data nor clinicopathologic parameters (serum albumin, serum creatinine, urine protein-to-creatinine ratio, and blood pressure) differed among the various types of lipid lesions. During the time course of this study, all dogs diagnosed with glomerular lipid thromboemboli were Miniature Schnauzers, underscoring the importance of recognizing these clear spaces within capillary loops as lipid. PMID:28005494

Solar-powered turbocompressor heat pump system

DOEpatents

Landerman, A.M.; Biancardi, F.R.; Melikian, G.; Meader, M.D.; Kepler, C.E.; Anderson, T.J.; Sitler, J.W.

1982-08-12

The turbocompressor comprises a power turbine and a compressor turbine having respective rotors and on a common shaft, rotatably supported by bearings. A first working fluid is supplied by a power loop and is expanded in the turbine. A second working fluid is compressed in the turbine and is circulated in a heat pump loop. A lubricant is mixed with the second working fluid but is excluded from the first working fluid. The bearings are cooled and lubricated by a system which circulates the second working fluid and the intermixed lubricant through the bearings. Such system includes a pump, a thermostatic expansion valve for expanding the working fluid into the space between the bearings, and a return conduit system for withdrawing the expanded working fluid after it passes through the bearings and for returning the working fluid to the evaporator. A shaft seal excludes the lubricant from the power turbine. The power loop includes a float operable by liquid working fluid in the condenser for controlling a recirculation valve so as to maintain a minimum liquid level in the condenser, while causing a feed pump to pump most of the working fluid into the vapor generator. The heat pump compressor loop includes a float in the condenser for operating and expansion valve to maintain a minimum liquid working fluid level in the condenser while causing most of the working fluid to be expanded into the evaporator.

Chimeric microbial rhodopsins for optical activation of Gs-proteins

PubMed Central

Yoshida, Kazuho; Yamashita, Takahiro; Sasaki, Kengo; Inoue, Keiichi; Shichida, Yoshinori; Kandori, Hideki

2017-01-01

We previously showed that the chimeric proteins of microbial rhodopsins, such as light-driven proton pump bacteriorhodopsin (BR) and Gloeobacter rhodopsin (GR) that contain cytoplasmic loops of bovine rhodopsin, are able to activate Gt protein upon light absorption. These facts suggest similar protein structural changes in both the light-driven proton pump and animal rhodopsin. Here we report two trials to engineer chimeric rhodopsins, one for the inserted loop, and another for the microbial rhodopsin template. For the former, we successfully activated Gs protein by light through the incorporation of the cytoplasmic loop of β2-adrenergic receptor (β2AR). For the latter, we did not observe any G-protein activation for the light-driven sodium pump from Indibacter alkaliphilus (IndiR2) or a light-driven chloride pump halorhodopsin from Natronomonas pharaonis (NpHR), whereas the light-driven proton pump GR showed light-dependent G-protein activation. This fact suggests that a helix opening motion is common to G protein coupled receptor (GPCR) and GR, but not to IndiR2 and NpHR. Light-induced difference FTIR spectroscopy revealed similar structural changes between WT and the third loop chimera for each light-driven pump. A helical structural perturbation, which was largest for GR, was further enhanced in the chimera. We conclude that similar structural dynamics that occur on the cytoplasmic side of GPCR are needed to design chimeric microbial rhodopsins. PMID:29362703

The Solar Dynamic radiator with a historical perspective

NASA Technical Reports Server (NTRS)

Mclallin, K. L.; Fleming, M. L.; Hoehn, F. W.; Howerton, R.

1988-01-01

A historical perspective on pumped loop space radiators provides a basis for the design of the Space Station Solar Dynamic (SD) power module radiator. SD power modules, capable of generating 25 kWe each, are planned for growth Station power requirements. The Brayton (cycle) SD module configuration incorporates a pumped loop radiator that must reject up to 99 kW. The thermal/hydraulic design conditions in combination with required radiator orientation and packaging envelope form a unique set of constraints as compared to previous pumped loop radiator systems. Nevertheless, past program successes have demonstrated a technology base which can be applied to the SD radiator development program to ensure a low risk, low cost system.

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.

An Advanced Loop Heat Pipe for Cryogenic Applications

NASA Technical Reports Server (NTRS)

Ku, Jentung; Hoang, Triem

2017-01-01

A loop heat pipe (LHP) is a very versatile heat transfer device that can transport a large heat load over a long distance with a small temperature difference. All LHPs currently servicing orbiting spacecraft are designed to operate in the room temperature range. Future space telescopes and space-based Earth resource imaging satellites require passive cryogenic heat transport devices that can thermally couple remote cryocoolers to sensor or instrument of interest while providing the capability of payload vibration jitter isolation, implementation of redundant coolers, and coupling of multiple sensors to a common heat sink. All of these requirements can be satisfied by using a cryogenic LHP (CLHP). Although the development of CLHPs faces several technical challenges, NASA Goddard Space Flight Center has devoted extensive efforts in developing CLHP technology over the past decade and has made significant progress. In particular, the combination of the innovative ideas of using a secondary capillary pump to manage the parasitic heat gain and using a hot reservoir to reduce the system pressure under the ambient condition has led to the successful development of the CLHP. Several CLHPs charged with nitrogen and hydrogen were built and tested in thermal vacuum chambers. These CLHPs demonstrated reliable start-up and robust operation during power cycle and sink temperature cycle tests.

An Advanced Loop Heat Pipe for Cryogenic Applications

NASA Technical Reports Server (NTRS)

Ku, Jentung; Hoang, Triem

2016-01-01

A loop heat pipe (LHP) is a very versatile heat transfer device which can transport a large heat load over a long distance with a small temperature difference. All LHPs currently servicing orbiting spacecraft are designed to operate in the room temperature range. Future space telescopes and space-based Earth resource imaging satellites require passive cryogenic heat transport devices that can thermally couple remote cryocoolers to sensor or instrument of interest while providing the capability of payload vibration/jitter isolation, implementation of redundant coolers, and coupling of multiple sensors to a common heat sink. All of these requirements can be satisfied by using a cryogenic LHP (CLHP). Although the development of CLHPs faces several technical challenges, NASA Goddard Space Flight Center has devoted extensive efforts in developing CLHP technology over the past decade and has made significant progress. In particular, the combination of the innovative ideas of using a secondary capillary pump to manage the parasitic heat gain and using a hot reservoir to reduce the system pressure under the ambient condition has led to the successful development of the CLHP. Several CLHPs charged with nitrogen and hydrogen were built and tested in thermal vacuum chambers. These CLHPs demonstrated reliable start-up and robust operation during power cycle and sink temperature cycle tests.

Component and Technology Development for Advanced Liquid Metal Reactors

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

Anderson, Mark

2017-01-30

The following report details the significant developments to Sodium Fast Reactor (SFR) technologies made throughout the course of this funding. This report will begin with an overview of the sodium loop and the improvements made over the course of this research to make it a more advanced and capable facility. These improvements have much to do with oxygen control and diagnostics. Thus a detailed report of advancements with respect to the cold trap, plugging meter, vanadium equilibration loop, and electrochemical oxygen sensor is included. Further analysis of the university’s moving magnet pump was performed and included in a section ofmore » this report. A continuous electrical resistance based level sensor was built and tested in the sodium with favorable results. Materials testing was done on diffusion bonded samples of metal and the results are presented here as well. A significant portion of this work went into the development of optical fiber temperature sensors which could be deployed in an SFR environment. Thus, a section of this report presents the work done to develop an encapsulation method for these fibers inside of a stainless steel capillary tube. High temperature testing was then done on the optical fiber ex situ in a furnace. Thermal response time was also explored with the optical fiber temperature sensors. Finally these optical fibers were deployed successfully in a sodium environment for data acquisition. As a test of the sodium deployable optical fiber temperature sensors they were installed in a sub-loop of the sodium facility which was constructed to promote the thermal striping effect in sodium. The optical fibers performed exceptionally well, yielding unprecedented 2 dimensional temperature profiles with good temporal resolution. Finally, this thermal striping loop was used to perform cross correlation velocimetry successfully over a wide range of flow rates.« less

Operation of a cascade air conditioning system with two-phase loop

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

Feng, Yinshan; Wang, Jinliang; Zhao, Futao

A method of operating a heat transfer system includes starting operation of a first heat transfer fluid vapor/compression circulation loop including a fluid pumping mechanism, a heat exchanger for rejecting thermal energy from a first heat transfer fluid, and a heat absorption side of an internal heat exchanger. A first conduit in a closed fluid circulation loop circulates the first heat transfer fluid therethrough. Operation of a second two-phase heat transfer fluid circulation loop is started after starting operation of the first heat transfer fluid circulation loop. The second heat transfer fluid circulation loop transfers heat to the first heatmore » transfer fluid circulation loop through the internal heat exchanger and includes a heat rejection side of the internal heat exchanger, a liquid pump, and a heat exchanger evaporator. A second conduit in a closed fluid circulation loop circulates a second heat transfer fluid therethrough.« less

Status of Kilowatt-Class Stirling Power Conversion Using a Pumped NaK Loop for Thermal Input

NASA Technical Reports Server (NTRS)

Briggs, Maxwell H.; Geng, Steven M.; Robbie, Malcolm G.

2010-01-01

Free-piston Stirling power conversion has been identified as a viable option for potential Fission Surface Power (FSP) systems on the Moon and Mars. Proposed systems consist of two or more Stirling convertors, in a dual-opposed configuration, coupled to a low-temperature uranium-dioxide-fueled, liquid-metal-cooled reactor. To reduce developmental risks associated with liquid-metal loop integration, a test rig has been built to evaluate the performance of a pair of 1-kW free-piston Stirling convertors using a pumped sodium-potassium (NaK) loop for thermal energy input. Baseline performance maps have been generated at the Glenn Research Center (GRC) for these 1-kW convertors operating with an electric heat source. Each convertor was then retrofitted with a custom-made NaK heater head and integrated into a pumped NaK system at the Marshall Space Flight Center (MSFC). This paper documents baseline testing at GRC as well as the progress made in integrating the Stirling convertors into the pumped NaK loop.

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.

Modelling and experimental performance analysis of solar-assisted ground source heat pump system

NASA Astrophysics Data System (ADS)

Esen, Hikmet; Esen, Mehmet; Ozsolak, Onur

2017-01-01

In this study, slinky (the slinky-loop configuration is also known as the coiled loop or spiral loop of flexible plastic pipe)type ground heat exchanger (GHE) was established for a solar-assisted ground source heat pump system. System modelling is performed with the data obtained from the experiment. Artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) are used in modelling. The slinky pipes have been laid horizontally and vertically in a ditch. The system coefficient of performance (COPsys) and the heat pump coefficient of performance (COPhp) have been calculated as 2.88 and 3.55, respectively, at horizontal slinky-type GHE, while COPsys and COPhp were calculated as 2.34 and 2.91, respectively, at vertical slinky-type GHE. The obtained results showed that the ANFIS is more successful than that of ANN for forecasting performance of a solar ground source heat pump system.

TEM Pump With External Heat Source And Sink

NASA Technical Reports Server (NTRS)

Nesmith, Bill J.

1991-01-01

Proposed thermoelectric/electromagnetic (TEM) pump driven by external source of heat and by two or more heat pipe radiator heat sink(s). Thermoelectrics generate electrical current to circulate liquid metal in secondary loop of two-fluid-loop system. Intended for use with space and terrestrial dual loop liquid metal nuclear reactors. Applications include spacecraft on long missions or terrestrial beacons or scientific instruments having to operate in remote areas for long times. Design modified to include multiple radiators, converters, and ducts, as dictated by particular application.

Cold-end Subsystem Testing for the Fission Power System Technology Demonstration Unit

NASA Technical Reports Server (NTRS)

Briggs, Maxwell; Gibson, Marc; Ellis, David; Sanzi, James

2013-01-01

The Fission Power System (FPS) Technology Demonstration Unit (TDU) consists of a pumped sodium-potassium (NaK) loop that provides heat to a Stirling Power Conversion Unit (PCU), which converts some of that heat into electricity and rejects the waste heat to a pumped water loop. Each of the TDU subsystems is being tested independently prior to full system testing at the NASA Glenn Research Center. The pumped NaK loop is being tested at NASA Marshall Space Flight Center; the Stirling PCU and electrical controller are being tested by Sunpower Inc.; and the pumped water loop is being tested at Glenn. This paper describes cold-end subsystem setup and testing at Glenn. The TDU cold end has been assembled in Vacuum Facility 6 (VF 6) at Glenn, the same chamber that will be used for TDU testing. Cold-end testing in VF 6 will demonstrate functionality; validated cold-end fill, drain, and emergency backup systems; and generated pump performance and system pressure drop data used to validate models. In addition, a low-cost proof-of concept radiator has been built and tested at Glenn, validating the design and demonstrating the feasibility of using low-cost metal radiators as an alternative to high-cost composite radiators in an end-to-end TDU test.

Cold-End Subsystem Testing for the Fission Power System Technology Demonstration Unit

NASA Technical Reports Server (NTRS)

Briggs, Mazwell; Gibson, Marc; Ellis, David; Sanzi, James

2013-01-01

The Fission Power System (FPS) Technology Demonstration Unit (TDU) consists of a pumped sodiumpotassium (NaK) loop that provides heat to a Stirling Power Conversion Unit (PCU), which converts some of that heat into electricity and rejects the waste heat to a pumped water loop. Each of the TDU subsystems is being tested independently prior to full system testing at the NASA Glenn Research Center. The pumped NaK loop is being tested at NASA Marshall Space Flight Center; the Stirling PCU and electrical controller are being tested by Sunpower Inc.; and the pumped water loop is being tested at Glenn. This paper describes cold-end subsystem setup and testing at Glenn. The TDU cold end has been assembled in Vacuum Facility 6 (VF 6) at Glenn, the same chamber that will be used for TDU testing. Cold-end testing in VF 6 will demonstrate functionality; validated coldend fill, drain, and emergency backup systems; and generated pump performance and system pressure drop data used to validate models. In addition, a low-cost proof-of concept radiator has been built and tested at Glenn, validating the design and demonstrating the feasibility of using low-cost metal radiators as an alternative to highcost composite radiators in an end-to-end TDU test.

Liquid-Vapor Interface Configurations Investigated in Low Gravity

NASA Technical Reports Server (NTRS)

Concus, Paul; Finn, Robert; Weislogel, Mark M.

1998-01-01

The Interface Configuration Experiment (ICE) is part of a multifaceted study that is exploring the often striking behavior of liquid-vapor interfaces in low-gravity environments. Although the experiment was posed largely as a test of current mathematical theory, applications of the results should be manifold. In space almost every fluid system is affected, if not dominated, by capillarity (the effects of surface tension). As a result, knowledge of fluid interface behavior, in particular an equilibrium interface shape from which any analysis must begin, is fundamental--from the control of liquid fuels and oxygen in storage tanks to the design and development of inspace thermal systems, such as heat pipes and capillary pumped loops. ICE has increased, and should continue to increase, such knowledge as it probes the specific peculiarities of current theory upon which our present understanding rests. Several versions of ICE have been conducted in the drop towers at the NASA Lewis Research Center, on the space shuttles during the first and second United States Microgravity Laboratory missions (USML-1 and USML-2), and most recently aboard the Russian Mir space station. These studies focused on interfacial problems concerning the existence, uniqueness, configuration, stability, and flow characteristics of liquid-vapor interfaces. Results to date have clearly demonstrated the value of the present theory and the extent to which it can predict the behavior of capillary systems.

Characteristics of a capillary-discharge flash x-ray generator

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Hayasi, Yasuomi; Usuki, Tatsumi; Sato, Koetsu; Takayama, Kazuyoshi; Ido, Hideaki

2002-11-01

The fundamental experiments for measuring soft x-ray characteristics from the vacuum capillary are described. These experiments are primarily performed in order to generate line spectra such as x-ray lasers. The generator consists of a high-voltage power supply, a polarity-inversion ignitron pulse generator, a turbo-molecular pump, and a radiation tube with a capillary. A high-voltage condenser of 0.2 μF in the pulse generator is charged up to 20 kV by the power supply, and the electric charges in the condenser are discharged to the capillary in the tube after closing the ignitron. During the discharge, weakly ionized plasma forms on the inner and outer sides of a capillary. In the present work, the pump evacuates air from the tube with a pressure of about 1 mPa, and a demountable capillary was developed in order to measure x-ray spectra according to changes in the capillary length. In this capillary, the anode (target) and cathode elements can be changed corresponding to the objectives. The capillary diameter is 2.0 mm, and the length is adjusted from 1 to 50 mm. When a capillary with aluminum anode and cathode electrodes was employed, both the cathode voltage and the discharge current almost displayed damp oscillations. The peak values of the voltage and current increased when the charging voltage was increased and their maximum values were -10.8 kV and 4.7 kV, respectively. The x-ray durations observed by a 1.6 μm aluminum filter were less than 30 μs, and we detected the aluminum characteristic x-ray intensity using a 6.8 μm aluminum filter. In the spectrum measurement, two sets of aluminum and titanium electrodes were employed, and we observed multi-line spectra. The line photon energies seldom varied according to changes in teh condenser charging voltage and to changes in the electrode element. In the case where the titanium electrode was employed, the line number decreased with corresponding decreases in the capillary length. Compared with incoherent visible light, these rays from the capillary were diffracted greatly after pass through two slits.

Integrated fountain effect pump device for fluid management at low gravity

NASA Astrophysics Data System (ADS)

Yuan, S. W. K.; Frank, D. J.

1988-02-01

To transfer He II in space, the supply tank must be drained at low gravity. Conventional capillary devices such as the gallery system make use of the capillary retention capability of the screens for fluid management. Liquid helium is collected into gallery channels and then conveyed to the downstream fountain effect pump (FEP) or mechanical pump. In this Paper, a new fluid management device is proposed. The screens along the gallery channels are replaced by porous plugs which are responsible for both the fluid retention and pumping (by mechanical effect) of He II. No downstream pump is needed. The plugs in contact with liquid helium on both sides act as FEPs, and plugs exposed to vapour on one side behave as vapour-liquid phase separators (VLPSs). The total net transfer rate of He II into the receiving tank is the mass flow rate through the FEP minus the liquid loss from the VLPS plugs. The performance of the integrated FEP device (IFD) was analysed. The possibility of liquid breakthrough in the IFD was studied. The IFD is a very promising system for the fluid management of He II at low gravity.

The solar dynamic radiator with a historical perspective

NASA Technical Reports Server (NTRS)

Mclallin, K. L.; Fleming, M. L.; Hoehn, F. W.; Howerton, R. L.

1988-01-01

A historical perspective on pumped-fluid loop space radiators provides a basis for the design of the Space Station Solar Dynamic (SD) power module radiator. SD power modules, capable of generating 25 kW (electrical) each, are planned for growth in Station power requirements. The Brayton cycle SD module configuration incorporates a pumped-fluid loop radiator that must reject up to 99 kW (thermal). The thermal/hydraulic design conditions in combination with required radiator orientation and packaging envelope form a unique set of constraints as compared to previous pumped-fluid loop radiator systems. Nevertheless, past program successes have demonstrated a technology base that can be applied to the SD radiator development program to ensure a low risk, low cost system.

Active thermal control systems for lunar and Martian exploration

NASA Technical Reports Server (NTRS)

Ewert, Michael K.; Petete, Patricia A.; Dzenitis, John

1990-01-01

Several ATCS options including heat pumps, radiator shading devices, and single-phase flow loops were considered. The ATCS chosen for both lunar and Martian habitats consists of a heat pump integral with a nontoxic fluid acquisition and transport loop, and vertically oriented modular reflux-boiler radiators. The heat pump operates only during the lunar day. The lunar and Martian transfer vehicles have an internal single-phase water-acquisition loop and an external two-phase ammonia rejection system with rotating inflatable radiators. The lunar and Martian excursion vehicles incorporate internal single-phase water acquisition, which is connected via heat exchangers to external body-mounted single-phase radiators. A water evaporation system is used for the transfer vehicles during periods of high heating.

Simulation of sodium pumps for nuclear power plants. Technical report 1 Oct 80-1 May 81

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

Boadu, H.O.

1981-05-01

A single-phase pump model for analysis of transients in sodium cooled fast breeder nuclear power plants has been presented, where homologous characteristic curves are used to predict the behavior of the pump during operating transients. The pump model has been incorporated into BRENDA and FFTF; two system cases to simulate Clinch River Breeder Reactor Plant (CRBRP) and the Fast Flux Test Facility (FFTF) respectively. Two simulation test results for BRENDA which is one loop representation of a three loop plant have been presented. They are: (1) Primary pump coastdown to natural circulation coupled with scram failure, and (2) 10 percentmore » deviation of primary speed with plant controllers incorporated.« less

Determination of artificial sweeteners by capillary electrophoresis with contactless conductivity detection optimized by hydrodynamic pumping.

PubMed

Stojkovic, Marko; Mai, Thanh Duc; Hauser, Peter C

2013-07-17

The common sweeteners aspartame, cyclamate, saccharin and acesulfame K were determined by capillary electrophoresis with contactless conductivity detection. In order to obtain the best compromise between separation efficiency and analysis time hydrodynamic pumping was imposed during the electrophoresis run employing a sequential injection manifold based on a syringe pump. Band broadening was avoided by using capillaries of a narrow 10 μm internal diameter. The analyses were carried out in an aqueous running buffer consisting of 150 mM 2-(cyclohexylamino)ethanesulfonic acid and 400 mM tris(hydroxymethyl)aminomethane at pH 9.1 in order to render all analytes in the fully deprotonated anionic form. The use of surface modification to eliminate or reverse the electroosmotic flow was not necessary due to the superimposed bulk flow. The use of hydrodynamic pumping allowed easy optimization, either for fast separations (80s) or low detection limits (6.5 μmol L(-1), 5.0 μmol L(-1), 4.0 μmol L(-1) and 3.8 μmol L(-1) for aspartame, cyclamate, saccharin and acesulfame K respectively, at a separation time of 190 s). The conditions for fast separations not only led to higher limits of detection but also to a narrower dynamic range. However, the settings can be changed readily between separations if needed. The four compounds were determined successfully in food samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Nailfold capillaroscopic changes in Kindler syndrome.

PubMed

Dobrev, Hristo P; Vutova, Nina I

2015-11-01

Kindler syndrome (KS), the fourth major type of hereditary epidermolysis bullosa (HEB), is a rare, autosomal recessive disorder characterized by skin fragility and blistering at birth followed by development of marked photosensitivity and progressive poikilodermatous skin changes in later years. We reported here the case of a 54-year-old woman, who fulfills the diagnostic criteria of KS type of HEB, putting accent on the nailfold capillaroscopic changes. Using videocapillaroscopy we observed pronounced alterations in finger nail capillaries including reduction in capillary density, features of neoangiogenesis (architectural derangement, elongated loops, extremely tortuous, bushy or branching capillaries, thin, branching and interconnected capillaries), enlarged and giant capillaries. We consider the changes observed as an adaptive mechanism that compensate the loss of capillaries due to chronic periungual trauma. Further studies with larger number of patients are needed to confirm the significance of capillaroscopy findings for patients with HEB.

Jet pump assisted artery

NASA Technical Reports Server (NTRS)

1975-01-01

A procedure for priming an arterial heat pump is reported; the procedure also has a means for maintaining the pump in a primed state. This concept utilizes a capillary driven jet pump to create the necessary suction to fill the artery. Basically, the jet pump consists of a venturi or nozzle-diffuser type constriction in the vapor passage. The throat of this venturi is connected to the artery. Thus vapor, gas, liquid, or a combination of the above is pumped continuously out of the artery. As a result, the artery is always filled with liquid and an adequate supply of working fluid is provided to the evaporator of the heat pipe.

Capillarics: pre-programmed, self-powered microfluidic circuits built from capillary elements.

PubMed

Safavieh, Roozbeh; Juncker, David

2013-11-07

Microfluidic capillary systems employ surface tension effects to manipulate liquids, and are thus self-powered and self-regulated as liquid handling is structurally and chemically encoded in microscale conduits. However, capillary systems have been limited to perform simple fluidic operations. Here, we introduce complex capillary flow circuits that encode sequential flow of multiple liquids with distinct flow rates and flow reversal. We first introduce two novel microfluidic capillary elements including (i) retention burst valves and (ii) robust low aspect ratio trigger valves. These elements are combined with flow resistors, capillary retention valves, capillary pumps, and open and closed reservoirs to build a capillary circuit that, following sample addition, autonomously delivers a defined sequence of multiple chemicals according to a preprogrammed and predetermined flow rate and time. Such a circuit was used to measure the concentration of C-reactive protein. This work illustrates that as in electronics, complex capillary circuits may be built by combining simple capillary elements. We define such circuits as "capillarics", and introduce symbolic representations. We believe that more complex circuits will become possible by expanding the library of building elements and formulating abstract design rules.

Fuel control for gas turbine with continuous pilot flame

DOEpatents

Swick, Robert M.

1983-01-01

An improved fuel control for a gas turbine engine having a continuous pilot flame and a fuel distribution system including a pump drawing fuel from a source and supplying a line to the main fuel nozzle of the engine, the improvement being a control loop between the pump outlet and the pump inlet to bypass fuel, an electronically controlled throttle valve to restrict flow in the control loop when main nozzle demand exists and to permit substantially unrestricted flow without main nozzle demand, a minimum flow valve in the control loop downstream of the throttle valve to maintain a minimum pressure in the loop ahead of the flow valve, a branch tube from the pilot flame nozzle to the control loop between the throttle valve and the minimum flow valve, an orifice in the branch tube, and a feedback tube from the branch tube downstream of the orifice to the minimum flow valve, the minimum flow valve being operative to maintain a substantially constant pressure differential across the orifice to maintain constant fuel flow to the pilot flame nozzle.

A Mechanical Cryogenic Cooler for the Hubble Space Telescope

NASA Technical Reports Server (NTRS)

Jedrich, Nicholas; Zimbelman, Darell; Swift, Walter; Dolan, Francis; Brumfield, Mark (Technical Monitor)

2002-01-01

This paper presents a description of the Hubble Space Telescope (HST) Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) Cryo Cooler (NCC), the cutting edge technology involved, its evolution, performance, and future space applications. The NCC is the primary hardware component of the NICMOS Cooling System comprised of the NCC, an Electronics Support Module, a Capillary Pumped Loop/Radiator, and associated interface harnessing. The system will be installed during extravehicular activities on HST during Servicing Mission 3B scheduled for launch in February 2002. The NCC will be used to revive the NICMOS instrument, which experienced a reduced operational lifetime due to an internal thermal short in its dewar structure, and restore HST scientific infrared capability to operational status. The NCC is a state-of-the-art reverse Turbo-Brayton cycle cooler employing gas bearing micro turbo machinery, driven by advanced power conversion electronics, operating at speeds up to 7300 revolutions per second (rps) to remove heat from the NICMOS instrument.

STS-69 postflight presentation

NASA Astrophysics Data System (ADS)

1995-10-01

A postflight conference of the STS-69 mission is presented. The flightcrew ('The Dog Team') consisted of Cmdr. David Walker, Pilot Kenneth Cockrell, Payload Cmdr. James Voss, and Mission Specialists James Newman and Michael Gernhardt. The mission's primary objective was the deployment and retrieval of the SPARTAN-201 satellite, which investigated the interaction between the Sun and it's solar wind. Other secondary experiments and shuttle payloads included the Wake Shield Facility (WSF), which grew several layers of semiconductor films, the International Extreme Ultraviolet Hitchhiker (IEH-1), the Capillary Pumped Loop-2/Gas Bridge Assembly (CAPL-2/GBA), several Get Away Specials (GAS) experiments, the Electrolysis Performance Improvement Concept Study (EPICS), the Thermal Energy Storage (TES-2) experiment, the Commercial Generic Bioprocessing Apparatus-7 (CGBA-7), the National Institutes of Health-Cells 4 (NIH-C4) experiment, and the Biological Research in Canister-6 (BRIC-6) experiment. Earth views consisted of Saudi Arabia water wells, uncommon vortices over Oman, the Amazon River, the Bahamas, Somalia, a sunset over the Earth's horizon, and two hurricanes, Luis and Marilyn.

Numerical simulation of gas-phonon coupling in thermal transpiration flows.

PubMed

Guo, Xiaohui; Singh, Dhruv; Murthy, Jayathi; Alexeenko, Alina A

2009-10-01

Thermal transpiration is a rarefied gas flow driven by a wall temperature gradient and is a promising mechanism for gas pumping without moving parts, known as the Knudsen pump. Obtaining temperature measurements along capillary walls in a Knudsen pump is difficult due to extremely small length scales. Meanwhile, simplified analytical models are not applicable under the practical operating conditions of a thermal transpiration device, where the gas flow is in the transitional rarefied regime. Here, we present a coupled gas-phonon heat transfer and flow model to study a closed thermal transpiration system. Discretized Boltzmann equations are solved for molecular transport in the gas phase and phonon transport in the solid. The wall temperature distribution is the direct result of the interfacial coupling based on mass conservation and energy balance at gas-solid interfaces and is not specified a priori unlike in the previous modeling efforts. Capillary length scales of the order of phonon mean free path result in a smaller temperature gradient along the transpiration channel as compared to that predicted by the continuum solid-phase heat transfer. The effects of governing parameters such as thermal gradients, capillary geometry, gas and phonon Knudsen numbers and, gas-surface interaction parameters on the efficiency of thermal transpiration are investigated in light of the coupled model.

A displacement pump procedure to load extracts for automated gel permeation chromatography.

PubMed

Daft, J; Hopper, M; Hensley, D; Sisk, R

1990-01-01

Automated gel permeation chromatography (GPC) effectively separates lipids from pesticides in sample extracts that contain fat. Using a large syringe to load sample extracts manually onto GPC models having 5 mL holding loops is awkward, slow, and potentially hazardous. Loading with a small-volume displacement pump, however, is convenient and fast (ca 1 loop every 20 s). And more importantly, the analyst is not exposed to toxic organic vapors because the loading pump and its connecting lines do not leak in the way that a syringe does.

Predicting the scanning branches of hysteretic soil water-retention capacity with use of the method of mathematical modeling

NASA Astrophysics Data System (ADS)

Terleev, V.; Ginevsky, R.; Lazarev, V.; Nikonorov, A.; Togo, I.; Topaj, A.; Moiseev, K.; Abakumov, E.; Melnichuk, A.; Dunaieva, I.

2017-10-01

A mathematical model of the hysteresis of the water-retention capacity of the soil is proposed. The parameters of the model are interpreted within the framework of physical concepts of the structure and capillary properties of soil pores. On the basis of the model, a computer program with an interface that allows for dialogue with the user is developed. The program has some of options: visualization of experimental data; identification of the model parameters with use of measured data by means of an optimizing algorithm; graphical presentation of the hysteresis loop with application of the assigned parameters. Using the program, computational experiments were carried out, which consisted in verifying the identifiability of the model parameters from data on the main branches, and also in testing the ability to predict the scanning branches of the hysteresis loop. For the experiments, literature data on two sandy soils were used. The absence of an “artificial pump effect” is proved. A sufficiently high accuracy of the prediction of the scanning branches of the hysteresis loop has been achieved in comparison with the three models of the precursors. The practical importance of the proposed model and computer program, which is developed on its basis, is to ensure the calculation of precision irrigation rates. The application of such rates in irrigation farming will help to prevent excess moisture from flowing beyond the root layer of the soil and, thus, minimize the unproductive loss of irrigation water and agrochemicals, as well as reduce the risk of groundwater contamination and natural water eutrophication.

Effect of wave action on near-well zone cleaning

NASA Astrophysics Data System (ADS)

Pen'kovskii, V. I.; Korsakova, N. K.

2017-10-01

Drilling filtrate invasion into the producing formation and native water accumulating of the near-well zone in well operation reduce the well productivity. As a result of that, depending on characteristic capillary pressure scale and differential pressure drawdown, oil production rate may become lower than expected one. In this paper, it is considered the hysteresis effects of capillary pressure after reversion of displacement. As applied to laboratory experiment conditions, the solution of problem of oil flow in formation model with a pressure drop on the model sides harmonically varied with time is presented. It was estimated a range of fluid vibration effective action on the near-well zone cleaning from capillary locking water. The plant simulating extraction of oil from formation using widely practised sucker-rod pump has been created. Formation model is presented as a slot filled with broken glass between two plates. In the process, natural oil and sodium chloride solution were used as working fluids. The experiments qualitatively confirm a positive effect of jack pumps on the near-well zone cleaning.

Study of liquid and vapor flow into a Centaur capillary device

NASA Technical Reports Server (NTRS)

Blatt, M. H.; Risberg, J. A.

1979-01-01

The following areas of liquid and vapor flow were analyzed and experimentally evaluated; 1) the refilling of capillary devices with settled liquid, and 2) vapor flow across wetted screens. These investigations resulted in: 1) the development of a versatile computer program that was successfully correlated with test data and used to predict Centaur D-1S LO2 and LH2 start basket refilling; 2) the development of a semi-empirical model that was only partially correlated with data due to difficulties in obtaining repeatable test results. Also, a comparison was made to determine the best propellant management system for the Centaur D-1S vehicle. The comparison identified the basline Centaur D-1S system (using pressurization, boost pumps and propellant settling) as the best candidate based on payload weight penalty. However, other comparison criteria and advanced mission condition were identified where pressure fed systems, thermally subcooled boost pumps and capillary devices would be selected as attractive alternatives.

Pressure Profiles in a Loop Heat Pipe Under Gravity Influence

NASA Technical Reports Server (NTRS)

Ku, Jentung

2015-01-01

During the operation of a loop heat pipe (LHP), the viscous flow induces pressure drops in various elements of the loop. The total pressure drop is equal to the sum of pressure drops in vapor grooves, vapor line, condenser, liquid line and primary wick, and is sustained by menisci at liquid and vapor interfaces on the outer surface of the primary wick in the evaporator. The menisci will curve naturally so that the resulting capillary pressure matches the total pressure drop. In ground testing, an additional gravitational pressure head may be present and must be included in the total pressure drop when LHP components are placed in a non-planar configuration. Under gravity-neutral and anti-gravity conditions, the fluid circulation in the LHP is driven solely by the capillary force. With gravity assist, however, the flow circulation can be driven by the combination of capillary and gravitational forces, or by the gravitational force alone. For a gravity-assist LHP at a given elevation between the horizontal condenser and evaporator, there exists a threshold heat load below which the LHP operation is gravity driven and above which the LHP operation is capillary force and gravity co-driven. The gravitational pressure head can have profound effects on the LHP operation, and such effects depend on the elevation, evaporator heat load, and condenser sink temperature. This paper presents a theoretical study on LHP operations under gravity neutral, anti-gravity, and gravity-assist modes using pressure diagrams to help understand the underlying physical processes. Effects of the condenser configuration on the gravitational pressure head and LHP operation are also discussed.

Pressure Profiles in a Loop Heat Pipe under Gravity Influence

NASA Technical Reports Server (NTRS)

Ku, Jentung

2015-01-01

During the operation of a loop heat pipe (LHP), the viscous flow induces pressure drops in various elements of the loop. The total pressure drop is equal to the sum of pressure drops in vapor grooves, vapor line, condenser, liquid line and primary wick, and is sustained by menisci at liquid and vapor interfaces on the outer surface of the primary wick in the evaporator. The menisci will curve naturally so that the resulting capillary pressure matches the total pressure drop. In ground testing, an additional gravitational pressure head may be present and must be included in the total pressure drop when LHP components are placed in a non-planar configuration. Under gravity-neutral and anti-gravity conditions, the fluid circulation in the LHP is driven solely by the capillary force. With gravity assist, however, the flow circulation can be driven by the combination of capillary and gravitational forces, or by the gravitational force alone. For a gravity-assist LHP at a given elevation between the horizontal condenser and evaporator, there exists a threshold heat load below which the LHP operation is gravity driven and above which the LHP operation is capillary force and gravity co-driven. The gravitational pressure head can have profound effects on the LHP operation, and such effects depend on the elevation, evaporator heat load, and condenser sink temperature. This paper presents a theoretical study on LHP operations under gravity-neutral, anti-gravity, and gravity-assist modes using pressure diagrams to help understand the underlying physical processes. Effects of the condenser configuration on the gravitational pressure head and LHP operation are also discussed.

Automated Parallel Capillary Electrophoretic System

DOEpatents

Li, Qingbo; Kane, Thomas E.; Liu, Changsheng; Sonnenschein, Bernard; Sharer, Michael V.; Kernan, John R.

2000-02-22

An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

Fluid Delivery System For Capillary Electrophoretic Applications.

DOEpatents

Li, Qingbo; Liu, Changsheng; Kane, Thomas E.; Kernan, John R.; Sonnenschein, Bernard; Sharer, Michael V.

2002-04-23

An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carrousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

A Conceptual Design Study on the Application of Liquid Metal Heat Transfer Technology to the Solar Thermal Power Plant

NASA Technical Reports Server (NTRS)

Zimmerman, W. F.; Robertson, C. S.; Ehde, C. L.; Divakaruni, S. M.; Stacy, L. E.

1979-01-01

Alkali metal heat transfer technology was used in the development of conceptual designs for the transport and storage of sensible and latent heat thermal energy in distributed concentrator, solar Stirling power conversion systems at a power level of 15 kWe per unit. Both liquid metal pumped loop and heat pipe thermal transport were considered; system configurations included: (1) an integrated, focal mounted sodium heat pipe solar receiver (HPSR) with latent heat thermal energy storage; (2) a liquid sodium pumped loop with the latent heat storage, Stirling engine-generator, pump and valves located on the back side of the concentrator; and (3) similar pumped loops serving several concentrators with more centralized power conversion and storage. The focus mounted HPSR was most efficient, lightest and lowest in estimated cost. Design confirmation testing indicated satisfactory performance at all angles of inclination of the primary heat pipes to be used in the solar receiver.

An AC electroosmotic micropump for circular chromatographic applications.

PubMed

Debesset, S; Hayden, C J; Dalton, C; Eijkel, J C T; Manz, A

2004-08-01

Flow rates of up to 50 microm s(-1) have been successfully achieved in a closed-loop channel using an AC electroosmotic pump. The AC electroosmotic pump is made of an interdigitated array of unequal width electrodes located at the bottom of a channel, with an AC voltage applied between the small and the large electrodes. The flow rate was found to increase linearly with the applied voltage and to decrease linearly with the applied frequency. The pump is expected to be suitable for circular chromatography for the following reasons: the driving forces are distributed over the channel length and the pumping direction is set by the direction of the interdigitated electrodes. Pumping in a closed-loop channel can be achieved by arranging the electrode pattern in a circle. In addition the inherent working principle of AC electroosmotic pumping enables the independent optimisation of the channel height or the flow velocity.

Computerized nailfold video capillaroscopy--a new tool for assessment of Raynaud's phenomenon.

PubMed

Anderson, Marina E; Allen, P Danny; Moore, Tonia; Hillier, Val; Taylor, Christopher J; Herrick, Ariane L

2005-05-01

To develop a computer based nailfold video capillaroscopy system with enhanced image quality and to assess its disease-subgroup resolving power in patients with primary and secondary Raynaud's phenomenon (RP). Using frame registration software, digitized video images from the microscope were combined to form a panoramic mosaic of the nailfold. Capillary dimensions (apex, arterial, venous, and total width) and density were measured onscreen. Significantly, the new system could guarantee analysis of the same set of capillaries by 2 observers. Forty-eight healthy control subjects, 21 patients with primary RP, 40 patients with limited cutaneous systemic sclerosis (lcSSc), and 11 patients with diffuse cutaneous SSc (dcSSc) were studied. Intra- and interobserver variability were calculated in a subset of 30 subjects. The number of loops/mm was significantly lower, and all 4 capillary dimensions significantly greater, in SSc patients versus controls plus primary RP patients (p < 0.001 for all measures). When comparing control (+ primary RP) patients with SSc patients (lcSSc + dcSSc) the most powerful discriminator was found to be the number of loops/mm. Results for intra- and interobserver reproducibility showed that the limits of agreement were closer when both observers measured the same capillaries. The key feature of the newly developed system is that it improves reproducibility of nailfold capillary measurements by allowing reidentification of the same capillaries by different observers. By allowing access to previous measurements, the new system should improve reliability in longitudinal studies, and therefore has the potential of being a valuable outcome measure of microvessel disease/involvement in clinical trials of scleroderma spectrum disorders.

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

N. Mittereder, A. Poerschke

This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab.

Investigation of Low Power Operation in a Loop Heat Pipe

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura; Rogers, Paul; Cheung, Kwok; Powers, Edward I. (Technical Monitor)

2001-01-01

This paper presents test results of an experimental study of low power operation in a loop heat pipe. The main objective was to demonstrate how changes in the vapor void fraction inside the evaporator core would affect the loop behavior, The fluid inventory and the relative tilt between the evaporator and the compensation chamber were varied so as to create different vapor void fractions in the evaporator core. The effect on the loop start-up, operating temperature, and capillary limit was investigated. Test results indicate that the vapor void fraction inside the evaporator core is the single most important factor in determining the loop operation at low powers.

Electrphoretic Sample Excitation Light Assembly.

DOEpatents

Li, Qingbo; Liu, Changsheng

2002-04-02

An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carrousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

Motorized Positioning Apparatus Having Coaxial Carrousels.

DOEpatents

Li, Qingbo; Kane, Thomas E.; Liu, Changsheng; Sonnenschein, Bernard; Sharer, Michael V.; Kernan, John R.

2002-04-02

An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carrousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

Experiments of Transient Condensation Heat Transfer on the Heat Flux Senor

NASA Astrophysics Data System (ADS)

Wang, Xuwen; Liu, Qiusheng; Zhu, Zhiqiang; Chen, Xue

2015-09-01

The influence of transient heat transfer in different condensation condition was investigated experimentally in the present paper. Getting condensation heat and mass transfer regularity and characteristics in space can provide theoretical basis for thermodynamic device such as heat pipes, loop heat pipes and capillary pumped loops as well as other fluid management engineering designing. In order to study the condensation process in space, an experimental study has been carried out on the ground for space experiment. The results show that transit heat transfer coefficient of film condensation is related to the condensation film width, the flow condition near the two phase interface and the pressure of the vapor and non-condensable gas in chamber. On the ground, the condensation heat flux on vertical surface is higher than it on horizontal surface. The transit heat flux of film condensation is affected by the temperature of superheated vapor, the temperature of condensation surface and non-condensable gas pressure. Condensation heat flux with vapor forced convection is many times more than it with natural convection. All of heat flux for both vapor forced convection and natural convection condensation in limited chamber declines dramatically over time. The present experiment is preliminary work for our future space experiments of the condensation and heat transfer process onboard the Chinese Spacecraft "TZ-1" to be launched in 2016.

In-situ Condition Monitoring of Components in Small Modular Reactors Using Process and Electrical Signature Analysis. Final report, volume 1. Development of experimental flow control loop, data analysis and plant monitoring

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

Upadhyaya, Belle; Hines, J. Wesley; Damiano, Brian

The research and development under this project was focused on the following three major objectives: Objective 1: Identification of critical in-vessel SMR components for remote monitoring and development of their low-order dynamic models, along with a simulation model of an integral pressurized water reactor (iPWR). Objective 2: Development of an experimental flow control loop with motor-driven valves and pumps, incorporating data acquisition and on-line monitoring interface. Objective 3: Development of stationary and transient signal processing methods for electrical signatures, machinery vibration, and for characterizing process variables for equipment monitoring. This objective includes the development of a data analysis toolbox. Themore » following is a summary of the technical accomplishments under this project: - A detailed literature review of various SMR types and electrical signature analysis of motor-driven systems was completed. A bibliography of literature is provided at the end of this report. Assistance was provided by ORNL in identifying some key references. - A review of literature on pump-motor modeling and digital signal processing methods was performed. - An existing flow control loop was upgraded with new instrumentation, data acquisition hardware and software. The upgrading of the experimental loop included the installation of a new submersible pump driven by a three-phase induction motor. All the sensors were calibrated before full-scale experimental runs were performed. - MATLAB-Simulink model of a three-phase induction motor and pump system was completed. The model was used to simulate normal operation and fault conditions in the motor-pump system, and to identify changes in the electrical signatures. - A simulation model of an integral PWR (iPWR) was updated and the MATLAB-Simulink model was validated for known transients. The pump-motor model was interfaced with the iPWR model for testing the impact of primary flow perturbations (upsets) on plant parameters and the pump electrical signatures. Additionally, the reactor simulation is being used to generate normal operation data and data with instrumentation faults and process anomalies. A frequency controller was interfaced with the motor power supply in order to vary the electrical supply frequency. The experimental flow control loop was used to generate operational data under varying motor performance characteristics. Coolant leakage events were simulated by varying the bypass loop flow rate. The accuracy of motor power calculation was improved by incorporating the power factor, computed from motor current and voltage in each phase of the induction motor.- A variety of experimental runs were made for steady-state and transient pump operating conditions. Process, vibration, and electrical signatures were measured using a submersible pump with variable supply frequency. High correlation was seen between motor current and pump discharge pressure signal; similar high correlation was exhibited between pump motor power and flow rate. Wide-band analysis indicated high coherence (in the frequency domain) between motor current and vibration signals. - Wide-band operational data from a PWR were acquired from AMS Corporation and used to develop time-series models, and to estimate signal spectrum and sensor time constant. All the data were from different pressure transmitters in the system, including primary and secondary loops. These signals were pre-processed using the wavelet transform for filtering both low-frequency and high-frequency bands. This technique of signal pre-processing provides minimum distortion of the data, and results in a more optimal estimation of time constants of plant sensors using time-series modeling techniques.« less

Heat removal from bipolar transistor by loop heat pipe with nickel and copper porous structures.

PubMed

Nemec, Patrik; Smitka, Martin; Malcho, Milan

2014-01-01

Loop heat pipes (LHPs) are used in many branches of industry, mainly for cooling of electrical elements and systems. The loop heat pipe is a vapour-liquid phase-change device that transfers heat from evaporator to condenser. One of the most important parts of the LHP is the porous wick structure. The wick structure provides capillary force to circulate the working fluid. To achieve good thermal performance of LHP, capillary wicks with high permeability and porosity and fine pore radius are expected. The aim of this work was to develop porous structures from copper and nickel powder with different grain sizes. For experiment copper powder with grain size of 50 and 100 μm and nickel powder with grain size of 10 and 25 μm were used. Analysis of these porous structures and LHP design are described in the paper. And the measurements' influences of porous structures in LHP on heat removal from the insulated gate bipolar transistor (IGBT) have been made.

Heat Removal from Bipolar Transistor by Loop Heat Pipe with Nickel and Copper Porous Structures

PubMed Central

Smitka, Martin; Malcho, Milan

2014-01-01

Loop heat pipes (LHPs) are used in many branches of industry, mainly for cooling of electrical elements and systems. The loop heat pipe is a vapour-liquid phase-change device that transfers heat from evaporator to condenser. One of the most important parts of the LHP is the porous wick structure. The wick structure provides capillary force to circulate the working fluid. To achieve good thermal performance of LHP, capillary wicks with high permeability and porosity and fine pore radius are expected. The aim of this work was to develop porous structures from copper and nickel powder with different grain sizes. For experiment copper powder with grain size of 50 and 100 μm and nickel powder with grain size of 10 and 25 μm were used. Analysis of these porous structures and LHP design are described in the paper. And the measurements' influences of porous structures in LHP on heat removal from the insulated gate bipolar transistor (IGBT) have been made. PMID:24959622

Fiber lasers with loop reflectors.

PubMed

Urquhart, P

1989-09-01

The theory of homogeneously broadened four level fiber lasers, which use fiber loops as distributed reflective elements, is examined. Such cavities can be made entirely from rare earth doped fiber. The amplifying characteristics of doped fiber loops are examined. The threshold pump power and the loop reflectivity necessary to optimize the lasing output power from an oscillator formed from two loops in series are predicted.

Capillary Discharge Soft X-ray Laser Experiments at Air Force Research Laboratory

NASA Astrophysics Data System (ADS)

Ruden, E. L.; Gale, D. G.

1997-11-01

The Air Force Research Laboratory (previously Phillips Laboratory) is presently attempting to reproduce the high gain laser results of J.J. Rocca's capillary discharge z-pinch pumped 46.9 nm Ne-like Ar laser. This poster presents progress to date at measuring our laser's intensity and gain. The capillary circuit consists of a low inductance 3 nH water capacitor discharged by a coaxial spark gap into a 12 cm long, 4 mm ID plastic capillary. The capillary is supplied with 39 kA of current with a 20 ns risetime. The principle radiation diagnostic consists of a VUV monochrometer coupled to a custom high speed vacuum X-ray diode with an aluminum cathode. The signal is recorded on a fast transient digitizer (Tektronix SCD 5000). The total detector system's analog bandwidth is about 3 GHz.

A capillary-based multiplexed isothermal nucleic acid-based test for sexually transmitted diseases in patients.

PubMed

Xu, Gaolian; Zhao, Hang; Cooper, Jonathan M; Reboud, Julien

2016-10-06

We demonstrate a multiplexed loop mediated isothermal amplification (LAMP) assay for infectious disease diagnostics, where the analytical process flow of target pathogens genomic DNA is performed manually by moving magnetic beads through a series of plugs in a capillary. Heat is provided by a water bath and the results are read by the naked eye, enabling applications in low resource settings.

Modeling of High Capacity Passive Cooling System

DTIC Science & Technology

2009-03-01

Pulsating Heat Pipes : Closed Loop Pulsating Heat Pipes , which is also known as Meandering Capillary Tube Heat Pipe or Closed Loop Oscillating Heat ... Pipe , has emerged in the recent years as a new electronics cooling technology. The Pulsating Heat Pipe is an innovating technology that has gained...horizontal orientation, the operating temperatures are lower. Pulsating heat pipes are capable of higher heat

Nailfold capillaroscopy abnormalities as predictors of mortality in patients with systemic sclerosis.

PubMed

Kayser, Cristiane; Sekiyama, Juliana Y; Próspero, Lucas C; Camargo, Cintia Z; Andrade, Luis E C

2013-01-01

Peripheral microangiopathy is a hallmark of systemic sclerosis (SSc) and can be early detected by nailfold capillaroscopy (NFC). This study aimed to examine whether more severe peripheral microangiopathy at NFC are predictive factor for death in SSc patients. 135 SSc patients who performed NFC between June 2001 and July 2009 were included. The following NFC parameters were evaluated: number of capillary loops/mm, avascular score (scored from 0 to 3), and number of enlarged and giant capillary loops. Univariate and multivariate regression models were used to analyse the association of mortality with NFC and clinical parameters. At the time of the analysis (August 2010), 123 patients were alive, and 12 were dead. By univariate analysis, male gender, forced vital capacity <75% predicted, higher number of giant capillary loops, and an avascular score >1.5 on NFC were associated with a significantly increase risk of death. By multivariate analysis, an avascular score >1.5 was the only independent predictor of death (hazard ratio 2.265). Survival rates from diagnosis at 1, 5 and 10 years were lower in patients with avascular score >1.5 (97%, 86%, and 59%, respectively) compared with those with avascular score ≤1.5 (97%, 97%, and 91% respectively) (p=0.009 by log rank test). Avascular scores higher than 1.5 at NFC was an independent predictor of death in SSc, suggesting that NFC can be useful for predicting SSc outcome.

An accessible micro-capillary electrophoresis device using surface-tension-driven flow

PubMed Central

Mohanty, Swomitra K.; Warrick, Jay; Gorski, Jack; Beebe, David J.

2010-01-01

We present a rapidly fabricated micro-capillary electrophoresis chip that utilizes surface-tension-driven flow for sample injection and extraction of DNA. Surface-tension-driven flow (i.e. passive pumping) injects a fixed volume of sample that can be predicted mathematically. Passive pumping eliminates the need for tubing, valves, syringe pumps, and other equipment typically needed for interfacing with microelectrophoresis chips. This method requires a standard micropipette to load samples before separation, and remove the resulting bands after analysis. The device was made using liquid phase photopolymerization to rapidly fabricate the chip without the need of special equipment typically associated with the construction of microelectrophoresis chips (e.g. cleanroom). Batch fabrication time for the device presented here was 1.5 h including channel coating time to suppress electroosmotic flow. Devices were constructed out of poly-isobornyl acrylate and glass. A standard microscope with a UV source was used for sample detection. Separations were demonstrated using Promega BenchTop 100 bp ladder in hydroxyl ethyl cellulose (HEC) and oligonucleotides of 91 and 118 bp were used to characterize sample injection and extraction of DNA bands. The end result was an inexpensive micro-capillary electrophoresis device that uses tools (e.g. micropipette, electrophoretic power supplies, and microscopes) already present in most labs for sample manipulation and detection, making it more accessible for potential end users. PMID:19425002

An Examination of Potential Causes of the Persistent Capillary Fringe Extension Observed During a Pumping Test in an Unconfined Aquifer

NASA Astrophysics Data System (ADS)

Bunn, M. I.; Jones, J.; Endres, A. L.

2008-12-01

Hydrogeologists quantify the properties of unconfined aquifers by analyzing the data from pumping tests. The most appropriate method of incorporating flow contributions from the vadose zone into these analyses has been the subject of debate for decades. Recently, a highly detailed data set was collected during a seven- day pumping test at CFB Borden, Ontario (Bevan et al., 2005) which has allowed a close examination of the vadose zone response to pumping. Water table drawdown was monitored using pressure transducers in 11 monitoring wells, while moisture profiles were collected 19 times during the 7-day test using neutron logging. The Borden aquifer system is quite homogeneous, and numerical simulations using the variably saturated model InHM resulted in excellent reproduction of the observed hydraulic head drawdowns. Conversely, the simulated moisture profiles correlated poorly with neutron-logging-derived observed profiles. Specifically, the field results show delayed drawdown in the vadose zone, resulting in a persistent and significant extension of the capillary fringe, with the shape of the moisture profile remaining constant through the transition zone. Numerical simulations using various forms of the capillary pressure-saturation relationship with reasonable parameter sets were unable produce the extension. Neutron moisture profiles were selected from three locations (3, 5, and 15 m radial distance from the pumping well) at which an adjacent shallow deep piezometer pair could be used to accurately estimate water table location. Using this data in conjunction with the inverse modeling tool PEST, a set of van Genuchten capillary pressure-saturation parameters was generated to match each observed moisture profile. Horizontal and vertical hydraulic gradients and flow rates at the water table were generated using model output and compared to the fitted parameters. The van Genuchten parameter n was found to have significant scatter in both profile location and observation time when compared to any of the modeled results. The van Genuchten parameter alpha was found to vary linearly as a function of horizontal hydraulic gradient; further the results from all observation locations and times were found to follow the same linear relationship. The likely effects of consolidation, entrapped air, heterogeneity, and hydraulic gradients on the observed moisture profile were also evaluated. Results indicate a need for further investigation into the applicability of laboratory derived steady-state water retention curves for field scale simulations.

Stability analysis for capillary channel flow: 1d and 3d computations

NASA Astrophysics Data System (ADS)

Grah, Aleksander; Klatte, Jörg; Dreyer, Michael E.

The subject of the presentation are numerical studies on capillary channel flow, based on results of the sounding rocket TEXUS experiments. The flow through a capillary channel is established by a gear pump at the outlet. The channel, consists of two parallel glass plates with a width of 25 mm, a gap of 10 mm and a length of 12 mm. The meniscus of a compensation tube maintains a constant system pressure. Steady and dynamic pressure effects in the system force the surfaces to bend inwards. A maximum flow rate is achieved when the free surface collapses and gas ingestion occurs at the outlet. This critical flow rate depends on the channel geometry, the flow regime and the liquid properties. The aim of the experiments is the determination of the free surface shape and to find the maximum flow rate. In order to study the unsteady liquid loop behavior, a dimensionless one-dimensional model and a corresponding three-dimensional model were developed. The one-dimensional model is based on the unsteady Bernoulli equation, the unsteady continuity equation and geometrical conditions for the surface curvature and the flow cross-section. The experimental and evaluated contour data show good agreement for a sequence of transient flow rate perturbations. In the case of steady flow at maximum flow rate, when the "choking" effect occurs, the surfaces collapse and cause gas ingestion into the channel. This effect is related to the Speed Index. At the critical flow rate the Speed Index reaches the value 1, in analogy to the Mach Number. Unsteady choking does not necessarily cause surface collapse. We show, that temporarily Speed Index values exceeding One may be achieved for a perfectly stable supercritical dynamic flow. As a supercritical criterion for the dynamic free surface stability we define a Dynamic Index considering the local capillary pressure and the convective pressure, which is a function of the local velocity. The Dynamic Index is below One for stable flow while D = 1 indicates surface collapse. This studies lead to a stability diagram, which defines the limits of flow dynamics and the maximum unsteady flow rate.

Summary of Test Results From a 1 kW(sub e)-Class Free-Piston Stirling Power Convertor Integrated With a Pumped NaK Loop

NASA Technical Reports Server (NTRS)

Briggs, Maxwell H.; Geng, Steven M.; Pearson, J. Boise; Godfroy, Thomas J.

2010-01-01

As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1 kW class free-piston Stirling convertors was modified to operate with a NaK liquid metal pumped loop for thermal energy input. This was the first-ever attempt at powering a free-piston Stirling engine with a pumped liquid metal heat source and is a major FSP project milestone towards demonstrating technical feasibility. The tests included performance mapping the convertors over various hot and cold-end temperatures, piston amplitudes and NaK flow rates; and transient test conditions to simulate various start-up and fault scenarios. Performance maps of the convertors generated using the pumped NaK loop for thermal input show increases in power output over those measured during baseline testing using electric heating. Transient testing showed that the Stirling convertors can be successfully started in a variety of different scenarios and that the convertors can recover from a variety of fault scenarios.

Summary of Test Results From a 1 kWe-Class Free-Piston Stirling Power Convertor Integrated With a Pumped NaK Loop

NASA Technical Reports Server (NTRS)

Briggs, Maxwell H.; Geng, Steven M.; Pearson, J. Boise; Godfroy, Thomas J.

2010-01-01

As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1 kW class free-piston Stirling convertors was modified to operate with a NaK liquid metal pumped loop for thermal energy input. This was the first-ever attempt at powering a free-piston Stirling engine with a pumped liquid metal heat source and is a major FSP project milestone towards demonstrating technical feasibility. The tests included performance mapping the convertors over various hot and cold-end temperatures, piston amplitudes and NaK flow rates; and transient test conditions to simulate various start-up and fault scenarios. Performance maps of the convertors generated using the pumped NaK loop for thermal input show increases in power output over those measured during baseline testing using electric heating. Transient testing showed that the Stirling convertors can be successfully started in a variety of different scenarios and that the convertors can recover from a variety of fault scenarios.

Thermal Control Utilizing an Thermal Control Utilizing an Two-Phase Loop with High Heat Flux Source

NASA Technical Reports Server (NTRS)

Jeong, Seong-Il; Didion, Jeffrey

2004-01-01

The electric field applied in dielectric fluids causes an imbalance in the dissociation-recombination reaction generated free space charges. The generated charges are redistributed by the applied electric field resulting in the heterocharge layers in the Vicinity of the electrodes. Proper design of the electrodes generates net axial flow motion pumping the fluid. The electrohydrodynamic (EHD) conduction pump is a new device that pumps dielectric fluids utilizing heterocharge layers formed by imposition of electrostatic fields. This paper evaluates the experimental performance of a two-phase breadboard thermal control loop consisting of an EHD conduction pump, condenser, pre-heater, high heat flux evaporator (HE), transport lines, and reservoir (accumulator). The generated pressure head and the maximum applicable heat flux are experimentally determined at various applied voltages and sink temperatures. Recovery from dryout condition by increasing the applied voltage to the pump is also demonstrated.

A microfluidic flow injection system for DNA assay with fluids driven by an on-chip integrated pump based on capillary and evaporation effects.

PubMed

Xu, Zhang-Run; Zhong, Chong-Hui; Guan, Yan-Xia; Chen, Xu-Wei; Wang, Jian-Hua; Fang, Zhao-Lun

2008-10-01

A miniaturized flow injection analysis (FIA) system integrating a micropump on a microfluidic chip based on capillary and evaporation effects was developed. The pump was made by fixing a filter paper plug with a vent tube at the channel end, it requires no peripheral equipment and provides steady flow in the microl min(-1) range for FIA operation. Valve-free sample injection was achieved at nanolitre level using an array of slotted vials. The practical applicability of the system was demonstrated by DNA assay with laser-induced fluorescence (LIF) detection. A precision of 1.6% RSD (10.0 ng microl(-1), n=15) was achieved with a sampling throughput of 76 h(-1) and sample consumption of 95 nl.

Magnetic flux pumping in 3D nonlinear magnetohydrodynamic simulations

NASA Astrophysics Data System (ADS)

Krebs, I.; Jardin, S. C.; Günter, S.; Lackner, K.; Hoelzl, M.; Strumberger, E.; Ferraro, N.

2017-10-01

A self-regulating magnetic flux pumping mechanism in tokamaks that maintains the core safety factor at q ≈1 , thus preventing sawteeth, is analyzed in nonlinear 3D magnetohydrodynamic simulations using the M3D-C1 code. In these simulations, the most important mechanism responsible for the flux pumping is that a saturated (m =1 ,n =1 ) quasi-interchange instability generates an effective negative loop voltage in the plasma center via a dynamo effect. It is shown that sawtoothing is prevented in the simulations if β is sufficiently high to provide the necessary drive for the (m =1 ,n =1 ) instability that generates the dynamo loop voltage. The necessary amount of dynamo loop voltage is determined by the tendency of the current density profile to centrally peak which, in our simulations, is controlled by the peakedness of the applied heat source profile.

Magnetic flux pumping in 3D nonlinear magnetohydrodynamic simulations

DOE PAGES

Krebs, I.; Jardin, S. C.; Gunter, S.; ...

2017-09-27

A self-regulating magnetic flux pumping mechanism in tokamaks that maintains the core safety factor at q≈1, thus preventing sawteeth, is analyzed in nonlinear 3D magnetohydrodynamic simulations using the M3D-C1 code. In these simulations, the most important mechanism responsible for the flux pumping is that a saturated (m=1,n=1) quasi-interchange instability generates an effective negative loop voltage in the plasma center via a dynamo effect. It is shown that sawtoothing is prevented in the simulations if β is sufficiently high to provide the necessary drive for the (m=1,n=1) instability that generates the dynamo loop voltage. In conclusion, the necessary amount of dynamomore » loop voltage is determined by the tendency of the current density profile to centrally peak which, in our simulations, is controlled by the peakedness of the applied heat source profile.« less

Day-and-Night Hybrid Closed-Loop Insulin Delivery in Adolescents With Type 1 Diabetes: A Free-Living, Randomized Clinical Trial.

PubMed

Tauschmann, Martin; Allen, Janet M; Wilinska, Malgorzata E; Thabit, Hood; Stewart, Zoë; Cheng, Peiyao; Kollman, Craig; Acerini, Carlo L; Dunger, David B; Hovorka, Roman

2016-07-01

To evaluate feasibility, safety, and efficacy of day-and-night hybrid closed-loop insulin delivery in adolescents with type 1 diabetes under free-living conditions without remote monitoring or supervision. In an open-label, randomized, free-living, crossover study design, 12 adolescents receiving insulin pump therapy (mean [±SD] age 15.4 ± 2.6 years; HbA1c 8.3 ± 0.9%; duration of diabetes 8.2 ± 3.4 years) underwent two 7-day periods of sensor-augmented insulin pump therapy or hybrid closed-loop insulin delivery without supervision or remote monitoring. During the closed-loop insulin delivery, a model predictive algorithm automatically directed insulin delivery between meals and overnight; prandial boluses were administered by participants using a bolus calculator. The proportion of time when the sensor glucose level was in the target range (3.9-10 mmol/L) was increased during closed-loop insulin delivery compared with sensor-augmented pump therapy (72 vs. 53%, P < 0.001; primary end point), the mean glucose concentration was lowered (8.7 vs. 10.1 mmol/L, P = 0.028), and the time spent above the target level was reduced (P = 0.005) without changing the total daily insulin amount (P = 0.55). The time spent in the hypoglycemic range was low and comparable between interventions. Unsupervised day-and-night hybrid closed-loop insulin delivery at home is feasible and safe in young people with type 1 diabetes. Compared with sensor-augmented insulin pump therapy, closed-loop insulin delivery may improve glucose control without increasing the risk of hypoglycemia in adolescents with suboptimally controlled type 1 diabetes. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Regenerative Hydride Heat Pump

NASA Technical Reports Server (NTRS)

Jones, Jack A.

1992-01-01

Hydride heat pump features regenerative heating and single circulation loop. Counterflow heat exchangers accommodate different temperatures of FeTi and LaNi4.7Al0.3 subloops. Heating scheme increases efficiency.

Switch loop flexibility affects substrate transport of the AcrB efflux pump

DOE PAGES

Muller, Reinke T.; Travers, Timothy; Cha, Hi-jea; ...

2017-10-05

The functionally important switch-loop of the trimeric multidrug transporter AcrB separates the access and deep drug binding pockets in every protomer. This loop, comprising 11 amino acid residues, has been shown to be crucial for substrate transport, as drugs have to travel past the loop to reach the deep binding pocket and from there are transported outside the cell via the connected AcrA and TolC channels. It contains four symmetrically arranged glycine residues suggesting that flexibility is a key feature for pump activity. Upon combinatorial substitution of these glycine residues to proline, functional and structural asymmetry was observed. Proline substitutionsmore » on the PC1 proximal side completely abolished transport and reduced backbone flexibility of the switch loop, which adopted a conformation restricting the pathway towards the deep binding pocket. Here, two phenylalanine residues located adjacent to the substitution sensitive glycine residues play a role in blocking the pathway upon rigidification of the loop, since the removal of the phenyl rings from the rigid loop restores drug transport activity.« less

Switch loop flexibility affects substrate transport of the AcrB efflux pump

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

Muller, Reinke T.; Travers, Timothy; Cha, Hi-jea

The functionally important switch-loop of the trimeric multidrug transporter AcrB separates the access and deep drug binding pockets in every protomer. This loop, comprising 11 amino acid residues, has been shown to be crucial for substrate transport, as drugs have to travel past the loop to reach the deep binding pocket and from there are transported outside the cell via the connected AcrA and TolC channels. It contains four symmetrically arranged glycine residues suggesting that flexibility is a key feature for pump activity. Upon combinatorial substitution of these glycine residues to proline, functional and structural asymmetry was observed. Proline substitutionsmore » on the PC1 proximal side completely abolished transport and reduced backbone flexibility of the switch loop, which adopted a conformation restricting the pathway towards the deep binding pocket. Here, two phenylalanine residues located adjacent to the substitution sensitive glycine residues play a role in blocking the pathway upon rigidification of the loop, since the removal of the phenyl rings from the rigid loop restores drug transport activity.« less

CRBR pump water test experience

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

Cook, M.E.; Huber, K.A.

1983-01-01

The hydraulic design features and water testing of the hydraulic scale model and prototype pump of the sodium pumps used in the primary and intermediate sodium loops of the Clinch River Breeder Reactor Plant (CRBRP) are described. The Hydraulic Scale Model tests are performed and the results of these tests are discussed. The Prototype Pump tests are performed and the results of these tests are discussed.

A Selected Operational History of the Internal Thermal Control System (ITCS) for International Space Station (ISS)

NASA Technical Reports Server (NTRS)

Patel, Vipul P.; Winton, Dale; Ibarra, Thomas H.

2004-01-01

The Internal Thermal Control System (ITCS) has been developed jointly by Boeing Corporation, Huntsville, Alabama and Honeywell Engines & Systems, Torrance, California to meet the internal thermal control needs for the International Space Station (ISS). The ITCS provides heat removal for the critical life support systems and thermal conditioning for numerous experiment racks. The ITCS will be fitted on a number of modules on the ISS. The first US Element containing the ITCS, Node 1, was launched in December 1998. Since Node 1 does not contain a pump to circulate the fluid it was not filled with ITCS fluid until after the US Laboratory Module was installed. The second US Element module, US Laboratory Module, which contains the pumps and all the major ITCS control hardware, was launched in February 2001. The third US Element containing the ITCS, the US Airlock, was launched in July 2001. The dual loop system of the ITCS is comprised of a lowtemperature loop (LTL) and a moderate-temperature loop (MTL). Each loop has a pump package assembly (PPA), a system flow control assembly (SFCA), a threeway mixing valve (TWMV), several rack flow control assemblies (RFCA), cold plates, pressure sensors, temperature sensors, pump bypass assembly (PBA) and a heat exchanger. In addition, the MTL has an additional TWMV, a payload regeneration heat exchanger (P/RHE) and a manual flow control valve (MFCV). The LTL has a service performance and checkout unit (SPCU) heat exchanger. The two loops are linked via one loop crossover assembly (LCA) providing cross loop capabilities and a single PPA, two-loop functionality. One important parameter monitored by the ground stations and on-orbit is the amount of fluid leakage from the ITCS. ISS fluid leakage is of importance since ITCS fluid is costly to re-supply, may be difficult to clean up in zero-g, and if uncontained could lead to equipment failures and potential hazards. This paper examines the nominal leakage observed over period of a year of on-orbit operation and compares this with analysis predictions. This paper also addresses the off-nominal leakage and a fluid transfer event causing significant changes in accumulator quantity.

Assessing performance of closed-loop insulin delivery systems by continuous glucose monitoring: drawbacks and way forward.

PubMed

Hovorka, Roman; Nodale, Marianna; Haidar, Ahmad; Wilinska, Malgorzata E

2013-01-01

We investigated whether continuous glucose monitoring (CGM) levels can accurately assess glycemic control while directing closed-loop insulin delivery. Data were analyzed retrospectively from 33 subjects with type 1 diabetes who underwent closed-loop and conventional pump therapy on two separate nights. Glycemic control was evaluated by reference plasma glucose and contrasted against three methods based on Navigator (Abbott Diabetes Care, Alameda, CA) CGM levels. Glucose mean and variability were estimated by unmodified CGM levels with acceptable clinical accuracy. Time when glucose was in target range was overestimated by CGM during closed-loop nights (CGM vs. plasma glucose median [interquartile range], 86% [65-97%] vs. 75% [59-91%]; P=0.04) but not during conventional pump therapy (57% [32-72%] vs. 51% [29-68%]; P=0.82) providing comparable treatment effect (mean [SD], 28% [29%] vs. 23% [21%]; P=0.11). Using the CGM measurement error of 15% derived from plasma glucose-CGM pairs (n=4,254), stochastic interpretation of CGM gave unbiased estimate of time in target during both closed-loop (79% [62-86%] vs. 75% [59-91%]; P=0.24) and conventional pump therapy (54% [33-66%] vs. 51% [29-68%]; P=0.44). Treatment effect (23% [24%] vs. 23% [21%]; P=0.96) and time below target were accurately estimated by stochastic CGM. Recalibrating CGM using reference plasma glucose values taken at the start and end of overnight closed-loop was not superior to stochastic CGM. CGM is acceptable to estimate glucose mean and variability, but without adjustment it may overestimate benefit of closed-loop. Stochastic CGM provided unbiased estimate of time when glucose is in target and below target and may be acceptable for assessment of closed-loop in the outpatient setting.

Advanced Hybrid Cooling Loop Technology for High Performance Thermal Management

DTIC Science & Technology

2006-06-01

and Chung, 2003; Estes and Mudawar , 1995]. Because of the pumping pressure and flow rate requirements, such pumped systems require large pumping and...United States, April 24-25, 2003. 8. Estes, K. and Mudawar , I., “Comparison of Two-Phase Electronic Cooling Using Free Jets and Sprays”, Journal of

Pleural pressure theory revisited: a role for capillary equilibrium.

PubMed

Casha, Aaron R; Caruana-Gauci, Roberto; Manche, Alexander; Gauci, Marilyn; Chetcuti, Stanley; Bertolaccini, Luca; Scarci, Marco

2017-04-01

Theories elucidating pleural pressures should explain all observations including the equal and opposite recoil of the chest wall and lungs, the less than expected pleural hydrostatic gradient and its variation at lobar margins, why pleural pressures are negative and how pleural fluid circulation functions. A theoretical model describing equilibrium between buoyancy, hydrostatic forces, and capillary forces is proposed. The capillary equilibrium model described depends on control of pleural fluid volume and protein content, powered by an active pleural pump. The interaction between buoyancy forces, hydrostatic pressure and capillary pressure was calculated, and values for pleural thickness and pressure were determined using values for surface tension, contact angle, pleural fluid and lung densities found in the literature. Modelling can explain the issue of the differing hydrostatic vertical pleural pressure gradient at the lobar margins for buoyancy forces between the pleural fluid and the lung floating in the pleural fluid according to Archimedes' hydrostatic paradox. The capillary equilibrium model satisfies all salient requirements for a pleural pressure model, with negative pressures maximal at the apex, equal and opposite forces in the lung and chest wall, and circulatory pump action. This model predicts that pleural effusions cannot occur in emphysema unless concomitant heart failure increases lung density. This model also explains how the non-confluence of the lung with the chest wall (e.g., lobar margins) makes the pleural pressure more negative, and why pleural pressures would be higher after an upper lobectomy compared to a lower lobectomy. Pathological changes in pleural fluid composition and lung density alter the equilibrium between capillarity and buoyancy hydrostatic pressure to promote pleural effusion formation.

Flash water-window x-ray generator with a ferrite capillary

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Sagae, Michiaki; Ichimaru, Toshio; Takayama, Kazuyoshi; Sakamaki, Kimio; Tamakawa, Yoshiharu

1997-12-01

The fundamental study on a flash water-window x-ray generator is described. This generator is composed of a high-voltage power supply, a polarity-inversion high-voltage pulser, a krytron pulser as a trigger device, an oil-diffusion pump, and a vacuum chamber with a capillary. A combined ceramic condenser of about 5 nF in the pulser is charged up to 70 kV by the power supply, and the electric charges in the condenser are discharged to the capillary in the tube after closing a gap switch by the krytron pulser. In the present work, the chamber is evacuated by the pump with a pressure of about 1 by 10-3 Pa, and the titanium anode and cathode electrodes are employed to produce L-series characteristic x rays in the water-window range. The diameter and the length of the ferrite capillary are 2.0 and 30 mm, respectively. Both the cathode voltage and the discharge current displayed damped oscillations. The peak values of the voltage and current increased when the charging voltage was increased, and their maximum values were minus 24 kV and 2.8 kA, respectively. The pulse durations of the water-window x-rays were nearly equivalent to those of the damped oscillations of the voltage and current, and their values were less than 10 microseconds.

Mechanically Pumped Fluid Loop (MPFL) Technologies for Thermal Control of Future Mars Rovers

NASA Technical Reports Server (NTRS)

Birur, Gaj; Bhandari, Pradeep; Prina, Mauro; Bame, Dave; Yavrouian, Andre; Plett, Gary

2006-01-01

Mechanically pumped fluid loop has been the basis of thermal control architecture for the last two Mars lander and rover missions and is the key part of the MSL thermal architecture. Several MPFL technologies are being developed for the MSL rover include long-life pumps, thermal control valves, mechanical fittings for use with CFC-11 at elevated temperatures of approx.100 C. Over three years of life tests and chemical compatibility tests on these MPFL components show that MPFL technology is mature for use on MSL. The advances in MPFL technologies for MSL Rover will benefit any future MPFL applications on NASA s Moon, Mars and Beyond Program.

Comprehensive and Critical Literature Review on Insitu Micro-Sensors for Application in Tribology

DTIC Science & Technology

1994-04-01

Electroosmotic flow provides a pumping method that is convenient for small capillaries. Electrophoretic separation is shown to be useful. On the left hand...analysis systems on glass chips (1 centimeter by 2 centimeters or larger) that utilize electroosmotic pumping to drive fluid flow and electrophoretic...elucidate the interaction mechanism. Additionally, using two types of sensors in a mixed array increases selectivity by providing different information

Building America Case Study: Simplified Air Distribution, Desuperheaters, and Sub-Slab Geothermal Heat Exchangers, Pittsburgh, Pennsylvania

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

This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab.

Closed-loop helium circulation system for actuation of a continuously operating heart catheter pump.

PubMed

Karabegovic, Alen; Hinteregger, Markus; Janeczek, Christoph; Mohl, Werner; Gföhler, Margit

2017-06-09

Currently available, pneumatic-based medical devices are operated using closed-loop pulsatile or open continuous systems. Medical devices utilizing gases with a low atomic number in a continuous closed loop stream have not been documented to date. This work presents the construction of a portable helium circulation addressing the need for actuating a novel, pneumatically operated catheter pump. The design of its control system puts emphasis on the performance, safety and low running cost of the catheter pump. Static and dynamic characteristics of individual elements in the circulation are analyzed to ensure a proper operation of the system. The pneumatic circulation maximizes the working range of the drive unit inside the catheter pump while reducing the total size and noise production.Separate flow and pressure controllers position the turbine's working point into the stable region of the pressure creation element. A subsystem for rapid gas evacuation significantly decreases the duration of helium removal after a leak, reaching subatmospheric pressure in the intracorporeal catheter within several milliseconds. The system presented in the study offers an easy control of helium mass flow while ensuring stable behavior of its internal components.

60. BOILER CHAMBER No. 1, D LOOP STEAM GENERATOR AND ...

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

60. BOILER CHAMBER No. 1, D LOOP STEAM GENERATOR AND MAIN COOLANT PUMP LOOKING NORTHEAST (LOCATION OOO) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

NASA Advanced Radiator Technology Development

NASA Astrophysics Data System (ADS)

Koester, J. Kent; Juhasz, Albert J.

1994-07-01

A practical implementation of the two-phase working fluid of lithium and NaK has been developed experimentally for pumped loop radiator designs. The benefits of the high heat capacity and low mass of lithium have been integrated with the shutdown capability enabled by the low freezing temperature of NaK by mixing these liquid metals directly. The stable and reliable start up and shutdown of a lithium/NaK pumped loop has been demonstrated through the development of a novel lithium freeze-separation technique within the flowing header ducts. The results of a highly instrumented liquid metal test loop are presented in which both lithium fraction as well as loop gravitational effects were varied over a wide range of values. Diagnostics based on dual electric probes are presented in which the convective behavior of the lithium component is directly measured during loop operation. The uniform distribution of the lithium after a freeze separation is verified by neutron radiography. The operating regime for reliable freeze/thaw flow behavior is described in terms of correlations based on dimensional analysis.

Photothermal trace detection in capillary electrophoresis for biomedical diagnostics and toxic materials (invited)

NASA Astrophysics Data System (ADS)

Faubel, Werner; Heissler, Stefan; Pyell, Ute; Ragozina, Natalia

2003-01-01

Two applications of a near-field thermal lens capillary electrophoresis detector in the deep ultraviolet region (pump beam 257 nm wavelength) will be presented: (1) Capillary electrophoretic determination of the pharmaceuticals Tramadol, Verapamil, and Papaverin. Direct separation techniques were used for the different classes of substances with characteristic absorbance spectra. The combination of capillary electrophoresis and the highly sensitive detection with thermal lens spectroscopy permits the analysis of nanoliter volume samples common in biomedical diagnostics without any preconcentration step. (2) The determination of (nonfluorescent) nitro aromatic explosives in contaminated soil. These compounds are detected with the laboratory built thermal lens detector after their separation by micellar electrokinetic chromatography. Its shown that this type of detection makes it possible to obtain limits of detection 1-2 orders of magnitude lower than those obtained with classical absorption spectrometric detection.

Power flow control based solely on slow feedback loop for heart pump applications.

PubMed

Wang, Bob; Hu, Aiguo Patrick; Budgett, David

2012-06-01

This paper proposes a new control method for regulating power flow via transcutaneous energy transfer (TET) for implantable heart pumps. Previous work on power flow controller requires a fast feedback loop that needs additional switching devices and resonant capacitors to be added to the primary converter. The proposed power flow controller eliminates these additional components, and it relies solely on a slow feedback loop to directly drive the primary converter to meet the heart pump power demand and ensure zero voltage switching. A controlled change in switching frequency varies the resonant tank shorting period of a current-fed push-pull resonant converter, thus changing the magnitude of the primary resonant voltage, as well as the tuning between primary and secondary resonant tanks. The proposed controller has been implemented successfully using an analogue circuit and has reached an end-to-end power efficiency of 79.6% at 10 W with a switching frequency regulation range of 149.3 kHz to 182.2 kHz.

Insulin Patch Pumps: Their Development and Future in Closed-Loop Systems

PubMed Central

Bohannon, Nancy J.V.

2010-01-01

Abstract Steady progress is being made toward the development of a so-called “artificial pancreas,” which may ultimately be a fully automated, closed-loop, glucose control system comprising a continuous glucose monitor, an insulin pump, and a controller. The controller will use individualized algorithms to direct delivery of insulin without user input. A major factor propelling artificial pancreas development is the substantial incidence of—and attendant patient, parental, and physician concerns about—hypoglycemia and extreme hyperglycemia associated with current means of insulin delivery for type 1 diabetes mellitus (T1DM). A successful fully automated artificial pancreas would likely reduce the frequency of and anxiety about hypoglycemia and marked hyperglycemia. Patch-pump systems (“patch pumps”) are likely to be used increasingly in the control of T1DM and may be incorporated into the artificial pancreas systems of tomorrow. Patch pumps are free of tubing, small, lightweight, and unobtrusive. This article describes features of patch pumps that have been approved for U.S. marketing or are under development. Included in the review is an introduction to control algorithms driving insulin delivery, particularly the two major types: proportional integrative derivative and model predictive control. The use of advanced algorithms in the clinical development of closed-loop systems is reviewed along with projected next steps in artificial pancreas development. PMID:20515308

Fluid mechanics of electroosmotic flow and its effect on band broadening in capillary electrophoresis.

PubMed

Ghosal, Sandip

2004-01-01

Electroosmotic flow (EOF) usually accompanies electrophoretic migration of charged species in capillary electrophoresis unless special precautions are taken to suppress it. The presence of the EOF provides certain advantages in separations. It is an alternative to mechanical pumps, which are inefficient and difficult to build at small scales, for transporting reagents and analytes on microfluidic chips. The downside is that any imperfection that distorts the EOF profile reduces the separation efficiency. In this paper, the basic facts about EOF are reviewed from the perspective of fluid mechanics and its effect on separations in free solution capillary zone electrophoresis is discussed in the light of recent advances.

In-air PIXE analysis by means of glass capillary optics

NASA Astrophysics Data System (ADS)

Nebiki, Takuya; Kabir, M. Hasnat; Narusawa, Tadashi

2006-08-01

A novel technique to introduce high energy ion beams to atmospheric environment is presented, which enables in-air PIXE measurements. Slightly tapered glass capillary optics is applied to work as a differential pumping orifice as well as a focusing lens. The flux intensity is enhanced by at least one order of magnitude due to the focusing effect. Using capillaries of 10-20 μm outlet diameters, we obtain several hundreds pA of 4 MeV He2+ ion beam and apply it to PIXE analysis of the seabed sludge without any sample treatments. A comparison of spectra between wet and dry sludge samples suggests the usefulness of our new technique.

Anatomical evaluation of oral microcirculation: capillary characteristics associated with sex or age group.

PubMed

Scardina, Giuseppe Alessandro; Giuseppe Alessandro, Scardina; Cacioppo, Antonino; Antonino, Cacioppo; Messina, Pietro

2009-10-01

There are various types of oral mucosa specific to different parts of the mouth and each of these has a unique histological structure. The variations in the epithelial structure are consistently related to observable differences in the underlying microcirculation: i.e. differences in the course, conformation, and density of capillaries. The aim of this research has been to investigate oral microcirculatory differences between men and women as well as between various age groups, in order to map the oral mucosa, and to highlight changes occurring during aging. A total of 45 healthy subjects were enrolled for this study (12 men and 33 women; mean age 60.37; range 30-82). A complete in-vivo videocapillaroscopic mapping of the oral mucosa was done on each subject. The capillaroscopic patterns of the various areas differ particularly in the course of the loops in relation to the mucosal surface. On the basis of statistical analysis of the collected data, it emerges that there are many differences in capillary loop density between men and women and between different age groups. This study demonstrates the necessity of approaching the investigation of patient microcirculation in different ways depending on sex or age.

On-line DNA analysis system with rapid thermal cycling

DOEpatents

Swerdlow, Harold P.; Wittwer, Carl T.

1999-01-01

An apparatus particularly suited for subjecting biological samples to any necessary sample preparation tasks, subjecting the sample to rapid thermal cycling, and then subjecting the sample to subsequent on-line analysis using one or more of a number of analytical techniques. The apparatus includes a chromatography device including an injection means, a chromatography pump, and a chromatography column. In addition, the apparatus also contains a capillary electrophoresis device consisting of a capillary electrophoresis column with an inlet and outlet end, a means of injection, and means of applying a high voltage to cause the differential migration of species of interest through the capillary column. Effluent from the liquid chromatography column passes over the inlet end of the capillary electrophoresis column through a tee structure and when the loading of the capillary electrophoresis column is desired, a voltage supply is activated at a precise voltage and polarity over a specific duration to cause sample species to be diverted from the flowing stream to the capillary electrophoresis column. A laser induced fluorescence detector preferably is used to analyze the products separated while in the electrophoresis column.

On-line DNA analysis system with rapid thermal cycling

DOEpatents

Swerdlow, H.P.; Wittwer, C.T.

1999-08-10

This application describes an apparatus particularly suited for subjecting biological samples to any necessary sample preparation tasks, subjecting the sample to rapid thermal cycling, and then subjecting the sample to subsequent on-line analysis using one or more of a number of analytical techniques. The apparatus includes a chromatography device including an injection means, a chromatography pump, and a chromatography column. In addition, the apparatus also contains a capillary electrophoresis device consisting of a capillary electrophoresis column with an inlet and outlet end, a means of injection, and means of applying a high voltage to cause the differential migration of species of interest through the capillary column. Effluent from the liquid chromatography column passes over the inlet end of the capillary electrophoresis column through a tee structure and when the loading of the capillary electrophoresis column is desired, a voltage supply is activated at a precise voltage and polarity over a specific duration to cause sample species to be diverted from the flowing stream to the capillary electrophoresis column. A laser induced fluorescence detector preferably is used to analyze the products separated while in the electrophoresis column. 6 figs.

Flow Components in a NaK Test Loop Designed to Simulate Conditions in a Nuclear Surface Power Reactor

NASA Astrophysics Data System (ADS)

Polzin, Kurt A.; Godfroy, Thomas J.

2008-01-01

A test loop using NaK as the working fluid is presently in use to study material compatibility effects on various components that comprise a possible nuclear reactor design for use on the lunar surface. A DC electromagnetic (EM) pump has been designed and implemented as a means of actively controlling the NaK flow rate through the system and an EM flow sensor is employed to monitor the developed flow rate. These components allow for the matching of the flow rate conditions in test loops with those that would be found in a full-scale surface-power reactor. The design and operating characteristics of the EM pump and flow sensor are presented. In the EM pump, current is applied to a set of electrodes to produce a Lorentz body force in the fluid. A measurement of the induced voltage (back-EMF) in the flow sensor provides the means of monitoring flow rate. Both components are compact, employing high magnetic field strength neodymium magnets thermally coupled to a water-cooled housing. A vacuum gap limits the heat transferred from the high temperature NaK tube to the magnets and a magnetically-permeable material completes the magnetic circuit. The pump is designed to produce a pressure rise of 34.5 kPa, and the flow sensor's predicted output is roughly 20 mV at the loop's nominal flow rate of 0.114 m3/hr.

Flow Components in a NaK Test Loop Designed to Simulate Conditions in a Nuclear Surface Power Reactor

NASA Technical Reports Server (NTRS)

Polzin, Kurt A.; Godfroy, Thomas J.

2008-01-01

A test loop using NaK as the working fluid is presently in use to study material compatibility effects on various components that comprise a possible nuclear reactor design for use on the lunar surface. A DC electromagnetic (EM) pump has been designed and implemented as a means of actively controlling the NaK flow rate through the system and an EM flow sensor is employed to monitor the developed flow rate. These components allow for the matching of the flow rate conditions in test loops with those that would be found in a full-scale surface-power reactor. The design and operating characteristics of the EM pump and flow sensor are presented. In the EM pump, current is applied to a set of electrodes to produce a Lorentz body force in the fluid. A measurement of the induced voltage (back-EMF) in the flow sensor provides the means of monitoring flow rate. Both components are compact, employing high magnetic field strength neodymium magnets thermally coupled to a water-cooled housing. A vacuum gap limits the heat transferred from the high temperature NaK tube to the magnets and a magnetically-permeable material completes the magnetic circuit. The pump is designed to produce a pressure rise of 5 psi, and the flow sensor's predicted output is roughly 20 mV at the loop's nominal flow rate of 0.5 GPM.

Design of Test Loops for Forced Convection Heat Transfer Studies at Supercritical State

NASA Astrophysics Data System (ADS)

Balouch, Masih N.

Worldwide research is being conducted to improve the efficiency of nuclear power plants by using supercritical water (SCW) as the working fluid. One such SCW reactor considered for future development is the CANDU-Supercritical Water Reactor (CANDU-SCWR). For safe and accurate design of the CANDU-SCWR, a detailed knowledge of forced-convection heat transfer in SCW is required. For this purpose, two supercritical fluid loops, i.e. a SCW loop and an R-134a loop are developed at Carleton University. The SCW loop is designed to operate at pressures as high as 28 MPa, temperatures up to 600 °C and mass fluxes of up to 3000 kg/m2s. The R-134a loop is designed to operate at pressures as high as 6 MPa, temperatures up to 140 °C and mass fluxes in the range of 500-6000 kg/m2s. The test loops designs allow for up to 300 kW of heating power to be imparted to the fluid. Both test loops are of the closed-loop design, where flow circulation is achieved by a centrifugal pump in the SCW loop and three parallel-connected gear pumps in the R-134a loop, respectively. The test loops are pressurized using a high-pressure nitrogen cylinder and accumulator assembly, which allows independent control of the pressure, while simultaneously dampening pump induced pressure fluctuations. Heat exchangers located upstream of the pumps control the fluid temperature in the test loops. Strategically located measuring instrumentation provides information on the flow rate, pressure and temperature in the test loops. The test loops have been designed to accommodate a variety of test-section geometries, ranging from a straight circular tube to a seven-rod bundle, achieving heat fluxes up to 2.5 MW/m2 depending on the test-section geometry. The design of both test loops allows for easy reconfiguration of the test-section orientation relative to the gravitational direction. All the test sections are of the directly-heated design, where electric current passing through the pressure retaining walls of the test sections provides the Joule heating required to heat up the fluid to supercritical conditions. A high-temperature dielectric gasket isolates the current carrying parts of the test section from the rest of the assembly. Temperature and pressure drop data are collected at the inlet and outlet, and along the heated length of the test section. The test loops and test sections are designed according to American Society of Mechanical Engineers (ASME) Pressure Piping B31.1, and Boiler and Pressure Vessel Code, Section VIII-Division 1 rules. The final test loops and test sections assemblies are certified by Technical Standards and Safety Authority (TSSA). Every attempt is made to use off-the-shelf components where possible in order to streamline the design process and reduce costs. Following a rigorous selection process, stainless steel Types 316 and 316H are selected as the construction materials for the test loops, and Inconel 625 is selected as the construction material for the test sections. This thesis describes the design of the SCW and R-134a loops along with the three test-section geometries (i.e., tubular, annular and bundle designs).

Low-temperature thermal control for a lunar base

NASA Technical Reports Server (NTRS)

Swanson, Theodore D.; Radermacher, Reinhard; Costello, Frederick A.; Moore, James S., Jr.; Mengers, David R.

1990-01-01

The generic problem of rejecting low- to moderate-temperature heat from space facilities located in a hot thermal sink environment is studied, and the example of a lunar base located near the equator is described. The effective thermal sink temperature is often above or near nominal room temperature. A three heat pump assisted thermal bus concept appears to be the most viable as they are the least sensitive to environmental conditions. Weight estimates are also developed for each of the five thermal control concepts studied: (1) 149kg/kW for a central thermal loop with unitary heat pumps; (2) 133 kg/kW for a conventional bus connected to large, central heat pumps at the radiator; (3) 134 kg/kW for a central, dual loop heat pump concept; (4) 95 kg/kW for the selective field-of-view radiator; and (5) 126 kg/kW for the regolith concept.

Anthropomorphic cardiac ultrasound phantom.

PubMed

Smith, S W; Rinaldi, J E

1989-10-01

A new phantom is described which simulates the human cardiac anatomy for applications in ultrasound imaging, ultrasound Doppler, and color-flow Doppler imaging. The phantom consists of a polymer left ventricle which includes a prosthetic mitral and aortic valve and is connected to a mock circulatory loop. Aerated tap water serves as a blood simulating fluid and ultrasound contrast medium within the circulatory loop. The left ventricle is housed in a Lexan ultrasound visualization chamber which includes ultrasound viewing ports and acoustic absorbers. A piston pump connected to the visualization chamber by a single port pumps degassed water within the chamber which in turn pumps the left ventricle. Real-time ultrasound images and Doppler studies measure flow patterns through the valves and within the left ventricle.

Pleural pressure theory revisited: a role for capillary equilibrium

PubMed Central

Caruana-Gauci, Roberto; Manche, Alexander; Gauci, Marilyn; Chetcuti, Stanley; Bertolaccini, Luca

2017-01-01

Background Theories elucidating pleural pressures should explain all observations including the equal and opposite recoil of the chest wall and lungs, the less than expected pleural hydrostatic gradient and its variation at lobar margins, why pleural pressures are negative and how pleural fluid circulation functions. Methods A theoretical model describing equilibrium between buoyancy, hydrostatic forces, and capillary forces is proposed. The capillary equilibrium model described depends on control of pleural fluid volume and protein content, powered by an active pleural pump. Results The interaction between buoyancy forces, hydrostatic pressure and capillary pressure was calculated, and values for pleural thickness and pressure were determined using values for surface tension, contact angle, pleural fluid and lung densities found in the literature. Modelling can explain the issue of the differing hydrostatic vertical pleural pressure gradient at the lobar margins for buoyancy forces between the pleural fluid and the lung floating in the pleural fluid according to Archimedes’ hydrostatic paradox. The capillary equilibrium model satisfies all salient requirements for a pleural pressure model, with negative pressures maximal at the apex, equal and opposite forces in the lung and chest wall, and circulatory pump action. Conclusions This model predicts that pleural effusions cannot occur in emphysema unless concomitant heart failure increases lung density. This model also explains how the non-confluence of the lung with the chest wall (e.g., lobar margins) makes the pleural pressure more negative, and why pleural pressures would be higher after an upper lobectomy compared to a lower lobectomy. Pathological changes in pleural fluid composition and lung density alter the equilibrium between capillarity and buoyancy hydrostatic pressure to promote pleural effusion formation. PMID:28523153

Chimeric Proton-Pumping Rhodopsins Containing the Cytoplasmic Loop of Bovine Rhodopsin

PubMed Central

Sasaki, Kengo; Yamashita, Takahiro; Yoshida, Kazuho; Inoue, Keiichi; Shichida, Yoshinori; Kandori, Hideki

2014-01-01

G-protein-coupled receptors (GPCRs) transmit stimuli to intracellular signaling systems. Rhodopsin (Rh), which is a prototypical GPCR, possesses an 11-cis retinal. Photoisomerization of 11-cis to all-trans leads to structural changes in the protein of cytoplasmic loops, activating G-protein. Microbial rhodopsins are similar heptahelical membrane proteins that function as bacterial sensors, light-driven ion-pumps, or light-gated channels. They possess an all-trans retinal, and photoisomerization to 13-cis triggers structural changes in protein. Despite these similarities, there is no sequence homology between visual and microbial rhodopsins, and microbial rhodopsins do not activate G-proteins. In this study, new chimeric proton-pumping rhodopsins, proteorhodopsin (PR) and Gloeobacter rhodopsin (GR) were designed by replacing cytoplasmic loops with bovine Rh loops. Although G-protein was not activated by the PR chimeras, all 12 GR chimeras activated G-protein. The GR chimera containing the second cytoplasmic loop of bovine Rh did not activate G-protein. However, the chimera with a second and third double-loop further enhanced G-protein activation. Introduction of an E132Q mutation slowed the photocycle 30-fold and enhanced activation. The highest catalytic activity of the GR chimera was still 3,200 times lower than bovine Rh but only 64 times lower than amphioxus Go-rhodopsin. This GR chimera showed a strong absorption change of the amide-I band on a light-minus-dark difference FTIR spectrum which could represent a larger helical opening, important for G-protein activation. The light-dependent catalytic activity of this GR chimera makes it a potential optogenetic tool for enzymatic activation by light. PMID:24621599

Internal hydraulic loss in a seal-less centrifugal Gyro pump.

PubMed

Makinouchi, K; Ohara, Y; Sakuma, I; Damm, G; Mizuguchi, K; Jikuya, T; Takatani, S; Noon, G P; Nosé, Y

1994-01-01

A new index "loss factor Z" defined by Eq. 1 was introduced as the absolute expression of the mock loop resistance for testing a nonpulsatile pump. [formula: see text] where gamma is specific gravity of the fluid, g is the acceleration of gravity, delta P is total pressure head, and Q is flow. Z is expected to be constant, regardless of the pumping parameters. Z values obtained in the same mock loop but with different rotary blood pumps were almost identical and were defined as Z0. New methods of analysis of the flow-restrictive conditions of various rotary blood pumps are proposed in this paper: namely, differential loss factor delta Z, and loss factor sensitivity delta Z/delta A. The proposed Z-Q curves demonstrated better performance mapping than the conventional delta P-Q curves. Delta Z is the difference between the Z-Q curves of two different pumps. A is a design parameter of the pump; therefore delta Z/delta A is a quantitative expression of the effect of the design change on the hydraulic performance. These various indices were used to analyze the internal hydraulic loss of a centrifugal pump (Gyro pump). The relationship between its gap size (rotor casing) and hydraulic performance was assessed quantitatively by these indices. In this paper, the derivation processes and above-mentioned indices are described.

Effect of Variable Gravity on Evaporation of Binary Fluids in a Capillary Pore Evaporator

NASA Technical Reports Server (NTRS)

Girgis, Morris M.; Matta, Nabil S.; Kolli, Kiran; Brown, Leon; Bain, James, Jr.; McGown, Juantonio

1996-01-01

The research project focuses on experimental investigation of the capillary-pumped evaporative heat transfer phenomenon. The objective is to examine whether the heat transfer and stability of a heated meniscus in a capillary pore can be enhanced by adding trace amounts of a non-volatile solute to a solvent and to understand the changes that occur. The experimental setup consists of a single pore evaporator connected to a reservoir which supplies liquid to the evaporator. In addition to the experiments of capillary-pumped evaporation, a parallel experimental study has been conducted to systematically investigate the effects of gravity as well as the effects of bulk composition on the heat transfer characteristics of evaporating binary thin films near the contact line region along an inclined heated surface. To investigate the buoyancy effects on evaporation along an inclined heated surface, the angle of inclination from a horizontal plane was varied fro 15 C to 90 C. An optimum concentration between 0.5% and 1% decane in pentane/decane solutions has been demonstrated at different angles of inclination. Improved heat transfer was found for the geometry with the smallest angle of inclination of 15 degrees. In addition, flow visualization has revealed that at low inclination angles effective heat transfer takes place primarily due to an extension of the thin film near the contact line. At these low inclination angles, the optimum concentration is associated with enhanced wetting characteristics and reduced thermocapillary stresses along the interface.

Advancement of atmospheric-vacuum interfaces for mass spectrometers with a focus on increasing gas throughput for improving sensitivity.

PubMed

Prasad, Satendra; Wouters, Eloy R; Dunyach, Jean-Jacques

2015-08-18

Ion sampling from an electrospray ionization (ESI) source was improved by increasing gas conductance of the MS inlet by 4.3-fold. Converting the gas throughput (Q) into sensitivity improvement was dependent on ion desolvation and handling of the gas load. Desolvation was addressed by using a novel slot shaped inlet that exhibited desolvation properties identical to the 0.58 mm i.d capillary. An assay tailored for "small molecules" at high chromatographic flow rate (500 μL/min) yielded a compound dependent 6.5 to 14-fold signal gain while analysis at nano chromatographic flow rate (300 nL/min) showed 2 to 3.5-fold improvement for doubly charged peptides. Improvement exceeding the Q (4.3-fold) at high chromatographic flow rate was explained by superior sampling of the spatially dispersed ion spray when using the slot shaped capillary. Sensitivity improvement across a wide range of chromatographic flow rate confirmed no compromise in ion desolvation with the increase in Q. Another improvement included less overflow of gas into the mass analyzer from the foreline region owing to the slot shape of the capillary. By doubling the roughing pump capacity and operating the electrodynamic ion funnel (EDIF) at ∼4 Torr, a single pumping stage was sufficient to handle the gas load. The transport of solvent clusters from the LC effluent into the mass analyzer was prevented by a "wavy shaped" transfer quadrupole and was compared with a benchmark approach that delivered ions orthogonally into a differentially pumped dual EDIF at comparable gas Q.

On-line capillary electrophoresis/laser-induced fluorescence/mass spectrometry analysis of glycans labeled with Teal™ fluorescent dye using an electrokinetic sheath liquid pump-based nanospray ion source.

PubMed

Khan, Shaheer; Liu, Jenkuei; Szabo, Zoltan; Kunnummal, Baburaj; Han, Xiaorui; Ouyang, Yilan; Linhardt, Robert J; Xia, Qiangwei

2018-06-15

N-linked glycan analysis of recombinant therapeutic proteins, such as monoclonal antibodies, Fc-fusion proteins, and antibody-drug conjugates, provides valuable information regarding protein therapeutics glycosylation profile. Both qualitative identification and quantitative analysis of N-linked glycans on recombinant therapeutic proteins are critical analytical tasks in the biopharma industry during the development of a biotherapeutic. Currently, such analyses are mainly carried out using capillary electrophoresis/laser-induced fluorescence (CE/LIF), liquid chromatography/fluorescence (LC/FLR), and liquid chromatography/fluorescence/mass spectrometry (LC/FLR/MS) technologies. N-linked glycans are first released from glycoproteins by enzymatic digestion, then labeled with fluorescence dyes for subsequent CE or LC separation, and LIF or MS detection. Here we present an on-line CE/LIF/MS N-glycan analysis workflow that incorporates the fluorescent Teal™ dye and an electrokinetic pump-based nanospray sheath liquid capillary electrophoresis/mass spectrometry (CE/MS) ion source. Electrophoresis running buffer systems using ammonium acetate and ammonium hydroxide were developed for the negative ion mode CE/MS analysis of fluorescence-labeled N-linked glycans. Results show that on-line CE/LIF/MS analysis can be readily achieved using this versatile CE/MS ion source on common CE/MS instrument platforms. This on-line CE/LIF/MS method using Teal™ fluorescent dye and electrokinetic pump-based nanospray sheath liquid CE/MS coupling technology holds promise for on-line quantitation and identification of N-linked glycans on recombinant therapeutic proteins. Copyright © 2018 John Wiley & Sons, Ltd.

Functionalized core-shell hydrogel microsprings by anisotropic gelation with bevel-tip capillary

PubMed Central

Yoshida, Koki; Onoe, Hiroaki

2017-01-01

This study describes a novel microfluidic-based method for the synthesis of hydrogel microsprings that are capable of encapsulating various functional materials. A continuous flow of alginate pre-gel solution can spontaneously form a hydrogel microspring by anisotropic gelation around the bevel-tip of the capillary. This technique allows fabrication of hydrogel microsprings using only simple capillaries and syringe pumps, while their complex compartmentalization characterized by a laminar flow inside the capillary can contribute to the optimization of the microspring internal structure and functionality. Encapsulation of several functional materials including magnetic-responsive nanoparticles or cell dispersed collagen for tissue scaffold was demonstrated to functionalize the microsprings. Our core-shell hydrogel microsprings have immense potential for application in a number of fields, including biological/chemical microsensors, biocompatible soft robots/microactuators, drug release, self-assembly of 3D structures and tissue engineering. PMID:28378803

Fission Surface Power Technology Demonstration Unit Test Results

NASA Technical Reports Server (NTRS)

Briggs, Maxwell H.; Gibson, Marc A.; Geng, Steven M.; Sanzi, James L.

2016-01-01

The Fission Surface Power (FSP) Technology Demonstration Unit (TDU) is a system-level demonstration of fission power technology intended for use on manned missions to Mars. The Baseline FSP systems consists of a 190 kWt UO2 fast-spectrum reactor cooled by a primary pumped liquid metal loop. This liquid metal loop transfers heat to two intermediate liquid metal loops designed to isolate fission products in the primary loop from the balance of plant. The intermediate liquid metal loops transfer heat to four Stirling Power Conversion Units (PCU), each of which produce 12 kWe (48 kW total) and reject waste heat to two pumped water loops, which transfer the waste heat to titanium-water heat pipe radiators. The FSP TDU simulates a single leg of the baseline FSP system using an electrically heater core simulator, a single liquid metal loop, a single PCU, and a pumped water loop which rejects the waste heat to a Facility Cooling System (FCS). When operated at the nominal operating conditions (modified for low liquid metal flow) during TDU testing the PCU produced 8.9 kW of power at an efficiency of 21.7 percent resulting in a net system power of 8.1 kW and a system level efficiency of 17.2 percent. The reduction in PCU power from levels seen during electrically heated testing is the result of insufficient heat transfer from the NaK heater head to the Stirling acceptor, which could not be tested at Sunpower prior to delivery to the NASA Glenn Research Center (GRC). The maximum PCU power of 10.4 kW was achieved at the maximum liquid metal temperature of 875 K, minimum water temperature of 350 K, 1.1 kg/s liquid metal flow, 0.39 kg/s water flow, and 15.0 mm amplitude at an efficiency of 23.3 percent. This resulted in a system net power of 9.7 kW and a system efficiency of 18.7 percent.

Fission Surface Power Technology Demonstration Unit Test Results

NASA Technical Reports Server (NTRS)

Briggs, Maxwell H.; Gibson, Marc A.; Geng, Steven; Sanzi, James

2016-01-01

The Fission Surface Power (FSP) Technology Demonstration Unit (TDU) is a system-level demonstration of fission power technology intended for use on manned missions to Mars. The Baseline FSP systems consists of a 190 kWt UO2 fast-spectrum reactor cooled by a primary pumped liquid metal loop. This liquid metal loop transfers heat to two intermediate liquid metal loops designed to isolate fission products in the primary loop from the balance of plant. The intermediate liquid metal loops transfer heat to four Stirling Power Conversion Units (PCU), each of which produce 12 kWe (48 kW total) and reject waste heat to two pumped water loops, which transfer the waste heat to titanium-water heat pipe radiators. The FSP TDU simulates a single leg of the baseline FSP system using an electrically heater core simulator, a single liquid metal loop, a single PCU, and a pumped water loop which rejects the waste heat to a Facility Cooling System (FCS). When operated at the nominal operating conditions (modified for low liquid metal flow) during TDU testing the PCU produced 8.9 kW of power at an efficiency of 21.7% resulting in a net system power of 8.1 kW and a system level efficiency of 17.2%. The reduction in PCU power from levels seen during electrically heated testing is the result of insufficient heat transfer from the NaK heater head to the Stirling acceptor, which could not be tested at Sunpower prior to delivery to GRC. The maximum PCU power of 10.4 kW was achieved at the maximum liquid metal temperature of 875 K, minimum water temperature of 350 K, 1.1 kg/s liquid metal flow, 0.39 kg/s water flow, and 15.0 mm amplitude at an efficiency of 23.3%. This resulted in a system net power of 9.7 kW and a system efficiency of 18.7 %.

Hand-Portable Gradient Capillary Liquid Chromatography Pumping System.

PubMed

Sharma, Sonika; Plistil, Alex; Barnett, Hal E; Tolley, H Dennis; Farnsworth, Paul B; Stearns, Stanley D; Lee, Milton L

2015-10-20

In this work, a novel splitless nanoflow gradient generator integrated with a stop-flow injector was developed and evaluated using an on-column UV-absorption detector. The gradient pumping system consisted of two nanoflow pumps controlled by micro stepper motors, a mixer connected to a serpentine tube, and a high-pressure valve. The gradient system weighed only 4 kg (9 lbs) and could generate up to 55 MPa (8000 psi) pressure. The system could operate using a 24 V DC battery and required 1.2 A for operation. The total volume capacity of the pump was 74 μL, and a sample volume of 60 nL could be injected. The system provided accurate nanoflow rates as low as 10 nL/min without employing a splitter, making it ideal for capillary column use. The gradient dwell volume was calculated to be 1.3 μL, which created a delay of approximately 4 min with a typical flow rate of 350 nL/min. Gradient performance was evaluated for gradient step accuracy, and excellent reproducibility was obtained in day-to-day experiments (RSD < 1.2%, n = 4). Linear gradient reproducibility was tested by separating a three-component pesticide mixture on a poly(ethylene glycol) diacrylate (PEGDA) monolithic column. The retention time reproducibility was very good in run-to-run experiments (RSD < 1.42%, n = 4). Finally, excellent separation of five phenols was demonstrated using the nanoflow gradient system.

Note: Design and fabrication of a simple versatile microelectrochemical cell and its accessories

NASA Astrophysics Data System (ADS)

Rajan, Viswanathan; Neelakantan, Lakshman

2015-09-01

A microelectrochemical cell housed in an optical microscope and custom-made accessories have been designed and fabricated, which allows performing spatially resolved corrosion measurements. The cell assembly was designed to directly integrate the reference electrode close to the capillary tip to avoid air bubbles. A hard disk along with an old optical microscope was re-engineered into a microgrinder, which made the vertical grinding of glass capillary tips very easy. A stepper motor was customized into a microsyringe pump to dispense a controlled volume of electrolyte through the capillary. A force sensitive resistor was used to achieve constant wetting area. The functionality of the developed instrument is demonstrated by studying μ-electrochemical behavior of worn surface on AA2014-T6 alloy.

Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

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

Mittereder, N.; Poerschke, A.

2013-11-01

This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHPmore » in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season. Upon completion of the monitoring phase, measurements revealed that the initial TRNSYS simulated horizontal sub-slab ground loop heat exchanger fluid temperatures and heat transfer rates differed from the measured values. To determine the cause of this discrepancy, an updated model was developed utilizing a new TRNSYS subroutine for simulating sub-slab heat exchangers. Measurements of fluid temperature, soil temperature, and heat transfer were used to validate the updated model.« less

Ground Source Heat Pump Computational Results

DOE Data Explorer

James Menart

2013-07-31

This data submission includes simulation results for ground loop heat pump systems located in 6 different cities across the United States. The cities are Boston, MA, Dayton, OH, Omaha, NE, Orlando, FL, Sacramento, CA, and St. Paul, MN. These results were obtained from the two-dimensional geothermal computer code called GEO2D. GEO2D was written as part of this DOE funded grant. The results included in this submission for each of the 6 cities listed above are: 1) specific information on the building being heated or cooled by the ground loop geothermal system, 2) some extreme values for the building heating and cooling loads during the year, 3) the inputs required to carry out the simulation, 4) a plot of the hourly building heating and cooling loads throughout the year, 5) a plot of the fluid temperature exiting the ground loop for a 20 year period, 6) a plot of the heat exchange between the ground loop and the ground for a 20 year period, and 7) ground and ground loop temperature contour plots at different times of the year for the 20 year period.

Nanowicks

NASA Technical Reports Server (NTRS)

Noca, Flavio; Bronikowski, Michael; Sansom, Elijah; Zhou, Jijie; Gharib, Morteza

2007-01-01

Nanowicks are dense mats of nanoscale fibers that are expected to enable the development of a variety of novel capillary pumps, filters, and fluidic control devices. Nanowicks make it possible obtain a variety of novel effects, including capillary pressures orders of magnitude greater than those afforded by microscale and conventional macroscale wicks. While wicking serves the key purpose of transporting fluid, the nanofiber geometry of a nanowick makes it possible to exploit additional effects -- most notably, efficient nanoscale mixing, fluidic effects for logic or control, and ultrafiltration (in which mats of nanofibers act as biomolecular sieves).

The development of a cryogenic over-pressure pump

NASA Astrophysics Data System (ADS)

Alvarez, M.; Cease, H.; Flaugher, B.; Flores, R.; Garcia, J.; Lathrop, A.; Ruiz, F.

2014-01-01

A cryogenic over-pressure pump (OPP) was tested in the prototype telescope liquid nitrogen (LN2) cooling system for the Dark Energy Survey (DES) Project. This OPP consists of a process cylinder (PC), gas generator, and solenoid operated valves (SOVs). It is a positive displacement pump that provided intermittent liquid nitrogen (LN2) flow to an array of charge couple devices (CCDs) for the prototype Dark Energy Camera (DECam). In theory, a heater submerged in liquid would generate the drive gas in a closed loop cooling system. The drive gas would be injected into the PC to displace that liquid volume. However, due to limitations of the prototype closed loop nitrogen system (CCD cooling system) for DECam, a quasiclosed-loop nitrogen system was created. During the test of the OPP, the CCD array was cooled to its designed set point temperature of 173K. It was maintained at that temperature via electrical heaters. The performance of the OPP was captured in pressure, temperature, and flow rate in the CCD LN2 cooling system at Fermi National Accelerator Laboratory (FNAL).

Garan performs TCS Water Loop Degassing in Columbus

NASA Image and Video Library

2011-04-08

ISS027-E-011325 (8 April 2011) --- NASA astronaut Ron Garan, Expedition 27 flight engineer, works on degassing the water loop of the running Water Pump Assembly 2 / Thermal Control System (WPA2/TCS) in the Columbus laboratory of the International Space Station.

Garan performs TCS Water Loop Degassing in Columbus

NASA Image and Video Library

2011-04-08

ISS027-E-011324 (8 April 2011) --- NASA astronaut Ron Garan, Expedition 27 flight engineer, works on degassing the water loop of the running Water Pump Assembly 2 / Thermal Control System (WPA2/TCS) in the Columbus laboratory of the International Space Station.

In situ Monitoring of Atmospheric Nitrous Acid based on Multi-pumping flow system and Liquid Waveguide Capillary Cell: development and field applications

NASA Astrophysics Data System (ADS)

Liu, Yuhan; Lu, Keding

2015-04-01

In the last four decades, various techniques including spectroscopic method, wet chemical method and mass spectrometric method, etc, had been developed and applied for the detection of ambient nitrous acid (HONO) concentrations. Followed the instrumental framework prosposed by Heland et al., (2001), we developed a new version of LOng Path Absorpotion Photometer (LOPAP) system which consists of three independent modules: the sampling module, the fluid propulsion module and the detection module. The major modification of our setup compared to previous LOPAPs is the replacement of the peristaltic pumps to be the solenoid pumps. With solenoid pumps the pulsed flow could be computer controlled both in terms of pump stroke volume and pulse frequency, which enable the attainment of a very stable flow rate. The other significant modification of our setup is the exploit of the customized Liquid Waveguide Capillary Cell (LWCC) manufactured by World Precision Instrument Inc, who offers a versatile path length between 50 and 500 cm. The customized LWCC pre-setup the optical fiber in-coupling with the liquid wave guide, providing us an option of fast startup and easy maintenance of the absorption photometry. With our new LOPAP system, we already performed amibient HONO measurements in three Chinese megacity regions - North China Plain, Yangtze River Delta and Pearl River Delta. In all those locations, we found strong diurnal variations of HONO. The typical daytime HONO concentrations were about several hundred ppts while the nighttime concentrations were about several ppbs.

Preliminary design of a Primary Loop Pump Assembly (PLPA), using electromagnetic pumps

NASA Technical Reports Server (NTRS)

Moss, T. A.; Matlin, G.; Donelan, L.; Johnson, J. L.; Rowe, I.

1972-01-01

A preliminary design study of flight-type dc conduction-permanent magnetic, ac helical induction, and ac linear induction pumps for circulating 883 K (1130 F) NaK at 9.1 kg/sec (20 lb/sec) is described. Various electromagnetic pump geometrics are evaluated against hydraulic performance, and the effects of multiple windings and numbers of pumps per assembly on overall reliability were determined. The methods used in the electrical-hydraulic, stress, and thermal analysis are discussed, and the high temperature electrical materials selected for the application are listed.

Visual detection of multiple genetically modified organisms in a capillary array.

PubMed

Shao, Ning; Chen, Jianwei; Hu, Jiaying; Li, Rong; Zhang, Dabing; Guo, Shujuan; Hui, Junhou; Liu, Peng; Yang, Litao; Tao, Sheng-Ce

2017-01-31

There is an urgent need for rapid, low-cost multiplex methodologies for the monitoring of genetically modified organisms (GMOs). Here, we report a C[combining low line]apillary A[combining low line]rray-based L[combining low line]oop-mediated isothermal amplification for M[combining low line]ultiplex visual detection of nucleic acids (CALM) platform for the simple and rapid monitoring of GMOs. In CALM, loop-mediated isothermal amplification (LAMP) primer sets are pre-fixed to the inner surface of capillaries. The surface of the capillary array is hydrophobic while the capillaries are hydrophilic, enabling the simultaneous loading and separation of the LAMP reaction mixtures into each capillary by capillary forces. LAMP reactions in the capillaries are then performed in parallel, and the results are visually detected by illumination with a hand-held UV device. Using CALM, we successfully detected seven frequently used transgenic genes/elements and five plant endogenous reference genes with high specificity and sensitivity. Moreover, we found that measurements of real-world blind samples by CALM are consistent with results obtained by independent real-time PCRs. Thus, with an ability to detect multiple nucleic acids in a single easy-to-operate test, we believe that CALM will become a widely applied technology in GMO monitoring.

A portable pressure pump for microfluidic lab-on-a-chip systems using a porous polydimethylsiloxane (PDMS) sponge.

PubMed

Cha, Kyoung Je; Kim, Dong Sung

2011-10-01

In this paper, we propose a novel portable and disposable pressure pump using a porous polydimethylsiloxane (PDMS) sponge and demonstrate its application to a microfluidic lab-on-a-chip. The porous PDMS sponge was simply fabricated by a sugar leaching technique based on capillary suction of pre-cured PDMS into lumps of sugar, thereby enabling us to achieve the porous PDMS sponge composed of interconnected micropores. To indicate the characteristics of the porous PDMS sponge and pump, we measured the average porosities of them whose values were 0.64 and 0.34, respectively. A stress-strain relationship of the fabricated portable pressure pump represented a linear behavior in the compressive strain range of 0 to 20%. Within this range, a pumping volume of the pressure pump could be linearly controlled by the compressed strain. Finally, the fabricated porous PDMS pump was successfully demonstrated as a portable pressure pump for a disposable microfluidic lab-on-a-chip for efficient detection of agglutination. The proposed portable pressure pump can be potentially applicable to various disposable microfluidic lab-on-a-chip systems.

Pressure-assisted introduction of urine samples into a short capillary for electrophoretic separation with contactless conductivity and UV spectrometry detection.

PubMed

Makrlíková, Anna; Opekar, František; Tůma, Petr

2015-08-01

A computer-controlled hydrodynamic sample introduction method has been proposed for short-capillary electrophoresis. In the method, the BGE flushes sample from the loop of a six-way sampling valve and is carried to the injection end of the capillary. A short pressure impulse is generated in the electrolyte stream at the time when the sample zone is at the capillary, leading to injection of the sample into the capillary. Then the electrolyte flow is stopped and the separation voltage is turned on. This way of sample introduction does not involve movement of the capillary and both of its ends remain constantly in the solution during both sample injection and separation. The amount of sample introduced to the capillary is controlled by the duration of the pressure pulse. The new sample introduction method was tested in the determination of ammonia, creatinine, uric acid, and hippuric acid in human urine. The determination was performed in a capillary with an overall length of 10.5 cm, in two BGEs with compositions 50 mM MES + 5 mM NaOH (pH 5.1) and 1 M acetic acid + 1.5 mM crown ether 18-crown-6 (pH 2.4). A dual contactless conductivity/UV spectrometric detector was used for the detection. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impact of mixing chemically heterogeneous groundwaters on the sustainability of an open-loop groundwater heat pump

NASA Astrophysics Data System (ADS)

Burté, L.; Farasin, J.; Cravotta, C., III; Gerard, M. F.; Cotiche Baranger, C.; Aquilina, L.; Le Borgne, T.

2017-12-01

Geothermal systems using shallow aquifers are commonly used for heating and cooling. The sustainability of these systems can be severely impacted by the occurrence of clogging process. The geothermal loop operation (including pumping of groundwater, filtering and heat extraction through exchangers and cooled water injection) can lead to an unexpected biogeochemical reactivity and scaling formation that can ultimately lead to the shutdown of the geothermal doublet. Here, we report the results of investigations carried out on a shallow geothermal doublet (< 40 m depth) affected by rapid clogging processes linked to iron and manganese oxidation. Using a reactive transport model, we determine the parameters controlling clogging. To characterize the biogeochemical processes induced by the operation of the production well, we combined hydrodynamic measurements by flowmeter and in-situ chemical depth profiles. We thus investigated the chemical heterogeneity into the pumping well as a function of the operating conditions (static or dynamic). Hydrochemical data collected at the pumping well showed that groundwater was chemically heterogeneous long the 11 meters well screen. While the aquifer was dominantly oxic, a localized inflow of anoxic water was detected and evaluated to produce about 40% of the total flow . The mixture of chemically heterogeneous water induced by pumping lead to the oxidation of reductive species and thus to the formation of biogenic precipitates responsible for clogging. The impact of pumping waters of different redox potential and chemical characteristics was quantified by numerical modeling using PHREEQC. These results shows that natural chemical heterogeneity can occur at a small scale in heterogeneous aquifers and highlight the importance of their characterization during the production well testing and the geothermal loop operation in order to take preventive measures to avoid clogging.

Laser head for simultaneous optical pumping of several dye lasers. [with single flash lamp

NASA Technical Reports Server (NTRS)

Mumola, P. B.; Mcalexander, B. T. (Inventor)

1975-01-01

The invention is a laser head for simultaneous pumping several dye lasers with a single flash lamp. The laser head includes primarily a multi-elliptical cylinder cavity with a single flash lamp placed along the common focal axis of the cavity and with capillary tube dye cells placed along each of the other focal axes of the cavity. The inside surface of the cavity is polished. Hence, the single flash lamp supplies the energy to the several dye cells.

Acquisition system testing with superfluid helium. [cryopumping for space

NASA Technical Reports Server (NTRS)

Anderson, John E.; Fester, Dale A.; Dipirro, Michael J.

1988-01-01

Minus one-g outflow tests were conducted with superfluid helium in conjunction with a thermomechanical pump setup in order to study the use of capillary acquisition systems for NASA's Superfluid Helium On-Orbit Transfer (SHOOT) flight experiment. Results show that both fine mesh screen and porous sponge systems are capable of supplying superfluid helium to the thermomechanical pump inlet against a one-g head up to 4 cm, fulfilling the SHOOT requirements. Sponge results were found to be reproducible, while the screen results were not.

Quality evaluation of six bioactive constituents in goji berry based on capillary electrophoresis field amplified sample stacking.

PubMed

Wang, Wei-Feng; Yang, Jun-Li; Shi, Yan-Ping

2018-04-27

Goji berry, fruits of the plant Lycium barbarum L., has long been used as traditional medicine and functional food in China. In this work, a simple and easy-operation on-line concentration capillary electrophoresis (CE) for detection flavonoids in goji berry was developed by coupling of field amplified sample stacking (FASS) with an electroosmotic (EOF) pump driving water removal process. Due to the EOF pump and electrokinetic injection showing different influence on the concentration, the analytes injection condition should be systemically studied. Thereafter, the verification of the analytes injection conditions was achieved using response surface experimental design. Under the optimum conditions, 86-271 folds sensitivity enhancement upon normal capillary zone electrophoresis (CZE, 50 mbar × 5 s) were achieved for six flavonoids, and the detection limits ranged from 0.35 to 1.82 ng/mL; the LOQ ranged from 1.20 to 6.01 ng/mL. Eventually, the proposed method was applied to detect flavonoids in 30 goji berry samples from different habitats of China; and the results indicated that the flavonoids were rich in the eluent of 30-60% methanol, which provided a reference for extraction of goji berry flavonoids. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Continuous monitoring of L-glutamate released from cultured nerve cells by an online sensor coupled with micro-capillary sampling.

PubMed

Niwa, O; Horiuchi, T; Torimitsu, K

1997-01-01

A small volume L-glutamate online sensor was developed in order to monitor changes in the local concentration of L-glutamate released from cultured nerve cells. Syringe pump in the suction mode is used to sample extracellular fluid continuously from a glass micro-capillary and the concentration of L-glutamate can be determined by using a glassy carbon (GC) electrode modified with an Os-polyvinylpyridine mediator bottom film containing horseradish peroxidase and a bovine serum albumin top layer containing L-glutamate oxidase. The overall efficiency of L-glutamate detection with a sensor is 71% under optimum conditions due to an efficient enzymatic reaction at the modified electrode in the thin layer radial flow cell. As a result, we achieved a detection limit of 7-15 nM and a linear range of 50 nM to 10 microM. In an in vitro experiment, the extracellular fluid near a particular nerve cell can be sampled with this micro-pipet and continuously introduced into the modified GC electrode in the radial flow cell via suction provided by a syringe pump. The nerve cells are stimulated by the KCl in a glass capillary and the L-glutamate concentration change can be monitored by changing the distance between the sampling pipet and the nerve cells.

Subsurface Thermal Energy Storage for Improved Heating and Air Conditioning Efficiency

DTIC Science & Technology

2016-11-21

This project involved a field demonstration of subsurface thermal energy storage for improving the geothermal heat pump air conditioning efficiency... geothermal heat pump systems, undesirable heating of the ground may occur. This demonstration was performed at the MCAS, Beaufort, SC, where several...buildings with geothermal heat pump systems were exhibiting excessively high ground loop temperatures. These buildings were retrofitted with dry fluid

Insulin Pump and Continuous Glucose Monitor Initiation in Hospitalized Patients with Type 2 Diabetes Mellitus.

PubMed

Levitt, David L; Spanakis, Elias K; Ryan, Kathleen A; Silver, Kristi D

2018-01-01

Insulin pumps and continuous glucose monitoring (CGM) are commonly used by patients with diabetes mellitus in the outpatient setting. The efficacy and safety of initiating inpatient insulin pumps and CGM in the nonintensive care unit setting is unknown. In a prospective pilot study, inpatients with type 2 diabetes were randomized to receive standard subcutaneous basal-bolus insulin and blinded CGM (group 1, n = 5), insulin pump and blinded CGM (group 2, n = 6), or insulin pump and nonblinded CGM (group 3, n = 5). Feasibility, glycemic control, and patient satisfaction were evaluated among groups. Group 1 had lower mean capillary glucose levels, 144.5 ± 19.5 mg/dL, compared with groups 2 and 3, 191.5 ± 52.3 and 182.7 ± 59.9 mg/dL (P 1 vs. 2+3  = 0.05). CGM detected 19 hypoglycemic episodes (glucose <70 mg/dL) among all treatment groups, compared with 12 episodes detected by capillary testing, although not statistically significant. No significant differences were found for the total daily dose of insulin or percentage of time spent below target glucose range (<90 mg/dL), in target glucose range (90-180 mg/dL), or above target glucose range (>180 mg/dL). On the Diabetes Treatment Satisfaction Questionnaire-Change, group 3 reported increased hyperglycemia and decreased hypoglycemia frequency compared with the other two groups, although the differences did not reach statistical significance. Insulin pump and CGM initiation are feasible during hospitalization, although they are labor intensive. Although insulin pump initiation may not lead to improved glycemic control, there is a trend toward CGM detecting a greater number of hypoglycemic episodes. Larger studies are needed to determine whether use of this technology can lower inpatient morbidity and mortality.

Study and development of an air conditioning system operating on a magnetic heat pump cycle (design and testing of flow directors)

NASA Astrophysics Data System (ADS)

Wang, Pao-Lien

1992-09-01

This report describes the fabrication, design of flow director, fluid flow direction analysis and testing of flow director of a magnetic heat pump. The objectives of the project are: (1) to fabricate a demonstration magnetic heat pump prototype with flow directors installed; and (2) analysis and testing of flow director and to make sure working fluid loops flow through correct directions with minor mixing. The prototype was fabricated and tested at the Development Testing Laboratory of Kennedy Space Center. The magnetic heat pump uses rear earth metal plates rotate in and out of a magnetic field in a clear plastic housing with water flowing through the rotor plates to provide temperature lift. Obtaining the proper water flow direction has been a problem. Flow directors were installed as flow barriers between separating point of two parallel loops. Function of flow directors were proven to be excellent both analytically and experimentally.

Study and development of an air conditioning system operating on a magnetic heat pump cycle (design and testing of flow directors)

NASA Technical Reports Server (NTRS)

Wang, Pao-Lien

1992-01-01

This report describes the fabrication, design of flow director, fluid flow direction analysis and testing of flow director of a magnetic heat pump. The objectives of the project are: (1) to fabricate a demonstration magnetic heat pump prototype with flow directors installed; and (2) analysis and testing of flow director and to make sure working fluid loops flow through correct directions with minor mixing. The prototype was fabricated and tested at the Development Testing Laboratory of Kennedy Space Center. The magnetic heat pump uses rear earth metal plates rotate in and out of a magnetic field in a clear plastic housing with water flowing through the rotor plates to provide temperature lift. Obtaining the proper water flow direction has been a problem. Flow directors were installed as flow barriers between separating point of two parallel loops. Function of flow directors were proven to be excellent both analytically and experimentally.

Paper pump for passive and programmable transport

PubMed Central

Wang, Xiao; Hagen, Joshua A.; Papautsky, Ian

2013-01-01

In microfluidic systems, a pump for fluid-driving is often necessary. To keep the size of microfluidic systems small, a pump that is small in size, light-weight and needs no external power source is advantageous. In this work, we present a passive, simple, ultra-low-cost, and easily controlled pumping method based on capillary action of paper that pumps fluid through conventional polymer-based microfluidic channels with steady flow rate. By using inexpensive cutting tools, paper can be shaped and placed at the outlet port of a conventional microfluidic channel, providing a wide range of pumping rates. A theoretical model was developed to describe the pumping mechanism and aid in the design of paper pumps. As we show, paper pumps can provide steady flow rates from 0.3 μl/s to 1.7 μl/s and can be cascaded to achieve programmable flow-rate tuning during the pumping process. We also successfully demonstrate transport of the most common biofluids (urine, serum, and blood). With these capabilities, the paper pump has the potential to become a powerful fluid-driving approach that will benefit the fielding of microfluidic systems for point-of-care applications. PMID:24403999

Self-Sealed Bionic Long Microchannels with Thin Walls and Designable Nanoholes Prepared by Line-Contact Capillary-Force Assembly.

PubMed

Lao, Zhao-Xin; Hu, Yan-Lei; Pan, Deng; Wang, Ren-Yan; Zhang, Chen-Chu; Ni, Jin-Cheng; Xu, Bing; Li, Jia-Wen; Wu, Dong; Chu, Jia-Ru

2017-06-01

Long microchannels with thin walls, small width, and nanoholes or irregular shaped microgaps, which are similar to capillaries or cancerous vessels, are urgently needed to simulate the physiological activities in human body. However, the fabrication of such channels remains challenging. Here, microchannels with designable holes are manufactured by combining laser printing with line-contact capillary-force assembly. Two microwalls are first printed by femtosecond laser direct-writing, and subsequently driven to collapse into a channel by the capillary force that arises in the evaporation of developer. The channel can remain stable in solvent due to the enhanced Van der Waals' force caused by the line-contact of microwalls. Microchannels with controllable nanoholes and almost arbitrary patterns can be fabricated without any bonding or multistep processes. As-prepared microchannels, with wall thicknesses less than 1 µm, widths less than 3 µm, lengths more than 1 mm, are comparable with human capillaries. In addition, the prepared channels also exhibit the ability to steer the flow of liquid without any external pump. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of High-Performance Satellite Bus System

NASA Astrophysics Data System (ADS)

Shirai, Tatsuya; Noda, Atsushi; Tsuiki, Atsuo

2002-01-01

Speaking of Low Earth Orbit (LEO) satellites like earth observation satellites, the light-weighing and high performance bus system will make an great contribution to mission components development.Also, the rising ratio of payload to total mass will reduce the launch cost.Office of Research and Development in National Space Development Agency of Japan (NASDA) is studying such a sophisticated satellite bus system.The system is expected to consist of the following advanced components and subsystems which in parallel have been developed from the element level by the Office. (a) Attitude control system (ACS) This subsystem will provide function to very accurately determine and control the satellite attitude with a next generation star tracker, a GPS receiver, and the onboard software to achieve this function. (b) Electric power system (EPS) This subsystem will be getting much lighter and powerful by utilizing the more efficient solar battery cell, power MOS FET, and DC/DC converter.Besides, to cumulate and supply the power, the Office will also study a Litium battery for space which is light and small enough to contribute to reducing size and weight of the EPS. (c) Onboard computing system (OCS) This computing system will provide function of high speed processing.The MPU (Multi Processing Unit) cell in the OCS is capable of executing approximately 200 MIPS (Mega Instructions Per Second).The OCS will play an important role not only enough for the ACS to function well but also enough for the image processing data to be handled. (d) Thermal control system (TCS) As a thermal control system, mission-friendly system is under study.A small hybrid fluid thermal control system that the Office is studying with a combination of mechanical pump loop and capillary pump loop will be robust to change of thermal loads and facilitate the system to control the temperature. (e) Communications system (CS) In order to transmit high rate data, the office is studying an optical link system.The optical communications system will provide the much smaller size of component than the microwave, while it simultaneously provides transmission of a quantity of data at a high speed.

Transpiration-Cooled Spacecraft-Insulation-Repair Fasteners

NASA Technical Reports Server (NTRS)

Camarda, Charles J.; Pettit, Donald R.; Glass, David; Scotti, Stephen J.; Vaughn, Wallace Lee; Rawal, Suraj

2012-01-01

Transpiration-cooled fasteners are proposed that operate like an open-loop heat pipe (self-tapping screws, bolts, and spikes) for use in on-orbit repair of thermal- insulation of a space shuttle or other spacecraft. By limiting the temperature rise of such a fastener and of the adjacent repair material and thermal protection system, the transpiration cooling would contribute to the ability of the repair to retain its strength and integrity in the high-heat-flux, oxidizing environment of reentry into the atmosphere of the Earth. A typical fastener according to the proposal would include a hollow refractory-metal, refractory-composite, or ceramic screw or bolt, the central cavity of which would be occupied by a porous refractory- metal or ceramic plug that would act as both a reservoir and a wick for a transpirant liquid. The plug dimensions, the plug material, and the sizes of the pores would be chosen in conjunction with the transpirant liquid so that (1) capillary pumping could be relied upon to transport the liquid to the heated surface, where the liquid would be vaporized, and (2) the amount of liquid would suffice for protecting against the anticipated heat flux and integrated heat load.

Transport, manipulation, and reaction of biological cells on-chip using electrokinetic effects.

PubMed

Li, P C; Harrison, D J

1997-04-15

A microfluidic system was fabricated on a glass chip to study mobilization of biological cells on-chip. Electroosmotic and/or electrophoretic pumping were used to drive the cell transport within a network of capillary channels. Whole cells such as Saccharomyces cerevisiae, canine erythrocyte, and Escherichia coli were employed in this work. Photographs are presented to illustrate how cells are selected and transported from one location to another within the capillary network, with velocities up to about 0.5 mm/s in capillaries with a 15- x 55-microns cross section. The mixing of canine erythrocytes with the lysing agent sodium dodecyl sulfate, at an intersection within the chip, was performed to demonstrate that cell selection and subsequent reaction can be accomplished within the microchip.

Design and Operation of a Cryogenic Nitrogen Pulsating Heat Pipe

NASA Astrophysics Data System (ADS)

Diego Fonseca, Luis; Miller, Franklin; Pfotenhauer, John

2015-12-01

We report the design, experimental setup and successful test results using an innovative passive cooling system called a “Pulsating Heat Pipe” (PHP) operating at temperatures ranging from 77 K to 80 K and using nitrogen as the working fluid. PHPs, which transfer heat by two phase flow mechanisms through a closed loop tubing have the advantage that no electrical pumps are needed to drive the fluid flow. In addition, PHPs have an advantage over copper straps and thermal conductors since they are lighter in weight, exhibit lower temperature gradients and have higher heat transfer rates. PHPs consist of an evaporator section, thermally anchored to a solid, where heat is received at the saturation temperature where the liquid portion of the two-phase flow evaporates, and a condenser where heat is rejected at the saturation temperature where the vapor is condensed. The condenser section in our experiment has been thermally interfaced to a CT cryocooler from SunPower that has a cooling capacity of 10 W at 77 K. Alternating regions of liquid slugs and small vapor plugs fill the capillary tubing, with the vapor regions contracting in the condenser section and expanding in the evaporator section due to an electric heater that will generate heat loads up to 10 W. This volumetric expansion and contraction provides the oscillatory flow of the fluid throughout the capillary tubing thereby transferring heat from one end to the other. The thermal performance and temperature characteristics of the PHP will be correlated as a function of average condenser temperature, PHP fill liquid ratio, and evaporator heat load. The experimental data show that the heat transfer between the evaporator and condenser sections can produce an effective thermal conductivity up to 35000 W/m-K at a 3.5 W heat load.

A 15 W 1152 nm Raman fiber laser with 6 nm spectral width for Ho3+-doped crystal's pumping source

NASA Astrophysics Data System (ADS)

Chen, Xiuyan; Jiang, Huawei

2016-12-01

A 11.5 W 1152 nm Raman fiber laser with 6 nm spectral width was demonstrated based on the resonator constructed with one fiber loop mirror and one fiber Bragg grating. By mans of experimental measurement and theoretical calculation, the reflectivity of the fiber loop mirror was confirmed as 0.93. The Yb3+-doped 1090 nm fiber length was about 5 m. When the maximum pumping power of 976 nm laser was 54.8 W, 32.2 W 1090 nm laser was obtained and the optical to optical conversion efficiency from 1090 nm to 1152 nm light was 48%. Finally, the 1152 nm Raman fiber laser was used for pumping Ho3+:LLF crystal, and the 1194 nm fluorescence emission peak was detected for the first time.

Urea functionalized surface-bonded sol-gel coating for on-line hyphenation of capillary microextraction with high-performance liquid chromatography.

PubMed

Jillani, Shehzada Muhammad Sajid; Alhooshani, Khalid

2018-03-30

Sol-gel urea functionalized-[bis(hydroxyethyl)amine] terminated polydimethylsiloxane coating was developed for capillary microextraction-high performance liquid chromatographic analysis from aqueous samples. A fused silica capillary is coated from the inside with surface bonded coating material and is created through in-situ sol-gel reaction. The urea-functionalized coating was immobilized to the inner surface of the capillary by the condensation reaction of silanol groups of capillary and sol-solution. The characterization of the coating material was successfully done by using X-ray photoelectron spectroscopy, thermogravimetric analysis, field emission scanning electron microscope, and energy dispersive X-ray spectrometer. To make a setup of online capillary microextraction-high performance liquid chromatography, the urea functionalized capillary was installed in the HPLC manual injection port. The analytes of interest were pre-concentrated in the coated sampling loop, desorbed by the mobile phase, chromatographically separated on C-18 column, and analyzed by UV detector. Sol-gel coated capillaries were used for online extraction and high-performance liquid chromatographic analysis of phenols, ketones, aldehydes, and polyaromatic hydrocarbons. This newly developed coating showed excellent extraction for a variety of analytes ranging from highly polar to non-polar in nature. The analysis using sol-gel coating showed excellent overall sensitivity in terms of lower detection limits (S/N = 3) for the analytes (0.10 ng mL -1 -14.29 ng mL -1 ) with acceptable reproducibility that is less than 12.0%RSD (n = 3). Moreover, the capillary to capillary reproducibility of the analysis was also tested by changing the capillary of the same size. This provided excellent%RSD of less than 10.0% (n = 3). Copyright © 2018 Elsevier B.V. All rights reserved.

JPL Advanced Thermal Control Technology Roadmap - 2008

NASA Technical Reports Server (NTRS)

Birur, Gaj

2008-01-01

This slide presentation reviews the status of thermal control technology at JPL and NASA.It shows the active spacecraft that are in vairous positions in the solar syatem, and beyond the solar system and the future missions that are under development. It then describes the challenges that the past missions posed with the thermal control systems. The various solutions that were implemented duirng the decades prior to 1990 are outlined. A review of hte thermal challenges of the future misions is also included. The exploration plan for Mars is then reviewed. The thermal challenges of the Mars Rovers are then outlined. Also the challenges of systems that would be able to be used in to explore Venus, and Titan are described. The future space telescope missions will also need thermal control technological advances. Included is a review of the thermal requirements for manned missions to the Moon. Both Active and passive technologies that have been used and will be used are reviewed. Those that are described are Mechanically Pumped Fluid Loops (MPFL), Loop Heat Pipes, an M3 Passive Cooler, Heat Siwtch for Space and Mars surface applications, phase change material (PCM) technology, a Gas Gap Actuateor using ZrNiH(x), the Planck Sorption Cooler (PCS), vapor compression -- Hybrid two phase loops, advanced pumps for two phase cooling loops, and heat pumps that are lightweight and energy efficient.

Reactor Simulator Testing

NASA Technical Reports Server (NTRS)

Schoenfeld, Michael P.; Webster, Kenny L.; Pearson, Boise J.

2013-01-01

As part of the Nuclear Systems Office Fission Surface Power Technology Demonstration Unit (TDU) project, a reactor simulator test loop (RxSim) was design & built to perform integrated testing of the TDU components. In particular, the objectives of RxSim testing was to verify the operation of the core simulator, the instrumentation and control system, and the ground support gas and vacuum test equipment. In addition, it was decided to include a thermal test of a cold trap purification design and a pump performance test at pump voltages up to 150 V since the targeted mass flow rate of 1.75 kg/s was not obtained in the RxSim at the originally constrained voltage of 120 V. This paper summarizes RxSim testing. The gas and vacuum ground support test equipment performed effectively in NaK fill, loop pressurization, and NaK drain operations. The instrumentation and control system effectively controlled loop temperature and flow rates or pump voltage to targeted settings. The cold trap design was able to obtain the targeted cold temperature of 480 K. An outlet temperature of 636 K was obtained which was lower than the predicted 750 K but 156 K higher than the cold temperature indicating the design provided some heat regeneration. The annular linear induction pump (ALIP) tested was able to produce a maximum flow rate of 1.53 kg/s at 800 K when operated at 150 V and 53 Hz.

Reactor Simulator Integration and Testing

NASA Technical Reports Server (NTRS)

Schoenfield, M. P.; Webster, K. L.; Pearson, J. B.

2013-01-01

As part of the Nuclear Systems Office Fission Surface Power Technology Demonstration Unit (TDU) project, a reactor simulator (RxSim) test loop was designed and built to perform integrated testing of the TDU components. In particular, the objectives of RxSim testing were to verify the operation of the core simulator, the instrumentation and control system, and the ground support gas and vacuum test equipment. In addition, it was decided to include a thermal test of a cold trap purification design and a pump performance test at pump voltages up to 150 V because the targeted mass flow rate of 1.75 kg/s was not obtained in the RxSim at the originally constrained voltage of 120 V. This Technical Memorandum summarizes RxSim testing. The gas and vacuum ground support test equipment performed effectively in NaK fill, loop pressurization, and NaK drain operations. The instrumentation and control system effectively controlled loop temperature and flow rates or pump voltage to targeted settings. The cold trap design was able to obtain the targeted cold temperature of 480 K. An outlet temperature of 636 K was obtained, which was lower than the predicted 750 K but 156 K higher than the cold temperature, indicating the design provided some heat regeneration. The annular linear induction pump tested was able to produce a maximum flow rate of 1.53 kg/s at 800 K when operated at 150 V and 53 Hz.

Jet pump assisted arterial heat pipe

NASA Technical Reports Server (NTRS)

Bienert, W. B.; Ducao, A. S.; Trimmer, D. S.

1978-01-01

This paper discusses the concept of an arterial heat pipe with a capillary driven jet pump. The jet pump generates a suction which pumps vapor and noncondensible gas from the artery. The suction also forces liquid into the artery and maintains it in a primed condition. A theoretical model was developed which predicts the existence of two stable ranges. Up to a certain tilt the artery will prime by itself once a heat load is applied to the heat pipe. At higher tilts, the jet pump can maintain the artery in a primed condition but self-priming is not possible. A prototype heat pipe was tested which self-primed up to a tilt of 1.9 cm, with a heat load of 500 watts. The heat pipe continued to prime reliably when operated as a VCHP, i.e., after a large amount of noncondensible gas was introduced.

Development of a jet pump-assisted arterial heat pipe

NASA Technical Reports Server (NTRS)

Bienert, W. B.; Ducao, A. S.; Trimmer, D. S.

1977-01-01

The development of a jet pump assisted arterial heat pipe is described. The concept utilizes a built-in capillary driven jet pump to remove vapor and gas from the artery and to prime it. The continuous pumping action also prevents depriming during operation of the heat pipe. The concept is applicable to fixed conductance and gas loaded variable conductance heat pipes. A theoretical model for the jet pump assisted arterial heat pipe is presented. The model was used to design a prototype for laboratory demonstration. The 1.2 m long heat pipe was designed to transport 500 watts and to prime at an adverse elevation of up to 1.3 cm. The test results were in good agreement with the theoretical predictions. The heat pipe carried as much as 540 watts and was able to prime up to 1.9 cm. Introduction of a considerable amount of noncondensible gas had no adverse effect on the priming capability.

Whole glove permeation of cyclohexanol through disposable nitrile gloves on a dextrous robot hand and comparison with the modified closed-loop ASTM F739 method 1. No fist clenching.

PubMed

Mathews, Airek R; Que Hee, Shane S

2017-04-01

The aim was to develop a whole glove permeation method for cyclohexanol to generate permeation parameter data for a non-moving dextrous robot hand (normalized breakthrough time t b , standardized breakthrough time t s , steady state permeation rate P s , and diffusion coefficient D). Four types of disposable powderless, unsupported, and unlined nitrile gloves from the same producer were investigated: Safeskin Blue and Kimtech Science Blue, Purple, and Sterling. The whole glove method developed involved a peristaltic pump for water circulation through chemically resistant Viton tubing to continually wash the inner surface of the test glove via holes in the tubing, a dextrous robot hand operated by a microprocessor, a chemically protective nitrile glove to protect the robot hand, an incubator to maintain 35°C temperature, and a hot plate to maintain 35°C at the sampling point of the circulating water. Aliquots of 1.0 mL were sampled at regular time intervals for the first 60 min followed by removal of 0.5 mL aliquots every hour to 8 hr. Quantification was by the internal standard method after gas chromatography-selective ion electron impact mass spectrometry using a non-polar capillary column. The individual glove values of t b and t s differed for the ASTM closed loop method except for Safeskin Blue, but did not for the whole glove method. Most of the kinetic parameters agreed within an order of magnitude for the two techniques. The order of most protective to least protective glove was Blue and Safeskin, then Purple followed by Sterling for the whole gloves. The analogous order for the modified F739 ASTM closed loop method was: Safeskin, Blue, Purple, and Sterling, almost the same as for the whole glove. The Sterling glove was "not recommended" from the modified ASTM data, and was "poor" from the whole glove data.

Steam-jet Chiller for Army Field Kitchens

DTIC Science & Technology

2009-08-01

Steam-Jet Test-Loop Schematic A vacuum pump removes air from the entire system on startup, and is occasionally used to expel air during...delivered to the tube and shell condenser. The steam is condensed and drains to the vacuum sump tank. 11 Periodically, the condensate pump ... Vacuum Roughing Pump The condenser must be held at vacuum to prevent air from insulating the condenser tubes or create a back-pressure that would

ZmPUMP encodes a fully functional monocot plant uncoupling mitochondrial protein whose affinity to fatty acid is increased with the introduction of a His pair at the second matrix loop

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

Favaro, Regiane Degan; Borecky, Jiri; Colombi, Debora

Uncoupling proteins (UCPs) are specialized mitochondrial transporter proteins that uncouple respiration from ATP synthesis. In this study, cDNA encoding maize uncoupling protein (ZmPUMP) was expressed in Escherichia coli and recombinant ZmPUMP reconstituted in liposomes. ZmPUMP activity was associated with a linoleic acid (LA)-mediated H{sup +} efflux with K {sub m} of 56.36 {+-} 0.27 {mu}M and V {sub max} of 66.9 {mu}mol H{sup +} min{sup -1} (mg prot){sup -1}. LA-mediated H{sup +} fluxes were sensitive to ATP inhibition with K {sub i} of 2.61 {+-} 0.36 mM (at pH 7.2), a value similar to those for dicot UCPs. ZmPUMP wasmore » also used to investigate the importance of a histidine pair present in the second matrix loop of mammalian UCP1 and absent in plant UCPs. ZmPUMP with introduced His pair (Lys155His and Ala157His) displayed a 1.55-fold increase in LA-affinity while its activity remained unchanged. Our data indicate conserved properties of plant UCPs and suggest an enhancing but not essential role of the histidine pair in proton transport mechanism.« less

Day-and-night glycaemic control with closed-loop insulin delivery versus conventional insulin pump therapy in free-living adults with well controlled type 1 diabetes: an open-label, randomised, crossover study.

PubMed

Bally, Lia; Thabit, Hood; Kojzar, Harald; Mader, Julia K; Qerimi-Hyseni, Jehona; Hartnell, Sara; Tauschmann, Martin; Allen, Janet M; Wilinska, Malgorzata E; Pieber, Thomas R; Evans, Mark L; Hovorka, Roman

2017-04-01

Tight control of blood glucose concentration in people with type 1 diabetes predisposes to hypoglycaemia. We aimed to investigate whether day-and-night hybrid closed-loop insulin delivery can improve glucose control while alleviating the risk of hypoglycaemia in adults with HbA 1c below 7·5% (58 mmol/mol). In this open-label, randomised, crossover study, we recruited adults (aged ≥18 years) with type 1 diabetes and HbA 1c below 7·5% from Addenbrooke's Hospital (Cambridge, UK) and Medical University of Graz (Graz, Austria). After a 2-4 week run-in period, participants were randomly assigned (1:1), using web-based randomly permuted blocks of four, to receive insulin via the day-and-night hybrid closed-loop system or usual pump therapy for 4 weeks, followed by a 2-4 week washout period and then the other intervention for 4 weeks. Treatment interventions were unsupervised and done under free-living conditions. During the closed-loop period, a model-predictive control algorithm directed insulin delivery, and prandial insulin delivery was calculated with a standard bolus wizard. The primary outcome was the proportion of time when sensor glucose concentration was in target range (3·9-10·0 mmol/L) over the 4 week study period. Analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT02727231, and is completed. Between March 21 and June 24, 2016, we recruited 31 participants, of whom 29 were randomised. One participant withdrew during the first closed-loop period because of dissatisfaction with study devices and glucose control. The proportion of time when sensor glucose concentration was in target range was 10·5 percentage points higher (95% CI 7·6-13·4; p<0·0001) during closed-loop delivery compared with usual pump therapy (65·6% [SD 8·1] when participants used usual pump therapy vs 76·2% [6·4] when they used closed-loop). Compared with usual pump therapy, closed-loop delivery also reduced the proportion of time spent in hypoglycaemia: the proportion of time with glucose concentration below 3·5 mmol/L was reduced by 65% (53-74, p<0·0001) and below 2·8 mmol/L by 76% (59-86, p<0·0001). No episodes of serious hypoglycaemia or other serious adverse events occurred. Use of day-and-night hybrid closed-loop insulin delivery under unsupervised, free-living conditions for 4 weeks in adults with type 1 diabetes and HbA 1c below 7·5% is safe and well tolerated, improves glucose control, and reduces hypoglycaemia burden. Larger and longer studies are warranted. Swiss National Science Foundation (P1BEP3_165297), JDRF, UK National Institute for Health Research Cambridge Biomedical Research Centre, and Wellcome Strategic Award (100574/Z/12/Z). Copyright © 2017 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY license. Published by Elsevier Ltd.. All rights reserved.

In situ monitoring of atmospheric nitrous acid based on multi-pumping flow system and liquid waveguide capillary cell.

PubMed

Liu, Yuhan; Lu, Keding; Dong, Huabin; Li, Xin; Cheng, Peng; Zou, Qi; Wu, Yusheng; Liu, Xingang; Zhang, Yuanhang

2016-05-01

In the last four decades, various techniques including spectroscopic, wet chemical and mass spectrometric methods, have been developed and applied for the detection of ambient nitrous acid (HONO). We developed a HONO detection system based on long path photometry which consists of three independent modules i.e., sampling module, fluid propulsion module and detection module. In the propulsion module, solenoid pumps are applied. With solenoid pumps the pulsed flow can be computer controlled both in terms of pump stroke volume and pulse frequency, which enables the attainment of a very stable flow rate. In the detection module, a customized Liquid Waveguide Capillary Cell (LWCC) is used. The customized LWCC pre-sets the optical fiber in-coupling with the liquid wave guide, providing the option of fast startup and easy maintenance of the absorption photometry. In summer 2014, our system was deployed in a comprehensive campaign at a rural site in the North China Plain. More than one month of high quality HONO data spanning from the limit of detection to 5ppb were collected. Intercomparison of our system with another established system from Forschungszentrum Juelich is presented and discussed. In conclusion, our instrument achieved a detection limit of 10pptV within 2min and a measurement uncertainty of 7%, which is well suited for investigation of the HONO budget from urban to rural conditions in China. Copyright © 2016. Published by Elsevier B.V.

AN AFFORDABLE HIGH PERFORMANCE PUMPING SYSTEM FOR GRADIENT CAPILLARY LIQUID CHROMATOGRAPHY. (R825344)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

AN ENZYME-IMMOBILIZATION PROCEDURE FOR THE ANALYSIS OF ENZYME-INHIBITING CHEMICALS IN WATER

EPA Science Inventory

The enzymes cholinesterase and urease were mixed individually with gelatin and immobilized onto the inside surface of glass capillary tubes. After the gelatin-enzyme mixture had dried, water samples containing various enzyme inhibiting test chemicals were pumped through the tubes...

Energy 101: Geothermal Heat Pumps

ScienceCinema

None

2018-02-13

An energy-efficient heating and cooling alternative, the geothermal heat pump system moves heat from the ground to a building (or from a building to the ground) through a series of flexible pipe "loops" containing water. This edition of Energy 101 explores the benefits Geothermal and the science behind how it all comes together.

Protection of tokamak plasma facing components by a capillary porous system with lithium

NASA Astrophysics Data System (ADS)

Lyublinski, I.; Vertkov, A.; Mirnov, S.; Lazarev, V.

2015-08-01

Development of plasma facing material (PFM) based on the Capillary-Porous System (CPS) with lithium and activity on realization of lithium application strategy are addressed to meet the challenges under the creation of steady-state tokamak fusion reactor and fusion neutron source. Presented overview of experimental study of lithium CPS in plasma devices demonstrates the progress in protection of tokamak plasma facing components (PFC) from damage, stabilization and self-renewal of liquid lithium surface, elimination of plasma pollution and lithium accumulation in tokamak chamber. The possibility of PFC protection from the high power load related to cooling of the tokamak boundary plasma by radiation of non-fully stripped lithium ions supported by experimental results. This approach demonstrated in scheme of closed loops of Li circulation in the tokamak vacuum chamber and realized in a series of design of tokamak in-vessel elements.

[The combined use of capillaroscopy and skin thermometry in health surveillance of workers exposed to hand-arm vibration].

PubMed

Riolfi, A; Perbellini, L

2010-01-01

The use of nailfold capillaroscopy combined with skin thermometry in the study of microcirculation of the hands in workers exposed to hand-arm vibration is assessed. Fifty-eight subjects were studied; 40 asymptomatic forestry workers exposed to hand-arm vibration, 13 forestry workers exposed to hand-arm vibration with Raynaud-like symptoms confirmed by skin thermometry; 5 controls. Reduction of capillary density was observed in workers exposed to vibrating tools with respect to controls. Tortuosity of capillary loops was significantly more frequent in subjects exposed to vibrating tools than in controls. No statistically significant difference in capillary vessels of the hands was found between asymptomatic exposed subjects and workers affected by Raynaud-like symptoms. In our sample nailfold capillaroscopy shows good sensibilty and specificity in detecting capillary modifications secondary to exposure to hand-vibration. Weaker evidence is instead given in order to actual disturbances of hands circulation in chronic exposure to vibrating tools.

Tunable erbium-doped fiber laser based on optical fiber Sagnac interference loop with angle shift spliced polarization maintaining fibers

NASA Astrophysics Data System (ADS)

Ding, Zhenming; Wang, Zhaokun; Zhao, Chunliu; Wang, Dongning

2018-05-01

In this paper, we propose and experimentally demonstrate a tunable erbium-doped fiber laser (EDFL) with Sagnac interference loop with 45° angle shift spliced polarization maintaining fibers (PMFs). In the Sagnac loop, two PMFs with similar lengths. The Sagnac loop outputs a relatively complex interference spectrum since two beams transmitted in clockwise and counterclockwise encounter at the 3 dB coupler, interfere, and form two interference combs when the light transmitted in the Sagnac loop. The laser will excite and be stable when two interference lines in these two interference combs overlap together. Then by adjusting the polarization controller, the wide wavelength tuning is realized. Experimental results show that stable single wavelength laser can be realized in the wavelength range of 1585 nm-1604 nm under the pump power 157.1 mW. The side-mode suppression ratio is not less than 53.9 dB. The peak power fluctuation is less than 0.29 dB within 30 min monitor time and the side-mode suppression ratio is great than 57.49 dB when the pump power is to 222.7 mW.

A glass capillary based microfluidic electromembrane extraction of basic degradation products of nitrogen mustard and VX from water.

PubMed

Tak, Vijay; Kabra, Ankur; Pardasani, Deepak; Goud, D Raghavender; Jain, Rajeev; Dubey, D K

2015-12-24

In this work, a glass capillary based microfluidic electromembrane extraction (μ-EME) was demonstrated for the first time. The device was made by connecting an auxillary borosilicate glass tubing (O.D. 3mm, I.D. 2mm) perpendicular to main borosilicate glass capillary just below one end of the capillary (O.D. 8mm, I.D. 1.2mm). It generated the distorted T-shaped device with inlet '1' and inlet '2' for the introduction of sample and acceptor solutions, respectively. At one end of this device (inlet '2'), a microsyringe containing acceptor solution along with hollow fiber (O.D. 1000μm) was introduced. This configuration creates the micro-channel between inner wall of glass capillary and outer surface of hollow fiber. Sample solution was pumped into the system through another end of glass capillary (inlet '1'), with a micro-syringe pump. The sample was in direct contact with the supported liquid membrane (SLM), consisted of 20% (w/w) di-(2-ethylhexyl)phosphate in 2-nitrophenyl octyl ether immobilized in the pores of the hollow fiber. In the lumen of the hollow fiber, the acceptor phase was present. The driving force for extraction was direct current (DC) electrical potential sustained over the SLM. Highly polar (logP=-2.5 to 1.4) basic degradation products of nitrogen mustard and VX were selected as model analytes. The influence of chemical composition of SLM, extraction time, voltage and pH of donor and acceptor phase were investigated. The model analytes were extracted from 10μL of pure water with recoveries ranging from 15.7 to 99.7% just after 3min of operation time. Under optimized conditions, good limits of detection (2-50ngmL(-1)), linearity (from 5-1000 to 100-1000ngmL(-1)), and repeatability (RSDs below 11.9%, n=3) were achieved. Applicability of the proposed μ-EME was proved by recovering triethanolamine (31.3%) from 10μL of five times diluted original water sample provided by the Organization for the Prohibition of Chemical Weapons during 28th official proficiency test. Copyright © 2015 Elsevier B.V. All rights reserved.

Home Use of Day-and-Night Hybrid Closed-Loop Insulin Delivery in Suboptimally Controlled Adolescents With Type 1 Diabetes: A 3-Week, Free-Living, Randomized Crossover Trial.

PubMed

Tauschmann, Martin; Allen, Janet M; Wilinska, Malgorzata E; Thabit, Hood; Acerini, Carlo L; Dunger, David B; Hovorka, Roman

2016-11-01

This study evaluated the feasibility, safety, and efficacy of day-and-night hybrid closed-loop insulin delivery in adolescents with type 1 diabetes under free-living conditions. In an open-label randomized crossover study, 12 suboptimally controlled adolescents on insulin pump therapy (mean ± SD age 14.6 ± 3.1 years; HbA 1c 69 ± 8 mmol/mol [8.5 ± 0.7%]; duration of diabetes 7.8 ± 3.5 years) underwent two 21-day periods in which hybrid closed-loop insulin delivery was compared with sensor-augmented insulin pump therapy in random order. During the closed-loop intervention, a model predictive algorithm automatically directed insulin delivery between meals and overnight. Participants used a bolus calculator to administer prandial boluses. The proportion of time that sensor glucose was in the target range (3.9-10 mmol/L; primary end point) was increased during the closed-loop intervention compared with sensor-augmented insulin pump therapy by 18.8 ± 9.8 percentage points (mean ± SD; P < 0.001), the mean sensor glucose level was reduced by 1.8 ± 1.3 mmol/L (P = 0.001), and the time spent above target was reduced by 19.3 ± 11.3 percentage points (P < 0.001). The time spent with sensor glucose levels below 3.9 mmol/L was low and comparable between interventions (median difference 0.4 [interquartile range -2.2 to 1.3] percentage points; P = 0.33). Improved glucose control during closed-loop was associated with increased variability of basal insulin delivery (P < 0.001) and an increase in the total daily insulin dose (53.5 [39.5-72.1] vs. 51.5 [37.6-64.3] units/day; P = 0.006). Participants expressed positive attitudes and experience with the closed-loop system. Free-living home use of day-and-night closed-loop in suboptimally controlled adolescents with type 1 diabetes is safe, feasible, and improves glucose control without increasing the risk of hypoglycemia. Larger and longer studies are warranted. © 2016 by the American Diabetes Association.

Miniaturized technology for DNA typing: cassette PCR.

PubMed

Manage, Dammika P; Pilarski, Linda M

2015-01-01

With the smaller size, low cost, and rapid testing capabilities, miniaturized lab-on-a-chip devices can change the way medical diagnostics are currently performed in the health-care system. We have demonstrated such a device that is self-contained, simple, disposable, and inexpensive. It is capable of performing DNA amplification on an inexpensive instrument suitable for near point of care settings. This technology will enable on the spot evaluation of patients in the clinic for faster medical decision-making and more informed therapeutic choices. Our device, a gel capillary cassette, termed cassette PCR, contains capillary reaction units each holding a defined primer set, with arrays of capillary reaction units for simultaneously detecting multiple targets. With the exception of the sample to be tested, each capillary reaction unit holds all the reagents needed for PCR in a desiccated form that can be stored at room temperature for up to 3 months and even longer in colder conditions. It relies on capillary forces for sample delivery of microliter volumes through capillaries, hence avoiding the need for pumps or valves. In the assembled cassette, the wax architecture supporting the capillaries melts during the PCR and acts as a vapor barrier as well as segregating capillaries with different primer sets. No other chip sealing techniques are required. Cassette PCR accepts raw samples such as urine, genital swabs, and blood. The cassette is made with off-the-shelf components and contains integrated positive and negative controls.

Direct visualization of minimal cerebral capillary flow during retrograde cerebral perfusion: an intravital fluorescence microscopy study in pigs.

PubMed

Duebener, Lennart F; Hagino, Ikuo; Schmitt, Katharina; Sakamoto, Takahiko; Stamm, Christof; Zurakowski, David; Schäfers, Hans-Joachim; Jonas, Richard A

2003-04-01

Retrograde cerebral perfusion (RCP) is used in some centers during aortic arch surgery for brain protection during hypothermic circulatory arrest. It is still unclear however whether RCP provides adequate microcirculatory blood flow at a capillary level. We used intravital microscopy to directly visualize the cerebral capillary blood flow in a piglet model of RCP. Twelve pigs (weight 9.7 +/- 0.9 kg) were divided into two groups (n = 6 each): deep hypothermic circulatory arrest (DHCA) and RCP. After the creation of a window over the parietal cerebral cortex, pigs underwent 10 minutes of normothermic bypass and 40 minutes of cooling to 15 degrees C on cardiopulmonary bypass ([CPB] pH-stat, hemocrit 30%, pump flow 100 mL x kg(-1) x min(-1)). This was followed by 45 minutes of DHCA and rewarming on CPB to 37 degrees C. In the RCP group the brain was retrogradely perfused (pump flow 30 mL x kg(-1) x min(-1)) during DHCA through the superior vena cava after inferior vena cava occlusion. Plasma was labeled with fluorescein-isothiocyanate-dextran for assessing microvascular diameter and functional capillary density (FCD), defined as total length of erythrocyte-perfused capillaries per observation area. Cerebral tissue oxygenation was determined by nicotinamide adenine dinucleotide hydrogen (NADH) autofluorescence, which increases during tissue ischemia. During normothermic and hypothermic antegrade cerebral perfusion the FCD did not significantly change from base line (97% +/- 14% and 96% +/- 12%, respectively). During retrograde cerebral perfusion the FCD decreased highly significantly to 2% +/- 2% of base line values (p < 0.001). Thus there was no evidence of significant capillary blood flow during retrograde cerebral perfusion. The microvascular diameter of cerebral arterioles that were slowly perfused significantly decreased to 27% +/- 6% of base line levels during RCP. NADH fluorescence progressively and significantly increased during RCP, indicating poorer tissue oxygenation. At the end of retrograde cerebral perfusion there was macroscopic evidence of significant brain edema. RCP does not provide adequate cerebral capillary blood flow and does not prevent cerebral ischemia. Prolonged RCP induces brain edema. However, there might be a role for a short period of RCP to remove air and debris from the cerebral circulation after DHCA because retrograde flow could be detected in cerebral arterioles.

Open-loop heat-recovery dryer

DOEpatents

TeGrotenhuis, Ward Evan

2013-11-05

A drying apparatus is disclosed that includes a drum and an open-loop airflow pathway originating at an ambient air inlet, passing through the drum, and terminating at an exhaust outlet. A passive heat exchanger is included for passively transferring heat from air flowing from the drum toward the exhaust outlet to air flowing from the ambient air inlet toward the drum. A heat pump is also included for actively transferring heat from air flowing from the passive heat exchanger toward the exhaust outlet to air flowing from the passive heat exchanger toward the drum. A heating element is also included for further heating air flowing from the heat pump toward the drum.

Single frequency 1083nm ytterbium doped fiber master oscillator power amplifier laser.

PubMed

Huang, Shenghong; Qin, Guanshi; Shirakawa, Akira; Musha, Mitsuru; Ueda, Ken-Ichi

2005-09-05

Single frequency 1083nm ytterbium fiber master oscillator power amplifier system was demonstrated. The oscillator was a linear fiber cavity with loop mirror filter and polarization controller. The loop mirror with unpumped ytterbium fiber as a narrow bandwidth filter discriminated and selected laser longitudinal modes efficiently. Spatial hole burning effect was restrained by adjusting polarization controller appropriately in the linear cavity. The amplifier was 5 m ytterbium doped fiber pumped by 976nm pigtail coupled laser diode. The linewidth of the single frequency laser was about 2 KHz. Output power up to 177 mW was produced under the launched pump power of 332 mW.

Development of a Compact Efficient Cooling Pump for Space Suit Life Support Systems

NASA Technical Reports Server (NTRS)

vanBoeyen, Roger W.; Reeh, Jonathan A.; Trevino, Luis

2008-01-01

With the increasing demands placed on extravehicular activity (EVA) for the International Space Station (ISS) assembly and maintenance, along with planned lunar and Martian missions, the need for increased human productivity and capability becomes ever more critical. This is most readily achieved by reduction in space suit weight and volume, and increased hardware reliability, durability, and operating lifetime. Considerable progress has been made with each successive generation of space suit design; from the Apollo A7L suit, to the current Shuttle Extravehicular Mobile Unit (EMU) suit, and the next generation Constellation Space Suit Element (CSSE). However, one area of space suit design which has continued to lag is the fluid pump used to drive the water cooling loop of the Primary Life Support System (PLSS). The two main types of fluid pumps typically used in space applications are rotodynamic pumps (pumping is achieved through a rotary vaned impeller) and displacement pumps (which includes rotary and diaphragm pumps). The rotating and moving parts found in the pumps and electric motor add significantly to the susceptibility to wear and friction, thermal mismatch, and complexity of the pumps. Electric motor-driven pumps capable of achieving high operational reliability are necessarily large, heavy, and energy inefficient. This report describes a development effort conducted for NASA by Lynntech, Inc., who recently demonstrated the feasibility of an electrochemically-driven fluid cooling pump. With no electric motor and minimal lightweight components, an electrochemically-driven pump is expected to be significantly smaller, lighter and achieve a longer life time than conventional rotodynamic and displacement pumps. By employing sulfonated polystyrene-based proton exchange membranes, rather than conventional Nafion membranes, a significant reduction in the actuator power consumption was demonstrated. It was also demonstrated that these membranes possess the necessary mechanical strength, durability, and temperature range for long life space operation. The preliminary design for a Phase II prototype pump compares very favorably to the fluid cooling pumps currently used in space suit portable life support systems (PLSS). Characteristics of the electrochemically-driven pump are described and the benefits of the technology as a replacement for electric motor pumps in mechanically pumped single-phase fluid loops (MPFLs) is discussed.

Integrated fountain effect pump device for fluid management at low gravity

NASA Technical Reports Server (NTRS)

Yuan, S. W. K.; Frank, D. J.

1988-01-01

A new device for fluid management at low gravity is described. The system is basically the same as the enclosed capillary device using screens, in which the screens along the gallery channels are replaced by porous plugs which are responsible for both the fluid retention and pumping of He II; in this device, no downstream pump is needed. The plugs in contact with liquid He on both sides act as a fountain-effect pumps (FEPs), while plugs exposed to vapor on one side behave as vapor-liquid phase separators (VLPSs). The total net rate of He II transfer into the receiving tank equals the mass flow rate through the FEP plugs minus the liquid loss from the VLPS plugs. The results of the performance analysis of this integrated FEP device are presented together with its schematic diagram.

Pumping Test Determination of Unsaturated Aquifer Properties

NASA Astrophysics Data System (ADS)

Mishra, P. K.; Neuman, S. P.

2008-12-01

Tartakovsky and Neuman [2007] presented a new analytical solution for flow to a partially penetrating well pumping at a constant rate from a compressible unconfined aquifer considering the unsaturated zone. In their solution three-dimensional, axially symmetric unsaturated flow is described by a linearized version of Richards' equation in which both hydraulic conductivity and water content vary exponentially with incremental capillary pressure head relative to its air entry value, the latter defining the interface between the saturated and unsaturated zones. Both exponential functions are characterized by a common exponent k having the dimension of inverse length, or equivalently a dimensionless exponent kd=kb where b is initial saturated thickness. The authors used their solution to analyze drawdown data from a pumping test conducted by Moench et al. [2001] in a Glacial Outwash Deposit at Cape Cod, Massachusetts. Their analysis yielded estimates of horizontal and vertical saturated hydraulic conductivities, specific storage, specific yield and k . Recognizing that hydraulic conductivity and water content seldom vary identically with incremental capillary pressure head, as assumed by Tartakovsky and Neuman [2007], we note that k is at best an effective rather than a directly measurable soil parameter. We therefore ask to what extent does interpretation of a pumping test based on the Tartakovsky-Neuman solution allow estimating aquifer unsaturated parameters as described by more common constitutive water retention and relative hydraulic conductivity models such as those of Brooks and Corey [1964] or van Genuchten [1980] and Mualem [1976a]? We address this question by showing how may be used to estimate the capillary air entry pressure head k and the parameters of such constitutive models directly, without a need for inverse unsaturated numerical simulations of the kind described by Moench [2003]. To assess the validity of such direct estimates we use maximum likelihood- based model selection criteria to compare the abilities of numerical models based on the STOMP code to reproduce observed drawdowns during the test when saturated and unsaturated aquifer parameters are estimated either in the above manner or by means of the inverse code PEST.

DynMo: Dynamic Simulation Model for Space Reactor Power Systems

NASA Astrophysics Data System (ADS)

El-Genk, Mohamed; Tournier, Jean-Michel

2005-02-01

A Dynamic simulation Model (DynMo) for space reactor power systems is developed using the SIMULINK® platform. DynMo is modular and could be applied to power systems with different types of reactors, energy conversion, and heat pipe radiators. This paper presents a general description of DynMo-TE for a space power system powered by a Sectored Compact Reactor (SCoRe) and that employs off-the-shelf SiGe thermoelectric converters. SCoRe is liquid metal cooled and designed for avoidance of a single point failure. The reactor core is divided into six equal sectors that are neutronically, but not thermal-hydraulically, coupled. To avoid a single point failure in the power system, each reactor sector has its own primary and secondary loops, and each loop is equipped with an electromagnetic (EM) pump. A Power Conversion assembly (PCA) and a Thermoelectric Conversion Assembly (TCA) of the primary and secondary EM pumps thermally couple each pair of a primary and a secondary loop. The secondary loop transports the heat rejected by the PCA and the pumps TCA to a rubidium heat pipes radiator panel. The primary loops transport the thermal power from the reactor sector to the PCAs for supplying a total of 145-152 kWe to the load at 441-452 VDC, depending on the selections of the primary and secondary liquid metal coolants. The primary and secondary coolant combinations investigated are lithium (Li)/Li, Li/sodium (Na), Na-Na, Li/NaK-78 and Na/NaK-78, for which the reactor exit temperature is kept below 1250 K. The results of a startup transient of the system from an initial temperature of 500 K are compared and discussed.

Highly sensitive oligosaccharide analysis in capillary electrophoresis using large-volume sample stacking with an electroosmotic flow pump.

PubMed

Kawai, Takayuki; Watanabe, Masato; Sueyoshi, Kenji; Kitagawa, Fumihiko; Otsuka, Koji

2012-04-06

To obtain high sensitivity in capillary electrophoresis of oligosaccharide without reducing the high resolution with an easy experimental procedure, large-volume sample stacking with an electroosmotic flow pump (LVSEP) was investigated. As a fundamental study, effect of the conductivity of a sample solution in LVSEP was examined. It was revealed that LVSEP was successfully carried out even in using a sample solution with the ionic strength of 150 μM and the conductivity ratio of 20, indicating a good applicability of LVSEP to the analysis of real samples containing salts. When glucose oligomer was analyzed as a model sample in LVSEP-capillary zone electrophoresis (CZE), all peaks were well resolved with decreasing only 5% of the peak-to-peak distance, which suggested 95% of the whole capillary could be used for the effective separation. In the analysis of maltoheptaose, a good calibration line with correlation coefficient of 0.9995 was obtained. The limit of detection was estimated as 2 pM, which was 500-fold lower than that in the conventional CZE. N-linked glycans released from three glycoproteins, bovine ribonuclease B, bovine fetuin, and human α(1)-acid glycoprotein were also analyzed by LVSEP-CZE. By the sample purification with a gel filtration column, further sample dilution to reduce the sample conductivity for LVSEP was not needed. All glycan samples were well concentrated and separated with up to a 770-fold sensitivity increase. The run-to-run repeatabilities of the migration time, peak height, and peak area were good with relative standard deviations of 0.1-1.3%, 1.2-1.7%, and 2.8-4.9%, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

Single-bead arrays for fluorescence-based immunoassays on capillary-driven microfluidic chips

NASA Astrophysics Data System (ADS)

Temiz, Yuksel; Lim, Michel; Delamarche, Emmanuel

2016-03-01

We report a concept for the simple fabrication of easy-to-use chips for immunoassays in the context of point-of-care diagnostics. The chip concept comprises mainly three features: (1) the efficient integration of reagents using beads functionalized with receptors, (2) the generation of capillary-driven liquid flows without using external pumps, and (3) a high-sensitivity detection of analytes using fluorescence microscopy. We fabricated prototype chips using dry etching of Si wafers. 4.5-μm-diameter beads were integrated into hexagonal arrays by sedimentation and removing the excess using a stream of water. We studied the effect of different parameters and showed that array occupancies from 30% to 50% can be achieved by pipetting a 250 nL droplet of 1% bead solution and allowing the beads sediment for 3 min. Chips with integrated beads were sealed using a 50-μm-thick dry-film resist laminated at 45 °C. Liquids pipetted to loading pads were autonomously pulled by capillary pumps at a rate of 0.35 nL s-1 for about 30 min. We studied ligand-receptor interactions and binding kinetics using time-lapse fluorescence microscopy and demonstrated a 5 pM limit of detection (LOD) for an anti-biotin immunoassay. As a clinically-relevant example, we implemented an immunoassay to detect prostate specific antigen (PSA) and showed an LOD of 108 fM (i.e. 3.6 pg mL-1). While a specific implementation is provided here for the detection of PSA, we believe that combining capillary-driven microfluidics with arrays of single beads and fluorescence readout to be very flexible and sufficiently sensitive for the detection of other clinically-relevant analytes.

Freeze-tolerant condenser for a closed-loop heat-transfer system

NASA Technical Reports Server (NTRS)

Crowley, Christopher J. (Inventor); Elkouh, Nabil A. (Inventor)

2002-01-01

A freeze tolerant condenser (106) for a two-phase heat transfer system is disclosed. The condenser includes an enclosure (110) and a porous artery (112) located within and extending along the length of the enclosure. A vapor space (116) is defined between the enclosure and the artery, and a liquid space (114) is defined by a central passageway within the artery. The artery includes a plurality of laser-micromachined capillaries (130) extending from the outer surface of the artery to its inner surface such that the vapor space is in fluid communication with the liquid space. In one embodiment of the invention, the capillaries (130) are cylindrical holes having a diameter of no greater than 50 microns. In another embodiment, the capillaries (130') are slots having widths of no greater than 50 microns. A method of making an artery in accordance with the present invention is also disclosed. The method includes providing a solid-walled tube and laser-micromachining a plurality of capillaries into the tube along a longitudinal axis, wherein each capillary has at least one cross-sectional dimension transverse to the longitudinal axis of less than 50 microns.

Monitoring Enzymatic Reactions in Real Time Using Venturi Easy Ambient Sonic-Spray Ionization Mass Spectrometry

PubMed Central

2016-01-01

We developed a technique to monitor spatially confined surface reactions with mass spectrometry under ambient conditions, without the need for voltage or organic solvents. Fused-silica capillaries immersed in an aqueous solution, positioned in close proximity to each other and the functionalized surface, created a laminar flow junction with a resulting reaction volume of ∼5 pL. The setup was operated with a syringe pump, delivering reagents to the surface through a fused-silica capillary. The other fused-silica capillary was connected to a Venturi easy ambient sonic-spray ionization source, sampling the resulting analytes at a slightly higher flow rate compared to the feeding capillary. The combined effects of the inflow and outflow maintains a chemical microenvironment, where the rate of advective transport overcomes diffusion. We show proof-of-concept where acetylcholinesterase was immobilized on an organosiloxane polymer through electrostatic interactions. The hydrolysis of acetylcholine by acetylcholinesterase into choline was monitored in real-time for a range of acetylcholine concentrations, fused-silica capillary geometries, and operating flow rates. Higher reaction rates and conversion yields were observed with increasing acetylcholine concentrations, as would be expected. PMID:27249533

Reactor Simulator Testing

NASA Technical Reports Server (NTRS)

Schoenfeld, Michael P.; Webster, Kenny L.; Pearson, Boise Jon

2013-01-01

As part of the Nuclear Systems Office Fission Surface Power Technology Demonstration Unit (TDU) project, a reactor simulator test loop (RxSim) was design & built to perform integrated testing of the TDU components. In particular, the objectives of RxSim testing was to verify the operation of the core simulator, the instrumentation and control system, and the ground support gas and vacuum test equipment. In addition, it was decided to include a thermal test of a cold trap purification design and a pump performance test at pump voltages up to 150 V since the targeted mass flow rate of 1.75 kg/s was not obtained in the RxSim at the originally constrained voltage of 120 V. This paper summarizes RxSim testing. The gas and vacuum ground support test equipment performed effectively in NaK fill, loop pressurization, and NaK drain operations. The instrumentation and control system effectively controlled loop temperature and flow rates or pump voltage to targeted settings. The cold trap design was able to obtain the targeted cold temperature of 480 K. An outlet temperature of 636 K was obtained which was lower than the predicted 750 K but 156 K higher than the cold temperature indicating the design provided some heat regeneration. The annular linear induction pump (ALIP) tested was able to produce a maximum flow rate of 1.53 kg/s at 800 K when operated at 150 V and 53 Hz. Keywords: fission, space power, nuclear, liquid metal, NaK.

Residential Photovoltaic/Thermal Energy System

NASA Technical Reports Server (NTRS)

Selcuk, M. K.

1987-01-01

Proposed system supplies house with both heat and electricity. Pair of reports describes concept for self-sufficient heating, cooling, and power-generating system for house. Panels on walls of house provide hot water, space heating, and heat to charge heat-storage system, and generate electricity for circulation pumps and fans. Roof panels generate electricity for household, operate heat pump for summer cooling, and provide supplementary winter heating via heat pump, using solar-cell cooling-fluid loop. Wall and roof panels used independently.

Heat transfer in an evaporation-condensation system in simulated weightlessness conditions

NASA Astrophysics Data System (ADS)

Bologa, M. K.; Grosu, F. P.; Kozhevnikov, I. V.; Motorin, O. V.; Polikarpov, A. A.

2017-10-01

The process of heat transfer in an evaporation-condensation system (ECS) at circulation of dielectric liquid in a closed thermoelectrohydrodynamic (TEHD) loop consisting of an evaporator, a condenser and electrohydrodynamic (EHD) pump for pumping of heat carrier, is considered. Previously, the authors studied the dependence of heat transfer on the angle of rotation of TEHD loop in a vertical plane. The report contains the results of studies of heat transfer at electrohydrodynamic pumping of the heat carrier (8% solution of acetone in Freon 113) in the condenser area by means of EHD pump of “cone-cone” type. All elements of the ECS are arranged in a horizontal plane and the heat transfer from the heater to the condenser without EHD pumping is impossible. A pulsating heat carrier flow mode, depending on the heat input and the voltage applied to the pump, takes place at EHD pumping. As the input power is decreasing the frequency of the coolant pulsations as well as the departure diameter and number of vapour bubbles are also decreasing. At some critical heat input the pulsations disappear and the transition from turbulent mode to the laminar one takes place causing the decrease of the heat transfer coefficient. The increase of the pumping flow rate by raising the voltage applied to the EHD pump, results in a partial suppression of boiling. The maximum intensification of heat transfer is reached at pulsation frequency of 1.25 Hz. The maximum heat flow from the heater was 4.2·104 W/m2. Graphical representation and the physical interpretation of the results, which reflect the essence of the process, are given.

An open-loop ground-water heat pump system: transient numerical modeling and site experimental results

NASA Astrophysics Data System (ADS)

Lo Russo, S.; Taddia, G.; Gnavi, L.

2012-04-01

KEY WORDS: Open-loop ground water heat pump; Feflow; Low-enthalpy; Thermal Affected Zone; Turin; Italy The increasing diffusion of low-enthalpy geothermal open-loop Groundwater Heat Pumps (GWHP) providing buildings air conditioning requires a careful assessment of the overall effects on groundwater system, especially in the urban areas where several plants can be close together and interfere. One of the fundamental aspects in the realization of an open loop low-enthalpy geothermal system is therefore the capacity to forecast the effects of thermal alteration produced in the ground, induced by the geothermal system itself. The impact on the groundwater temperature in the surrounding area of the re-injection well (Thermal Affected Zone - TAZ) is directly linked to the aquifer properties. The transient dynamic of groundwater discharge and temperature variations should be also considered to assess the subsurface environmental effects of the plant. The experimental groundwater heat pump system used in this study is installed at the "Politecnico di Torino" (NW Italy, Piedmont Region). This plant provides summer cooling needs for the university buildings. This system is composed by a pumping well, a downgradient injection well and a control piezometer. The system is constantly monitored by multiparameter probes measuring the dynamic of groundwater temperature. A finite element subsurface flow and transport simulator (FEFLOW) was used to investigate the thermal aquifer alteration. Simulations were continuously performed during May-October 2010 (cooling period). The numerical simulation of the heat transport in the aquifer was solved with transient conditions. The simulation was performed by considering only the heat transfer within the saturated aquifer, without any heat dispersion above or below the saturated zone due to the lack of detailed information regarding the unsaturated zone. Model results were compared with experimental temperature data derived from groundwater monitoring in the surrounding area of the injection well. Such analysis showed that the measured values differ slightly from the simulated values. That small difference is probably due to the simplification assumptions in the modelling. This hypothesis is still under investigation.

Developmental changes in metabolism and transport properties of capillaries isolated from rat brain.

PubMed

Betz, A L; Goldstein, G W

1981-03-01

1. Capillaries were isolated from the brains of 1- to 45-day-old rats in order to study the development of metabolic and transport aspects of the blood-brain barrier. 2. The hydroxyproline content of capillary hydrolysates increased nearly threefold between 5 and 45 days of age. This finding is consistent with histological studies showing thickening of capillary basement membrane during development. 3. The activities of L-DOPA decarboxylase and monoamine oxidase were greatest in capillaries from 10-day-old rat brain. Thus, the metabolic blood-brain barrier for amine precursors is present during early development. 4. Capillaries from all ages were able to metabolize glucose, beta-hydroxybutyrate and palmitate. The rate of glucose oxidation more than doubled between 21 and 30 days of age but subsequently decreased. In contrast, beta-hydroxybutyrate and palmitate oxidation increased throughout development. These data suggest a sparing effect by alternate fuels on glucose metabolism. 5. Capillary glucose uptake was similar at 10 and 30 days of age and activity of the ouabain-sensitive K+ pump (measured using 86Rb+) was relatively constant at all ages. In contrast, Na+-dependent neutral amino acid transport was not present until after 21 days of age. Since this transport system may be responsible for the active efflux of neutral amino acids from brain to blood, it is likely that this process does not occur at the immature blood-brain barrier. 6. We conclude that various aspects of brain capillary functions show distinct developmental patterns which may be related to changes in blood-brain barrier permeability during development.

Pumped Fluid Loop Heat Rejection and Recovery Systems for Thermal Control of the Mars Science Laboratory

NASA Technical Reports Server (NTRS)

Bhandari, Pradeep; Birur, Gajanana; Prina, Mauro; Ramirez, Brenda; Paris, Anthony; Novak, Keith; Pauken, Michael

2006-01-01

This viewgraph presentation reviews the heat rejection and heat recovery system for thermal control of the Mars Science Laboratory (MSL). The MSL mission will use mechanically pumped fluid loop based architecture for thermal control of the spacecraft and rover. The architecture is designed to harness waste heat from an Multi Mission Radioisotope Thermo-electric Generator (MMRTG) during Mars surface operations for thermal control during cold conditions and also reject heat during the cruise aspect of the mission. There are several test that are being conducted that will insure the safety of this concept. This architecture can be used during any future interplanetary missions utilizing radioisotope power systems for power generation.

Two-dimensional simulation of a two-phase, regenerative pumped radiator loop utilizing direct contact heat transfer with phase change

NASA Astrophysics Data System (ADS)

Rhee, Hyop S.; Begg, Lester L.; Wetch, Joseph R.; Jang, Jong H.; Juhasz, Albert J.

An innovative pumped loop concept for 600 K space power system radiators utilizing direct contact heat transfer, which facilitates repeated startup/shutdown of the power system without complex and time-consuming coolant thawing during power startup, is under development. The heat transfer process with melting/freezing of Li in an NaK flow was studied through two-dimensional time-dependent numerical simulations to characterize and predict the Li/NaK radiator performance during startup (thawing) and shutdown (cold-trapping). Effects of system parameters and the criteria for the plugging domain are presented together with temperature distribution patterns in solid Li and subsequent melting surface profile variations in time.

Free-piston Stirling Engine system considerations for various space power applications

NASA Technical Reports Server (NTRS)

Dochat, George R.; Dhar, Manmohan

1991-01-01

Free-Piston Stirling Engines (FPSE) have the potential to provide high reliability, long life, and efficient operation. Therefore, they are excellent candidates for the dynamic power conversion module of a space-based, power-generating system. FPSE can be coupled with many potential heat sources (radioisotope, solar, or nuclear reactor), various heat input systems (pumped loop, heat pipe), heat rejection (pumped loop or heat pipe), and various power management and distribution systems (ac, dc, high or low voltage, and fixed or variable load). This paper reviews potential space missions that can be met using free-piston Stirling engines and discusses options of various system integration approaches. This paper briefly outlines the program and recent progress.

Development of a Compact, Efficient Cooling Pump for Space Suit Life Support Systems

NASA Technical Reports Server (NTRS)

van Boeyen, Roger; Reeh, Jonathan; Trevino, Luis

2009-01-01

A compact, low-power electrochemically-driven fluid cooling pump is currently being developed by Lynntech, Inc. With no electric motor and minimal lightweight components, the pump is significantly lighter than conventional rotodynamic and displacement pumps. Reliability and robustness is achieved with the absence of rotating or moving components (apart from the bellows). By employing sulfonated polystyrene-based proton exchange membranes, rather than conventional Nafion membranes, a significant reduction in the actuator power consumption was demonstrated. Lynntech also demonstrated that these membranes possess the necessary mechanical strength, durability, and temperature range for long life space operation. The preliminary design for a Phase II prototype pump compares very favorably to the fluid cooling pumps currently used in space suit primary life support systems (PLSSs). Characteristics of the electrochemically-driven pump are described and the benefits of the technology as a replacement for electric motor pumps in mechanically pumped single-phase fluid loops is discussed.

High-sensitivity temperature sensor based on highly-birefringent microfiber

NASA Astrophysics Data System (ADS)

Sun, Li-Peng; Li, Jie; Jin, Long; Gao, Shuai; Tian, Zhuang; Ran, Yang; Guan, Bai-Ou

2013-09-01

We demonstrate an ultrasensitive temperature sensor by sealing a highly-birefringent microfiber into an alcoholinfiltrated copper capillary. With a Sagnac loop configuration, the interferometric spectrum is strongly dependent on the external refractive index (RI) with sensitivity of 36800nm/RIU around RI=1.356. As mainly derived from the ultrahigh RI sensitivity, the temperature response can reach as high as -14.72 nm/°C in the range of 30.9-36.9 °C. The measured response time is ~8s, as determined by the heat-conducting characteristic of the device and the diameter of the copper capillary. Our sensor is featured with low cost, easy fabrication and robustness.

Design of a Mechanical NaK Pump for Fission Space Power Systems

NASA Technical Reports Server (NTRS)

Mireles, Omar R.; Bradley, David; Godfroy, Thomas

2010-01-01

Alkali liquid metal cooled fission reactor concepts are under development for mid-range spaceflight power requirements. One such concept utilizes a sodium-potassium eutectic (NaK) as the primary loop working fluid. Traditionally, linear induction pumps have been used to provide the required flow and head conditions for liquid metal systems but can be limited in performance. This paper details the design, build, and check-out test of a mechanical NaK pump. The pump was designed to meet reactor cooling requirements using commercially available components modified for high temperature NaK service.

Pulmonary hemodynamics and gas exchange in off pump coronary artery bypass grafting.

PubMed

Vedin, Jenny; Jensen, Ulf; Ericsson, Anders; Samuelsson, Sten; Vaage, Jarle

2005-10-01

To investigate the influence of cardiopulmonary bypass on pulmonary hemodynamics and gas exchange. Low risk patients admitted for elective coronary artery bypass grafting were randomized to either on (n=25) or off pump (n=25) surgery. Central hemodynamics, gas exchange, and venous admixture were studied during and up to 20 h after surgery. There was no difference in pulmonary vascular resistance index (P=0.16), right ventricular stroke work index (P>0.2), mean pulmonary artery pressure (P>0.2) or pulmonary capillary wedge pressure (P>0.2) between groups. Soon after surgery there was a tendency towards higher cardiac index (P=0.07) in the off pump group. Arterial oxygen tension (P>0.2), hematocrit (P>0.2), venous admixture (P>0.2), and arterial-venous oxygen content difference (P=0.12) did not differ between groups. This prospective, randomized study showed no difference in pulmonary hemodynamics, pulmonary gas exchange, and venous admixture, in low risk patients undergoing off pump compared to on pump coronary artery bypass surgery.

GHPsRUS Project

DOE Data Explorer

Battocletti, Liz

2013-07-09

The GHPsRUS Project's full name is "Measuring the Costs and Benefits of Nationwide Geothermal Heat Pump Deployment." The dataset contains employment and installation price data collected by four economic surveys: (1)GHPsRUS Project Manufacturer & OEM Survey, (2) GHPsRUS Project Geothermal Loop Survey, (3) GHPsRUS Project Mechanical Equipment Installation Survey, and (4) GHPsRUS Geothermal Heat Pump Industry Survey

Analysis & Tools to Spur Increased Deployment of “Waste Heat” Rejection/Recycling Hybrid Ground-source Heat Pump Systems in Hot, Arid or Semiarid Climates Like Texas

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

Masada, Glenn; Moon, Tess

2013-09-01

This project team analyzed supplemental heat rejection/recovery (SHR) devices or systems that could be used in hybrid ground source heat pump (HGHP) systems located in arid or semi-arid regions in southwestern U.S. Identification of effective SHR solutions would enhance the deployment of ground source heat pumps (GHP) in these regions. In a parallel effort, the team developed integrated GHP models that coupled the building load, heat pump, and ground loop subsystems and which could be applied to residential and commercial office buildings. Then GHP and HGHP performances could be compared in terms of operational performance and life-cycle costs. Several potentialmore » SHR devices were analyzed by applying two strategies: 1) to remove heat directly from the water in the ground loop before it enters the ground and 2) to remove heat in the refrigerant loop of the vapor compression cycle (VCC) of the heat pump so less heat is transferred to the water loop at the condenser of the VCC. Cooling towers, adsorption coolers, and thermoelectric liquid coolers were included in strategy 1, and expanded desuperheaters, thermosyphons, and an optimized VCC were included in strategy 2. Of all SHR devices analyzed, only the cooling tower provided a cost-effective performance enhancement. For the integrated GHP model, the project team selected the building load model HAMBASE and its powerful computational Simulink/MatLab platform, empirical performance map models of the heat pumps based upon manufacturers’ performance data, and a ground loop model developed by Oklahoma State University and rewritten for this project in Simulink/MatLab. The design process used GLHEPRO, also from Oklahoma State University, to size the borehole fields. The building load and ground loop models were compared with simulations from eQuest, ASHRAE 140-2008 standards, EnergyPlus, and GLHEPRO and were found to predict those subsystems’ performance well. The integrated GHP model was applied to a 195m 2 (2100ft 2) residential building and a 4,982m 2 (53,628ft 2) three-story commercial office building, and it ran 10-15 year simulations. The integrated GHP model and its Simulink platform provided residential data, ranging from seconds to years, and commercial office building data, ranging from minutes to years. A cooling tower model was coupled to the base case integrated GHP model for the residential building and the resulting HGHP system provided a cost-effective solution for the Austin, TX location. Simulations for both the residential and commercial building models were run with varying degrees of SHR (device/system not identified) and the results were found to significantly decrease installation costs, increase heat pump efficiency (lower entering water temperature), and prolong the lifetime of the borehole field. Lifetime cycle costs were estimated from the simulation results. Sensitivity studies on system operating performance and lifetime costs were performed on design parameters, such as construction materials, borehole length, borehole configuration and spacing, grout conductivity, and effects of SHR. While some of the results are intuitive, these studies provided quantitative estimates of improved performance and cost. One of the most important results of this sensitivity study is that overall system performance is very sensitive to these design parameters and that modeling and simulation are essential tools to design cost-effective systems.« less

Two Phase Technology Development Initiatives

NASA Technical Reports Server (NTRS)

Didion, Jeffrey R.

1999-01-01

Three promising thermal technology development initiatives, vapor compression thermal control system, electronics cooling, and electrohydrodynamics applications are outlined herein. These technologies will provide thermal engineers with additional tools to meet the thermal challenges presented by increased power densities and reduced architectural options that will be available in future spacecraft. Goddard Space Flight Center and the University of Maryland are fabricating and testing a 'proto- flight' vapor compression based thermal control system for the Ultra Long Duration Balloon (ULDB) Program. The vapor compression system will be capable of transporting approximately 400 W of heat while providing a temperature lift of 60C. The system is constructed of 'commercial off-the-shelf' hardware that is modified to meet the unique environmental requirements of the ULDB. A demonstration flight is planned for 1999 or early 2000. Goddard Space Flight Center has embarked upon a multi-discipline effort to address a number of design issues regarding spacecraft electronics. The program addressed the high priority design issues concerning the total mass of standard spacecraft electronics enclosures and the impact of design changes on thermal performance. This presentation reviews the pertinent results of the Lightweight Electronics Enclosure Program. Electronics cooling is a growing challenge to thermal engineers due to increasing power densities and spacecraft architecture. The space-flight qualification program and preliminary results of thermal performance tests of copper-water heat pipes are presented. Electrohydrodynamics (EHD) is an emerging technology that uses the secondary forces that result from the application of an electric field to a flowing fluid to enhance heat transfer and manage fluid flow. A brief review of current EHD capabilities regarding heat transfer enhancement of commercial heat exchangers and capillary pumped loops is presented. Goddard Space Flight Center research efforts applying this technique to fluid management and fluid pumping are discussed.

An Alternating Current Electroosmotic Pump Based on Conical Nanopore Membranes.

PubMed

Wu, Xiaojian; Ramiah Rajasekaran, Pradeep; Martin, Charles R

2016-04-26

Electroosmotic flow (EOF) is used to pump solutions through microfluidic devices and capillary electrophoresis columns. We describe here an EOF pump based on membrane EOF rectification, an electrokinetic phenomenon we recently described. EOF rectification requires membranes with asymmetrically shaped pores, and conical pores in a polymeric membrane were used here. We show here that solution flow through the membrane can be achieved by applying a symmetrical sinusoidal voltage waveform across the membrane. This is possible because the alternating current (AC) carried by ions through the pore is rectified, and we previously showed that rectified currents yield EOF rectification. We have investigated the effect of both the magnitude and frequency of the voltage waveform on flow rate through the membrane, and we have measured the maximum operating pressure. Finally, we show that operating in AC mode offers potential advantages relative to conventional DC-mode EOF pumps.

A calibration loop to test hot-wire response under supercritical conditions

NASA Astrophysics Data System (ADS)

Radulović, Ivana; Vukoslavčević, P. V.; Wallace, J. M.

2004-11-01

A calibration facility to test the response of hot-wires in CO2 flow under supercritical conditions has been designed and constructed. It is capable of inducing variable speeds at different temperatures and pressures in the ranges of 0.15 - 2 m/s, 15 - 70 deg. C and 1 - 100 bar. The facility is designed as a closed loop with a test section, pump, electrical heater, DC motor and different regulating and measuring devices. The test section is a small tunnel, with a diffuser, honeycomb, screens and a nozzle to provide a uniform flow with a low turbulence level. The speed variation is created by a sealed, magnetic driven gear pump, with a variable rpm DC motor. Using the electrical heater and regulating the amount of CO2 in the facility, the desired temperature and pressure can be reached. The dimensions of the instalation are minimized to reduce the heat, pump power required, and CO2 consumption and to optimize safety. Preliminary testing of a single hot-wire velocity sensor at constant pressure (80 bar) and variable speed and temperature will be briefly described. The hot-wire probes calibrated in this loop will be used to measure turbulence properties in supercritical CO2 in support of improved designs of nuclear reactors to be cooled by supercritical fluids.

Optimization of the open-loop liquid crystal adaptive optics retinal imaging system

NASA Astrophysics Data System (ADS)

Kong, Ningning; Li, Chao; Xia, Mingliang; Li, Dayu; Qi, Yue; Xuan, Li

2012-02-01

An open-loop adaptive optics (AO) system for retinal imaging was constructed using a liquid crystal spatial light modulator (LC-SLM) as the wavefront compensator. Due to the dispersion of the LC-SLM, there was only one illumination source for both aberration detection and retinal imaging in this system. To increase the field of view (FOV) for retinal imaging, a modified mechanical shutter was integrated into the illumination channel to control the size of the illumination spot on the fundus. The AO loop was operated in a pulsing mode, and the fundus was illuminated twice by two laser impulses in a single AO correction loop. As a result, the FOV for retinal imaging was increased to 1.7-deg without compromising the aberration detection accuracy. The correction precision of the open-loop AO system was evaluated in a closed-loop configuration; the residual error is approximately 0.0909λ (root-mean-square, RMS), and the Strehl ratio ranges to 0.7217. Two subjects with differing rates of myopia (-3D and -5D) were tested. High-resolution images of capillaries and photoreceptors were obtained.

Wideband Electrically-Pumped 1050 nm MEMS-Tunable VCSEL for Ophthalmic Imaging.

PubMed

John, Demis D; Burgner, Christopher B; Potsaid, Benjamin; Robertson, Martin E; Lee, Byung Kun; Choi, Woo Jhon; Cable, Alex E; Fujimoto, James G; Jayaraman, Vijaysekhar

2015-08-15

In this paper, we present a 1050 nm electrically-pumped micro-electro-mechanically-tunable vertical-cavity-surface-emitting-laser (MEMS-VCSEL) with a record dynamic tuning bandwidth of 63.8 nm, suitable for swept source optical coherence tomography (SS-OCT) imaging. These devices provide reduced cost & complexity relative to previously demonstrated optically pumped devices by obviating the need for a pump laser and associated hardware. We demonstrate ophthalmic SS-OCT imaging with the electrically-pumped MEMS-VCSEL at a 400 kHz axial scan rate for wide field imaging of the in vivo human retina over a 12 mm × 12 mm field and for OCT angiography of the macula over 6 mm × 6 mm & 3 mm × 3 mm fields to show retinal vasculature and capillary structure near the fovea. These results demonstrate the feasibility of electrically pumped MEMS-VCSELs in ophthalmic instrumentation, the largest clinical application of OCT. In addition, we estimate that the 3 dB coherence length in air is 225 meters ± 51 meters, far greater than required for ophthalmic SS-OCT and suggestive of other distance ranging applications.

P39-T Analysis of Oligosaccharides by Capillary-Scale High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (CHPAEC-PAD) and On-Line Electrospray-Ionization Ion-Trap Mass Spectrometry (CHPAEC-ITMS)

PubMed Central

Bruggink, C.; Koeleman, C.; Barreto, V.; Lui, Y.; Pohl, C.; Ingendoh, A.; Wuhrer, M.; Hokke, C.; Deelder, A.

2007-01-01

High-pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) is an established technique for selective separation and analysis of underivatized carbohydrates. The miniaturization of chromatographic techniques by means of capillary columns, and on-line coupling to mass spectrometry are critical to the further development of glycan analysis methods that are compatible with the current requirements in clinical settings. A system has been developed based on the Dionex BioLC equipped with a microbore gradient pump with PEEK flow splitter, a FAMOS micro autosampler, a modified electrochemical cell for on-line capillary PAD, and a capillary column (380 μm i.d.) packed with a new type of anion-exchange resin. This system operates with sensitivity in the low femtomol range. In addition, an on-line capillary desalter has been developed to allow direct coupling to the Bruker Esquire 3000 ion-trap mass spectrometer with electrospray ionization interface (ESI-IT-MS). Both systems have been evaluated using oligosaccharide standards as well as urine samples exhibiting various lysosomal oligosaccharide storage diseases. Initial data indicate that the robust and selective anion-exchange system, in combination with ESI-IT-MS for structure confirmation and analysis, provides a powerful platform that complements existing nano/capillary LC-MS methods for analytical determination of oligosaccharides in biological matrices.

Detection system of capillary array electrophoresis microchip based on optical fiber

NASA Astrophysics Data System (ADS)

Yang, Xiaobo; Bai, Haiming; Yan, Weiping

2009-11-01

To meet the demands of the post-genomic era study and the large parallel detections of epidemic diseases and drug screening, the high throughput micro-fluidic detection system is needed urgently. A scanning laser induced fluorescence detection system based on optical fiber has been established by using a green laser diode double-pumped solid-state laser as excitation source. It includes laser induced fluorescence detection subsystem, capillary array electrophoresis micro-chip, channel identification unit and fluorescent signal processing subsystem. V-shaped detecting probe composed with two optical fibers for transmitting the excitation light and detecting induced fluorescence were constructed. Parallel four-channel signal analysis of capillary electrophoresis was performed on this system by using Rhodamine B as the sample. The distinction of different samples and separation of samples were achieved with the constructed detection system. The lowest detected concentration is 1×10-5 mol/L for Rhodamine B. The results show that the detection system possesses some advantages, such as compact structure, better stability and higher sensitivity, which are beneficial to the development of microminiaturization and integration of capillary array electrophoresis chip.

The Use of Opto-Electronics in Viscometry.

ERIC Educational Resources Information Center

Mazza, R. J.; Washbourn, D. H.

1982-01-01

Describes a semi-automatic viscometer which incorporates a microprocessor system and uses optoelectronics to detect flow of liquid through the capillary, flow time being displayed on a timer with accuracy of 0.01 second. The system could be made fully automatic with an additional microprocessor circuit and inclusion of a pump. (Author/JN)

Fibronectin non-amyloid glomerulopathy.

PubMed

Yong, Jim L; Killingsworth, Murray C; Spicer, S Timothy; Wu, Xiao-Juan

2009-11-20

A 41-year-old Burmese man presented with nephrotic syndrome, a creatinine level of 150 micromol/L and limited clinical history. His renal biopsy demonstrated glomerulopathy with large eosinophilic deposits in the mesangium and capillary loops that were negative for Congo red, slightly positive for periodic acid-Schiff and blue with Masson trichrome stain. Immunofluorescence microscopy with a routine antibody panel was unhelpful. Electron microscopy demonstrated extensive, moderately electron-dense deposits in the subendothelial space, subepithelial space and mesangium that could be differentiated from adjacent basement membrane by their increased electron density. The deposits contained finely granular material and occasional filaments with variable diameter ranging from 9-16 nm. Fibronectin glomerulopathy was suspected from anti-fibronectin immunohistochemistry that showed positive staining of thickened capillary loops. This staining was subsequently confirmed by immunoelectron microscopy demonstrating the presence of cellular fibronectin (cFN) in deposits. Significantly, deposition of fibronectin appeared to have occurred in the absence of thickening or folding of the adjacent basement membrane. The prominent mesangial location of deposits containing a cFN isotype may indicate that retention of local fibronectin produced in the mesangium has contributed to this pathology.

Fibronectin non-amyloid glomerulopathy

PubMed Central

Yong, Jim L; Killingsworth, Murray C; Spicer, S Timothy; Wu, Xiao-Juan

2010-01-01

A 41-year-old Burmese man presented with nephrotic syndrome, a creatinine level of 150 µmol/L and limited clinical history. His renal biopsy demonstrated glomerulopathy with large eosinophilic deposits in the mesangium and capillary loops that were negative for Congo red, slightly positive for periodic acid-Schiff and blue with Masson trichrome stain. Immunofluorescence microscopy with a routine antibody panel was unhelpful. Electron microscopy demonstrated extensive, moderately electron-dense deposits in the subendothelial space, subepithelial space and mesangium that could be differentiated from adjacent basement membrane by their increased electron density. The deposits contained finely granular material and occasional filaments with variable diameter ranging from 9-16 nm. Fibronectin glomerulopathy was suspected from anti-fibronectin immunohistochemistry that showed positive staining of thickened capillary loops. This staining was subsequently confirmed by immunoelectron microscopy demonstrating the presence of cellular fibronectin (cFN) in deposits. Significantly, deposition of fibronectin appeared to have occurred in the absence of thickening or folding of the adjacent basement membrane. The prominent mesangial location of deposits containing a cFN isotype may indicate that retention of local fibronectin produced in the mesangium has contributed to this pathology. PMID:20126589

Integration of a Micro-Chip Amino Acid Chirality Detector into the MOD Instrument Concept

NASA Technical Reports Server (NTRS)

Bada, Jeffrey L.; Grunthaner, Frank; Mathies, Richard

2004-01-01

The MOD (Mars Organic Detector) instrument concept consists of a sublimation apparatus for organic compound isolation connected to a microfabricated microfluidic analyzer containing a sipper, pumps and a separation channel for organic compound characterization. The target organic compounds are amino acids and polycyclic aromatic hydrocarbons (PAHs). Solid samples are placed within the sublimation apparatus and heated to release organic compounds which sublime onto a cold finger. Half of the cold finger is coated with fluorescamine. which reacts with amino acids and other primary amines to generate an intense fluorescent derivative while the other half is uncoated and is used to directly detect PAH fluorescence, A capillary sipper is then used to dissolve and sample the labeled amino acids and integrated microfabricated pumps transport the labeled amino acids to the chip for analysis. The sample is separated using capillary zone electrophoresis (CZE) together with chiral dextrins to determine amino acid composition and chirality. During the grant period, the following steps have been completed toward the development of a robust instrument and chemistry.

Characterization of Site for Installing Open Loop Ground Source Heat Pump System

NASA Astrophysics Data System (ADS)

Yun, S. W.; Park, Y.; Lee, J. Y.; Yi, M. J.; Cha, J. H.

2014-12-01

This study was conducted to understand hydrogeological properties of site where open loop ground source heat pump system will be installed and operated. Groundwater level and water temperature were hourly measured at the well developed for usage of open loop ground source heat pump system from 11 October 2013 to 8 January 2014. Groundwater was sampled in January and August 2013 and its chemical and isotopic compositions were analyzed. The bedrock of study area is the Jurassic granodiorite that mainly consists of quartz (27.9 to 46.8%), plagioclase (26.0 to 45.5%), and alkali feldspar (9.5 to 18.7%). The groundwater level ranged from 68.30 to 68.94 m (above mean sea level). Recharge rate was estimated using modified watertable fluctuation method and the recharge ratios was 9.1%. The water temperature ranged from 14.8 to 15.0oC. The vertical Increase rates of water temperature were 1.91 to 1.94/100 m. The water temperature showed the significant seasonal variation above 50 m depth, but had constant value below 50 m depth. Therefore, heat energy of the groundwater can be used securely in open loop ground source heat pump system. Electrical conductivity ranged from 120 to 320 µS/cm in dry season and from 133 to 310 µS/cm in wet season. The electrical conductivity gradually decreased with depth. In particular, electrical conductivity in approximately 30 m depth decreased dramatically (287 to 249 µS/cm) in wet season. The groundwater was Ca-HCO3 type. The concentrations of dissolved components did not show the vertically significant variations from 0 to 250 m depth. The δ18O and δD ranged from -9.5 to -9.4‰ and from -69 to -68‰. This work is supported by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.20123040110010).

Design of Accumulators and Liquid/Gas Charging of Single Phase Mechanically Pumped Fluid Loop Heat Rejection Systems

NASA Technical Reports Server (NTRS)

Bhandari, Pradeep; Dudik, Brenda; Birur, Gajanana; Karlmann, Paul; Bame, David; Mastropietro, A. J.

2012-01-01

For single phase mechanically pumped fluid loops used for thermal control of spacecraft, a gas charged accumulator is typically used to modulate pressures within the loop. This is needed to accommodate changes in the working fluid volume due to changes in the operating temperatures as the spacecraft encounters varying thermal environments during its mission. Overall, the three key requirements on the accumulator to maintain an appropriate pressure range throughout the mission are: accommodation of the volume change of the fluid due to temperature changes, avoidance of pump cavitation and prevention of boiling in the liquid. The sizing and design of such an accumulator requires very careful and accurate accounting of temperature distribution within each element of the working fluid for the entire range of conditions expected, accurate knowledge of volume of each fluid element, assessment of corresponding pressures needed to avoid boiling in the liquid, as well as the pressures needed to avoid cavitation in the pump. The appropriate liquid and accumulator strokes required to accommodate the liquid volume change, as well as the appropriate gas volumes, require proper sizing to ensure that the correct pressure range is maintained during the mission. Additionally, a very careful assessment of the process for charging both the gas side and the liquid side of the accumulator is required to properly position the bellows and pressurize the system to a level commensurate with requirements. To achieve the accurate sizing of the accumulator and the charging of the system, sophisticated EXCEL based spreadsheets were developed to rapidly come up with an accumulator design and the corresponding charging parameters. These spreadsheets have proven to be computationally fast and accurate tools for this purpose. This paper will describe the entire process of designing and charging the system, using a case study of the Mars Science Laboratory (MSL) fluid loops, which is en route to Mars for an August 2012 landing.

Long-term pumping test to study the impact of an open-loop geothermal system on seawater intrusion in a coastal aquifer: the case study of Bari (Southern Italy)

NASA Astrophysics Data System (ADS)

Clementina Caputo, Maria; Masciale, Rita; Masciopinto, Costantino; De Carlo, Lorenzo

2016-04-01

The high cost and scarcity of fossil fuels have promoted the increased use of natural heat for a number of direct applications. Just as for fossil fuels, the exploitation of geothermal energy should consider its environmental impact and sustainability. Particular attention deserves the so-called open loop geothermal groundwater heat pump (GWHP) system, which uses groundwater as geothermal fluid. From an economic point of view, the implementation of this kind of geothermal system is particularly attractive in coastal areas, which have generally shallow aquifers. Anyway the potential problem of seawater intrusion has led to laws that restrict the use of groundwater. The scarcity of freshwater could be a major impediment for the utilization of geothermal resources. In this study a new methodology has been proposed. It was based on an experimental approach to characterize a coastal area in order to exploit the low-enthalpy geothermal resource. The coastal karst and fractured aquifer near Bari, in Southern Italy, was selected for this purpose. For the purpose of investigating the influence of an open-loop GWHP system on the seawater intrusion, a long-term pumping test was performed. The test simulated the effects of a prolonged withdrawal on the chemical-physical groundwater characteristics of the studied aquifer portion. The duration of the test was programmed in 16 days, and it was performed with a constant pumping flowrate of 50 m3/h. The extracted water was outflowed into an adjacent artificial channel, by means of a piping system. Water depth, temperature and electrical conductivity of the pumped water were monitored for 37 days, including also some days before and after the pumping duration. The monitored parameters, collected in the pumping and in five observation wells placed 160 m down-gradient with respect to the groundwater flow direction, have been used to estimate different scenarios of the impact of the GWHP system on the seawater intrusion by mean of a numerical model. Model flow simulations were carried out under transient flow conditions, in order to determine perturbations of the saline front into the Bari fractured aquifer, caused by the long-term pumping at 50 m3/h.

A new model of centrifugal blood pump for cardiopulmonary bypass: design improvement, performance, and hemolysis tests.

PubMed

Leme, Juliana; Fonseca, Jeison; Bock, Eduardo; da Silva, Cibele; da Silva, Bruno Utiyama; Dos Santos, Alex Eugênio; Dinkhuysen, Jarbas; Andrade, Aron; Biscegli, José F

2011-05-01

A new model of blood pump for cardiopulmonary bypass (CPB) application has been developed and evaluated in our laboratories. Inside the pump housing is a spiral impeller that is conically shaped and has threads on its surface. Worm gears provide an axial motion of the blood column. Rotational motion of the conical shape generates a centrifugal pumping effect and improves pumping performance. One annular magnet with six poles is inside the impeller, providing magnetic coupling to a brushless direct current motor. In order to study the pumping performance, a mock loop system was assembled. Mock loop was composed of Tygon tubes (Saint-Gobain Corporation, Courbevoie, France), oxygenator, digital flowmeter, pressure monitor, electronic driver, and adjustable clamp for flow control. Experiments were performed on six prototypes with small differences in their design. Each prototype was tested and flow and pressure data were obtained for rotational speed of 1000, 1500, 2000, 2500, and 3000 rpm. Hemolysis was studied using pumps with different internal gap sizes (1.35, 1.45, 1.55, and 1.7 mm). Hemolysis tests simulated CPB application with flow rate of 5 L/min against total pressure head of 350 mm Hg. The results from six prototypes were satisfactory, compared to the results from the literature. However, prototype #6 showed the best results. Best hemolysis results were observed with a gap of 1.45 mm, and showed a normalized index of hemolysis of 0.013 g/100 L. When combined, axial and centrifugal pumping principles produce better hydrodynamic performance without increasing hemolysis. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Feasibility of outpatient fully integrated closed-loop control: first studies of wearable artificial pancreas.

PubMed

Kovatchev, Boris P; Renard, Eric; Cobelli, Claudio; Zisser, Howard C; Keith-Hynes, Patrick; Anderson, Stacey M; Brown, Sue A; Chernavvsky, Daniel R; Breton, Marc D; Farret, Anne; Pelletier, Marie-Josée; Place, Jérôme; Bruttomesso, Daniela; Del Favero, Simone; Visentin, Roberto; Filippi, Alessio; Scotton, Rachele; Avogaro, Angelo; Doyle, Francis J

2013-07-01

To evaluate the feasibility of a wearable artificial pancreas system, the Diabetes Assistant (DiAs), which uses a smart phone as a closed-loop control platform. Twenty patients with type 1 diabetes were enrolled at the Universities of Padova, Montpellier, and Virginia and at Sansum Diabetes Research Institute. Each trial continued for 42 h. The United States studies were conducted entirely in outpatient setting (e.g., hotel or guest house); studies in Italy and France were hybrid hospital-hotel admissions. A continuous glucose monitoring/pump system (Dexcom Seven Plus/Omnipod) was placed on the subject and was connected to DiAs. The patient operated the system via the DiAs user interface in open-loop mode (first 14 h of study), switching to closed-loop for the remaining 28 h. Study personnel monitored remotely via 3G or WiFi connection to DiAs and were available on site for assistance. The total duration of proper system communication functioning was 807.5 h (274 h in open-loop and 533.5 h in closed-loop), which represented 97.7% of the total possible time from admission to discharge. This exceeded the predetermined primary end point of 80% system functionality. This study demonstrated that a contemporary smart phone is capable of running outpatient closed-loop control and introduced a prototype system (DiAs) for further investigation. Following this proof of concept, future steps should include equipping insulin pumps and sensors with wireless capabilities, as well as studies focusing on control efficacy and patient-oriented clinical outcomes.

Design of a Mechanical NaK Pump for Fission Space Power

NASA Technical Reports Server (NTRS)

Mireles, Omar R.; Bradley, David E.; Godfroy, Thomas

2011-01-01

Alkali liquid metal cooled fission reactor concepts are under development for spaceflight power requirements. One such concept utilizes a sodium-potassium eutectic (NaK) as the primary loop working fluid, which has specific pumping requirements. Traditionally, electromagnetic linear induction pumps have been used to provide the required flow and pressure head conditions for NaK systems but they can be limited in performance, efficiency, and number of available vendors. The objective of the project was to develop a mechanical NaK centrifugal pump that takes advantages of technology advances not available in previous liquid metal mechanical pump designs. This paper details the design, build, and performance test of a mechanical NaK pump developed at NASA Marshall Space Flight Center. The pump was designed to meet reactor cooling requirements using commercially available components modified for high temperature NaK service.

Output characteristics of a series three-port axial piston pump

NASA Astrophysics Data System (ADS)

Zhang, Xiaogang; Quan, Long; Yang, Yang; Wang, Chengbin; Yao, Liwei

2012-05-01

Driving a hydraulic cylinder directly by a closed-loop hydraulic pump is currently a key research area in the field of electro-hydraulic control technology, and it is the most direct means to improve the energy efficiency of an electro-hydraulic control system. So far, this technology has been well applied to the pump-controlled symmetric hydraulic cylinder. However, for the differential cylinder that is widely used in hydraulic technology, satisfactory results have not yet been achieved, due to the asymmetric flow constraint. Therefore, based on the principle of the asymmetric valve controlled asymmetric cylinder in valve controlled cylinder technology, an innovative idea for an asymmetric pump controlled asymmetric cylinder is put forward to address this problem. The scheme proposes to transform the oil suction window of the existing axial piston pump into two series windows. When in use, one window is connected to the rod chamber of the hydraulic cylinder and the other is linked with a low-pressure oil tank. This allows the differential cylinders to be directly controlled by changing the displacement or rotation speed of the pumps. Compared with the loop principle of offsetting the area difference of the differential cylinder through hydraulic valve using existing technology, this method may simplify the circuits and increase the energy efficiency of the system. With the software SimulationX, a hydraulic pump simulation model is set up, which examines the movement characteristics of an individual piston and the compressibility of oil, as well as the flow distribution area as it changes with the rotation angle. The pump structure parameters, especially the size of the unloading groove of the valve plate, are determined through digital simulation. All of the components of the series arranged three distribution-window axial piston pump are designed, based on the simulation analysis of the flow pulse characteristics of the pump, and then the prototype pump is made. The basic characteristics, such as the pressure, flow and noise of the pumps under different rotation speeds, are measured on the test bench. The test results verify the correctness of the principle. The proposed research lays a theoretical foundation for the further development of a new pump-controlled cylinder system.

Nailfold capillaroscopy in 430 patients with rheumatoid arthritis.

PubMed

Rajaei, Alireza; Dehghan, Pooneh; Amiri, Ali

2017-01-01

Microvascular changes are one of the first obvious steps in numerous inflammatory diseases such as rheumatoid arthritis (RA). Nailfold video capillaroscopy (NFC) is an easy, reliable and safe method for evaluating peripheral microangiopathy. The objective of this study was to examine nailfold microcirculation in RA patients, assess morphological and structural changes quantitatively and qualitatively, and recognize useful changes. A total of 430 patients diagnosed with RA were examined in a period of 4 years. NFC was performed on all fingers of both hands in each patient. Different parameters indicating microvascular changes were detected and analyzed; such as microvascular architecture, capillary distribution disturbances, capillary morphology, capillary density, efferent/afferent limb ratio, subpapillary venular plexus and morphological abnormalities. The obtained results were categorized into normal pattern, nonspecific morphological abnormality and scleroderma pattern. The mean age of participants was 51.03±14.54 (19-87 years) that consisted of 359 females and 71 males. Based on the findings, angiogenesis (74.7%) was the most pathological condition observed after tortuosity (99.5%). 7.2% and 20.9% of patients were categorized into normal and scleroderma pattern group, respectively. Among morphological abnormalities, angiogenesis, isolated enlarged loop, irregular enlarged loop and architectural derangement were significantly more frequent in scleroderma than normal pattern (p<0.001). NFC may play an important role in monitoring RA disease and patients' follow-up. Therefore, in our opinion it could be considered in the course and follow-up of rheumatoid arthritis.

Nailfold capillaroscopy in 430 patients with rheumatoid arthritis

PubMed Central

Rajaei, Alireza; Dehghan, Pooneh; Amiri, Ali

2017-01-01

Background: Microvascular changes are one of the first obvious steps in numerous inflammatory diseases such as rheumatoid arthritis (RA). Nailfold video capillaroscopy (NFC) is an easy, reliable and safe method for evaluating peripheral microangiopathy. The objective of this study was to examine nailfold microcirculation in RA patients, assess morphological and structural changes quantitatively and qualitatively, and recognize useful changes. Methods: A total of 430 patients diagnosed with RA were examined in a period of 4 years. NFC was performed on all fingers of both hands in each patient. Different parameters indicating microvascular changes were detected and analyzed; such as microvascular architecture, capillary distribution disturbances, capillary morphology, capillary density, efferent/afferent limb ratio, subpapillary venular plexus and morphological abnormalities. The obtained results were categorized into normal pattern, nonspecific morphological abnormality and scleroderma pattern. Results: The mean age of participants was 51.03±14.54 (19-87 years) that consisted of 359 females and 71 males. Based on the findings, angiogenesis (74.7%) was the most pathological condition observed after tortuosity (99.5%). 7.2% and 20.9% of patients were categorized into normal and scleroderma pattern group, respectively. Among morphological abnormalities, angiogenesis, isolated enlarged loop, irregular enlarged loop and architectural derangement were significantly more frequent in scleroderma than normal pattern (p<0.001). Conclusion: NFC may play an important role in monitoring RA disease and patients’ follow-up. Therefore, in our opinion it could be considered in the course and follow-up of rheumatoid arthritis. PMID:29201317

Highly sensitive chiral analysis in capillary electrophoresis with large-volume sample stacking with an electroosmotic flow pump.

PubMed

Kawai, Takayuki; Koino, Hiroshi; Sueyoshi, Kenji; Kitagawa, Fumihiko; Otsuka, Koji

2012-07-13

To improve the sensitivity in chiral analysis by capillary electrophoresis without loss of optical resolution, application of large-volume sample stacking with an electroosmotic flow pump (LVSEP) was investigated. Effects of the addition of cyclodextrin (CD) into a running solution on the LVSEP preconcentration was theoretically studied, where the preconcentration efficiency and effective separation length would be slightly increased if the effective electrophoretic velocity (v(ep,eff,BGS)) of the analytes was decreased by interacting with CD. In LVSEP-CD-modified capillary zone electrophoresis (CDCZE) and LVSEP-CD electrokinetic chromatography with reduced v(ep,eff,BGS), up to 1000-fold sensitivity increases were achieved with almost no loss of resolution. In LVSEP-CD-modified micellar electrokinetic chromatography of amino acids with increased v(ep,eff,BGS), a 1300-fold sensitivity increase was achieved without much loss of resolution, indicating the versatile applicability of LVSEP to many separation modes. An enantio-excess (EE) assay was also carried out in LVSEP-CDCZE, resulting in successful analyses of up to 99.6% EE. Finally, we analyzed ibuprofen in urine by desalting with a C₁₈ solid-phase extraction column. As a typical result, 250ppb ibuprofen was well concentrated and optically resolved with 84.0-86.6% recovery in LVSEP-CDCZE, indicating the applicability of LVSEP to real samples containing a large amount of unnecessary background salts. Copyright © 2012 Elsevier B.V. All rights reserved.

Advanced two-phase heat transfer systems

NASA Technical Reports Server (NTRS)

Swanson, Theodore D.

1992-01-01

Future large spacecraft, such as the Earth Observing System (EOS) platforms, will require a significantly more capable thermal control system than is possible with current 'passive' technology. Temperatures must be controlled much more tightly over a larger surface area. Numerous heat load sources will often be located inside the body of the spacecraft without a good view to space. Power levels and flux densities may be higher than can be accommodated with traditional technology. Integration and ground testing will almost certainly be much more difficult with such larger, more complex spacecraft. For these and similar reasons, the Goddard Space Flight Center (GSFC) has been developing a new, more capable thermal control technology called capillary pumped loops (CPL's). CPL's represent an evolutionary improvement over heat pipes; they can transport much greater quantities of heat over much longer distances and can serve numerous heat load sources. In addition, CPL's can be fabricated into large cold plates that can be held to tight thermal gradients. Development of this technology began in the early 1980's and is now reaching maturity. CPL's have recently been baselined for the EOS-AM platform (1997 launch) and the COMET spacecraft (1992 launch). This presentation describes this new technology and its applications. Most of the viewgraphs are self descriptive. For those that are less clear additional comments are provided.

On Orbit ISS Oxygen Generation System Operation Status

NASA Technical Reports Server (NTRS)

Diderich, Greg S.; Polis, Pete; VanKeuren, Steven P.; Erickson, Robert; Mason, Richard

2011-01-01

The International Space Station (ISS) United States Orbital Segment (USOS) Oxygen Generation System (OGS) has accumulated almost a year of operation at varied oxygen production rates within the US Laboratory Module (LAB) since it was first activated in July 2007. It was operated intermittently through 2009 and 2010, due to filter clogging and acid accumulation in the recirculation loop. Since the installation of a deionizing bed in the recirculation loop in May of 2011 the OGA has been operated continuously. Filters in the recirculation loop have clogged and have been replaced. Hydrogen sensors have drifted apart, and a power failure may have condensed water on a hydrogen sensor. A pump delta pressure sensor failed, and a replacement new spare pump failed to start. Finally, the voltage across the cell stack increased out of tolerance due to cation contamination, and the cell stack was replaced. This paper will discuss the operating experience and characteristics of the OGS, as well as operational issues and their resolution.

High average power laser using a transverse flowing liquid host

DOEpatents

Ault, Earl R.; Comaskey, Brian J.; Kuklo, Thomas C.

2003-07-29

A laser includes an optical cavity. A diode laser pumping device is located within the optical cavity. An aprotic lasing liquid containing neodymium rare earth ions fills the optical cavity. A circulation system that provides a closed loop for circulating the aprotic lasing liquid into and out of the optical cavity includes a pump and a heat exchanger.

Shock and vibration tests of a SNAP-8 NaK pump

NASA Technical Reports Server (NTRS)

Stromquist, A. J.; Nelson, R. B.; Hibben, L.

1971-01-01

The pump used for reactor cooling in the SNAP 8 space power system was subjected to the expected vehicle launch vibration, and shock loading in accordance with the SNAP 8 environmental specification. Subsequent disassembly revealed damage to the thrust bearing pins, which should be redesigned and strengthened. The unit was operational, however, when run in a test loop after reassembly.

40 CFR 65.107 - Standards: Pumps in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

... or fuel gas system or connected by a closed vent system to a control device that complies with the requirements of § 65.115; or (C) Equipped with a closed-loop system that purges the barrier fluid into a... section. (3) Routed to a process or fuel gas system or equipped with a closed vent system. Any pump that...

Test Results From a Pair of 1-kWe Dual-Opposed Free-Piston Stirling Power Convertors Integrated With a Pumped NaK Loop

NASA Technical Reports Server (NTRS)

Geng, Steven M.; Briggs, Maxwell H.; Penswick, L. Barry; Pearson, J. Boise; Godfroy, Thomas J.

2011-01-01

As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1-kW-class free-piston Stirling convertors were modified to operate with a NaK (sodium (Na) and potassium (K)) liquid metal pumped loop for thermal energy input. This was the first-ever attempt at powering a free-piston Stirling engine with a pumped liquid metal heat source and is a major FSP project milestone towards demonstrating technical feasibility. The convertors were successfully tested at the Marshall Space Flight Center (MSFC) from June 6 through July 14, 2009. The convertors were operated for a total test time of 66 hr and 16 min. The tests included (a) performance mapping the convertors over various hot- and cold-end temperatures, piston amplitudes, and NaK flow rates and (b) transient test conditions to simulate various startup (i.e., low-, medium-, and high-temperature startups) and fault scenarios (i.e., loss of heat source, loss of NaK pump, convertor stall, etc.). This report documents the results of this testing

Thermodynamic stability of nanosized multicomponent bubbles/droplets: the square gradient theory and the capillary approach.

PubMed

Wilhelmsen, Øivind; Bedeaux, Dick; Kjelstrup, Signe; Reguera, David

2014-01-14

Formation of nanosized droplets/bubbles from a metastable bulk phase is connected to many unresolved scientific questions. We analyze the properties and stability of multicomponent droplets and bubbles in the canonical ensemble, and compare with single-component systems. The bubbles/droplets are described on the mesoscopic level by square gradient theory. Furthermore, we compare the results to a capillary model which gives a macroscopic description. Remarkably, the solutions of the square gradient model, representing bubbles and droplets, are accurately reproduced by the capillary model except in the vicinity of the spinodals. The solutions of the square gradient model form closed loops, which shows the inherent symmetry and connected nature of bubbles and droplets. A thermodynamic stability analysis is carried out, where the second variation of the square gradient description is compared to the eigenvalues of the Hessian matrix in the capillary description. The analysis shows that it is impossible to stabilize arbitrarily small bubbles or droplets in closed systems and gives insight into metastable regions close to the minimum bubble/droplet radii. Despite the large difference in complexity, the square gradient and the capillary model predict the same finite threshold sizes and very similar stability limits for bubbles and droplets, both for single-component and two-component systems.

Thermodynamic stability of nanosized multicomponent bubbles/droplets: The square gradient theory and the capillary approach

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

Wilhelmsen, Øivind, E-mail: oivind.wilhelmsen@ntnu.no; Bedeaux, Dick; Kjelstrup, Signe

Formation of nanosized droplets/bubbles from a metastable bulk phase is connected to many unresolved scientific questions. We analyze the properties and stability of multicomponent droplets and bubbles in the canonical ensemble, and compare with single-component systems. The bubbles/droplets are described on the mesoscopic level by square gradient theory. Furthermore, we compare the results to a capillary model which gives a macroscopic description. Remarkably, the solutions of the square gradient model, representing bubbles and droplets, are accurately reproduced by the capillary model except in the vicinity of the spinodals. The solutions of the square gradient model form closed loops, which showsmore » the inherent symmetry and connected nature of bubbles and droplets. A thermodynamic stability analysis is carried out, where the second variation of the square gradient description is compared to the eigenvalues of the Hessian matrix in the capillary description. The analysis shows that it is impossible to stabilize arbitrarily small bubbles or droplets in closed systems and gives insight into metastable regions close to the minimum bubble/droplet radii. Despite the large difference in complexity, the square gradient and the capillary model predict the same finite threshold sizes and very similar stability limits for bubbles and droplets, both for single-component and two-component systems.« less

Investigation of the capillary flow through open surface microfluidic structures

NASA Astrophysics Data System (ADS)

Taher, Ahmed; Jones, Benjamin; Fiorini, Paolo; Lagae, Liesbet

2017-02-01

The passive nature of capillary microfluidics for pumping and actuation of fluids is attractive for many applications including point of care medical diagnostics. For such applications, there is often the need to spot dried chemical reagents in the bottom of microfluidic channels after device fabrication; it is often more practical to have open surface devices (i.e., without a cover or lid). However, the dynamics of capillary driven flow in open surface devices have not been well studied for many geometries of interest. In this paper, we investigate capillary flow in an open surface microchannel with a backward facing step. An analytical model is developed to calculate the capillary pressure as the liquid-vapor interface traverses a backward facing step in an open microchannel. The developed model is validated against results from Surface Evolver liquid-vapor surface simulations and ANSYS Fluent two-phase flow simulations using the volume of fluid approach. Three different aspect ratios (inlet channel height by channel width) were studied. The analytical model shows good agreement with the simulation results from both modeling methods for all geometries. The analytical model is used to derive an expression for the critical aspect ratio (the minimum channel aspect ratio for flow to proceed across the backward facing step) as a function of contact angle.

Solvent-resistant sol-gel polydimethyldiphenylsiloxane coating for on-line hyphenation of capillary microextraction with high-performance liquid chromatography.

PubMed

Segro, Scott S; Malik, Abdul

2008-09-26

A sol-gel polydimethyldiphenylsiloxane (PDMDPS) coating was developed for capillary microextraction on-line hyphenated with high-performance liquid chromatography (HPLC). This coating was created using methyltrimethoxysilane (MTMS) as the sol-gel precursor and di-hydroxy-terminated PDMDPS as the sol-gel active polymer. The methyl and phenyl groups on the sol-gel active polymer and the methyl groups on the sol-gel precursor ultimately turned into pendant groups providing the ability to extract non-polar analytes. A 40-cm segment of 0.25 mm I.D. fused silica capillary containing the sol-gel PDMDPS coating was installed as an external sampling loop in an HPLC injection port. Aqueous samples containing polycyclic aromatic hydrocarbons (PAHs), aromatic compounds, ketones, and aldehydes were passed through this capillary wherein the analytes were extracted by the sol-gel coating. The extracted analytes were then transferred to the HPLC column using isocratic or gradient elution with an acetonitrile/water mobile phase. This capillary demonstrated excellent extraction capability for non-polar (e.g., polycyclic aromatic hydrocarbons and aromatic compounds) as well as moderately polar compounds, such as aromatic amines, ketones, and aldehydes. The test results indicate that PDMDPS can be successfully immobilized into a sol-gel network and that the resulting solvent-resistant sol-gel organic-inorganic hybrid coating can be effectively used for on-line hyphenation of capillary microextraction with high-performance liquid chromatography. The test results also indicate that the sol-gel PDMDPS coated capillary is resistant to high-temperature solvents, making it suitable for applications in high-temperature HPLC. To the best of our knowledge, this is the first report on the creation of a silica-based sol-gel PDMDPS coating used in capillary microextraction on-line hyphenated to HPLC.

IN-PILE LOOP IRRADIATION OF AQUEOUS THORIA-URANIA SLURRY AT ELEVATED TEMPERATURE. DESIGN AND IN-PILE OPERATION OF LOOP L-2-27S

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

Savage, H.C.; Compere, E.L.; Baker, J.M.

1962-02-14

An in-pile pump loop, designed to fit within horizontal beam hole HB-2 of the Low-Intensity Test Reactor (LlTR), was used to circulate an aqueous thoria- urania slurry while exposed to reactor irradiation. The total loop volume was about 1600 ml, including pump and pressurizer, but the slurry was confined to the 900-ml volume of the main loop stream by means of a sintered stainless steel filter. The filter was an important feature of the loop design in that it provided a thoria-free filtrate as a purge stream to the pressurizer and pump bearings to prevent entry and accumulation of thoriamore » in these two regions. Corrosion-test specimens of Zircaloy-2, titanium, and type 347 stainless steel were placed in the loop at three different locations for exposure to three different levels of irradiation. Duplicate sets of specimens in each position were exposed to flow velocities of 8 and 22 fps, respectively. For the in-pile irradiation, thorium oxide containing 0.43 wt of enriched U, based on Th, was used. This thoria-urania was produced by air calcination at l225 deg C of coprecipit.ited oxalates and had a me.in particle size of l.7 mu . A Pd catalyst w-as dispersed in the slurry for liquid-phase recombination of the radiolytic gas. The loop was operated in beam-holc HB-2 of the LlTR from July 19 to October l9, l960. During this period slurry was continuously eireulated at 280 deg C for 2220 hr without incident; 1839 hr were at full reactor power (3 Mwt), at which the estimated average thermal flux over the 300volume core section was 5 x l0/sup 12/ neutrons/cm/sup 2/- see. At the start of in-pile operation the loop was charged to a concei tration of 979 g of Th and 3.83 g of fully enriched U per li (at 280 deg C) which was reduced by sampling to 748 g of Th idnd 2.74 g of U per liter at the end of the irradiiition period bascd on the assunmption that no losses had occurrcd. Siinmples of slurry were withdrawn at intervals for analyses to determine the effects of radiation on the thoria-urania slurry. (auth)« less

Implementation of digital optical capillaroscopy for quantifying and estimating the microvascular abnormalities in type 2 diabetes mellitus

NASA Astrophysics Data System (ADS)

Gurfinkel, Yu. I.; Suchkova, O. V.; Sasonko, M. L.; Priezzhev, A. V.

2016-04-01

This study is aimed to define the extent of digital capillaroscopy possibilities for the quantification and estimation of microvascular abnormalities in type 2 diabetes mellitus (T2DM). A total of 196 adult persons were enrolled in the study including the group of compensated T2DM (n = 52), decompensated diabetics (n = 68), and healthy volunteers (n = 76) with normal blood glucose and without signs of cardiovascular pathology. All participants of the study were examined with the digital optical capillaroscope ("AET", Russia). This instrument is equipped with an image-processing program allowing for quantifying the diameters of the arterial and venous segments of the capillaries and their ratio (coefficient of remodeling), perivascular zone size, capillary blood velocity, and the degree of arterial loops narrowing and the density of the capillary network. Also we estimated the relative amount of coil-shaped capillaries. The study revealed significant difference in the capillary density and the remodeling coefficient in comparison of T2DM patients with non-diabetic individuals. Significant changes are found in the decompensated T2DM group compared to the compensated group of diabetic patients. Furthermore, the number of coil-shaped capillaries differed greatly in T2DM patients as compared to the healthy subjects. The study did not reveal any statistically significant differences in the capillary density between the patients with compensated and decompensated T2DM. The digital optical capillaroscope equipped with the advanced image-processing algorithm opens up new possibilities for obtaining clinically important information on microvascular abnormalities in patients suffering from diabetes mellitus.

Initial clinical trial of a closed loop, fully automatic intra-aortic balloon pump.

PubMed

Kantrowitz, A; Freed, P S; Cardona, R R; Gage, K; Marinescu, G N; Westveld, A H; Litch, B; Suzuki, A; Hayakawa, H; Takano, T

1992-01-01

A new generation, closed loop, fully automatic intraaortic balloon pump (CL-IABP) system continuously optimizes diastolic augmentation by adjusting balloon pump parameters beat by beat without operator intervention. In dogs in sinus rhythm and with experimentally induced arrhythmias, the new CL-IABP system provided safe, effective augmentation. To investigate the system's suitability for clinical use, 10 patients meeting standard indications for IABP were studied. The patients were pumped by the fully automatic IABP system for an average of 20 hr (range, 1-48 hr). At start-up, the system optimized pumping parameters within 7-20 sec. Evaluation of 186 recordings made at hourly intervals showed that inflation began within 20 msec of the dicrotic notch 99% of the time. In 100% of the recordings, deflation straddled the first half of ventricular ejection. Peak pressure across the balloon membrane averaged 55 mmHg and, in no case, exceeded 100 mmHg. Examination of the data showed that as soon as the system was actuated it provided consistently beneficial diastolic augmentation without any further operator intervention. Eight patients improved and two died (one of irreversible cardiogenic shock and one of ischemic cardiomyopathy). No complications were attributable to the investigational aspects of the system. A fully automated IABP is feasible in the clinical setting, and it may have advantages relative to current generation IABP systems.

Demonstration of a low bandwidth 1.06-micron optical phase-locked loop for coherent homodyne communication

NASA Technical Reports Server (NTRS)

Day, T.; Farinas, A. D.; Byer, R. L.

1990-01-01

A type II 1.06-micron optical phase-locked loop (OPLL) for use in a coherent homodyne receiver is discussed. Diode-laser-pumped solid-state lasers are used for both the local oscillator and transmitter, because their phase noise is significantly lower than that of diode lasers. Closed-loop RMS phase noise of less than 12 mrad (0.69 deg) is achieved, and modulation-demodulation in bulk modulators at rates from 20 kHz to 20 MHz with less than 19 deg of modulation depth is demonstrated.

The use of loop-seals for the control of the overpressures in hydraulic transients evolving in a sea service water system

NASA Astrophysics Data System (ADS)

Canetta, D.; Capozza, A.; Iovino, G.

The transient response following pump trip-offs and start-ups was investigated in the sea water system of a nuclear power plant. Specific care was devoted to water column separation and cavity collapse phenomena. A computer program designed for analysis of complex hydraulic networks was used. It is found that dangerous overpressures can be avoided by the use of loop seals. The design of the vacuum breaker valves of the loop seals and the optimization of overall transient behavior is discussed.

Absorption Heat Pump Cycles

NASA Astrophysics Data System (ADS)

Kunugi, Yoshifumi; Kashiwagi, Takao

Various advanced absorption cycles are studied, developed and invented. In this paper, their cycles are classified and arranged using the three categories: effect, stage and loop, then an outline of the cycles are explained on the Duehring diagram. Their cycles include high COP cycles for refrigerations and heat pumps, high temperature lift cycles for heat transformer, absorption-compression hybrid cycles and heat pump transformer cycle. The highest COPi is attained by the seven effect cycle. In addition, the cycles for low temperature are invented and explained. Furthermore the power generation • refrigeration cycles are illustrated.

Design and evaluation of a primary/secondary pumping system for a heat pump assisted solar thermal loop

NASA Astrophysics Data System (ADS)

Krockenberger, Kyle G.

A heat pump assisted solar thermal system was designed, commissioned, tested and analyzed over a period of two years. The unique system uses solar energy whenever it is available, but switches to heat pump mode at night or whenever there is a lack of solar energy. The solar thermal energy is added by a variety of flat plat solar collectors and an evacuated tube heat pipe solar collector. The working medium in the entire system is a 50% mixture of propylene glycol and water for freeze protection. During the design and evaluation the primary / secondary pumping system was the focus of the evaluation. Testing within this research focused on the operation modes, pump stability, and system efficiency. It was found that the system was in full operation, the pumps were stable and that the efficiency factor of the system was 1.95.

Pioneering Heat Pump Project

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

Aschliman, Dave; Lubbehusen, Mike

2015-06-30

This project was initiated at a time when ground coupled heat pump systems in this region were limited in size and quantity. There were economic pressures with costs for natural gas and electric utilities that had many organizations considering ground coupled heat pumps; The research has added to the understanding of how ground temperatures fluctuate seasonally and how this affects the performance and operation of the heat pumps. This was done by using a series of temperature sensors buried within the middle of one of the vertical bore fields with sensors located at various depths below grade. Trending of themore » data showed that there is a lag in ground temperature with respect to air temperatures in the shoulder months, however as full cooling and heating season arrives, the heat rejection and heat extraction from the ground has a significant effect on the ground temps; Additionally it is better understood that while a large community geothermal bore field serving multiple buildings does provide a convenient central plant to use, it introduces complexity of not being able to easily model and predict how each building will contribute to the loads in real time. Additional controllers and programming were added to provide more insight into this real time load profile and allow for intelligent shedding of load via a dry cooler during cool nights in lieu of rejecting to the ground loop. This serves as a means to ‘condition’ the ground loop and mitigate thermal creep of the field, as is typically observed; and It has been observed when compared to traditional heating and cooling equipment, there is still a cost premium to use ground source heat pumps that is driven mostly by the cost for vertical bore holes. Horizontal loop systems are less costly to install, but do not perform as well in this climate zone for heating mode« less

Nonazeotropic Heat Pump

NASA Technical Reports Server (NTRS)

Ealker, David H.; Deming, Glenn

1991-01-01

Heat pump collects heat from water circulating in heat-rejection loop, raises temperature of collected heat, and transfers collected heat to water in separate pipe. Includes sealed motor/compressor with cooling coils, evaporator, and condenser, all mounted in outer housing. Gradients of temperature in evaporator and condenser increase heat-transfer efficiency of vapor-compression cycle. Intended to recover relatively-low-temperature waste heat and use it to make hot water.

Sensitivity analysis on the performances of a closed-loop Ground Source Heat Pump

NASA Astrophysics Data System (ADS)

Casasso, Alessandro; Sethi, Rajandrea

2014-05-01

Ground Source Heat Pumps (GSHP) permit to achieve a significant reduction of greenhouse gas emissions, and the margins for economic saving of this technology are strongly correlated to the long-term sustainability of the exploitation of the heat stored in the soil. The operation of a GSHP over its lifetime should be therefore modelled considering realistic conditions, and a thorough characterization of the physical properties of the soil is essential to avoid large errors of prediction. In this work, a BHE modelling procedure with the finite-element code FEFLOW is presented. Starting from the governing equations of the heat transport in the soil around a GSHP and inside the BHE, the most important parameters are individuated and the adopted program settings are explained. A sensitivity analysis is then carried on both the design parameters of the heat exchanger, in order to understand the margins of improvement of a careful design and installation, and the physical properties of the soil, with the aim of quantifying the uncertainty induced by their variability. The relative importance of each parameter is therefore assessed by comparing the statistical distributions of the fluid temperatures and estimating the energy consumption of the heat pump, and practical conclusions are from these results about the site characterization, the design and the installation of a BHE. References Casasso A., Sethi R., 2014 Efficiency of closed loop geothermal heat pumps: A sensitivity analysis, Renewable Energy 62 (2014), pp. 737-746 Chiasson A.C., Rees S.J., Spitler J.D., 2000, A preliminary assessment of the effects of groundwater flow on closed-loop ground-source heat pump systems, ASHRAE Transactions 106 (2000), pp. 380-393 Delaleux F., Py X., Olives R., Dominguez A., 2012, Enhancement of geothermal borehole heat exchangers performances by improvement of bentonite grouts conductivity, Applied Thermal Engineering 33-34, pp. 92-99 Diao N., Li Q., Fang Z., 2004, Heat transfer in ground heat exchangers with groundwater advection, International Journal of Thermal Sciences 43, pp. 1203-1211 Michopoulos A., Kyriakis N., 2010, The influence of a vertical ground heat exchanger length on the electricity consumption of the heat pumps, Renewable Energy 35 (2010), pp. 1403-1407

Case Study of The ARRA-Funded GSHP Demonstration at the Natural Sources Building, Montana Tech

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

Malhotra, Mini; Liu, Xiaobing

Under the American Recovery and Reinvestment Act (ARRA), 26 ground source heat pump (GSHP) projects were competitively selected in 2009 to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. One of the selected demonstration projects was proposed by Montana Tech of the University of Montana for a 56,000 sq ft, newly constructed, on-campus research facility – the Natural Resources Building (NRB) located in Butte, Montana. This demonstrated GSHP system consists of a 50 ton water-to-water heat pump and a closed-loop ground heat exchanger with two redundant 7.5 hp constant-speed pumps to use watermore » in the nearby flooded mines as a heat source or heat sink. It works in conjunction with the originally installed steam HX and an aircooled chiller to provide space heating and cooling. It is coupled with the existing hot water and chilled water piping in the building and operates in the heating or cooling mode based on the outdoor air temperature. The ground loop pumps operate in conjunction with the existing pumps in the building hot and chilled water loops for the operation of the heat pump unit. The goal of this demonstration project is to validate the technical and economic feasibility of the demonstrated commercial-scale GSHP system in the region, and illustrate the feasibility of using mine waters as the heat sink and source for GSHP systems. Should the demonstration prove satisfactory and feasible, it will encourage similar GSHP applications using mine water, thus help save energy and reduce carbon emissions. The actual performance of the system is analyzed with available measured data for January through July 2014. The annual energy performance is predicted and compared with a baseline scenario, with the heating and cooling provided by the originally designed systems. The comparison is made in terms of energy savings, operating cost savings, cost-effectiveness, and environmental benefits. Finally, limitations in conducting the analysis are identified and recommendations for improvement in the control and operation of such systems are made.« less

Automated hybrid closed-loop control with a proportional-integral-derivative based system in adolescents and adults with type 1 diabetes: individualizing settings for optimal performance.

PubMed

Ly, Trang T; Weinzimer, Stuart A; Maahs, David M; Sherr, Jennifer L; Roy, Anirban; Grosman, Benyamin; Cantwell, Martin; Kurtz, Natalie; Carria, Lori; Messer, Laurel; von Eyben, Rie; Buckingham, Bruce A

2017-08-01

Automated insulin delivery systems, utilizing a control algorithm to dose insulin based upon subcutaneous continuous glucose sensor values and insulin pump therapy, will soon be available for commercial use. The objective of this study was to determine the preliminary safety and efficacy of initialization parameters with the Medtronic hybrid closed-loop controller by comparing percentage of time in range, 70-180 mg/dL (3.9-10 mmol/L), mean glucose values, as well as percentage of time above and below target range between sensor-augmented pump therapy and hybrid closed-loop, in adults and adolescents with type 1 diabetes. We studied an initial cohort of 9 adults followed by a second cohort of 15 adolescents, using the Medtronic hybrid closed-loop system with the proportional-integral-derivative with insulin feed-back (PID-IFB) algorithm. Hybrid closed-loop was tested in supervised hotel-based studies over 4-5 days. The overall mean percentage of time in range (70-180 mg/dL, 3.9-10 mmol/L) during hybrid closed-loop was 71.8% in the adult cohort and 69.8% in the adolescent cohort. The overall percentage of time spent under 70 mg/dL (3.9 mmol/L) was 2.0% in the adult cohort and 2.5% in the adolescent cohort. Mean glucose values were 152 mg/dL (8.4 mmol/L) in the adult cohort and 153 mg/dL (8.5 mmol/L) in the adolescent cohort. Closed-loop control using the Medtronic hybrid closed-loop system enables adaptive, real-time basal rate modulation. Initializing hybrid closed-loop in clinical practice will involve individualizing initiation parameters to optimize overall glucose control. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Experimental study of operation performance for hydrocarbon fuel pump with low specific speed

NASA Astrophysics Data System (ADS)

Wu, Xianyu; Yang, Jun; Jin, Xuan

2017-10-01

In this paper, a small flow rate hydrocarbon turbine pump was used to pressurize the fuel supply system of scramjet engine. Some experiments were carried out to investigate the characteristics of turbine pump driven by nitrogen or combustion gas under different operating conditions. A experimental database with regard to the curves of the rotational speed, mass flow rate and net head with regard to centrifugal pump were plotted. These curves were represented as functions of the pressure and temperature at turbine inlet/outlet and the throttle diameter at downstream of centrifugal pump. A sensitivity study has been carried out based on design of experiments. The experimental was employed to analyze net head of centrifugal and throttle characteristics. The research results can accumulate foundations for the close loop control system of turbine pump.

Structure of the periplasmic adaptor protein from a major facilitator superfamily (MFS) multidrug efflux pump.

PubMed

Hinchliffe, Philip; Greene, Nicholas P; Paterson, Neil G; Crow, Allister; Hughes, Colin; Koronakis, Vassilis

2014-08-25

Periplasmic adaptor proteins are key components of bacterial tripartite efflux pumps. The 2.85 Å resolution structure of an MFS (major facilitator superfamily) pump adaptor, Aquifex aeolicus EmrA, shows linearly arranged α-helical coiled-coil, lipoyl, and β-barrel domains, but lacks the fourth membrane-proximal domain shown in other pumps to interact with the inner membrane transporter. The adaptor α-hairpin, which binds outer membrane TolC, is exceptionally long at 127 Å, and the β-barrel contains a conserved disordered loop. The structure extends the view of adaptors as flexible, modular components that mediate diverse pump assembly, and suggests that in MFS tripartite pumps a hexamer of adaptors could provide a periplasmic seal. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

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

None

Oberlin College’s Adam Joseph Lewis Center for Environmental Studies is a high-performance building featuring an expansive photovoltaic system and a closed-loop groundwater heat pump system. Designers incorporated energy-efficient components and materials

Assessing the effectiveness of a 3-month day-and-night home closed-loop control combined with pump suspend feature compared with sensor-augmented pump therapy in youths and adults with suboptimally controlled type 1 diabetes: a randomised parallel study protocol

PubMed Central

Bally, Lia; Thabit, Hood; Tauschmann, Martin; Allen, Janet M; Hartnell, Sara; Wilinska, Malgorzata E; Exall, Jane; Huegel, Viki; Sibayan, Judy; Borgman, Sarah; Cheng, Peiyao; Blackburn, Maxine; Lawton, Julia; Elleri, Daniela; Leelarathna, Lalantha; Acerini, Carlo L; Campbell, Fiona; Shah, Viral N; Criego, Amy; Evans, Mark L; Dunger, David B; Kollman, Craig; Bergenstal, Richard M; Hovorka, Roman

2017-01-01

Introduction Despite therapeutic advances, many individuals with type 1 diabetes are unable to achieve tight glycaemic target without increasing the risk of hypoglycaemia. The objective of this study is to determine the effectiveness of a 3-month day-and-night home closed-loop glucose control combined with a pump suspend feature, compared with sensor-augmented insulin pump therapy in youths and adults with suboptimally controlled type 1 diabetes. Methods and analysis The study adopts an open-label, multi-centre, multi-national (UK and USA), randomised, single-period, parallel design and aims for 84 randomised patients. Participants are youths (6–21 years) or adults (>21 years) with type 1 diabetes treated with insulin pump therapy and suboptimal glycaemic control (glycated haemoglobin (HbA1c) ≥7.5% (58 mmol/mol) and ≤10% (86 mmol/mol)). Following a 4-week run-in period, eligible participants will be randomised to a 3-month use of automated closed-loop insulin delivery combined with pump suspend feature or to sensor-augmented insulin pump therapy. Analyses will be conducted on an intention-to-treat basis. The primary outcome is the time spent in the target glucose range from 3.9 to 10.0 mmol/L based on continuous glucose monitoring levels during the 3-month free-living phase. Secondary outcomes include HbA1c at 3 months, mean glucose, time spent below and above target; time with glucose levels <3.5 and <2.8 mmol/L; area under the curve when sensor glucose is <3.5 mmol/L, time with glucose levels >16.7 mmol/L, glucose variability; total, basal and bolus insulin dose and change in body weight. Participants’ and their families’ perception in terms of lifestyle change, daily diabetes management and fear of hypoglycaemia will be evaluated. Ethics and dissemination Ethics/institutional review board approval has been obtained. Before screening, all participants/guardians will be provided with oral and written information about the trial. The study will be disseminated by peer-reviewed publications and conference presentations. Trial registration number NCT02523131; Pre-results. PMID:28710224

Development and Testing of a Variable Conductance Thermal Acquisition, Transport, and Switching System

NASA Technical Reports Server (NTRS)

Bugby, D. C.; Farmer, J. T.; Stouffer, C. J.

2013-01-01

This paper describes the development and testing of a scalable thermal control architecture for instruments, subsystems, or systems that must operate in severe space environments with wide variations in sink temperature. The architecture is comprised by linking one or more hot-side variable conductance heat pipes (VCHPs) in series with one or more cold-side loop heat pipes (LHPs). The VCHPs provide wide area heat acquisition, limited distance thermal transport, modest against gravity pumping, concentrated LHP startup heating, and high switching ratio variable conductance operation. The LHPs provide localized heat acquisition, long distance thermal transport, significant against gravity pumping, and high switching ratio variable conductance operation. Combining two variable conductance devices in series ensures very high switching ratio isolation from severe environments like the Earth's moon, where each lunar day spans 15 Earth days (270 K sink, with a surface-shielded/space viewing radiator) and each lunar night spans 15 Earth days (80-100 K radiative sink, depending on location). The single VCHP-single LHP system described herein was developed to maintain thermal control of International Lunar Network (ILN) anchor node lander electronics, but it is also applicable to other variable heat rejection space missions in severe environments. The LHPVCHP system utilizes a stainless steel wire mesh wick ammonia VCHP, a Teflon wick propylene LHP, a pair of one-third square meter high ? radiators (one capillary-pumped horizontal radiator and a second gravity-fed vertical radiator), a half-meter of transport distance, and a wick-bearing co-located flow regulator (CLFR) to allow operation with a hot (deactivated) radiator. The VCHP was designed with a small reservoir formed by extending the length of its stainless steel heat pipe tubing. The system was able to provide end-to-end switching ratios of 300-500 during thermal vacuum testing at ATK, including 3-5 W/K ON conductance and 0.01 W/K OFF conductance. The test results described herein also include an in-depth analysis of VCHP condenser performance to explain VCHP switching operation in detail. Future multi-VCHP/multi-LHP thermal management system concepts that provide scalability to higher powers/longer transport lengths are also discussed in the paper.

Experimental and Numerical Analysis of Air Flow, Heat Transfer and Thermal Comfort in Buildings with Different Heating Systems

NASA Astrophysics Data System (ADS)

Sabanskis, A.; Virbulis, J.

2016-04-01

Monitoring of temperature, humidity and air flow velocity is performed in 5 experimental buildings with the inner size of 3×3×3 m3 located in Riga, Latvia. The buildings are equipped with different heating systems, such as an air-air heat pump, air-water heat pump, capillary heating mat on the ceiling and electric heater. Numerical simulation of air flow and heat transfer by convection, conduction and radiation is carried out using OpenFOAM software and compared with experimental data. Results are analysed regarding the temperature and air flow distribution as well as thermal comfort.

Evaluation of tantalum-alloy-clad uranium mononitride fuel specimens from 7500-hour, 1040 C pumped-lithium-loop test

NASA Technical Reports Server (NTRS)

Watson, G. K.

1974-01-01

Simulated nuclear fuel element specimens, consisting of uranium mononitride (UN) fuel cylinders clad with tungsten-lined T-111, were exposed for up to 7500 hr at 1040 C (1900 F) in a pumped-lithium loop. The lithium flow velocity was 1.5 m/sec (5 ft/sec) in the specimen test section. No evidence of any compatibility problems between the specimens and the flowing lithium was found based on appearance, weight change, chemistry, and metallography. Direct exposure of the UN to the lithium through a simulated cladding crack resulted in some erosion of the UN in the area of the defect. The T-111 cladding was ductile after lithium exposure, but it was sensitive to hydrogen embrittlement during post-test handling.

Gas turbine cooling system

DOEpatents

Bancalari, Eduardo E.

2001-01-01

A gas turbine engine (10) having a closed-loop cooling circuit (39) for transferring heat from the hot turbine section (16) to the compressed air (24) produced by the compressor section (12). The closed-loop cooling system (39) includes a heat exchanger (40) disposed in the flow path of the compressed air (24) between the outlet of the compressor section (12) and the inlet of the combustor (14). A cooling fluid (50) may be driven by a pump (52) located outside of the engine casing (53) or a pump (54) mounted on the rotor shaft (17). The cooling circuit (39) may include an orifice (60) for causing the cooling fluid (50) to change from a liquid state to a gaseous state, thereby increasing the heat transfer capacity of the cooling circuit (39).

A postscript to Circulation of the blood: men and ideas.

PubMed

Riley, R L

1982-10-01

Since 1964, when Fishman and Richards published Circulation of the Blood: Men and Ideas, Guyton's model of the circulation, in which mean circulatory pressure serves as the upstream pressure for venous return, has been extended, and the concept of vascular smooth muscle tone acting like the pressure surrounding a Starling resistor has been postulated. According to this scheme, the positive zero flow intercepts of rapidly determined arterial pressure-flow curves are the effective downstream pressures for arterial flow to different tissues. The arterioles, like Starling resistors, determine the downstream pressures and are followed by abrupt pressure drops, or "waterfalls." Capillary pressures are closely linked to those of the venules into which they flow. Capillary-venular pressures are the upstream pressures for venous return. In exercising muscles, reduced arteriolar tone lowers arteriolar pressure and increases arterial flow. This, in turn, raises capillary-venular pressure and increases venous flow. The arteriolar-capillary waterfall is decreased or eliminated. Total blood flow is increased by diversion of blood from tissues with slow venous drainage to muscles with fast venous drainage (low resistance X compliance). The heart pumps away the increased venous return by shifting to a new ventricular function curve.

A novel APPI-MS setup for in situ degradation product studies of atmospherically relevant compounds: capillary atmospheric pressure photo ionization (cAPPI).

PubMed

Kersten, Hendrik; Derpmann, Valerie; Barnes, Ian; Brockmann, Klaus J; O'Brien, Rob; Benter, Thorsten

2011-11-01

We report on the development of a novel atmospheric pressure photoionization setup and its applicability for in situ degradation product studies of atmospherically relevant compounds. A custom miniature spark discharge lamp was embedded into an ion transfer capillary, which separates the atmospheric pressure from the low pressure region in the first differential pumping stage of a conventional atmospheric pressure ionization mass spectrometer. The lamp operates with a continuous argon flow and produces intense light emissions in the VUV. The custom lamp is operated windowless and efficiently illuminates the sample flow through the transfer capillary on an area smaller than 1 mm(2). Limits of detection in the lower ppbV range, a temporal resolution of milliseconds in the positive as well as the quasi simultaneously operating negative ion mode, and a significant reduction of ion transformation processes render this system applicable to real time studies of rapidly changing chemical systems. The method termed capillary atmospheric pressure photo ionization (cAPPI) is characterized with respect to the lamp emission properties as a function of the operating conditions, temporal response, and its applicability for in situ degradation product studies of atmospherically relevant compounds, respectively.

Geothermal energy control system and method

DOEpatents

Matthews, Hugh B.

1976-01-01

A geothermal energy transfer and utilization system makes use of thermal energy stored in hot solute-bearing well water to generate super-heated steam from an injected flow of clean water; the super-heated steam is then used for operating a turbine-driven pump at the well bottom for pumping the hot solute-bearing water at high pressure and in liquid state to the earth's surface, where it is used by transfer of its heat to a closed-loop boiler-turbine-alternator combination for the generation of electrical or other power. Residual concentrated solute-bearing water is pumped back into the earth. The clean cooled water is regenerated at the surface-located system and is returned to the deep well pumping system also for lubrication of a novel bearing arrangement supporting the turbine-driven pump system.

Quick connect coupling

NASA Technical Reports Server (NTRS)

Lomax, Curtis (Inventor); Webbon, Bruce (Inventor)

1995-01-01

A cooling apparatus includes a container filled with a quantity of coolant fluid initially cooled to a solid phase, a cooling loop disposed between a heat load and the container, a pump for circulating a quantity of the same type of coolant fluid in a liquid phase through the cooling loop, and a pair of couplings for communicating the liquid phase coolant fluid into the container in a direct interface with the solid phase coolant fluid.

PRESSURE SYSTEM CONTROL

DOEpatents

Esselman, W.H.; Kaplan, G.M.

1961-06-20

The control of pressure in pressurized liquid systems, especially a pressurized liquid reactor system, may be achieved by providing a bias circuit or loop across a closed loop having a flow restriction means in the form of an orifice, a storage tank, and a pump connected in series. The subject invention is advantageously utilized where control of a reactor can be achieved by response to the temperature and pressure of the primary cooling system.

Temperature feedback control for long-term carrier-envelope phase locking.

PubMed

Yun, Chenxia; Chen, Shouyuan; Wang, He; Chini, Michael; Chang, Zenghu

2009-09-20

We report a double feedback loop for the improvement of the carrier-envelope phase stabilization of a chirped mirror based femtosecond laser oscillator. By combining the control of the Ti:sapphire crystal temperature and the modulation of the pump power, the carrier envelope offset frequency, fCEO, was locked for close to 20 h, which is much longer than the typical phase stabilization time with only pump power modulation.

Evolution in miniaturized column liquid chromatography instrumentation and applications: An overview.

PubMed

Nazario, Carlos E D; Silva, Meire R; Franco, Maraíssa S; Lanças, Fernando M

2015-11-20

The purpose of this article is to underline the miniaturized LC instrumental system and describe the evolution of commercially available systems by discussing their advantages and drawbacks. Nowadays, there are already many miniaturized LC systems available with a great variety of pump design, interface and detectors as well as efficient columns technologies and reduced connections devices. The solvent delivery systems are able to drive the mobile phase without flow splitters and promote gradient elution using either dual piston reciprocating or syringe-type pumps. The mass spectrometry as detection system is the most widely used detection system; among many alternative ionization sources direct-EI LC-MS is a promising alternative to APCI. In addition, capillary columns are now available showing many possibilities of stationary phases, inner diameters and hardware materials. This review provides a discussion about miniaturized LC demonstrating fundamentals and instrumentals' aspects of the commercially available miniaturized LC instrumental system mainly nano and micro LC formats. This review also covers the recent developments and trends in instrumentation, capillary and nano columns, and several applications of this very important and promising field. Copyright © 2015 Elsevier B.V. All rights reserved.

Computer Simulations of Valveless Pumping using the Immersed Boundary Method

NASA Astrophysics Data System (ADS)

Jung, Eunok; Peskin, Charles

2000-03-01

Pumping blood in one direction is the main function of the heart, and the heart is equipped with valves that ensure unidirectional flow. Is it possible, though, to pump blood without valves? This report is intended to show by numerical simulation the possibility of a net flow which is generated by a valveless mechanism in a circulatory system. Simulations of valveless pumping are motivated by biomedical applications: cardiopulmonary resuscitation (CPR); and the human foetus before the development of the heart valves. The numerical method used in this work is immersed boundary method, which is applicable to problems involving an elastic structure interacting with a viscous incompressible fluid. This method has already been applied to blood flow in the heart, platelet aggregation during blood clotting, aquatic animal locomotion, and flow in collapsible tubes. The direction of flow inside a loop of tubing which consists of (almost) rigid and flexible parts is investigated when the boundary of one end of the flexible segment is forced periodically in time. Despite the absence of valves, net flow around the loop may appear in these simulations. Furthermore, we present the new, unexpected results that the direction of this flow is determined not only by the position of the periodic compression, but also by the frequency and amplitude of the driving force.

Prognostic model based on nailfold capillaroscopy for identifying Raynaud's phenomenon patients at high risk for the development of a scleroderma spectrum disorder: PRINCE (prognostic index for nailfold capillaroscopic examination).

PubMed

Ingegnoli, Francesca; Boracchi, Patrizia; Gualtierotti, Roberta; Lubatti, Chiara; Meani, Laura; Zahalkova, Lenka; Zeni, Silvana; Fantini, Flavio

2008-07-01

To construct a prognostic index based on nailfold capillaroscopic examinations that is capable of predicting the 5-year transition from isolated Raynaud's phenomenon (RP) to RP secondary to scleroderma spectrum disorders (SSDs). The study involved 104 consecutive adult patients with a clinical history of isolated RP, and the index was externally validated in another cohort of 100 patients with the same characteristics. Both groups were followed up for 1-8 years. Six variables were examined because of their potential prognostic relevance (branching, enlarged and giant loops, capillary disorganization, microhemorrhages, and the number of capillaries). The only factors that played a significant prognostic role were the presence of giant loops (hazard ratio [HR] 2.64, P = 0.008) and microhemorrhages (HR 2.33, P = 0.01), and the number of capillaries (analyzed as a continuous variable). The adjusted prognostic role of these factors was evaluated by means of multivariate regression analysis, and the results were used to construct an algorithm-based prognostic index. The model was internally and externally validated. Our prognostic capillaroscopic index identifies RP patients in whom the risk of developing SSDs is high. This model is a weighted combination of different capillaroscopy parameters that allows physicians to stratify RP patients easily, using a relatively simple diagram to deduce the prognosis. Our results suggest that this index could be used in clinical practice, and its further inclusion in prospective studies will undoubtedly help in exploring its potential in predicting treatment response.

Evaluation of a commercial electro-kinetically pumped sheath-flow nanospray interface coupled to an automated capillary zone electrophoresis system.

PubMed

Peuchen, Elizabeth H; Zhu, Guije; Sun, Liangliang; Dovichi, Norman J

2017-03-01

Capillary zone electrophoresis-electrospray ionization-mass spectrometry (CZE-ESI-MS) is attracting renewed attention for proteomic and metabolomic analysis. An important reason for this interest is the maturation and commercialization of interfaces for coupling CZE with ESI-MS. One of these interfaces is an electro-kinetically pumped sheath flow nanospray interface developed by the Dovichi group, in which a very low sheath flow is generated based on electroosmosis within a glass emitter. CMP Scientific has commercialized this interface as the EMASS-II ion source. In this work, we compared the performance of the EMASS-II ion source with our in-house system. The performance of the systems is equivalent. We also coupled the EMASS-II ion source with a PrinCE Next|480 capillary electrophoresis autosampler and an Orbitrap mass spectrometer, and analyzed this system's performance in terms of sensitivity, reproducibility, and separation performance for separation of tryptic digests, intact proteins, and amino acids. The system produced reproducible analysis of BSA digest; the RSDs of peptide intensity and migration time across 24 runs were less than 20 and 6%, respectively. The system produced a linear calibration curve of intensity across a 30-fold range of tryptic digest concentration. The combination of a commercial autosampler and electrospray interface efficiently separated amino acids, peptides, and intact proteins, and only required 5 μL of sample for analysis. Graphical Abstract The commercial and locally constructed versions of the interface provide similar numbers of protein identifications from a Xenopus laevis fertilized egg digest.

Design and operation of a portable scanner for high performance microchip capillary array electrophoresis.

PubMed

Scherer, James R; Liu, Peng; Mathies, Richard A

2010-11-01

We have developed a compact, laser-induced fluorescence detection scanner, the multichannel capillary array electrophoresis portable scanner (McCAEPs) as a platform for electrophoretic detection and control of high-throughput, integrated microfluidic devices for genetic and other analyses. The instrument contains a confocal optical system with a rotary objective for detecting four different fluorescence signals, a pneumatic system consisting of two pressure/vacuum pumps and 28 individual addressable solenoid valves for control of on-chip microvalves and micropumps, four Polymerase Chain Reaction (PCR) temperature control systems, and four high voltage power supplies for electrophoresis. The detection limit of the instrument is ~20 pM for on-chip capillary electrophoresis of fluorescein dyes. To demonstrate the system performance for forensic short tandem repeat (STR) analysis, two experiments were conducted: (i) electrophoretic separation and detection of STR samples on a 96-lane microfabricated capillary array electrophoresis microchip. Fully resolved PowerPlex(®) 16 STR profiles amplified from 1 ng of 9947A female standard DNA were successfully obtained; (ii) nine-plex STR amplification, sample injection, separation, and fluorescence detection of 100-copy 9948 male standard DNA in a single integrated PCR- capillary electrophoresis microchip. These results demonstrate that the McCAEPs can be used as a versatile control and detection instrument that operates integrated microfluidic devices for high-performance forensic human identification.

Design and operation of a portable scanner for high performance microchip capillary array electrophoresis

NASA Astrophysics Data System (ADS)

Scherer, James R.; Liu, Peng; Mathies, Richard A.

2010-11-01

We have developed a compact, laser-induced fluorescence detection scanner, the multichannel capillary array electrophoresis portable scanner (McCAEPs) as a platform for electrophoretic detection and control of high-throughput, integrated microfluidic devices for genetic and other analyses. The instrument contains a confocal optical system with a rotary objective for detecting four different fluorescence signals, a pneumatic system consisting of two pressure/vacuum pumps and 28 individual addressable solenoid valves for control of on-chip microvalves and micropumps, four Polymerase Chain Reaction (PCR) temperature control systems, and four high voltage power supplies for electrophoresis. The detection limit of the instrument is ˜20 pM for on-chip capillary electrophoresis of fluorescein dyes. To demonstrate the system performance for forensic short tandem repeat (STR) analysis, two experiments were conducted: (i) electrophoretic separation and detection of STR samples on a 96-lane microfabricated capillary array electrophoresis microchip. Fully resolved PowerPlex® 16 STR profiles amplified from 1 ng of 9947A female standard DNA were successfully obtained; (ii) nine-plex STR amplification, sample injection, separation, and fluorescence detection of 100-copy 9948 male standard DNA in a single integrated PCR- capillary electrophoresis microchip. These results demonstrate that the McCAEPs can be used as a versatile control and detection instrument that operates integrated microfluidic devices for high-performance forensic human identification.

Preparation and evaluation of molecularly imprinted polymers based on 9-ethyladenine for the recognition of nucleotide bases in capillary electrochromatography.

PubMed

Huang, Yi-Chen; Lin, Chun-Chi; Liu, Chuen-Ying

2004-02-01

A molecularly imprinted polymer (MIP) comprising 9-ethyladenine was polymerized in situ inside the capillary for the electrochromatographic separation of nucleotide bases. The capillary wall was first functionalized with 3-trimethoxysilylpropyl methacrylate (10% v/v) and 1,1-diphenyl-2-picrylhydrazyl (0.01% w/v) in toluene. Following this treatment, the capillary was filled with acetonitrile containing 9-ethyladenine, methacrylic acid, ethylene glycol dimethacrylate, and initiator. After polymerization, the MIP was shrunk into a film against the inner wall of the capillary with the syringe pump. The template was then removed with methanol under nitrogen flow. For evaluation the feasibility of the MIP column for the separation of nucleotide bases, some parameters including the pH, concentration of the background electrolyte, the applied voltage as well as the effect of organic modifier were studied. The migration behavior of nucleotide bases on the MIP column was also compared with that on the bare fused-silica column. The results indicated that the MIP columns demonstrated better recognition properties at a pH range of 6-8. The efficiency (plates/m) at pH 8 for the nonimprinted analyte was 75,300 for cytosine, 50,200 for thymine, and 14,800 for guanine. However, the efficiency for the imprinted analyte, adenine, was quite low. This was evidenced by the broad peak, yielding only 2600 plates/m.

Ultra-high-stability, pH-resistant sol-gel titania poly(tetrahydrofuran) coating for capillary microextraction on-line coupled to high-performance liquid chromatography.

PubMed

Segro, Scott S; Cabezas, Yaniel; Malik, Abdul

2009-05-15

A sol-gel titania poly(tetrahydrofuran) (poly-THF) coating was developed for capillary microextraction hyphenated on-line with high-performance liquid chromatography (HPLC). Poly-THF was covalently bonded to the sol-gel titania network which, in turn, became chemically anchored to the inner surface of a 0.25mm I.D. fused silica capillary. For sample preconcentration, a 38-cm segment of the sol-gel titania poly-THF coated capillary was installed on an HPLC injection port as a sampling loop. Aqueous samples containing a variety of analytes were passed through the capillary and, during this process, the analytes were extracted by the sol-gel titania poly-THF coating on the inner surface of the capillary. Using isocratic and gradient elution with acetonitrile/water mobile phases, the extracted analytes were desorbed into the on-line coupled HPLC column for separation and UV detection. The sol-gel titania poly-THF coating was especially efficient in extracting polar analytes, such as underivatized phenols, alcohols, amines, and aromatic carboxylic acids. In addition, this coating was capable of extracting moderately polar and nonpolar analytes, such as ketones and polycyclic aromatic hydrocarbons. The sol-gel titania poly-THF coated capillary was also able to extract polypeptides at pH values near their respective isoelectric points. Extraction of these compounds can be important for environmental and biomedical applications. The observed extraction behavior can be attributed to the polar and nonpolar moieties in the poly-THF structure. This coating was found to be stable under extremely low and high pH conditions-even after 18h of exposure to 1M HCl (pH approximately 0.0) and 1M NaOH (pH approximately 14.0).

CO2/ brine substitution experiments at simulated reservoir conditions

NASA Astrophysics Data System (ADS)

Kummerow, Juliane; Spangenberg, Erik

2015-04-01

Capillary properties of rocks affect the mobility of fluids in a reservoir. Therefore, the understanding of the capillary pressure behaviour is essential to assess the long-term behaviour of CO2 reservoirs. Beyond this, a calibration of the petrophysical properties on water saturation of reservoir rocks at simulated in situ conditions is crucial for a proper interpretation of field monitoring data. We present a set-up, which allows for the combined measurements of capillary pressure, electric resistivity, and elastic wave velocities under controlled reservoir conditions (pconf = 400 bar, ppore = 180 bar, T = 65 ° C) at different brine-CO2 saturations. The capillary properties of the samples are measured using the micropore membrane technique. The sample is jacketed with a Viton tube (thickness = 4 mm) and placed between two current electrode endcaps, which as well contain pore fluid ports and ultrasonic P and S wave transducers. Between the sample and the lower endcap the hydrophilic semi-permeable micro-pore membrane (pore size = 100 nm) is integrated. It is embedded into filter papers to establish a good capillary contact and to protect the highly sensitive membrane against mechanical damage under load. Two high-precision syringe pumps are used to displace a quantified volume of brine by CO2 and determine the corresponding sample saturation. The fluid displacement induces a pressure gradient along the sample, which corresponds to the capillary pressure at a particular sample saturation. It is measured with a differential pressure sensor in the range between 0 - 0.2 MPa. Drainage and imbibition cycles are performed to provide information on the efficiency of capillary trapping and to get a calibration of the petrophysical parameters of the sample.

Adding the 'heart' to hanging drop networks for microphysiological multi-tissue experiments.

PubMed

Rismani Yazdi, Saeed; Shadmani, Amir; Bürgel, Sebastian C; Misun, Patrick M; Hierlemann, Andreas; Frey, Olivier

2015-11-07

Microfluidic hanging-drop networks enable culturing and analysis of 3D microtissue spheroids derived from different cell types under controlled perfusion and investigating inter-tissue communication in multi-tissue formats. In this paper we introduce a compact on-chip pumping approach for flow control in hanging-drop networks. The pump includes one pneumatic chamber located directly above one of the hanging drops and uses the surface tension at the liquid-air-interface for flow actuation. Control of the pneumatic protocol provides a wide range of unidirectional pulsatile and continuous flow profiles. With the proposed concept several independent hanging-drop networks can be operated in parallel with only one single pneumatic actuation line at high fidelity. Closed-loop medium circulation between different organ models for multi-tissue formats and multiple simultaneous assays in parallel are possible. Finally, we implemented a real-time feedback control-loop of the pump actuation based on the beating of a human iPS-derived cardiac microtissue cultured in the same system. This configuration allows for simulating physiological effects on the heart and their impact on flow circulation between the organ models on chip.

Reactor Simulator Testing Overview

NASA Technical Reports Server (NTRS)

Schoenfeld, Michael P.

2013-01-01

OBJECTIVE: Integrated testing of the TDU components TESTING SUMMARY: a) Verify the operation of the core simulator, the instrumentation and control system, and the ground support gas and vacuum test equipment. b) Thermal test heat regeneration design aspect of a cold trap purification filter. c) Pump performance test at pump voltages up to 150 V (targeted mass flow rate of 1.75 kg/s was not obtained in the RxSim at the originally constrained voltage of 120 V). TESTING HIGHLIGHTS: a) Gas and vacuum ground support test equipment performed effectively for NaK fill, loop pressurization, and NaK drain operations. b) Instrumentation and control system effectively controlled loop temperature and flow rates or pump voltage to targeted settings. c) Cold trap design was able to obtain the targeted cold temperature of 480 K. An outlet temperature of 636 K was obtained which was lower than the predicted 750 K but 156 K higher than the cold temperature indicating the design provided some heat regeneration. d) ALIP produce a maximum flow rate of 1.53 kg/s at 800 K when operated at 150 V and 53 Hz.

Analysis of boron dilution in a four-loop PWR

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

Sun, J.G.; Sha, W.T.

1995-12-31

Thermal mixing and boron dilution in a pressurized water reactor were analyzed with COMMIX codes. The reactor system was the four loop Zion reactor. Two boron dilution scenarios were analyzed. In the first scenario, the plant is in cold shutdown and the reactor coolant system has just been filled after maintenance on the steam generators. To flush the air out of the steam generator tubes, a reactor coolant pump (RCP) is started, with the water in the pump suction line devoid of boron and at the same temperature as the coolant in the system. In the second scenario, the plantmore » is at hot standby and the reactor coolant system has been heated up to operating temperature after a long outage. It is assumed that an RCP is started, with the pump suction line filled with cold unborated water, forcing a slug of diluted coolant down the downcomer and subsequently through the reactor core. The subsequent transient thermal mixing and boron dilution that would occur in the reactor system is simulated for these two scenarios. The reactivity insertion rate and the total reactivity are evaluated.« less

Thermal Interface Evaluation of Heat Transfer from a Pumped Loop to Titanium-Water Thermosyphons

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.; Sanzi, James L.; Gibson, Marc A.; Sechkar, Edward A.

2009-01-01

Titanium-water thermosyphons are being considered for use in the heat rejection system for lunar outpost fission surface power. Key to their use is heat transfer between a closed loop heat source and the heat pipe evaporators. This work describes laboratory testing of several interfaces that were evaluated for their thermal performance characteristics, in the temperature range of 350 to 400 K, utilizing a water closed loop heat source and multiple thermosyphon evaporator geometries. A gas gap calorimeter was used to measure heat flow at steady state. Thermocouples in the closed loop heat source and on the evaporator were used to measure thermal conductance. The interfaces were in two generic categories, those immersed in the water closed loop heat source and those clamped to the water closed loop heat source with differing thermal conductive agents. In general, immersed evaporators showed better overall performance than their clamped counterparts. Selected clamped evaporator geometries offered promise.

Research and application of key technology of electric submersible plunger pump

NASA Astrophysics Data System (ADS)

Qian, K.; Sun, Y. N.; Zheng, S.; Du, W. S.; Li, J. N.; Pei, G. Z.; Gao, Y.; Wu, N.

2018-06-01

Electric submersible plunger pump is a new generation of rodless oil production equipment, whose improvements and upgrades of key technologies are conducive to its large-scale application and reduce the cost and improve the efficiency. In this paper, the operating mechanism of the unit in-depth study, aimed at the problems existing in oilfield production, to propose an optimization method creatively, including the optimal design of a linear motor for submersible oil, development of new double-acting load-relief pump, embedded flexible closed-loop control technology, research and development of low-cost power cables. 90 oil wells were used on field application, the average pump inspection cycle is 608 days, the longest pump check cycle has exceeded 1037 days, the average power saving rate is 45.6%. Application results show that the new technology of optimization and upgrading can further improve the reliability and adaptability of electric submersible plunger pump, reduce the cost of investment.

Dual-pump Kerr Micro-cavity Optical Frequency Comb with varying FSR spacing

PubMed Central

Wang, Weiqiang; Chu, Sai T.; Little, Brent E.; Pasquazi, Alessia; Wang, Yishan; Wang, Leiran; Zhang, Wenfu; Wang, Lei; Hu, Xiaohong; Wang, Guoxi; Hu, Hui; Su, Yulong; Li, Feitao; Liu, Yuanshan; Zhao, Wei

2016-01-01

In this paper, we demonstrate a novel dual-pump approach to generate robust optical frequency comb with varying free spectral range (FSR) spacing in a CMOS-compatible high-Q micro-ring resonator (MRR). The frequency spacing of the comb can be tuned by an integer number FSR of the MRR freely in our dual-pump scheme. The dual pumps are self-oscillated in the laser cavity loop and their wavelengths can be tuned flexibly by programming the tunable filter embedded in the cavity. By tuning the pump wavelength, broadband OFC with the bandwidth of >180 nm and the frequency-spacing varying from 6 to 46-fold FSRs is realized at a low pump power. This approach could find potential and practical applications in many areas, such as optical metrology, optical communication, and signal processing systems, for its excellent flexibility and robustness. PMID:27338250

Synchronization of spin-transfer torque oscillators by spin pumping, inverse spin Hall, and spin Hall effects

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

Elyasi, Mehrdad; Bhatia, Charanjit S.; Yang, Hyunsoo, E-mail: eleyang@nus.edu.sg

2015-02-14

We have proposed a method to synchronize multiple spin-transfer torque oscillators based on spin pumping, inverse spin Hall, and spin Hall effects. The proposed oscillator system consists of a series of nano-magnets in junction with a normal metal with high spin-orbit coupling, and an accumulative feedback loop. We conduct simulations to demonstrate the effect of modulated charge currents in the normal metal due to spin pumping from each nano-magnet. We show that the interplay between the spin Hall effect and inverse spin Hall effect results in synchronization of the nano-magnets.

Method of filling a microchannel separation column

DOEpatents

Arnold, Don W.

2002-01-01

A method for packing a stationary phase into a small diameter fluid passageway or flow channel. Capillary action is employed to distribute a stationary phase uniformly along both the length and diameter of the flow channel. The method disclosed here: 1) eliminates the need for high pressure pumps and fittings and the safety hazards associated therewith; 2) allows the use of readily available commercial microparticles, either coated or uncoated, as the stationary phase; 3) provides for different types of particles, different particle sizes, and different particle size distributions to be packed in sequence, or simultaneously; 4) eliminates the need for plugging the flow channel prior to adding the stationary phase to retain the packing particles; and 5) many capillaries can be filled simultaneously.

Staged regenerative sorption heat pump

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor)

1995-01-01

A regenerative adsorbent heat pump process and system for cooling and heating a space. A sorbent is confined in a plurality of compressors of which at least four are first stage and at least four are second stage. The first stage operates over a first pressure region and the second stage over a second pressure region which is higher than the first. Sorbate from the first stage enters the second stage. The sorbate loop includes a condenser, expansion valve, evaporator and the compressors. A single sorbate loop can be employed for single-temperature-control such as air conditioning and heating. Two sorbate loops can be used for two-temperature-control as in a refrigerator and freezer. The evaporator temperatures control the freezer and refrigerator temperatures. Alternatively the refrigerator temperature can be cooled by the freezer with one sorbate loop. A heat transfer fluid is circulated in a closed loop which includes a radiator and the compressors. Low temperature heat is exhausted by the radiator. High temperature heat is added to the heat transfer fluid entering the compressors which are desorbing vapor. Heat is transferred from compressors which are sorbing vapor to the heat transfer fluid, and from the heat transfer fluid to the compressors which are desorbing vapor. Each compressor is subjected to the following phases, heating to its highest temperature, cooling down from its highest temperature, cooling to its lowest temperature, and warming up from its lowest temperature. The phases are repeated to complete a cycle and regenerate heat.

Automated stopped-in-dual-loop flow analysis system for catalytic determination of vanadium in drinking water.

PubMed

Teshima, Norio; Kuno, Masami; Ueda, Minoru; Ueda, Hisashi; Ohno, Shinsuke; Sakai, Tadao

2009-07-15

An automated stopped-in-dual-loop flow analysis (SIDL-FA) system is proposed for the determination of vanadium in drinking water. The chemistry is based on the vanadium-catalyzed oxidation reaction of p-anisidine by bromate in the presence of Tiron as an activator to produce a dye (lambda(max)=510 nm). A SIDL-FA system basically consists of a selection valve, three pumps (one is for delivering of standard/sample, and others are for reagents), two six-way injection valves, a spectrophotometric detector and a data acquisition device. A 100-microL coiled loop around a heated device is fitted onto each six-way injection valve. A well-mixed solution containing reagents and standard/sample is loaded into the first loop on a six-way valve, and then the same solution is loaded into the second loop on another six-way valve. The solutions are isolated by switching these two six-way valves, so that the catalytic reaction can be promoted. The net waste can be zero in this stage, because all pumps are turned off. Then each resulting solution is dispensed to the detector with suitable time lag. A touchscreen controller is developed to automatically carry out the original SIDL-FA protocol. The proposed SIDL-FA method allows vanadium to be quantified in the range of 0.1-2 microg L(-1) and is applied to the determination of vanadium in drinking water samples.

Electromagnetic Pumps for Conductive-Propellant Feed Systems

NASA Technical Reports Server (NTRS)

Markusic, Thomas E.; Polzin, Kurt A.; Dehoyos, Amado

2005-01-01

Prototype electromagnetic pumps for use with lithium and bismuth propellants were constructed and tested. Such pumps may be used to pressurize future electric propulsion liquid metal feed systems, with the primary advantages being the compactness and simplicity versus alternative pressurization technologies. Design details for two different pumps are described: the first was designed to withstand (highly corrosive) lithium propellant, and t he second was designed to tolerate the high temperature required to pump liquid bismuth. Both qualitative and quantitative test results are presented. Open-loop tests demonstrated the capability of each device to electromagnetically pump its design propellant (lithium or bismuth). A second set of tests accurately quantified the pump pressure developed as a function of current. These experiments, which utilized a more easily handled material (gallium), demonstrated continuously-adjustable pump pressure levels ranging from 0-100 Torr for corresponding input current levels of 0-75 A. While the analysis and testing in this study specifically targeted lithium and bismuth propellants, the underlying design principles should be useful in implementing liquid metal pumps in any conductive-propellant feed system.

New methods for the development of pneumatic displacement pumps for cardiac assist.

PubMed

Knierbein, B; Rosarius, N; Reul, H; Rau, G

1990-11-01

The primary goal of the presented project was to develop a pump family with stroke volumes of 20, 50, 70 and 90 ml, which could be produced at low cost but with sufficient quality. The housing parts of the pump were thermoformed from technical semifinished materials. All blood contacting surfaces of the pump were coated with biomaterials in a controlled dipping process. During the design and fabrication process a professional CAD-system was used. This facilitated spatial presentations of pump components for first evaluations at the initial draft stages. The CAD-design data were then transformed to CNC-controlled lathes and mill's for the fabrication of pump tools. The stresses and strains of the moving blood pump components, such as membranes and valves, were precalculated by means of Finite-Element-Analysis (FEM). After completion of the pump, the internal flow fields were investigated by flow-visualization techniques using non-Newtonian test fluids, and the pump characteristics (function curves) were investigated in appropriate circulatory mock loops. The paper covers all above aspects from first draft to final fabrication and testing.

ULTRAHIGH SPEED SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF RETINAL AND CHORIOCAPILLARIS ALTERATIONS IN DIABETIC PATIENTS WITH AND WITHOUT RETINOPATHY.

PubMed

Choi, WooJhon; Waheed, Nadia K; Moult, Eric M; Adhi, Mehreen; Lee, ByungKun; De Carlo, Talisa; Jayaraman, Vijaysekhar; Baumal, Caroline R; Duker, Jay S; Fujimoto, James G

2017-01-01

To investigate the utility of ultrahigh speed, swept source optical coherence tomography angiography in visualizing retinal microvascular and choriocapillaris (CC) changes in diabetic patients. The study was prospective and cross-sectional. A 1,050 nm wavelength, 400 kHz A-scan rate swept source optical coherence tomography prototype was used to perform volumetric optical coherence tomography angiography of the retinal and CC vasculatures in diabetic patients and normal subjects. Sixty-three eyes from 32 normal subjects, 9 eyes from 7 patients with proliferative diabetic retinopathy, 29 eyes from 16 patients with nonproliferative diabetic retinopathy, and 51 eyes from 28 diabetic patients without retinopathy were imaged. Retinal and CC microvascular abnormalities were observed in all stages of diabetic retinopathy. In nonproliferative diabetic retinopathy and proliferative diabetic retinopathy, optical coherence tomography angiography visualized a variety of vascular abnormalities, including clustered capillaries, dilated capillary segments, tortuous capillaries, regions of capillary dropout, reduced capillary density, abnormal capillary loops, and foveal avascular zone enlargement. In proliferative diabetic retinopathy, retinal neovascularization above the inner limiting membrane was visualized. Regions of CC flow impairment in patients with proliferative diabetic retinopathy and nonproliferative diabetic retinopathy were also observed. In 18 of the 51 of eyes from diabetic patients without retinopathy, retinal mircrovascular abnormalities were observed and CC flow impairment was found in 24 of the 51 diabetic eyes without retinopathy. The ability of optical coherence tomography angiography to visualize retinal and CC microvascular abnormalities suggests it may be a useful tool for understanding pathogenesis, evaluating treatment response, and earlier detection of vascular abnormalities in patients with diabetes.

Enhanced expression by the brain matrix of P-glycoprotein in brain capillary endothelial cells.

PubMed

Tatsuta, T; Naito, M; Mikami, K; Tsuruo, T

1994-10-01

P-glycoprotein (PGP), an active efflux pump of antitumor agents in multidrug-resistant tumor cells, exists in brain capillary endothelium and could be functionally involved in the blood-brain barrier. To study the regulatory mechanism of PGP expression in brain capillary endothelium, various mouse tissue matrices were tested for their abilities to enhance the expression of PGP in mouse brain capillary endothelial cells (MBEC), which express relatively small amounts of PGP. Of the four tissue matrices we examined, PGP expression in MBEC cultured on the brain matrix increased 2.0-fold. The PGP-inducing activity was similarly detected in bovine brain matrix, and the activity was enriched in the fraction of pl 9.0 by isoelectric focusing. The fraction, named PIC-fraction (PGP-inducing component), increased the PGP expression in MBEC 3.5-fold. By Northern blot analysis, a 3.3-fold enhancement of mdr gene expression was observed in MBEC cultured on the PIC-fraction. The PGP-inducing activity of the PIC-fraction was reduced by the treatment with trypsin but not with collagenase, suggesting that a proteinaceous factor distinct from type I collagen might be responsible for the PGP-inducing activity of PIC-fraction. Although the PIC-fraction increased the PGP expression in other mouse brain capillary endothelial cells, the PIC-fraction did not increase PGP expression in mouse aortic endothelial cells and KB carcinoma cell lines expressing various amounts of PGP. These observations suggest that PGP expression in brain capillary endothelium is specifically regulated by a tissue-specific factor in the brain matrix.

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

Not Available

Oberlin Colleges Adam Joseph Lewis Center for Environmental Studies is a high-performance building featuring an expansive photovoltaic system and a closed-loop groundwater heat pump system. Designers incorporated energy-efficient components and materials that are local, non-toxic, and durable.

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

None

Oberlin College's Adam Joseph Lewis Center for Environmental Studies is a high-performance building featuring an expansive photovoltaic system and a closed-loop groundwater heat pump system. Designers incorporated energy-efficient components and materials that are local, non-toxic, and durable.

Representative shuttle evaporative heat sink

NASA Technical Reports Server (NTRS)

Hixon, C. W.

1978-01-01

The design, fabrication, and testing of a representative shuttle evaporative heat sink (RSEHS) system which vaporizes an expendable fluid to provide cooling for the shuttle heat transport fluid loop is reported. The optimized RSEHS minimum weight design meets or exceeds the shuttle flash evaporator system requirements. A cold trap which cryo-pumps flash evaporator exhaust water from the CSD vacuum chamber test facility to prevent water contamination of the chamber pumping equipment is also described.

Designing the modern pump: engineering aspects of continuous subcutaneous insulin infusion software.

PubMed

Welsh, John B; Vargas, Steven; Williams, Gary; Moberg, Sheldon

2010-06-01

Insulin delivery systems attracted the efforts of biological, mechanical, electrical, and software engineers well before they were commercially viable. The introduction of the first commercial insulin pump in 1983 represents an enduring milestone in the history of diabetes management. Since then, pumps have become much more than motorized syringes and have assumed a central role in diabetes management by housing data on insulin delivery and glucose readings, assisting in bolus estimation, and interfacing smoothly with humans and compatible devices. Ensuring the integrity of the embedded software that controls these devices is critical to patient safety and regulatory compliance. As pumps and related devices evolve, software engineers will face challenges and opportunities in designing pumps that are safe, reliable, and feature-rich. The pumps and related systems must also satisfy end users, healthcare providers, and regulatory authorities. In particular, pumps that are combined with glucose sensors and appropriate algorithms will provide the basis for increasingly safe and precise automated insulin delivery-essential steps to developing a fully closed-loop system.

Design of a Sub-Picosecond Jitter with Adjustable-Range CMOS Delay-Locked Loop for High-Speed and Low-Power Applications

PubMed Central

Abdulrazzaq, Bilal I.; Ibrahim, Omar J.; Kawahito, Shoji; Sidek, Roslina M.; Shafie, Suhaidi; Yunus, Nurul Amziah Md.; Lee, Lini; Halin, Izhal Abdul

2016-01-01

A Delay-Locked Loop (DLL) with a modified charge pump circuit is proposed for generating high-resolution linear delay steps with sub-picosecond jitter performance and adjustable delay range. The small-signal model of the modified charge pump circuit is analyzed to bring forth the relationship between the DLL’s internal control voltage and output time delay. Circuit post-layout simulation shows that a 0.97 ps delay step within a 69 ps delay range with 0.26 ps Root-Mean Square (RMS) jitter performance is achievable using a standard 0.13 µm Complementary Metal-Oxide Semiconductor (CMOS) process. The post-layout simulation results show that the power consumption of the proposed DLL architecture’s circuit is 0.1 mW when the DLL is operated at 2 GHz. PMID:27690040

User's manual for the Heat Pipe Space Radiator design and analysis Code (HEPSPARC)

NASA Technical Reports Server (NTRS)

Hainley, Donald C.

1991-01-01

A heat pipe space radiatior code (HEPSPARC), was written for the NASA Lewis Research Center and is used for the design and analysis of a radiator that is constructed from a pumped fluid loop that transfers heat to the evaporative section of heat pipes. This manual is designed to familiarize the user with this new code and to serve as a reference for its use. This manual documents the completed work and is intended to be the first step towards verification of the HEPSPARC code. Details are furnished to provide a description of all the requirements and variables used in the design and analysis of a combined pumped loop/heat pipe radiator system. A description of the subroutines used in the program is furnished for those interested in understanding its detailed workings.

Solar-powered Rankine heat pump for heating and cooling

NASA Technical Reports Server (NTRS)

Rousseau, J.

1978-01-01

The design, operation and performance of a familyy of solar heating and cooling systems are discussed. The systems feature a reversible heat pump operating with R-11 as the working fluid and using a motor-driven centrifugal compressor. In the cooling mode, solar energy provides the heat source for a Rankine power loop. The system is operational with heat source temperatures ranging from 155 to 220 F; the estimated coefficient of performance is 0.7. In the heating mode, the vapor-cycle heat pump processes solar energy collected at low temperatures (40 to 80 F). The speed of the compressor can be adjusted so that the heat pump capacity matches the load, allowing a seasonal coefficient of performance of about 8 to be attained.

High-performance, low-voltage electroosmotic pumps with molecularly thin silicon nanomembranes

PubMed Central

Snyder, Jessica L.; Getpreecharsawas, Jirachai; Fang, David Z.; Gaborski, Thomas R.; Striemer, Christopher C.; Fauchet, Philippe M.; Borkholder, David A.; McGrath, James L.

2013-01-01

We have developed electroosmotic pumps (EOPs) fabricated from 15-nm-thick porous nanocrystalline silicon (pnc-Si) membranes. Ultrathin pnc-Si membranes enable high electroosmotic flow per unit voltage. We demonstrate that electroosmosis theory compares well with the observed pnc-Si flow rates. We attribute the high flow rates to high electrical fields present across the 15-nm span of the membrane. Surface modifications, such as plasma oxidation or silanization, can influence the electroosmotic flow rates through pnc-Si membranes by alteration of the zeta potential of the material. A prototype EOP that uses pnc-Si membranes and Ag/AgCl electrodes was shown to pump microliter per minute-range flow through a 0.5-mm-diameter capillary tubing with as low as 250 mV of applied voltage. This silicon-based platform enables straightforward integration of low-voltage, on-chip EOPs into portable microfluidic devices with low back pressures. PMID:24167263

Lymphatic System Flows

NASA Astrophysics Data System (ADS)

Moore, James E., Jr.; Bertram, Christopher D.

2018-01-01

The supply of oxygen and nutrients to tissues is performed by the blood system and involves a net leakage of fluid outward at the capillary level. One of the principal functions of the lymphatic system is to gather this fluid and return it to the blood system to maintain overall fluid balance. Fluid in the interstitial spaces is often at subatmospheric pressure, and the return points into the venous system are at pressures of approximately 20 cmH2O. This adverse pressure difference is overcome by the active pumping of collecting lymphatic vessels, which feature closely spaced one-way valves and contractile muscle cells in their walls. Passive vessel squeezing causes further pumping. The dynamics of lymphatic pumping have been investigated experimentally and mathematically, revealing complex behaviors that indicate that the system performance is robust against minor perturbations in pressure and flow. More serious disruptions can lead to incurable swelling of tissues called lymphedema.

Syn-Fuel reciprocating charge pump improvement program. Quarterly technical project report, April-June 1984

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

Not Available

1984-01-01

Major accomplishments during the second quarter of 1984 were completion of the Diaphragm Separation Seal clear liquid testing, and initiation of Phase III Field Testing. Diaphragm operational testing was conducted on a clear water test loop. The test goals were to ensure; mechanical reliability of the Diaphragm Seal, safe operation with simulated component failure, and proper operation of the Diaphragm Buffer Volume Control System. This latter system is essential in controlling the phasing of the diaphragm with its driving plunger. These tests were completed successfully. All operational problems were solved. However, it must be emphasized that the Diaphragm Seal wouldmore » be damaged by allowing the pump to operate in a cavitating condition for an extended period of time. A change in the Field Test phase of the program was made regarding choice of field test site. There is no operating Syn-Fuel pilot plant capable of inexpensively producing the slurry stream required for the reciprocating pump testing. The Field Tests will now be conducted by first testing the prototype pump and separation seals in an ambient temperature sand water slurry. This will determine resistence to abrasive wear and determine any operation problems at pressure over a lengthy period of time. After successful conclusion of these tests the pump and seals will be operated with a high temperature oil, but without solids, to identify any problems associated with thermal gradients, thermal shock and differential growth. After successful completion of the high temperature clean oil tests the pump will be deemed ready for in-line installation at a designated Syn-Fuel pilot plant. The above approach avoids the expense and complications of a separate hot slurry test loop. It also reduces risk of operational problems while in-line at the pilot plant. 5 figs.« less

Detecting dynamic causal inference in nonlinear two-phase fracture flow

NASA Astrophysics Data System (ADS)

Faybishenko, Boris

2017-08-01

Identifying dynamic causal inference involved in flow and transport processes in complex fractured-porous media is generally a challenging task, because nonlinear and chaotic variables may be positively coupled or correlated for some periods of time, but can then become spontaneously decoupled or non-correlated. In his 2002 paper (Faybishenko, 2002), the author performed a nonlinear dynamical and chaotic analysis of time-series data obtained from the fracture flow experiment conducted by Persoff and Pruess (1995), and, based on the visual examination of time series data, hypothesized that the observed pressure oscillations at both inlet and outlet edges of the fracture result from a superposition of both forward and return waves of pressure propagation through the fracture. In the current paper, the author explores an application of a combination of methods for detecting nonlinear chaotic dynamics behavior along with the multivariate Granger Causality (G-causality) time series test. Based on the G-causality test, the author infers that his hypothesis is correct, and presents a causation loop diagram of the spatial-temporal distribution of gas, liquid, and capillary pressures measured at the inlet and outlet of the fracture. The causal modeling approach can be used for the analysis of other hydrological processes, for example, infiltration and pumping tests in heterogeneous subsurface media, and climatic processes, for example, to find correlations between various meteorological parameters, such as temperature, solar radiation, barometric pressure, etc.

Thermal Management of a Nitrogen Cryogenic Loop Heat Pipe

NASA Astrophysics Data System (ADS)

Gully, Ph.; Yan, T.

2010-04-01

Efficient thermal links are needed to ease the distribution of the cold power in satellites. Loop heat pipes are widely used at room temperature as passive thermal links based on a two-phase flow generated by capillary forces. Transportation of the cold power at cryogenic temperatures requires a specific design. In addition to the main loop, the cryogenic loop heat pipe (CLHP) features a hot reservoir and a secondary loop with a cold reservoir and a secondary evaporator which allows the cool down and the thermal management of the thermal link in normal cold operation. We have studied the influence of a heated cold reservoir and investigated the effect of parasitic heat loads on the performance of a nitrogen CLHP at around 80 K. It is shown that heating of the cold reservoir with a small amount of power (0.1 W) allows controlling the system temperature difference, which can be kept constant at a very low level (1 K) regardless of the transferred cold power (0-10 W). Parasitic heat loads have a significant effect on the thermal resistance, and the power applied on the secondary evaporator has to be increased up to 4 W to get stable operation.

Vapor-Compression Heat Pumps for Operation Aboard Spacecraft

NASA Technical Reports Server (NTRS)

Ruemmele, Warren; Ungar, Eugene; Cornwell, John

2006-01-01

Vapor-compression heat pumps (including both refrigerators and heat pumps) of a proposed type would be capable of operating in microgravity and would be safe to use in enclosed environments like those of spacecraft. The designs of these pumps would incorporate modifications of, and additions to, vapor-compression cycles of heat pumps now used in normal Earth gravitation, in order to ensure efficiency and reliability during all phases of operation, including startup, shutdown, nominal continuous operation, and peak operation. Features of such a design might include any or all of the following: (1) Configuring the compressor, condenser, evaporator, valves, capillary tubes (if any), and controls to function in microgravitation; (2) Selection of a working fluid that satisfies thermodynamic requirements and is safe to use in a closed crew compartment; (3) Incorporation of a solenoid valve and/or a check valve to prevent influx of liquid to the compressor upon startup (such influx could damage the compressor); (4) Use of a diode heat pipe between the cold volume and the evaporator to limit the influx of liquid to the compressor upon startup; and (5) Use of a heated block to vaporize any liquid that arrives at the compressor inlet.

Assessing the effectiveness of a 3-month day-and-night home closed-loop control combined with pump suspend feature compared with sensor-augmented pump therapy in youths and adults with suboptimally controlled type 1 diabetes: a randomised parallel study protocol.

PubMed

Bally, Lia; Thabit, Hood; Tauschmann, Martin; Allen, Janet M; Hartnell, Sara; Wilinska, Malgorzata E; Exall, Jane; Huegel, Viki; Sibayan, Judy; Borgman, Sarah; Cheng, Peiyao; Blackburn, Maxine; Lawton, Julia; Elleri, Daniela; Leelarathna, Lalantha; Acerini, Carlo L; Campbell, Fiona; Shah, Viral N; Criego, Amy; Evans, Mark L; Dunger, David B; Kollman, Craig; Bergenstal, Richard M; Hovorka, Roman

2017-07-13

Despite therapeutic advances, many individuals with type 1 diabetes are unable to achieve tight glycaemic target without increasing the risk of hypoglycaemia. The objective of this study is to determine the effectiveness of a 3-month day-and-night home closed-loop glucose control combined with a pump suspend feature, compared with sensor-augmented insulin pump therapy in youths and adults with suboptimally controlled type 1 diabetes. The study adopts an open-label, multi-centre, multi-national (UK and USA), randomised, single-period, parallel design and aims for 84 randomised patients. Participants are youths (6-21 years) or adults (>21 years) with type 1 diabetes treated with insulin pump therapy and suboptimal glycaemic control (glycated haemoglobin (HbA1c) ≥7.5% (58 mmol/mol) and ≤10% (86 mmol/mol)). Following a 4-week run-in period, eligible participants will be randomised to a 3-month use of automated closed-loop insulin delivery combined with pump suspend feature or to sensor-augmented insulin pump therapy. Analyses will be conducted on an intention-to-treat basis. The primary outcome is the time spent in the target glucose range from 3.9 to 10.0 mmol/L based on continuous glucose monitoring levels during the 3-month free-living phase. Secondary outcomes include HbA1c at 3 months, mean glucose, time spent below and above target; time with glucose levels <3.5 and <2.8 mmol/L; area under the curve when sensor glucose is <3.5 mmol/L, time with glucose levels >16.7 mmol/L, glucose variability; total, basal and bolus insulin dose and change in body weight. Participants' and their families' perception in terms of lifestyle change, daily diabetes management and fear of hypoglycaemia will be evaluated. Ethics/institutional review board approval has been obtained. Before screening, all participants/guardians will be provided with oral and written information about the trial. The study will be disseminated by peer-reviewed publications and conference presentations. NCT02523131; Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

The influence of heat sink temperature on the seasonal efficiency of shallow geothermal heat pumps

NASA Astrophysics Data System (ADS)

Pełka, Grzegorz; Luboń, Wojciech; Sowiżdżał, Anna; Malik, Daniel

2017-11-01

Geothermal heat pumps, also known as ground source heat pumps (GSHP), are the most efficient heating and cooling technology utilized nowadays. In the AGH-UST Educational and Research Laboratory of Renewable Energy Sources and Energy Saving in Miękinia, shallow geothermal heat is utilized for heating. In the article, the seasonal efficiency of two geothermal heat pump systems are described during the 2014/2015 heating season, defined as the period between 1st October 2014 and 30th April 2015. The first system has 10.9 kW heating capacity (according to European Standard EN 14511 B0W35) and extracts heat from three vertical geothermal loops at a depth of 80m each. During the heating season, tests warmed up the buffer to 40°C. The second system has a 17.03 kW heating capacity and extracts heat from three vertical geothermal loops at a depth of 100 m each, and the temperature of the buffer was 50°C. During the entire heating season, the water temperatures of the buffers was constant. Seasonal performance factors were calculated, defined as the quotient of heat delivered by a heat pump to the system and the sum of electricity consumed by the compressor, source pump, sink pump and controller of heat pumps. The measurements and calculations give the following results: - The first system was supplied with 13 857 kWh/a of heat and consumed 3 388 kWh/a electricity. The SPF was 4.09 and the average temperature of outlet water from heat pump was 40.8°C, and the average temperature of brine flows into the evaporator was 3.7 °C; - The second system was supplied with 12 545 kWh/a of heat and consumed 3 874 kWh/a electricity. The SPF was 3.24 and the average temperature of outlet water from heat pump was 51.6°C, and the average temperature of brine flows into the evaporator was 5.3°C. To summarize, the data shown above presents the real SPF of the two systems. It will be significant in helping to predict the SPF of objects which will be equipped with ground source heat pumps.

Selective reduction of afterload in right heart assist therapy: a mock loop study†.

PubMed

Hsu, Po-Lin; Hatam, Nima; Unterkofler, Jan; Goetzenich, Andreas; McIntyre, Madeleine; Wong, Kai Chun; Egger, Christina; Schmitz-Rode, Thomas; Autschbach, Rüdiger; Steinseifer, Ulrich

2014-07-01

The treatment of right ventricular failure is closely linked to effects on pulmonary vascular resistance and thus the right ventricular (RV) afterload. Medical therapy includes afterload-decreasing drugs such as nitric oxide and prostacycline. However, current devices for mechanical unloading of the right ventricle aim at a decrease in preload increasing the pulmonary volume loading. In our concept study, we tested a minimally invasive right ventricular assist device (MIRVAD) that specifically reduces the afterload. The MIRVAD is supposed to be a foldable device for temporary transvascular placement in the pulmonary artery. We incorporated a MIRVAD prototype into a mock circulatory loop that can reproduce haemodynamic interaction between the pump and the physiological system. Pulmonary hypertension (PH), right heart failure (RHF) and MIRVAD-assisted cases were simulated. The key haemodynamic parameters for RV unloading were recorded. Mock loop simulation attested to a sufficient right ventricular unloading by serial application of a miniaturized impeller pump in the pulmonary artery. The afterload, represented by the pulmonary arterial root pressure, was recovered to the healthy range (32.62-10.93 mmHg) for the simulated PH case. In the simulated RHF case, the impaired pulmonary perfusion increased from 43.4 to 88.8% of the healthy level and the total ventricular work reduced from 0.381 to 0.197 J at a pump speed of 3500 rpm. At pump speeds higher than 3500 rpm, the pulmonary valve remains constantly open and the right ventricular configuration changes into a simple perfused hollow body. The feasibility of RV unloading by a selective decrease in RV afterload was proved in principle. By alternation of the pump speed, gradual reloading in sense of a myocardial training may be achieved. The results will be validated by future animal trials where the relationship between the level of support and pulmonary vascular pressure can be investigated in vivo. Further device design concerning foldable impeller leaflets will be carried out. At a final stage, the crimped version is supposed to reach a size below 1 cm to facilitate minimally invasive insertion. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Hydrodynamic sample injection into short electrophoretic capillary in systems with a flow-gating interface.

PubMed

Opekar, František; Tůma, Petr

2017-01-13

An electrophoretic apparatus with a flow-gating interface has been developed, enabling hydrodynamic sequence injection of the sample into the separation capillary from the liquid flow by underpressure generated in the outlet electrophoretic vessel. The properties of the apparatus were tested on an artificial sample of an equimolar mixture of 100μM potassium and sodium ions and arginine. The repeatability of the injection of the tested ions expressed as RSD (in%) for the peak area, peak height and migration time was in the range 0.76-2.08, 0.18-0.68 and 0.28-0.48, respectively. Under optimum conditions, the apparatus was used for sequence monitoring of the reaction between the antidiabetic drug phenyl biguanide and the glycation agent methyl glyoxal. The reaction solution was continuously sampled by a microdialysis probe from a thermostated external vessel using a syringe pump at a flow rate of 3μLmin -1 and was injected into a separation capillary at certain time intervals. The electrophoretic separation progressed in a capillary with an internal diameter of 50μm with a length of 11.5cm and was monitored using a contactless conductivity detector. Copyright © 2016 Elsevier B.V. All rights reserved.

Plasma discharge elemental detector for a mass spectrometer

NASA Astrophysics Data System (ADS)

Heppner, R. A.

1983-06-01

A material to be analyzed is injected into a mirowave-induced plasma discharge unit, in which the material is carried with a flow of buffer gas through an intense microwave energy field which produces a plasma discharge in the buffer gas. As the material exits from the plasma discharge, the material is sampled and conveyed along a capillary transfer tube to a mass spectrometer where it is analyzed. The plasma discharge causes dissociation of complex organic molecules into simpler molecules which return to the neutral ground state before they are analyzed in the mass spectrometer. The buffer gas is supplied to one end portion of the discharge tube and is withdrawn from the other end portion by a vacuum pump which maintains a subatmospheric pressure in the discharge tube. The sample material is injected by a capillary injection tube into the buffer gas flow as it enters the plasma discharge zone. The dissociated materials are sampled by an axial sampling tube having an entrance where the buffer gas exits from the plasma discharge zone. The sample material may be supplied by a gas chromatography having a capillary effluent line connected to the capillary injection tube, so that the effluent material is injected into the microwave induced plasma discharge. The microwave field is produced by a cavity resonator through which the discharge tube passes.

Gigahertz frequency comb from a diode-pumped solid-state laser.

PubMed

Klenner, Alexander; Schilt, Stéphane; Südmeyer, Thomas; Keller, Ursula

2014-12-15

We present the first stabilization of the frequency comb offset from a diode-pumped gigahertz solid-state laser oscillator. No additional external amplification and/or compression of the output pulses is required. The laser is reliably modelocked using a SESAM and is based on a diode-pumped Yb:CALGO gain crystal. It generates 1.7-W average output power and pulse durations as short as 64 fs at a pulse repetition rate of 1 GHz. We generate an octave-spanning supercontinuum in a highly nonlinear fiber and use the standard f-to-2f carrier-envelope offset (CEO) frequency f_CEO detection method. As a pump source, we use a reliable and cost-efficient commercial diode laser. Its multi-spatial-mode beam profile leads to a relatively broad frequency comb offset beat signal, which nevertheless can be phase-locked by feedback to its current. Using improved electronics, we reached a feedback-loop-bandwidth of up to 300 kHz. A combination of digital and analog electronics is used to achieve a tight phase-lock of f_CEO to an external microwave reference with a low in-loop residual integrated phase-noise of 744 mrad in an integration bandwidth of [1 Hz, 5 MHz]. An analysis of the laser noise and response functions is presented which gives detailed insights into the CEO stabilization of this frequency comb.

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.

Self sufficient wireless transmitter powered by foot-pumped urine operating wearable MFC.

PubMed

Taghavi, M; Stinchcombe, A; Greenman, J; Mattoli, V; Beccai, L; Mazzolai, B; Melhuish, C; Ieropoulos, I A

2015-12-10

The first self-sufficient system, powered by a wearable energy generator based on microbial fuel cell (MFC) technology is introduced. MFCs made from compliant material were developed in the frame of a pair of socks, which was fed by urine via a manual gaiting pump. The simple and single loop cardiovascular fish circulatory system was used as the inspiration for the design of the manual pump. A wireless programmable communication module, engineered to operate within the range of the generated electricity, was employed, which opens a new avenue for research in the utilisation of waste products for powering portable as well as wearable electronics.

Microvasculature of crotaline snake pit organs: possible function as a heat exchange mechanism.

PubMed

Amemiya, F; Nakano, M; Goris, R C; Kadota, T; Atobe, Y; Funakoshi, K; Hibiya, K; Kishida, R

1999-01-01

The infrared sensory membranes of the pit organs of pit vipers have an extremely rich capillary vasculature, which has been noted passim in the literature, but never illustrated or studied in detail. We rendered the pit vasculature visible in various ways, namely, by microinjection of India ink, by a combination of ink and succinate dehydrogenase staining, and by making resin casts for scanning electron microscope study. We also used transmission electron microscopy for identifying the types (arterioles, venules, capillaries) of blood vessels. Then we compared the pit vasculature with that of the retina and the dermis. Good visualization of the vasculature was obtained with both ink and resin injection. Arterioles, venules, and capillaries could be distinguished with all methods used. The monolayer vasculature was denser in the pit membrane than in the retina or skin. Each loop of the network enclosed a small number of infrared receptors so that all receptors were in contact with a capillary on at least one side. The forward-looking areas of the pit had a denser network than side-looking areas. Since infrared rays cause nerve impulses by raising the temperature of individual receptors, the capillary network functions not only as a supplier of energy but also as a cooling mechanism to reduce afterimages. Thus the denser network in the forward-looking areas causes these areas to be more sensitive and have better image resolution than the rest of the membrane.

Transferrin Receptor 1 Facilitates Poliovirus Permeation of Mouse Brain Capillary Endothelial Cells.

PubMed

Mizutani, Taketoshi; Ishizaka, Aya; Nihei, Coh-Ichi

2016-02-05

As a possible route for invasion of the CNS, circulating poliovirus (PV) in the blood is believed to traverse the blood-brain barrier (BBB), resulting in paralytic poliomyelitis. However, the underlying mechanism is poorly understood. In this study, we demonstrated that mouse transferrin receptor 1 (mTfR1) is responsible for PV attachment to the cell surface, allowing invasion into the CNS via the BBB. PV interacts with the apical domain of mTfR1 on mouse brain capillary endothelial cells (MBEC4) in a dose-dependent manner via its capsid protein (VP1). We found that F-G, G-H, and H-I loops in VP1 are important for this binding. However, C-D, D-E, and E-F loops in VP1-fused Venus proteins efficiently penetrate MBEC4 cells. These results imply that the VP1 functional domain responsible for cell attachment is different from that involved in viral permeation of the brain capillary endothelium. We observed that co-treatment of MBEC4 cells with excess PV particles but not dextran resulted in blockage of transferrin transport into cells. Using the Transwell in vitro BBB model, transferrin co-treatment inhibited permeation of PV into MBEC4 cells and delayed further viral permeation via mTfR1 knockdown. With mTfR1 as a positive mediator of PV-host cell attachment and PV permeation of MBEC4 cells, our results indicate a novel role of TfR1 as a cellular receptor for human PV receptor/CD155-independent PV invasion of the CNS. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

The MEMS Knudsen Compressor as a Vacuum Pump for Space Exploration Applications

NASA Technical Reports Server (NTRS)

Vargo, S. E.; Muntz, E. P.; Tang, W. C.

2000-01-01

Several lander, probe and rover missions currently under study at the Jet Propulsion Laboratory (JPL) and especially in the Microdevices Laboratory (MDL) Center for Space Microelectronics Technology, focus on utilizing microelectromechanical systems (MEMS) based instruments for science data gathering. These small instruments and NASA's commitment to "faster, better, cheaper" type missions has brought about the need for novel approaches to satisfying mission requirements. Existing in-situ instrument systems clearly lack novel and integrated methods for satisfying their vacuum needs. One attractive candidate for a MEMS vacuum pump is the Knudsen Compressor, which operates based on thermal transpiration. Thermal transpiration describes gas flows induced by temperature differences maintained across orifices, porous membranes or capillary tubes under rarefied conditions. This device has two overwhelmingly attractive features as a MEMS vacuum pump - no moving parts and no fluids. An initial estimate of a Knudsen Compressor's pumping power requirements for a surface atmospheric sampling task on Mars is less than 80 mW, significantly below than alternative pumps. Due to the relatively low energy use for this task and the applicability of the Knudsen Compressor to other applications, the development of a Knudsen Compressor utilizing MEMS fabrication techniques has been initiated. This paper discusses the initial fabrication of a single-stage MEMS Knudsen Compressor vacuum pump, provides performance criteria such as pumping speed, size, energy use and ultimate pressure and details vacuum pump applications in several MDL related in-situ instruments.

Insulin pump use compared with intravenous insulin during labour and delivery: the INSPIRED observational cohort study.

PubMed

Drever, E; Tomlinson, G; Bai, A D; Feig, D S

2016-09-01

To assess the safety and efficacy of pump therapy (continuous subcutaneous insulin infusion; CSII) during labour and delivery in women with Type 1 diabetes. A retrospective cohort study of 161 consecutive Type 1 diabetic pregnancies delivered during 2000-2010 at Mount Sinai Hospital, Toronto, Canada. Capillary blood glucose levels during labour and delivery and time in/out of target (target: 4-6 mmol/l) were compared along with neonatal outcomes for three groups: (1) women on pumps who stayed on pumps during labour (pump/pump n = 31), (2) women on pumps who switched to intravenous (IV) insulin infusion during labour (pump/IVn = 25), and (3) women on multiple daily injections who switched to IV insulin infusion during labour (MDIn = 105). There were no significant differences between the mean or median glucose values during labour and delivery across all three groups, and no significant difference in time spent hypoglycaemic. However, women in the pump/pump group had significantly better glycaemic control as defined by mean glucose (5.5 vs. 6.4 mmol/l; P = 0.01), median glucose (5.4 vs. 6.3 mmol/l; P = 0.02), and more time spent in target (60.9% vs. 39.2%; P = 0.06) compared with women in the pump/IV group (after removing one outlier). This study demonstrates that the continuation of CSII therapy during labour and delivery appears safe and efficacious. Moreover, women who choose to continue CSII have better glucose control during delivery than those who switch to IV insulin, suggesting that it should be standard practice to allow women the option of continuing CSII during labour and delivery. © 2016 Diabetes UK.

[An experimental study of the computer-controlled equipment for delivering volatile anesthetic agent].

PubMed

Sun, B; Li, W Z; Yue, Y; Jiang, C W; Xiao, L Y

2001-11-01

Our newly-designed computer-controlled equipment for delivering volatile anesthetic agent uses the subminiature singlechip processor as the central controlling unit. The variables, such as anesthesia method, anesthetic agent, the volume of respiratory loop, age of patient, sex, height, weight, environment temperature and the grade of ASA are all input from the keyboard. The anesthetic dosage, calculated by the singlechip processor, is converted into the signals controlling the pump to accurately deliver anesthetic agent into respiratory loop. We have designed an electrocircuit for the equipment to detect the status of the pump's operation, so we can assure of the safety and the stability of the equipment. The output precision of the equipment, with a good anti-jamming capability, is 1-2% for high flow anesthesia and 1-5% for closed-circuit anesthesia and its self-detecting working is reliable.

Aqueous Solution Heat Pipe Transport: Qu-Tube vs. Capillary-Pumped Heat Pipe

DTIC Science & Technology

2013-07-01

independently of gravity , exhibit very high conductivity, work over large distances and temperature ranges, and operate at a lower pressure than...tubes” or “Qu-tubes.” These purportedly superior tubes were claimed to have such desirable qualities as entirely dry operation, gravity -independence... gravity -dependent. Our detailed and quantitative findings suggest that the devices we purchased are not revolutionary in performance, and may in fact

Equations for nickel-chromium wire heaters of column transfer lines in gas chromatographic-electroantennographic detection (GC-EAD).

PubMed

Byers, John A

2004-05-30

Heating of chromatographic columns, transfer lines, and other devices is often required in neuroscience research. For example, volatile compounds passing through a capillary column of a gas chromatograph (GC) can be split, with half exiting the instrument through a heated transfer line to an insect antenna or olfactory sensillum for electroantennographic detector (GC-EAD) recordings. The heated transfer line is used to prevent condensation of various chemicals in the capillary that would otherwise occur at room temperature. Construction of such a transfer line heater is described using (80/20%) nickel-chromium heating wire wrapped in a helical coil and powered by a 120/220 V ac rheostat. Algorithms were developed in a computer program to estimate the voltage at which a rheostat should be set to obtain the desired heater temperature for a specific coil. The coil attributes (radius, width, number of loops, or length of each loop) are input by the user, as well as AWG size of heating wire and desired heater temperature. The program calculates total length of wire in the helix, resistance of the wire, amperage used, and the voltage to set the rheostat. A discussion of semiochemical isolation methods using the GC-EAD and bioassays is presented.

Continuous Glucose Monitoring: A Review of Successes, Challenges, and Opportunities.

PubMed

Rodbard, David

2016-02-01

Continuous glucose monitoring (CGM) provides information unattainable by intermittent capillary blood glucose, including instantaneous real-time display of glucose level and rate of change of glucose, alerts and alarms for actual or impending hypo- and hyperglycemia, "24/7" coverage, and the ability to characterize glycemic variability. Progressively more accurate and precise, reasonably unobtrusive, small, comfortable, user-friendly devices connect to the Internet to share information and are sine qua non for a closed-loop artificial pancreas. CGM can inform, educate, motivate, and alert people with diabetes. CGM is medically indicated for patients with frequent, severe, or nocturnal hypoglycemia, especially in the presence of hypoglycemia unawareness. Surprisingly, despite tremendous advances, utilization of CGM has remained fairly limited to date. Barriers to use have included the following: (1) lack of Food and Drug Administration approval, to date, for insulin dosing ("nonadjuvant use") in the United States and for use in hospital and intensive care unit settings; (2) cost and variable reimbursement; (3) need for recalibrations; (4) periodic replacement of sensors; (5) day-to-day variability in glycemic patterns, which can limit the predictability of findings based on retrospective, masked "professional" use; (6) time, implicit costs, and inconvenience for uploading of data for retrospective analysis; (7) lack of fair and reasonable reimbursement for physician time; (8) inexperience and lack of training of physicians and other healthcare professionals regarding interpretation of CGM results; (9) lack of standardization of software methods for analysis of CGM data; and (10) need for professional medical organizations to develop and disseminate additional clinical practice guidelines regarding the role of CGM. Ongoing advances in technology and clinical research have addressed several of these barriers. Use of CGM in conjunction with an insulin pump with automated suspension of insulin infusion in response to actual observed or predicted hypoglycemia, as well as progressive refinement of closed-loop systems, is expected to dramatically enhance the clinical utility and utilization of CGM.

Continuous Glucose Monitoring: A Review of Successes, Challenges, and Opportunities

PubMed Central

2016-01-01

Abstract Continuous glucose monitoring (CGM) provides information unattainable by intermittent capillary blood glucose, including instantaneous real-time display of glucose level and rate of change of glucose, alerts and alarms for actual or impending hypo- and hyperglycemia, “24/7” coverage, and the ability to characterize glycemic variability. Progressively more accurate and precise, reasonably unobtrusive, small, comfortable, user-friendly devices connect to the Internet to share information and are sine qua non for a closed-loop artificial pancreas. CGM can inform, educate, motivate, and alert people with diabetes. CGM is medically indicated for patients with frequent, severe, or nocturnal hypoglycemia, especially in the presence of hypoglycemia unawareness. Surprisingly, despite tremendous advances, utilization of CGM has remained fairly limited to date. Barriers to use have included the following: (1) lack of Food and Drug Administration approval, to date, for insulin dosing (“nonadjuvant use”) in the United States and for use in hospital and intensive care unit settings; (2) cost and variable reimbursement; (3) need for recalibrations; (4) periodic replacement of sensors; (5) day-to-day variability in glycemic patterns, which can limit the predictability of findings based on retrospective, masked “professional” use; (6) time, implicit costs, and inconvenience for uploading of data for retrospective analysis; (7) lack of fair and reasonable reimbursement for physician time; (8) inexperience and lack of training of physicians and other healthcare professionals regarding interpretation of CGM results; (9) lack of standardization of software methods for analysis of CGM data; and (10) need for professional medical organizations to develop and disseminate additional clinical practice guidelines regarding the role of CGM. Ongoing advances in technology and clinical research have addressed several of these barriers. Use of CGM in conjunction with an insulin pump with automated suspension of insulin infusion in response to actual observed or predicted hypoglycemia, as well as progressive refinement of closed-loop systems, is expected to dramatically enhance the clinical utility and utilization of CGM. PMID:26784127

Porous glass electroosmotic pumps: design and experiments.

PubMed

Yao, Shuhuai; Hertzog, David E; Zeng, Shulin; Mikkelsen, James C; Santiago, Juan G

2003-12-01

An analytical model for electroosmotic flow rate, total pump current, and thermodynamic efficiency reported in a previous paper has been applied as a design guideline to fabricate porous-structure EO pumps. We have fabricated sintered-glass EO pumps that provide maximum flow rates and pressure capacities of 33 ml/min and 1.3 atm, respectively, at applied potential 100 V. These pumps are designed to be integrated with two-phase microchannel heat exchangers with load capacities of order 100 W and greater. Experiments were conducted with pumps of various geometries and using a relevant, practical range of working electrolyte ionic concentration. Characterization of the pumping performance are discussed in the terms of porosity, tortuosity, pore size, and the dependence of zeta potential on bulk ion density of the working solution. The effects of pressure and flow rate on pump current and thermodynamic efficiency are analyzed and compared to the model prediction. In particular, we explore the important tradeoff between increasing flow rate capacity and obtaining adequate thermodynamic efficiency. This research aims to demonstrate the performance of EOF pump systems and to investigate optimal and practical pump designs. We also present a gas recombination device that makes possible the implementation of this pumping technology into a closed-flow loop where electrolytic gases are converted into water and reclaimed by the system.

[Recent advances and applications of capillary electrochromatography and pressurized capillary electrochromatography].

PubMed

Wu, Yi; Zhang, Xiaohui; Wei, Juan; Xue, Yunyun; Bahatibieke, Marjan; Wang, Yan; Yan, Chao

2009-09-01

Capillary electrochromatography (CEC), in which electroosmotic flow (EOF) created from the electrical double layer is made to act as a pump to drive the mobile phase in a capillary column packed with micro-particulates or coated with stationary phase. Both neutral and charged species can be resolved by CEC. It has been demonstrated that the efficiency of a separation obtained by electroosmotic propulsion is superior to that obtained by pressure-driven flow (as is the case in HPLC). CEC combines the best features of CE and versatile selectivity and large sample capacity of HPLC, promising high efficiency, high resolution, high selectivity and high peak capacity. However, in practice, when CEC is used without pressure, often used on a commercial CE instrument, there are problems and difficulties associated with bubbles formation and column dry-out. These difficulties can be overcome by a pressurized CEC (pCEC) system, in which a supplementary pressure is applied to the column in addition to the EOF. In such a system, a pressure can be applied to the capillary column to suppress bubbles formation. Quantitative sample introduction in pCEC can be easily achieved through a rotary-type injector. Most importantly, it is amenable for a solvent gradient mode, similar to that in HPLC, by programming the composition of mobile phase. The article brings a comprehensive survey of recent development of CEC and pCEC, including the development of instrumentation, capillary columns and stationary phase as well as CEC and pCEC applications in life science, biotechnology, pharmaceutical analysis, food safety and environmental security. Prospects for CEC and pCEC development and application are also discussed.

Josephson Parametric Amplifer Based on a Cavity-Embedded Cooper Pair Transistor

NASA Astrophysics Data System (ADS)

Li, Juliang; Rimberg, A. J.

In this experiment a cavity-embedded Cooper-pair transistor (cCPT) is used as a Josephson parametric amplifier. The cCPT consists of a Cooper pair transistor placed at the voltage antinode of a 5.7 GHz shorted quarter-wave resonator so that the CPT provides a galvanic connection between the cavity's central conductor and ground plane, which forms a SQUID loop. Both the flux threading the loop as well as the gate charge can be modulated, and each can provide the parametric pumping. The reflected signal from the cCPT is further amplified by both SLUG and HEMT amplifiers for characterizing the parametric amplification. A first application of the parametric amplification is to improve the charge sensitivity of a single electron charge detector. This can be done either by pumping on a side band or by shifting the charge state of the cCPT near a bifurcation point. Stimulated emission has been also observed when the cCPT is pumped at twice the resonant frequency in the absence of an input signal. This could allow investigation of the dynamic Casimir effect as well as generation of non-classical photon states. Supported by Grants ARO W911NF-13-10377 and NSF DMR 1507400.

Adding the ‘heart’ to hanging drop networks for microphysiological multi-tissue experiments†

PubMed Central

Yazdi, Saeed Rismani; Shadmani, Amir; Bürgel, Sebastian C.; Misun, Patrick M.; Hierlemann, Andreas; Frey, Olivier

2017-01-01

Microfluidic hanging-drop networks enable culturing and analysis of 3D microtissue spheroids derived from different cell types under controlled perfusion and investigating inter-tissue communication in multi-tissue formats. In this paper we introduce a compact on-chip pumping approach for flow control in hanging-drop networks. The pump includes one pneumatic chamber located directly above one of the hanging drops and uses the surface tension at the liquid–air-interface for flow actuation. Control of the pneumatic protocol provides a wide range of unidirectional pulsatile and continuous flow profiles. With the proposed concept several independent hanging-drop networks can be operated in parallel with only one single pneumatic actuation line at high fidelity. Closed-loop medium circulation between different organ models for multi-tissue formats and multiple simultaneous assays in parallel are possible. Finally, we implemented a real-time feedback control-loop of the pump actuation based on the beating of a human iPS-derived cardiac microtissue cultured in the same system. This configuration allows for simulating physiological effects on the heart and their impact on flow circulation between the organ models on chip. PMID:26401602

Peristaltic pump-based low range pressure sensor calibration system

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

Vinayakumar, K. B.; Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 5600012; Naveen Kumar, G.

2015-11-15

Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressuremore » leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.« less

Peristaltic pump-based low range pressure sensor calibration system

NASA Astrophysics Data System (ADS)

Vinayakumar, K. B.; Naveen Kumar, G.; Nayak, M. M.; Dinesh, N. S.; Rajanna, K.

2015-11-01

Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

Synthetic microfluidic paper: high surface area and high porosity polymer micropillar arrays.

PubMed

Hansson, Jonas; Yasuga, Hiroki; Haraldsson, Tommy; van der Wijngaart, Wouter

2016-01-21

We introduce Synthetic Microfluidic Paper, a novel porous material for microfluidic applications that consists of an OSTE polymer that is photostructured in a well-controlled geometry of slanted and interlocked micropillars. We demonstrate the distinct benefits of Synthetic Microfluidic Paper over other porous microfluidic materials, such as nitrocellulose, traditional paper and straight micropillar arrays: in contrast to straight micropillar arrays, the geometry of Synthetic Microfluidic Paper was miniaturized without suffering capillary collapse during manufacturing and fluidic operation, resulting in a six-fold increased internal surface area and a three-fold increased porous fraction. Compared to commercial nitrocellulose materials for capillary assays, Synthetic Microfluidic Paper shows a wider range of capillary pumping speed and four times lower device-to-device variation. Compared to the surfaces of the other porous microfluidic materials that are modified by adsorption, Synthetic Microfluidic Paper contains free thiol groups and has been shown to be suitable for covalent surface chemistry, demonstrated here for increasing the material hydrophilicity. These results illustrate the potential of Synthetic Microfluidic Paper as a porous microfluidic material with improved performance characteristics, especially for bioassay applications such as diagnostic tests.

Integrated microfluidic flowmeter based on a micro-FBG inscribed in Co²⁺-doped optical fiber.

PubMed

Liu, Zhengyong; Tse, Ming-Leung Vincent; Zhang, A Ping; Tam, Hwa-Yaw

2014-10-15

A novel microfluidic flowmeter integrated with microfiber Bragg grating (µFBG) is presented. Two glass capillaries and a short length of high-light-absorption Co²⁺-doped optical fiber were stacked inside a larger outer capillary tube. The stack was then drawn into a tapered device. Two microchannels with the diameter of ~50  μm were formed inside the capillaries for flowing of microfluidics. An FBG was inscribed in the tapered Co²⁺-doped fiber with waist diameter of ~70  μm, and acts as a flow-rate sensor. A pump laser with wavelength of 1480 nm was utilized to locally heat the µFBG, rendering the µFBG as miniature "hot-wire" flowmeter. The flow rate of the liquid in the microchannels is determined by the induced wavelength shift of the µFBG. The experimental results achieve a minimum detectable change of ~16  nL/s in flow rate, which is very promising in the use as part of biochips.

International Space Station (ISS) External Thermal Control System (ETCS) Loop A Pump Module (PM) Jettison Options Assessment

NASA Technical Reports Server (NTRS)

Murri, Daniel G.; Dwyer Cianciolo, Alicia; Shidner, Jeremy D.; Powell, Richard W.

2014-01-01

On December 11, 2013, the International Space Station (ISS) experienced a failure of the External Thermal Control System (ETCS) Loop A Pump Module (PM). To minimize the number of extravehicular activities (EVA) required to replace the PM, jettisoning the faulty pump was evaluated. The objective of this study was to independently evaluate the jettison options considered by the ISS Trajectory Operations Officer (TOPO) and to provide recommendations for safe jettison of the ETCS Loop A PM. The simulation selected to evaluate the TOPO options was the NASA Engineering and Safety Center's (NESC) version of Program to Optimize Simulated Trajectories II (POST2) developed to support another NESC assessment. The objective of the jettison analysis was twofold: (1) to independently verify TOPO posigrade and retrograde jettison results, and (2) to determine jettison guidelines based on additional sensitivity, trade study, and Monte Carlo (MC) analysis that would prevent PM recontact. Recontact in this study designates a propagated PM trajectory that comes within 500 m of the ISS propagated trajectory. An additional simulation using Systems Tool Kit (STK) was run for independent verification of the POST2 simulation results. Ultimately, the ISS Program removed the PM jettison option from consideration. However, prior to the Program decision, the retrograde jettison option remained part of the EVA contingency plan. The jettison analysis presented showed that, in addition to separation velocity/direction and the atmosphere conditions, the key variables in determining the time to recontact the ISS is highly dependent on the ballistic number (BN) difference between the object being jettisoned and the ISS.

Current topics in glycemic control by wearable artificial pancreas or bedside artificial pancreas with closed-loop system.

PubMed

Hanazaki, Kazuhiro; Munekage, Masaya; Kitagawa, Hiroyuki; Yatabe, Tomoaki; Munekage, Eri; Shiga, Mai; Maeda, Hiromichi; Namikawa, Tsutomu

2016-09-01

The incidence of diabetes is increasing at an unprecedented pace and has become a serious health concern worldwide during the last two decades. Despite this, adequate glycemic control using an artificial pancreas has not been established, although the 21st century has seen rapid developments in this area. Herein, we review current topics in glycemic control for both the wearable artificial pancreas for type 1 and type 2 diabetic patients and the bedside artificial pancreas for surgical diabetic patients. In type 1 diabetic patients, nocturnal hypoglycemia associated with insulin therapy remains a serious problem that could be addressed by the recent development of a wearable artificial pancreas. This smart phone-like device, comprising a real-time, continuous glucose monitoring system and insulin pump system, could potentially significantly reduce nocturnal hypoglycemia compared with conventional glycemic control. Of particular interest in this space are the recent inventions of a low-glucose suspend feature in the portable systems that automatically stops insulin delivery 2 h following a glucose sensor value <70 mg/dL and a bio-hormonal pump system consisting of insulin and glucagon pumps. Perioperative tight glycemic control using a bedside artificial pancreas with the closed-loop system has also proved safe and effective for not only avoiding hypoglycemia, but also for reducing blood glucose level variability resulting in good surgical outcomes. We hope that a more sophisticated artificial pancreas with closed-loop system will now be taken up for routine use worldwide, providing enormous relief for patients suffering from uncontrolled hyperglycemia, hypoglycemia, and/or variability in blood glucose concentrations.

A 2.2 sq m /24 sq ft/ self-controlled deployable heat pipe radiator - Design and test

NASA Technical Reports Server (NTRS)

Edelstein, F.

1975-01-01

An all heat pipe, deployable radiator has been developed which can effectively control pumped fluid loop temperatures under varying loads using variable conductance panel heat pipes. The 2.2 sq m (24 sq ft) aluminum panel can be coupled to either a fluid header or a flexible heat pipe header capable of transporting 850 watts in a 90-deg bent configuration. Test results support the feasibility of using this system to passively control Freon-21 loop temperatures.

A high-sensitivity push-pull magnetometer

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

Breschi, E.; Grujić, Z. D.; Knowles, P.

2014-01-13

We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/√(Hz), using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/√(Hz)

High precision innovative micropump for artificial pancreas

NASA Astrophysics Data System (ADS)

Chappel, E.; Mefti, S.; Lettieri, G.-L.; Proennecke, S.; Conan, C.

2014-03-01

The concept of artificial pancreas, which comprises an insulin pump, a continuous glucose meter and a control algorithm, is a major step forward in managing patient with type 1 diabetes mellitus. The stability of the control algorithm is based on short-term precision micropump to deliver rapid-acting insulin and to specific integrated sensors able to monitor any failure leading to a loss of accuracy. Debiotech's MEMS micropump, based on the membrane pump principle, is made of a stack of 3 silicon wafers. The pumping chamber comprises a pillar check-valve at the inlet, a pumping membrane which is actuated against stop limiters by a piezo cantilever, an anti-free-flow outlet valve and a pressure sensor. The micropump inlet is tightly connected to the insulin reservoir while the outlet is in direct communication with the patient skin via a cannula. To meet the requirement of a pump dedicated to closed-loop application for diabetes care, in addition to the well-controlled displacement of the pumping membrane, the high precision of the micropump is based on specific actuation profiles that balance effect of pump elasticity in low-consumption push-pull mode.

Solar Assisted Ground Source Heat Pump Performance in Nearly Zero Energy Building in Baltic Countries

NASA Astrophysics Data System (ADS)

Januševičius, Karolis; Streckienė, Giedrė

2013-12-01

In near zero energy buildings (NZEB) built in Baltic countries, heat production systems meet the challenge of large share domestic hot water demand and high required heating capacity. Due to passive solar design, cooling demand in residential buildings also needs an assessment and solution. Heat pump systems are a widespread solution to reduce energy use. A combination of heat pump and solar thermal collectors helps to meet standard requirements and increases the share of renewable energy use in total energy balance of country. The presented paper describes a simulation study of solar assisted heat pump systems carried out in TRNSYS. The purpose of this simulation was to investigate how the performance of a solar assisted heat pump combination varies in near zero energy building. Results of three systems were compared to autonomous (independent) systems simulated performance. Different solar assisted heat pump design solutions with serial and parallel solar thermal collector connections to the heat pump loop were modelled and a passive cooling possibility was assessed. Simulations were performed for three Baltic countries: Lithuania, Latvia and Estonia.

Portable gas chromatograph-mass spectrometer

DOEpatents

Andresen, Brian D.; Eckels, Joel D.; Kimmons, James F.; Myers, David W.

1996-01-01

A gas chromatograph-mass spectrometer (GC-MS) for use as a field portable organic chemical analysis instrument. The GC-MS is designed to be contained in a standard size suitcase, weighs less than 70 pounds, and requires less than 600 watts of electrical power at peak power (all systems on). The GC-MS includes: a conduction heated, forced air cooled small bore capillary gas chromatograph, a small injector assembly, a self-contained ion/sorption pump vacuum system, a hydrogen supply, a dual computer system used to control the hardware and acquire spectrum data, and operational software used to control the pumping system and the gas chromatograph. This instrument incorporates a modified commercial quadrupole mass spectrometer to achieve the instrument sensitivity and mass resolution characteristic of laboratory bench top units.

Fault Detection and Safety in Closed-Loop Artificial Pancreas Systems

PubMed Central

2014-01-01

Continuous subcutaneous insulin infusion pumps and continuous glucose monitors enable individuals with type 1 diabetes to achieve tighter blood glucose control and are critical components in a closed-loop artificial pancreas. Insulin infusion sets can fail and continuous glucose monitor sensor signals can suffer from a variety of anomalies, including signal dropout and pressure-induced sensor attenuations. In addition to hardware-based failures, software and human-induced errors can cause safety-related problems. Techniques for fault detection, safety analyses, and remote monitoring techniques that have been applied in other industries and applications, such as chemical process plants and commercial aircraft, are discussed and placed in the context of a closed-loop artificial pancreas. PMID:25049365

NORTH PORTAL-HOT WATER CIRCULATION PUMP CALCULATION-SHOP BUILDING #5006

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

R. Blackstone

1996-01-25

The purpose of this design analysis and calculation is to size a circulating pump for the service hot water system in the Shop Building 5006, in accordance with the Uniform Plumbing Code (Section 4.4.1) and U.S. Department of Energy Order 6430.1A-1540 (Section 4.4.2). The method used for the calculation is based on Reference 5.2. This consists of determining the total heat transfer from the service hot water system piping to the surrounding environment. The heat transfer is then used to define the total pumping capacity based on a given temperature change in the circulating hot water as it flows throughmore » the closed loop piping system. The total pumping capacity is used to select a pump model from manufacturer's literature. This established the head generation for that capacity and particular pump model. The total length of all hot water supply and return piping including fittings is then estimated from the plumbing drawings which defines the pipe friction losses that must fit within the available pump head. Several iterations may be required before a pump can be selected that satisfies the head-capacity requirements.« less

Experimental Determination of the Dynamic Hydraulic Transfer Function for the J-2X Oxidizer Turbopump. Part One; Methodology

NASA Technical Reports Server (NTRS)

Zoladz, Tom; Patel, Sandeep; Lee, Erik; Karon, Dave

2011-01-01

An advanced methodology for extracting the hydraulic dynamic pump transfer matrix (Yp) for a cavitating liquid rocket engine turbopump inducer+impeller has been developed. The transfer function is required for integrated vehicle pogo stability analysis as well as optimization of local inducer pumping stability. Laboratory pulsed subscale waterflow test of the J-2X oxygen turbo pump is introduced and our new extraction method applied to the data collected. From accurate measures of pump inlet and discharge perturbational mass flows and pressures, and one-dimensional flow models that represents complete waterflow loop physics, we are able to derive Yp and hence extract the characteristic pump parameters: compliance, pump gain, impedance, mass flow gain. Detailed modeling is necessary to accurately translate instrument plane measurements to the pump inlet and discharge and extract Yp. We present the MSFC Dynamic Lump Parameter Fluid Model Framework and describe critical dynamic component details. We report on fit minimization techniques, cost (fitness) function derivation, and resulting model fits to our experimental data are presented. Comparisons are made to alternate techniques for spatially translating measurement stations to actual pump inlet and discharge.

Air Source Cold Climate Heat Pump

DTIC Science & Technology

2013-08-01

nature of the system additional components were utilized as well. For instance, a capillary tube was used on all of the pressure switches and...Projects 97 August 2013 Building Automation Products, Inc. 750 North Royal Avenue, Gays Mills, WI 54631 USA Tel: +1-608-735·4800 ·Fax: +1-608-735-4804...Products, Inc 750 North Royal Ave. Gays Mills, WI 54631 USA ESTCP Final Report: 201136 Energy and Water Projects 98 August 2013 CE Declaration

United States Air Force Environmental Restoration Program. Guidance on Soil Vapor Extraction Optimization

DTIC Science & Technology

2001-06-01

Pump Exposed Capillary Fringe SVE System Pneumatic/ Hydraulic Fracturing Points Increased Advective Flow draw\\svehandbk1.cdr aee p1 4/5/01 022/736300...propagate further from the extraction well, increasing the advective flow zone round the well. Pneumatic and hydraulic fracturing are the primary methods...enhancing existing fractures and increasing the secondary fracture network. Hydraulic fracturing involves the injection of water or slurry into the

The mechanical design of a vapor compressor for a heat pump to be used in space

NASA Technical Reports Server (NTRS)

Berner, F.; Oesch, H.; Goetz, K.; Savage, C. J.

1982-01-01

A heat pump developed for use in Spacelab as a stand-alone refrigeration unit as well as within a fluid loop system is discussed. It will provide an active thermal control for payloads. Specifications for the heat pump were established: (1) heat removal rates at the source; (2) heat source temperatures from room temperature; (3) heat-sink fluid temperatures at condenser inlet; and (4) minimum power consumption. A reversed Carnot cycle heat pump using Freon 12 as working fluid incorporating a one-cylinder reciprocating compressor was selected. The maximum crankshaft speed was fixed relatively high at 100 rpm. The specified cooling rates then made it necessary to select a cylinder volume of 10 cu cm, which was obtained with a bore of 40 mm and a stroke of 8 mm.

Measurement of the differential pressure of liquid metals

DOEpatents

Metz, H.J.

1975-09-01

This patent relates to an improved means for measuring the differential pressure between any two points in a process liquid metal coolant loop, wherein the flow of liquid metal in a pipe is opposed by a permanent magnet liquid metal pump until there is almost zero flow shown by a magnetic type flowmeter. The pressure producing the liquid metal flow is inferred from the rate of rotation of the permanent magnet pump. In an alternate embodiment, a differential pressure transducer is coupled to a process pipeline by means of high-temperature bellows or diaphragm seals, and a permanent magnet liquid metal pump in the high-pressure transmission line to the pressure transducer can be utilized either for calibration of the transducer or for determining the process differential pressure as a function of the magnet pump speed. (auth)

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

Chatterton, Mike

The Recovery Act: Districtwide Geothermal Heating Conversion project performed by the Blaine County School District was part of a larger effort by the District to reduce operating costs, address deferred maintenance items, and to improve the learning environment of the students. This project evaluated three options for the ground source which were Open-Loop Extraction/Re-injection wells, Closed-Loop Vertical Boreholes, and Closed-Loop Horizontal Slinky approaches. In the end the Closed-Loop Horizontal Slinky approach had the lowest total cost of ownership but the majority of the sites associated with this project did not have enough available ground area to install the system somore » the second lowest option was used (Open-Loop). In addition to the ground source, this project looked at ways to retrofit existing HVAC systems with new high efficiency systems. The end result was the installation of distributed waterto- air heat pumps with water-to-water heat pumps installed to act as boilers/chillers for areas with a high ventilation demand such as they gymnasiums. A number of options were evaluated and the lowest total cost of ownership approach was implemented in the majority of the facilities. The facilities where the lowest total cost of ownership approaches was not selected were done to maintain consistency of the systems from facility to facility. This project had a number of other benefits to the Blaine County public. The project utilizes guaranteed energy savings to justify the levy funds expended. The project also developed an educational dashboard that can be used in the classrooms and to educate the community on the project and its performance. In addition, the majority of the installation work was performed by contractors local to Blaine County which acted as an economic stimulus to the area during a period of recession.« less

In silico preclinical trials: a proof of concept in closed-loop control of type 1 diabetes.

PubMed

Kovatchev, Boris P; Breton, Marc; Man, Chiara Dalla; Cobelli, Claudio

2009-01-01

Arguably, a minimally invasive system using subcutaneous (s.c.) continuous glucose monitoring (CGM) and s.c. insulin delivery via insulin pump would be a most feasible step to closed-loop control in type 1 diabetes mellitus (T1DM). Consequently, diabetes technology is focusing on developing an artificial pancreas using control algorithms to link CGM with s.c. insulin delivery. The future development of the artificial pancreas will be greatly accelerated by employing mathematical modeling and computer simulation. Realistic computer simulation is capable of providing invaluable information about the safety and the limitations of closed-loop control algorithms, guiding clinical studies, and out-ruling ineffective control scenarios in a cost-effective manner. Thus computer simulation testing of closed-loop control algorithms is regarded as a prerequisite to clinical trials of the artificial pancreas. In this paper, we present a system for in silico testing of control algorithms that has three principal components: (1) a large cohort of n=300 simulated "subjects" (n=100 adults, 100 adolescents, and 100 children) based on real individuals' data and spanning the observed variability of key metabolic parameters in the general population of people with T1DM; (2) a simulator of CGM sensor errors representative of Freestyle Navigator™, Guardian RT, or Dexcom™ STS™, 7-day sensor; and (3) a simulator of discrete s.c. insulin delivery via OmniPod Insulin Management System or Deltec Cozmo(®) insulin pump. The system has been shown to represent adequate glucose fluctuations in T1DM observed during meal challenges, and has been accepted by the Food and Drug Administration as a substitute to animal trials in the preclinical testing of closed-loop control strategies. © Diabetes Technology Society

Laser Doppler flowmetry for measurement of laminar capillary blood flow in the horse

NASA Astrophysics Data System (ADS)

Adair, Henry S., III

1998-07-01

Current methods for in vivo evaluation of digital hemodynamics in the horse include angiography, scintigraphy, Doppler ultrasound, electromagnetic flow and isolated extracorporeal pump perfused digit preparations. These techniques are either non-quantifiable, do not allow for continuous measurement, require destruction of the horse orare invasive, inducing non- physiologic variables. In vitro techniques have also been reported for the evaluation of the effects of vasoactive agents on the digital vessels. The in vitro techniques are non-physiologic and have evaluated the vasculature proximal to the coronary band. Lastly, many of these techniques require general anesthesia or euthanasia of the animal. Laser Doppler flowmetry is a non-invasive, continuous measure of capillary blood flow. Laser Doppler flowmetry has been used to measure capillary blood flow in many tissues. The principle of this method is to measure the Doppler shift, that is, the frequency change that light undergoes when reflected by moving objects, such as red blood cells. Laser Doppler flowmetry records a continuous measurement of the red cell motion in the outer layer of the tissue under study, with little or no influence on physiologic blood flow. This output value constitutes the flux of red cells and is reported as capillary perfusion units. No direct information concerning oxygen, nutrient or waste metabolite exchange in the surrounding tissue is obtained. The relationship between the flowmeter output signal and the flux of red blood cells is linear. The principles of laser Doppler flowmetry will be discussed and the technique for laminar capillary blood flow measurements will be presented.

Nailfold Capillaroscopy of Fingers and Toes - Variations of Normal.

PubMed

Lambova, Sevdalina Nikolova; Muller-Ladner, Ulf

2018-04-20

Nailfold capillaroscopy is the only method for morphological assessment of nutritive capillaries. The literature data about capillaroscopic findings in healthy individuals are scarce. To evaluate and compare the capillaroscopic findings of fingers and toes in healthy subjects. 22 healthy individuals were included in the study. Capillaroscopic examination was performed with videocapillaroscope Videocap 3.0 (DS Medica). Exclusion criteria were as follows: history of vasospasm, presence of accompanying diseases, taking any medications, arterial hypertension in first degree relatives, overweight or obesity (body mass index > 25kg/m2) and presence of chronic arterial or venous insufficiency. Poor visibility of nailfold capillaries was found significantly more frequently in the toes (22.7%, 5/22) as compared with fingers (0/22). Slight irregularities in capillary distribution and orientation to their parallel axis were significantly more common in the toes (31.8%, 7/22) as compared with fingers (9%, 2/22), (p<0.05). The mean diameter of the arterial (0.012±0.002mm) and the venous limb (0.017±0.002mm) of the toes did not differ significantly as compared to the respective parameters in the fingers (0.013±0.002mm for the arterial limb, p=0.46 and 0.018±0.002mm for the venous limb, p=0.25). The mean capillary density also did not differ significantly in the fingers and toes. The mean capillary length of the toes (0.165±0.096mm) was shorter as compared with hands (0.220±0.079mm), but the difference was not statistically significant (p=0.37). Presence of tortuous capillaries (>10%) was found significantly more often in the toes (12/22) as compared with fingers (6/22, χ2=6.769, p<0.05). Short capillary loops (length<100µm) were observed significantly more often in the toes (11/22 - toes, 1/22 - fingers, χ2=14.666, p<0.05). Capillaroscopic examination of the toes shows some differences as compared to those of the fingers such as greater number of cases with poor visibility and slight irregularities of distribution, greater number of shorter capillaries and increased tortuosity, which might be related to the thicker epidermis of the toes and increased capillary pressure due to gravity. The values of the major capillaroscopic parameters such as capillary diameters and capillary density in fingers and toes do not differ significantly. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

α1β1 Integrin/Rac1-Dependent Mesangial Invasion of Glomerular Capillaries in Alport Syndrome

PubMed Central

Zallocchi, Marisa; Johnson, Brianna M.; Meehan, Daniel T.; Delimont, Duane; Cosgrove, Dominic

2014-01-01

Alport syndrome, hereditary glomerulonephritis with hearing loss, results from mutations in type IV collagen COL4A3, COL4A4, or COL4A5 genes. The mechanism for delayed glomerular disease onset is unknown. Comparative analysis of Alport mice and CD151 knockout mice revealed progressive accumulation of laminin 211 in the glomerular basement membrane. We show mesangial processes invading the capillary loops of both models as well as in human Alport glomeruli, as the likely source of this laminin. l-NAME salt–induced hypertension accelerated mesangial cell process invasion. Cultured mesangial cells showed reduced migratory potential when treated with either integrin-linked kinase inhibitor or Rac1 inhibitor, or by deletion of integrin α1. Treatment of Alport mice with Rac1 inhibitor or deletion of integrin α1 reduced mesangial cell process invasion of the glomerular capillary tuft. Laminin α2–deficient Alport mice show reduced mesangial process invasion, and cultured laminin α2–null cells showed reduced migratory potential, indicating a functional role for mesangial laminins in progression of Alport glomerular pathogenesis. Collectively, these findings predict a role for biomechanical insult in the induction of integrin α1β1–dependent Rac1-mediated mesangial cell process invasion of the glomerular capillary tuft as an initiation mechanism of Alport glomerular pathology. PMID:23911822

In-Space technology experiments program. A high efficiency thermal interface (using condensation heat transfer) between a 2-phase fluid loop and heatpipe radiator: Experiment definition phase

NASA Technical Reports Server (NTRS)

Pohner, John A.; Dempsey, Brian P.; Herold, Leroy M.

1990-01-01

Space Station elements and advanced military spacecraft will require rejection of tens of kilowatts of waste heat. Large space radiators and two-phase heat transport loops will be required. To minimize radiator size and weight, it is critical to minimize the temperature drop between the heat source and sink. Under an Air Force contract, a unique, high-performance heat exchanger is developed for coupling the radiator to the transport loop. Since fluid flow through the heat exchanger is driven by capillary forces which are easily dominated by gravity forces in ground testing, it is necessary to perform microgravity thermal testing to verify the design. This contract consists of an experiment definition phase leading to a preliminary design and cost estimate for a shuttle-based flight experiment of this heat exchanger design. This program will utilize modified hardware from a ground test program for the heat exchanger.

Recombination-pumped XUV lasing in capillary discharges and dynamic z-pinches

NASA Astrophysics Data System (ADS)

Pöckl, M.; Hebenstreit, M.; Fertner, R.; Neger, T.; Aumayr, F.

1996-08-01

A fully time-dependent collisional - radiative model is employed to calculate relevant population densities in a recombining carbon/hydrogen z-pinch plasma. In particular, the dependence of the small signal gain G on the maximum electron temperature and cooling rate, as well as the influence of Lyman-0022-3727/29/8/005/img8 reabsorption, are studied. Although in conditions typical for dynamic z-pinches the maximum electron temperature and cooling rates would, in principle, be sufficiently high, gain on the Balmer-0022-3727/29/8/005/img8 transition is strongly reduced by Lyman-0022-3727/29/8/005/img8 reabsorption. In order to investigate vacuum spark capillary discharges, the system of rate equations is coupled with balance equations of the plasma energy and the total number of heavy particles. The resulting set of equations is solved self-consistently. Results are presented that show the systematic dependence of the small signal gain on electrical input power, wall material, and capillary geometry. High gain coefficients 0022-3727/29/8/005/img11 could be achieved by modelling high-voltage discharges with short ringing periods through capillaries containing boron or carbon. While the maximum achievable gain coefficient for lithium is rather poor 0022-3727/29/8/005/img12 the duration of population inversion would be long enough (a few tens of nanoseconds) to make multi-pass operation possible.

Space Cryogenics Workshop, University of Wisconsin, Madison, June 22, 23, 1987

NASA Technical Reports Server (NTRS)

1988-01-01

Papers are presented on liquid helium servicing from the Space Station, performance estimates in the Superfluid Helium On-Orbit Transfer Flight Experiment, an analytical study of He II flow characteristics in the SHOOT transfer line, a Dewar to Dewar model for superfluid helium transfer, and mechanical pumps for superfluid helium transfer in space. Attention is also given to the cavitation characteristics of a small centrifugal pump in He I and He II, turbulent flow pressure drop in various He II transfer system components, slip effects associated with Knudsen transport phenomena in porous media, and an integrated fountain effect pump device for fluid management at low gravity. Other papers are on liquid/vapor phase separation in He-4 using electric fields, an enclosed capillary device for low-gravity management of He II, cavitation in flowing superfluid helium, the long-term performance of the passive thermal control systems of the IRAS spacecraft, and a novel approach to supercritical helium flight cryostat support structures.

The three-dimensional feto-maternal vascular interrelationship during early bovine placental development: a scanning electron microscopical study

PubMed Central

PFARRER, CHRISTIANE; EBERT, BRIGITTE; MIGLINO, MARIA ANGELICA; KLISCH, KARL; LEISER, RUDOLF

2001-01-01

Both the fetal and maternal microvasculature of bovine placentomes was examined by scanning electron microscopy of vascular casts. So far the development of the vascular architecture of the bovine placentome in early gestation has only been studied 2-dimensionally due to technical difficulties arising from the fragility of the early placental blood vessels. Repeated experiments led to the selection of the microvascular corrosion casts presented here. The vasculature of the maternal compartment is supplied by large caruncular stalk or spiral arteries, which release short maternal stem arteries. In the 3rd month of gestation, these arteries branch into several arterioles at their base, thus providing the vascular framework for the lower part of the septal walls of the primary crypts. In the 4th month, due to progressive longitudinal growth of the stem arteries, branching into arterioles occurs not only at the base, but over the whole length of the stem arteries. These arterioles supply the capillary complexes of the septa which resemble the major part of the septal vasculature and face the secondary crypts. Further indentation results in the formation of tertiary crypt capillary complexes, encircling the earlier secondary unit. From the 6th month of gestation the architecture resembles the fully developed maternal placenta with stem arteries running directly to the fetal side to branch into 4 to 6 arterioles, which turn back to enter secondary and tertiary septa. Maternal venules, collecting the blood from the capillary bed of secondary and tertiary septa, converge onto stem veins leaving the caruncle via branches of the uterine vein. The fetal part of the placentome is supplied by the cotyledonary arteries, which branch into fetal stem arteries that are the tributary to single villous trees. Over their whole course towards the maternal side, these give off arterioles entering secondary villi. The tertiary or terminal villous vasculature consists of capillaries, which are organised in serial capillary loops. This system is progressively elaborated in the course of gestation. In the 4th month there are only finger-like loops, whereas from the 6th month large fan-like structures can be observed. In early gestation the maternal and fetal blood vessels meet predominantly in a countercurrent fashion, changing to the less efficient crosscurrent exchange when the tertiary unit develops. These results indicate the development of a highly elaborated fetomaternal villous-crypt exchange system, already established in the 1st half of gestation, thus meeting the increasing needs of the fetus. PMID:11430698

NaK Plugging Meter Design for the Feasibility Test Loops

NASA Technical Reports Server (NTRS)

Pearson, J. Boise; Godfroy, Thomas J.; Reid, Robert S.; Polzin, Kurt A.

2008-01-01

The design and predicted performance of a plugging meter for use in the measurement of NaK impurity levels are presented. The plugging meter is incorporated into a Feasibility Test Loop (FTL), which is a small pumped-NaK loop designed to enable the rapid, small-scale evaluation of techniques such as in situ purification methods and to permit the measurement of bulk material transport effects (not mechanisms) under flow conditions that are representative of a fission surface power reactor. The FTL operates at temperatures similar to those found in a reactor, with a maximum hot side temperature of 900 K and a corresponding cold side temperature of 860 K. In the plugging meter a low flow rate bypass loop is cooled until various impurities (primarily oxides) precipitate out of solution. The temperatures at which these impurities precipitate are indicative of the level of impurities in the NaK. The precipitates incrementally plug a small orifice in the bypass loop, which is detected by monitoring changes in the liquid metal flow rate.

The IRIS Spool-Type Reactor Coolant Pump

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

Kujawski, J.M.; Kitch, D.M.; Conway, L.E.

2002-07-01

IRIS (International Reactor Innovative and Secure) is a light water cooled, 335 MWe power reactor which is being designed by an international consortium as part of the US DOE NERI Program. IRIS features an integral reactor vessel that contains all the major reactor coolant system components including the reactor core, the coolant pumps, the steam generators and the pressurizer. This integral design approach eliminates the large coolant loop piping, and thus eliminates large loss-of-coolant accidents (LOCAs) as well as the individual component pressure vessels and supports. In addition, IRIS is being designed with a long life core and enhanced safetymore » to address the requirements defined by the US DOE for Generation IV reactors. One of the innovative features of the IRIS design is the adoption of a reactor coolant pump (called 'spool' pump) which is completely contained inside the reactor vessel. Background, status and future developments of the IRIS spool pump are presented in this paper. (authors)« less

[Research on magnetic coupling centrifugal blood pump control based on a self-tuning fuzzy PI algorithm].

PubMed

Yang, Lei; Yang, Ming; Xu, Zihao; Zhuang, Xiaoqi; Wang, Wei; Zhang, Haibo; Han, Lu; Xu, Liang

2014-10-01

The purpose of this paper is to report the research and design of control system of magnetic coupling centrifugal blood pump in our laboratory, and to briefly describe the structure of the magnetic coupling centrifugal blood pump and principles of the body circulation model. The performance of blood pump is not only related to materials and structure, but also depends on the control algorithm. We studied the algorithm about motor current double-loop control for brushless DC motor. In order to make the algorithm adjust parameter change in different situations, we used the self-tuning fuzzy PI control algorithm and gave the details about how to design fuzzy rules. We mainly used Matlab Simulink to simulate the motor control system to test the performance of algorithm, and briefly introduced how to implement these algorithms in hardware system. Finally, by building the platform and conducting experiments, we proved that self-tuning fuzzy PI control algorithm could greatly improve both dynamic and static performance of blood pump and make the motor speed and the blood pump flow stable and adjustable.

Geothermal energy control system and method

DOEpatents

Matthews, Hugh B.

1977-01-01

A geothermal energy transfer and utilization system makes use of thermal energy stored in hot solute-bearing well water to generate super-heated steam from an injected flow of clean water; the super-heated steam is then used for operating a turbine-driven pump at the well bottom for pumping the hot solute-bearing water at high pressure and in liquid state to the earth's surface, where it is used by transfer of its heat to a closed-loop boiler-turbine-alternator combination for the generation of electrical or other power. Residual concentrated solute-bearing water is pumped back into the earth. The clean cooled water is regenerated at the surface-located system and is returned to the deep well pumping system also for lubrication of a novel bearing arrangement supporting the turbine-driven pump system. The bearing system employs liquid lubricated thrust and radial bearings with all bearing surfaces bathed in clean water serving as a lubricant and maintained under pressure to prevent entry into the bearings of contaminated geothermal fluid, an auxiliary thrust ball bearing arrangement comes into operation when starting or stopping the pumping system.

Heat Rejection Concepts for Lunar Fission Surface Power Applications

NASA Technical Reports Server (NTRS)

Siamidis, John

2006-01-01

This paper describes potential heat rejection design concepts for lunar surface Brayton power conversion systems. Brayton conversion systems are currently under study by NASA for surface power applications. Surface reactors may be used for the moon to power human outposts enabling extended stays and closed loop life support. The Brayton Heat Rejection System (HRS) must dissipate waste heat generated by the power conversion system due to inefficiencies in the thermal-to-electric conversion process. Space Brayton conversion system designs tend to optimize at efficiencies of about 20 to 25 percent with radiator temperatures in the 400 K to 600 K range. A notional HRS was developed for a 100 kWe-class Brayton power system that uses a pumped water heat transport loop coupled to a water heat pipe radiator. The radiator panels employ a tube and fin construction consisting of regularly-spaced circular heat pipes contained within two composite facesheets. The water heat pipes interface to the coolant through curved sections partially contained within the cooling loop. The paper evaluates various design parameters including radiator panel orientation, coolant flow path, and facesheet thickness. Parameters were varied to compare design options on the basis of H2O pump pressure rise and required power, heat pipe unit power and radial flux, radiator area, radiator panel areal mass, and overall HRS mass.

Analysis of boron dilution in a four-loop PWR

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

Sun, J.G.; Sha, W.T.

1995-03-01

Thermal mixing and boron dilution in a pressurized water reactor were analyzed with COMMIX codes. The reactor system was the four-loop Zion reactor. Two boron dilution scenarios were analyzed. In the first scenario, the plant is in cold shutdown and the reactor coolant system has just been filled after maintenance on the steam generators. To flush the air out of the steam generator tubes, a reactor coolant pump (RCP) is started, with the water in the pump suction line devoid of boron and at the same temperature as the coolant in the system. In the second scenario, the plant ismore » at hot standby and the reactor coolant system has been heated to operating temperature after a long outage. It is assumed that an RCP is started, with the pump suction line filled with cold unborated water, forcing a slug of diluted coolant down the downcomer and subsequently through the reactor core. The subsequent transient thermal mixing and boron dilution that would occur in the reactor system is simulated for these two scenarios. The reactivity insertion rate and the total reactivity are evaluated and a sensitivity study is performed to assess the accuracy of the numerical modeling of the geometry of the reactor coolant system.« less

Heat exchanger with oscillating flow

NASA Technical Reports Server (NTRS)

Scotti, Stephen J. (Inventor); Blosser, Max L. (Inventor); Camarda, Charles J. (Inventor)

1992-01-01

Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators, or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit.

Heat exchanger with oscillating flow

NASA Technical Reports Server (NTRS)

Scotti, Stephen J. (Inventor); Blosser, Max L. (Inventor); Camarda, Charles J. (Inventor)

1993-01-01

Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit.

Advanced spacecraft thermal control techniques

NASA Technical Reports Server (NTRS)

Fritz, C. H.

1977-01-01

The problems of rejecting large amounts of heat from spacecraft were studied. Shuttle Space Laboratory heat rejection uses 1 kW for pumps and fans for every 5 kW (thermal) heat rejection. This is rather inefficient, and for future programs more efficient methods were examined. Two advanced systems were studied and compared to the present pumped-loop system. The advanced concepts are the air-cooled semipassive system, which features rejection of a large percentage of the load through the outer skin, and the heat pipe system, which incorporates heat pipes for every thermal control function.

Super-atmospheric pressure chemical ionization mass spectrometry.

PubMed

Chen, Lee Chuin; Rahman, Md Matiur; Hiraoka, Kenzo

2013-03-01

Super-atmospheric pressure chemical ionization (APCI) mass spectrometry was performed using a commercial mass spectrometer by pressurizing the ion source with compressed air up to 7 atm. Similar to typical APCI source, reactant ions in the experiment were generated with corona discharge using a needle electrode. Although a higher needle potential was necessary to initiate the corona discharge, discharge current and detected ion signal were stable at all tested pressures. A Roots booster pump with variable pumping speed was installed between the evacuation port of the mass spectrometer and the original rough pumps to maintain a same pressure in the first pumping stage of the mass spectrometer regardless of ion source pressure. Measurement of gaseous methamphetamine and research department explosive showed an increase in ion intensity with the ion source pressure until an optimum pressure at around 4-5 atm. Beyond 5 atm, the ion intensity decreased with further increase of pressure, likely due to greater ion losses inside the ion transport capillary. For benzene, it was found that besides molecular ion and protonated species, ion due to [M + 2H](+) which was not so common in APCI, was also observed with high ion abundance under super-atmospheric pressure condition. Copyright © 2013 John Wiley & Sons, Ltd.

Hand-portable liquid chromatographic instrumentation.

PubMed

Sharma, Sonika; Tolley, Luke T; Tolley, H Dennis; Plistil, Alex; Stearns, Stanley D; Lee, Milton L

2015-11-20

Over the last four decades, liquid chromatography (LC) has experienced an evolution to smaller columns and particles, new stationary phases and low flow rate instrumentation. However, the development of person-portable LC has not followed, mainly due to difficulties encountered in miniaturizing pumps and detectors, and in reducing solvent consumption. The recent introduction of small, non-splitting pumping systems and UV-absorption detectors for use with capillary columns has finally provided miniaturized instrumentation suitable for high-performance hand-portable LC. Fully integrated microfabricated LC still remains a significant challenge. Ion chromatography (IC) has been successfully miniaturized and applied for field analysis; however, applications are mostly limited to inorganic and small organic ions. This review covers advancements that make possible more rapid expansion of portable forms of LC and IC. Copyright © 2015 Elsevier B.V. All rights reserved.

Portable gas chromatograph-mass spectrometer

DOEpatents

Andresen, B.D.; Eckels, J.D.; Kimmons, J.F.; Myers, D.W.

1996-06-11

A gas chromatograph-mass spectrometer (GC-MS) is described for use as a field portable organic chemical analysis instrument. The GC-MS is designed to be contained in a standard size suitcase, weighs less than 70 pounds, and requires less than 600 watts of electrical power at peak power (all systems on). The GC-MS includes: a conduction heated, forced air cooled small bore capillary gas chromatograph, a small injector assembly, a self-contained ion/sorption pump vacuum system, a hydrogen supply, a dual computer system used to control the hardware and acquire spectrum data, and operational software used to control the pumping system and the gas chromatograph. This instrument incorporates a modified commercial quadrupole mass spectrometer to achieve the instrument sensitivity and mass resolution characteristic of laboratory bench top units. 4 figs.

Interface Configuration Experiments (ICE) Explore the Effects of Microgravity on Fluids

NASA Technical Reports Server (NTRS)

1996-01-01

The Interface Configuration Experiment (ICE) is actually a series of experiments that explore the striking behavior of liquid-vapor interfaces (i.e., fluid surfaces) in a low gravity environment under which major shifts in liquid position can arise from small changes in container shape or contact angle. Although these experiments are designed to test current mathematical theory, there are numerous practical applications that could result from these studies. When designing fluid management systems for space-based operations, it is important to be able to predict the locations and configurations that fluids will assume in containers under low-gravity conditions. The increased ability to predict, and hence control, fluid interfaces is vital to systems and/or processes where capillary forces play a significant role both in space and on the Earth. Some of these applications are in general coating processes (paints, pesticides, printing, etc.), fluid transport in porous media (ground water flows, oil recovery, etc.), liquid propellant systems in space (liquid fuel and oxygen), capillary-pumped loops and heat pipes, and space-based life-support systems. In space, almost every fluid system is affected, if not dominated, by capillarity. Knowledge of the liquid-vapor interface behavior, and in particular the interface shape from which any analysis must begin, is required as a foundation to predict how these fluids will react in microgravity and on Earth. With such knowledge, system designs can be optimized, thereby decreasing costs and complexity, while increasing performance and reliability. ICE has increased, and will continue to increase this knowledge, as it probes the specific peculiarities of current theory upon which our current understanding of these effects is based. Several versions of ICE were conducted in NASA Lewis Research Center's drop towers and on the space shuttle during the first and second United States Microgravity Laboratory missions (USML-1 and USML-2). Additional tests are planned for the space shuttle and for the Russian Mir space station. These studies will focus on interfacial problems concerning surface existence, uniqueness, configuration, stability, and flow characteristics.

Development of a high-performance boiling heat exchanger by improved liquid supply to narrow channels.

PubMed

Ohta, Haruhiko; Ohno, Toshiyuki; Hioki, Fumiaki; Shinmoto, Yasuhisa

2004-11-01

A two-phase flow loop is a promising method for application to thermal management systems for large-scale space platforms handling large amounts of energy. Boiling heat transfer reduces the size and weight of cold plates. The transportation of latent heat reduces the mass flow rate of working fluid and pump power. To develop compact heat exchangers for the removal of waste heat from electronic devices with high heat generation density, experiments on a method to increase the critical heat flux for a narrow heated channel between parallel heated and unheated plates were conducted. Fine grooves are machined on the heating surface in a transverse direction to the flow and liquid is supplied underneath flattened bubbles by the capillary pressure difference from auxiliary liquid channels separated by porous metal plates from the main heated channel. The critical heat flux values for the present heated channel structure are more than twice those for a flat surface at gap sizes 2 mm and 0.7 mm. The validity of the present structure with auxiliary liquid channels is confirmed by experiments in which the liquid supply to the grooves is interrupted. The increment in the critical heat flux compared to those for a flat surface takes a maximum value at a certain flow rate of liquid supply to the heated channel. The increment is expected to become larger when the length of the heated channel is increased and/or the gravity level is reduced.

Digital quantification of DNA via isothermal amplification on a self-driven microfluidic chip featuring hydrophilic film-coated polydimethylsiloxane.

PubMed

Ma, Yu-Dong; Chang, Wen-Hsin; Luo, Kang; Wang, Chih-Hung; Liu, Shih-Yuan; Yen, Wen-Hsiang; Lee, Gwo-Bin

2018-01-15

Loop-mediated isothermal amplification (LAMP) is a DNA amplification approach characterized by high sensitivity and specificity. In "digital LAMP", small quantities of both template DNA and reagents are encapsulated within a droplet or microwell, allowing for analysis of precious nucleic acid samples in shorter amounts of time relative to traditional DNA amplification protocols (e.g., PCR) with an improved limit of detection. In this study, an integrated, self-driven microfluidic chip was designed to carry out digital LAMP. The entire quantification process could be automatically performed on this chip via capillary forces enabled through microwells comprised of polydimethylsiloxane (PDMS) surfaces coated with a hydrophilic film; no external pumps were required. Moreover, digitized droplets could be separated from each other by normally-closed microvalves. The contact angle of the hydrophilic film-coated PDMS surface was only 14.3°. This is the first time that a rapid (30min) and simple method has been used to create hydrophilic PDMS surfaces that allow for digital LAMP to be performed in a self-driven microfluidic device. As a proof of concept, amplification of a gene specific to a vancomycin-resistant Enterococcus strain was performed on the developed microfluidic chip within 30min, and the limit of detection was only 11 copies with a volume of 30μL. This device may therefore become a promising tool for clinical diagnosis and point-of-care applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Browns Ferry-1 single-loop operation tests

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

March-Leuba, J.; Wood, R.T.; Otaduy, P.J.

1985-09-01

This report documents the results of the stability tests performed on February 9, 1985, at the Browns Ferry Nuclear Power Plant Unit 1 under single-loop operating conditions. The observed increase in neutron noise during single-loop operation is solely due to an increase in flow noise. The Browns Ferry-1 reactor has been found to be stable in all modes of operation attained during the present tests. The most unstable test plateau corresponded to minimum recirculation pump speed in single-loop operation (test BFTP3). This operating condition had the minimum flow and maximum power-to-flow ratio. The estimated decay ratio in this plateau ismore » 0.53. The decay ratio decreased as the flow was increased during single-loop operation (down to 0.34 for test plateau BFTP6). This observation implies that the core-wide reactor stability follows the same trends in single-loop as it does in two-loop operation. Finally, no local or higher mode instabilities were found in the data taken from local power range monitors. The decay ratios estimated from the local power range monitors were not significantly different from those estimated from the average power range monitors.« less

Characterizing the microcirculation of atopic dermatitis using angiographic optical coherence tomography

NASA Astrophysics Data System (ADS)

Byers, R. A.; Maiti, R.; Danby, S. G.; Pang, E. J.; Mitchell, B.; Carré, M. J.; Lewis, R.; Cork, M. J.; Matcher, S. J.

2017-02-01

Background and Aim: With inflammatory skin conditions such as atopic dermatitis (AD), epidermal thickness is mediated by both pathological hyperplasia and atrophy such as that resulting from corticosteroid treatment. Such changes are likely to influence the depth and shape of the underlying microcirculation. Optical coherence tomography (OCT) provides a non-invasive view into the tissue, however structural measures of epidermal thickness are made challenging due to the lack of a delineated dermal-epidermal junction in AD patients. Instead, angiographic extensions to OCT may allow for direct measurement of vascular depth, potentially presenting a more robust method of estimating the degree of epidermal thickening. Methods and results: To investigate microcirculatory changes within AD patients, volumes of angiographic OCT data were collected from 5 healthy volunteers and compared to that of 5 AD patients. Test sites included the cubital and popliteal fossa, which are commonly affected by AD. Measurements of the capillary loop and superficial arteriolar plexus (SAP) depth were acquired and used to estimate the lower and upper bounds of the undulating basement membrane of the dermal-epidermal junction. Furthermore, quantitative parameters such as vessel density and diameter were derived from each dataset and compared between groups. Capillary loop depth increased slightly for AD patients at the poplitial fossa and SAP was found to be measurably deeper in AD patients at both sites, likely due to localized epidermal hyperplasia.

Numerical Investigation of Transient Flow in a Prototype Centrifugal Pump during Startup Period

NASA Astrophysics Data System (ADS)

Zhang, Yu-Liang; Zhu, Zu-Chao; Dou, Hua-Shu; Cui, Bao-Ling; Li, Yi; Zhou, Zhao-Zhong

2017-05-01

Transient performance of pumps during transient operating periods, such as startup and stopping, has drawn more and more attentions recently due to the growing engineering needs. During the startup period of a pump, the performance parameters such as the flow rate and head would vary significantly in a broad range. Therefore, it is very difficult to accurately specify the unsteady boundary conditions for a pump alone to solve the transient flow in the absence of experimental results. The closed-loop pipe system including a centrifugal pump is built to accomplish the self-coupling calculation. The three-dimensional unsteady incompressible viscous flow inside the passage of the pump during startup period is numerically simulated using the dynamic mesh method. Simulation results show that there are tiny fluctuations in the flow rate even under stable operating conditions and this can be attributed to influence of the rotor-stator interaction. At the very beginning of the startup, the rising speed of the flow rate is lower than that of the rotational speed. It is also found that it is not suitable to predict the transient performance of pumps using the calculation method of quasi-steady flow, especially at the earlier period of the startup.

Experimental study on pore structure and performance of sintered porous wick

NASA Astrophysics Data System (ADS)

He, Da; Wang, Shufan; Liu, Rutie; Wang, Zhubo; Xiong, Xiang; Zou, Jianpeng

2018-02-01

Porous wicks were prepared via powder metallurgy using NH4HCO3 powders as pore-forming agent. The pore-forming agent particle size was varied to control the pore structure and equivalent pore size distribution feature of porous wick. The effect of pore-forming agent particle size on the porosity, pore structures, equivalent pore size distribution and capillary pumping performance were investigated. Results show that with the particle size of pore-forming agent decrease, the green density and the volume shrinkage of the porous wicks gradually increase and the porosity reduces slightly. There are two types of pores inside the porous wick, large-sized prefabricated pores and small-sized gap pores. With the particle size of pore-forming agent decrease, the size of the prefabricated pores becomes smaller and the distribution tends to be uniform. Gap pores and prefabricated pores inside the wick can make up different types of pore channels. The equivalent pore size of wick is closely related to the structure of pore channels. Furthermore, the equivalent pore size distribution of wick shows an obvious double-peak feature when the pore-forming agent particle size is large. With the particle size of pore-forming agent decrease, the two peaks of equivalent pore size distribution approach gradually to each other, resulting in a single-peak feature. Porous wick with single-peak feature equivalent pore size distribution possesses the better capillary pumping performances.

Pumped lithium loop test to evaluate advanced refractory metal alloys and simulated nuclear fuel elements

NASA Technical Reports Server (NTRS)

Brandenburf, G. P.; Hoffman, E. E.; Smith, J. P.

1974-01-01

The performance was determined of refractory metal alloys and uranium nitride fuel element specimens in flowing 1900F (1083C) lithium. The results demonstrate the suitability of the selected materials to perform satisfactorily from a chemical compatibility standpoint.

18 CFR 1304.205 - Other water-use facilities.

Code of Federal Regulations, 2014 CFR

2014-04-01

... concrete boat launching ramp with associated driveway may be located within the access corridor... concrete is allowable; asphalt is not permitted. (b) Tables or benches for cleaning fish are permitted on... adjacent structures during winter drawdown. (h) Closed loop heat exchanges for residential heat pump...

18 CFR 1304.205 - Other water-use facilities.

Code of Federal Regulations, 2013 CFR

2013-04-01

... concrete boat launching ramp with associated driveway may be located within the access corridor... concrete is allowable; asphalt is not permitted. (b) Tables or benches for cleaning fish are permitted on... adjacent structures during winter drawdown. (h) Closed loop heat exchanges for residential heat pump...

18 CFR 1304.205 - Other water-use facilities.

Code of Federal Regulations, 2012 CFR

2012-04-01

... concrete boat launching ramp with associated driveway may be located within the access corridor... concrete is allowable; asphalt is not permitted. (b) Tables or benches for cleaning fish are permitted on... adjacent structures during winter drawdown. (h) Closed loop heat exchanges for residential heat pump...

Magnetic heat pumping

NASA Technical Reports Server (NTRS)

Brown, G. V. (Inventor)

1978-01-01

A ferromagnetic or ferrimagnetic element is used to control the temperature and applied magnetic field of the element to cause the state of the element as represented on a temperature-magnetic entropy diagram to repeatedly traverse a loop. The loop may have a first portion of concurrent substantially isothermal or constant temperature and increasing applied magnetic field, a second portion of lowering temperature and constant applied magnetic field, a third portion of isothermal and decreasing applied magnetic field, and a fourth portion of increasing temperature and constant applied magnetic field. Other loops may be four-sided, with two isotherms and two adiabats. Preferably, a regenerator is used to enhance desired cooling or heating effects, with varied magnetic fields, or varying temperatures including three-sided figures traversed by the representative point.

Modified nonlinear amplifying loop mirror for mode-locked fibre oscillators with record-high energy and high-average-power pulsed output

NASA Astrophysics Data System (ADS)

Kobtsev, Sergey; Ivanenko, Alexey; Smirnov, Sergey; Kokhanovsky, Alexey

2018-02-01

The present work proposes and studies approaches for development of new modified non-linear amplifying loop mirror (NALM) allowing flexible and dynamic control of their non-linear properties within a relatively broad range of radiation powers. Using two independently pumped active media in the loop reflector constitutes one of the most promising approaches to development of better NALM with nonlinear properties controllable independently of the intra-cavity radiation power. This work reports on experimental and theoretical studies of the proposed redesigned NALM allowing both a higher level of energy parameters of output generated by mode-locked fibre oscillators and new possibilities of switching among different mode-locked regimes.

Design of a Modular Test Loop for Study of Two-Phase Flow and Heat Transfer in Low and High Accelerations

DTIC Science & Technology

1990-07-01

probably cannot afford to have such a large pressure drop (orifice or throttling valve ) in the loop to stabilize the flow. For a given flow rate, the...rate was set by a calibrated valve and the water flow rate was set by the pump speed. The loop was not equipped with flowmeters and it was assumed that...Configuration. 3-28 jCk z < [D - a~ - Z Li-c I Li CL- a ow L~j Z 4) ,,l C0 0 Q.(-C - CL Li Ln LJ r o~C:) Z CC Ck LLj ZJ LOL Li Ln ( 3-2 ~ Tf1 FFFFF ~< L~iK

Operation and maintenance of the Sol-Dance Building solar system. Final report

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

Gaultney, J.R.

1980-07-29

A 16,400 square foot general office facility has its primary heating provided by a flat plate solar system using hydronic storage and water-to-air transfer coils for distribution. Backup heat is provided by 10 individually controlled air source heat pumps ranging from 3 tons to 5 tons in capacity. These heat pumps also contain electric resistive elements for use during extremely low ambient temperatures. Cooling is also provided by the heat pumps. Each of the two buildings contains a separate domestic hot water system. Primary heat is provided by a closed loop solar unit with electric elements providing backup heat. Amore » 10,000 gallon black steel water tank provides heat storage.« less

A pumped, two-phase flow heat transport system for orbiting instrument payloads

NASA Technical Reports Server (NTRS)

Fowle, A. A.

1981-01-01

A pumped two-phase (heat absorption/heat rejection) thermal transport system for orbiting instrument payloads is investigated. The thermofluid characteristics necessary for the system design are discussed. A preliminary design with a series arrangement of four instrument heat stations and six radiators in a single loop is described in detail, and the total mass is estimated to be 134 kg, with the radiators, instrument heat stations, and fluid reservoir accounting for approximately 86, 24, and 12 kg, respectively. The evaluation of preliminary test results shows that the system has potential advantages; however, further research is necessary in the areas of one-g and zero-g heat transfer coefficients/fluid regimes, fluid by-pass temperature control, and reliability of small pumps.

Investigation of drying kinetics of tomato slices dried by using a closed loop heat pump dryer

NASA Astrophysics Data System (ADS)

Coşkun, Salih; Doymaz, İbrahim; Tunçkal, Cüneyt; Erdoğan, Seçil

2017-06-01

In this study, tomato slices were dried at three different drying air temperatures (35, 40 and 45 °C) and at 1 m/s air velocities by using a closed loop heat pump dryer (HPD). To explain the drying characteristics of tomato slices, ten thin-layer drying models were applied. The drying of tomato slices at each temperature occurred in falling-rate period; no constant-rate period of drying was observed. The drying rate was significantly influenced by drying temperature. The effective moisture diffusivity varied between 8.28 × 10-11 and 1.41 × 10-10 m2/s, the activation energy was found to be 43.12 kJ/mol. Besides, at the end of drying process, the highest mean specific moisture extraction ratio and coefficient of performance of HPD system were obtained as 0.324 kg/kWh and 2.71, respectively, at the highest drying air temperature (45 °C).

Sensitivity enhancement of remotely coupled NMR detectors using wirelessly powered parametric amplification.

PubMed

Qian, Chunqi; Murphy-Boesch, Joseph; Dodd, Stephen; Koretsky, Alan

2012-09-01

A completely wireless detection coil with an integrated parametric amplifier has been constructed to provide local amplification and transmission of MR signals. The sample coil is one element of a parametric amplifier using a zero-bias diode that mixes the weak MR signal with a strong pump signal that is obtained from an inductively coupled external loop. The NMR sample coil develops current gain via reduction in the effective coil resistance. Higher gain can be obtained by adjusting the level of the pumping power closer to the oscillation threshold, but the gain is ultimately constrained by the bandwidth requirement of MRI experiments. A feasibility study here shows that on a NaCl/D(2) O phantom, (23) Na signals with 20 dB of gain can be readily obtained with a concomitant bandwidth of 144 kHz. This gain is high enough that the integrated coil with parametric amplifier, which is coupled inductively to external loops, can provide sensitivity approaching that of direct wire connection. Copyright © 2012 Wiley Periodicals, Inc.

System design description of forced-convection molten-salt corrosion loops MSR-FCL-3 and MSR-FCL-4

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

Huntley, W.R.; Silverman, M.D.

1976-11-01

Molten-salt corrosion loops MSR-FCL-3 and MSR-FCL-4 are high-temperature test facilities designed to evaluate corrosion and mass transfer of modified Hastelloy N alloys for future use in Molten-Salt Breeder Reactors. Salt is circulated by a centrifugal sump pump to evaluate material compatibility with LiF-BeF/sub 2/-ThF/sub 4/-UF/sub 4/ fuel salt at velocities up to 6 m/s (20 fps) and at salt temperatures from 566 to 705/sup 0/C (1050 to 1300/sup 0/F). The report presents the design description of the various components and systems that make up each corrosion facility, such as the salt pump, corrosion specimens, salt piping, main heaters, salt coolers,more » salt sampling equipment, and helium cover-gas system, etc. The electrical systems and instrumentation and controls are described, and operational procedures, system limitations, and maintenance philosophy are discussed.« less

A liquid-metal filling system for pumped primary loop space reactors

NASA Astrophysics Data System (ADS)

Crandall, D. L.; Reed, W. C.

Some concepts for the SP-100 space nuclear power reactor use liquid metal as the primary coolant in a pumped loop. Prior to filling ground engineering test articles or reactor systems, the liquid metal must be purified and circulated through the reactor primary system to remove contaminants. If not removed, these contaminants enhance corrosion and reduce reliability. A facility was designed and built to support Department of Energy Liquid Metal Fast Breeder Reactor tests conducted at the Idaho National Engineering Laboratory. This test program used liquid sodium to cool nuclear fuel in in-pile experiments; thus, a system was needed to store and purify sodium inventories and fill the experiment assemblies. This same system, with modifications and potential changeover to lithium or sodium-potassium (NaK), can be used in the Space Nuclear Power Reactor Program. This paper addresses the requirements, description, modifications, operation, and appropriateness of using this liquid-metal system to support the SP-100 space reactor program.

Macroscopic Floquet topological crystalline steel and superconductor pump

NASA Astrophysics Data System (ADS)

Rossi, Anna M. E. B.; Bugase, Jonas; Fischer, Thomas M.

2017-08-01

The transport of a macroscopic steel sphere and a superconducting sphere on top of two-dimensional periodic magnetic patterns is studied experimentally and compared with the theory and with experiments on topological transport of magnetic colloids. Transport of the steel and superconducting sphere is achieved by moving an external permanent magnet on a closed loop around the two-dimensional crystal. The transport is topological, i.e., the spheres are transported by a primitive unit vector of the lattice when the external magnet loop winds around specific directions. We experimentally determine the set of directions the loops must enclose for nontrivial transport of the spheres into various directions. We show that the loops can be used to sort steel and superconducting spheres. We show that the topological transport is robust with respect to the scale of the system and therefore speculate on its down scalability to the molecular scale.

Optical phase locked loop for transparent inter-satellite communications.

PubMed

Herzog, F; Kudielka, K; Erni, D; Bächtold, W

2005-05-16

A novel type of optical phase locked loop (OPLL), optimized for homodyne inter-satellite communication, is presented. The loop employs a conventional 180? 3 dB optical hybrid and an AC-coupled balanced front end. No residual carrier transmission is required for phase locking. The loop accepts analog as well as digital data and various modulation formats. The only requirement to the transmitted user signal is a constant envelope. Phase error extraction occurs through applying a small sinusoidal local oscillator (LO) phase disturbance, while measuring its impact on the power of the baseband output signal. First experimental results indicate a receiver sensitivity of 36 photons/bit (-55.7 dBm) for a BER of 10 ;-9, when transmitting a PRBS-31 signal at a data rate of 400 Mbit/s. The system setup employs diode-pumped Nd:YAG lasers at a wavelength of 1.06 mum.

Optical phase locked loop for transparent inter-satellite communications

NASA Astrophysics Data System (ADS)

Herzog, F.; Kudielka, K.; Erni, D.; Bächtold, W.

2005-05-01

A novel type of optical phase locked loop (OPLL), optimized for homodyne inter-satellite communication, is presented. The loop employs a conventional 180◦ 3 dB optical hybrid and an AC-coupled balanced front end. No residual carrier transmission is required for phase locking. The loop accepts analog as well as digital data and various modulation formats. The only requirement to the transmitted user signal is a constant envelope. Phase error extraction occurs through applying a small sinusoidal local oscillator (LO) phase disturbance, while measuring its impact on the power of the baseband output signal. First experimental results indicate a receiver sensitivity of 36 photons/bit (-55.7 dBm) for a BER of 10 ^-9, when transmitting a PRBS-31 signal at a data rate of 400 Mbit/s. The system setup employs diode-pumped Nd:YAG lasers at a wavelength of 1.06 μm.

Nanokit for single-cell electrochemical analyses.

PubMed

Pan, Rongrong; Xu, Mingchen; Jiang, Dechen; Burgess, Jame D; Chen, Hong-Yuan

2016-10-11

The development of more intricate devices for the analysis of small molecules and protein activity in single cells would advance our knowledge of cellular heterogeneity and signaling cascades. Therefore, in this study, a nanokit was produced by filling a nanometer-sized capillary with a ring electrode at the tip with components from traditional kits, which could be egressed outside the capillary by electrochemical pumping. At the tip, femtoliter amounts of the kit components were reacted with the analyte to generate hydrogen peroxide for the electrochemical measurement by the ring electrode. Taking advantage of the nanotip and small volume injection, the nanokit was easily inserted into a single cell to determine the intracellular glucose levels and sphingomyelinase (SMase) activity, which had rarely been achieved. High cellular heterogeneities of these two molecules were observed, showing the significance of the nanokit. Compared with the current methods that use a complicated structural design or surface functionalization for the recognition of the analytes, the nanokit has adapted features of the well-established kits and integrated the kit components and detector in one nanometer-sized capillary, which provides a specific device to characterize the reactivity and concentrations of cellular compounds in single cells.

Methods of analysis by the U. S. Geological Survey National Water Quality Laboratory - determination of organonitrogen herbicides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring

USGS Publications Warehouse

Sandstrom, Mark W.; Wydoski, Duane S.; Schroeder, Michael P.; Zamboni, Jana L.; Foreman, William T.

1992-01-01

A method for the isolation of organonitrogen herbicides from natural water samples using solid-phase extraction and analysis by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction cartridges containing octadecyl-bonded porous silica to remove the herbicides. The cartridges are dried using carbon dioxide, and adsorbed herbicides are removed from the cartridges by elution with 1.8 milliliters of hexaneisopropanol (3:1). Extracts of the eluants are analyzed by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring of at least three characteristic ions. The method detection limits are dependent on sample matrix and each particular herbicide. The method detection limits, based on a 100-milliliter sample size, range from 0.02 to 0.25 microgram per liter. Recoveries averaged 80 to 115 percent for the 23 herbicides and 2 metabolites in 1 reagent-water and 2 natural-water samples fortified at levels of 0.2 and 2.0 micrograms per liter.

Surface-enhanced Raman spectroscopic monitor of triglyceride hydrolysis in a skin pore phantom

NASA Astrophysics Data System (ADS)

Weldon, Millicent K.; Morris, Michael D.

1999-04-01

Bacterial hydrolysis of triglycerides is followed in a sebum probe phantom by microprobe surface-enhanced Raman scattering (SERS) spectroscopy. The phantom consists of a purpose-built syringe pump operating at physiological flow rates connected to a 300 micron i.d. capillary. We employ silicon substrate SERS microprobes to monitor the hydrolysis products. The silicon support allows some tip flexibility that makes these probes ideal for insertion into small structures. Propionibacterium acnes are immobilized on the inner surface of the capillary. These bacteria hydrolyze the triglycerides in a model sebum emulsion flowing through the capillary. The transformation is followed in vitro as changes in the SERS caused by hydrolysis of triglyceride to fatty acid. The breakdown products consists of a mixture of mono- and diglycerides and their parent long chain fatty acids. The fatty acids adsorb as their carboxylates and can be readily identified by their characteristic spectra. The technique can also confirm the presence of bacteria by detection of short chain carboxylic acids released as products of glucose fermentation during the growth cycle of these cells. Co-adsorption of propionate is observed. Spatial localization of the bacteria is obtained by ex-situ line imaging of the probe.

Mechanics of airway and alveolar collapse in human breath-hold diving.

PubMed

Fitz-Clarke, John R

2007-11-15

A computational model of the human respiratory tract was developed to study airway and alveolar compression and re-expansion during deep breath-hold dives. The model incorporates the chest wall, supraglottic airway, trachea, branched airway tree, and elastic alveoli assigned time-dependent surfactant properties. Total lung collapse with degassing of all alveoli is predicted to occur around 235 m, much deeper than estimates for aquatic mammals. Hysteresis of the pressure-volume loop increases with maximum diving depth due to progressive alveolar collapse. Reopening of alveoli occurs stochastically as airway pressure overcomes adhesive and compressive forces on ascent. Surface area for gas exchange vanishes at collapse depth, implying that the risk of decompression sickness should reach a plateau beyond this depth. Pulmonary capillary transmural stresses cannot increase after local alveolar collapse. Consolidation of lung parenchyma might provide protection from capillary injury or leakage caused by vascular engorgement due to outward chest wall recoil at extreme depths.

High resolution coherence domain depth-resolved nailfold capillaroscopy based on correlation mapping optical coherence tomography

NASA Astrophysics Data System (ADS)

Subhash, Hrebesh M.; O'Gorman, Sean; Neuhaus, Kai; Leahy, Martin

2014-03-01

In this paper we demonstrate a novel application of correlation mapping optical coherence tomography (cm-OCT) for volumetric nailfold capillaroscopy (NFC). NFC is a widely used non-invasive diagnostic method to analyze capillary morphology and microvascular abnormalities of nailfold area for a range of disease conditions. However, the conventional NFC is incapable of providing volumetric imaging, when volumetric quantitative microangiopathic parameters such as plexus morphology, capillary density, and morphologic anomalies of the end row loops most critical. cm-OCT is a recently developed well established coherence domain magnitude based angiographic modality, which takes advantage of the time-varying speckle effect, which is normally dominant in the vicinity of vascular regions compared to static tissue region. It utilizes the correlation coefficient as a direct measurement of decorrelation between two adjacent B-frames to enhance the visibility of depth-resolved microcirculation.

Condensing Heat Exchanger with Hydrophilic Antimicrobial Coating

NASA Technical Reports Server (NTRS)

Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor)

2014-01-01

A multi-layer antimicrobial hydrophilic coating is applied to a substrate of anodized aluminum, although other materials may form the substrate. A silver layer is sputtered onto a thoroughly clean anodized surface of the aluminum to about 400 nm thickness. A layer of crosslinked, silicon-based macromolecular structure about 10 nm thickness overlies the silver layer, and the outermost surface of the layer of crosslinked, silicon-based macromolecular structure is hydroxide terminated to produce a hydrophilic surface with a water drop contact angle of less than 10.degree.. The coated substrate may be one of multiple fins in a condensing heat exchanger for use in the microgravity of space, which has narrow channels defined between angled fins such that the surface tension of condensed water moves water by capillary flow to a central location where it is pumped to storage. The antimicrobial coating prevents obstruction of the capillary passages.

Spectroscopic chemical analysis methods and apparatus

NASA Technical Reports Server (NTRS)

Hug, William F. (Inventor); Reid, Ray D. (Inventor)

2009-01-01

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted simultaneously with native fluorescence spectroscopy to provide high levels of sensitivity and specificity in the same instrument.

Rational design of capillary-driven flows for paper-based microfluidics.

PubMed

Elizalde, Emanuel; Urteaga, Raúl; Berli, Claudio L A

2015-05-21

The design of paper-based assays that integrate passive pumping requires a precise programming of the fluid transport, which has to be encoded in the geometrical shape of the substrate. This requirement becomes critical in multiple-step processes, where fluid handling must be accurate and reproducible for each operation. The present work theoretically investigates the capillary imbibition in paper-like substrates to better understand fluid transport in terms of the macroscopic geometry of the flow domain. A fluid dynamic model was derived for homogeneous porous substrates with arbitrary cross-sectional shapes, which allows one to determine the cross-sectional profile required for a prescribed fluid velocity or mass transport rate. An extension of the model to slit microchannels is also demonstrated. Calculations were validated by experiments with prototypes fabricated in our lab. The proposed method constitutes a valuable tool for the rational design of paper-based assays.

An oncological view on the blood-testis barrier.

PubMed

Bart, Joost; Groen, Harry J M; van der Graaf, Winette T A; Hollema, Harry; Hendrikse, N Harry; Vaalburg, Willem; Sleijfer, Dirk T; de Vries, Elisabeth G E

2002-06-01

The function of the blood-testis barrier is to protect germ cells from harmful influences; thus, it also impedes the delivery of chemotherapeutic drugs to the testis. The barrier has three components: first, a physicochemical barrier consisting of continuous capillaries, Sertoli cells in the tubular wall, connected together with narrow tight junctions, and a myoid-cell layer around the seminiferous tubule. Second, an efflux-pump barrier that contains P-glycoprotein in the luminal capillary endothelium and on the myoid-cell layer; and multidrug-resistance associated protein 1 located basolaterally on Sertoli cells. Third, an immunological barrier, consisting of Fas ligand on Sertoli cells. Inhibition of P-glycoprotein function offers the opportunity to increase the delivery of cytotoxic drugs to the testis. In the future, visualisation of function in the blood-testis barrier may also be helpful to identify groups of patients in whom testis conservation is safe or to select drugs that are less harmful to fertility.

Microgravity condensing heat exchanger

NASA Technical Reports Server (NTRS)

Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)

2011-01-01

A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches 90.degree.. Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

Spectroscopic chemical analysis methods and apparatus

NASA Technical Reports Server (NTRS)

Reid, Ray D. (Inventor); Hug, William F. (Inventor)

2010-01-01

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted simultaneously with native fluorescence spectroscopy to provide high levels of sensitivity and specificity in the same instrument.

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

Robb, Kevin R.; Jain, Prashant K.; Hazelwood, Thomas J.

Fluoride salt cooled high-temperature reactor (FHR) concepts include pumps for forced circulation of the primary and secondary coolants. As part of a cooperative research and development agreement between the Shanghai Institute of Applied Physics and the Oak Ridge National Laboratory (ORNL), a research project was initiated to aid in the development of pumps for high-temperature salts. The objectives of the task included characterization of the behavior of an existing ORNL LSTL pump; design and test a modified impeller and volute for improved pump characteristics; and finally, provide lessons learned, recommendations, and guidelines for salt pump development and design. The pumpmore » included on the liquid salt test loop (LSTL) at ORNL served as a case study. This report summarizes the progress to date. The report is organized as follows. First, there is a review, focused on pumps, of the significant amount of work on salts at ORNL during the 1950s 1970s. The existing pump on the LSTL is then described. Plans for hot and cold testing of the pump are then discussed, including the design for a cold shakedown test stand and the required LSTL modifications for hot testing. Initial hydraulic and vibration modeling of the LSTL pump is documented. Later, test data from the LSTL will be used to validate the modeling approaches, which could then be used for future pump design efforts. Some initial insights and test data from the pump are then provided. Finally, some preliminary design goals and requirements for a future LSTL pump are provided as examples of salt pump design considerations.« less

Contributions to the initial development of a microelectromechanical loop heat pipe, which is based on coherent porous silicon

NASA Astrophysics Data System (ADS)

Cytrynowicz, Debra G.

The research project itself was the initiation of the development of a planar miniature loop heat pipe based on a capillary wick structure made of coherent porous silicon. Work on this project fell into four main categories, which were component fabrication, test system construction, characterization testing and test data collection, performance analysis and thermal modeling. Component fabrication involved the production of various components for the evaporator. When applicable, these components were to be produced by microelectronic and MEMS or microelectromechanical fabrication techniques. Required work involved analyses and, where necessary, modifications to the wafer processing sequence, the photo-electrochemical etching process, system and controlling computer program to make it more reliable, flexible and efficient. The development of more than one wick production process was also extremely necessary in the event of equipment failure. Work on developing this alternative also involved investigations into various details of the photo-electrochemical etching process itself. Test system construction involved the actual assembly of open and closed loop test systems. Characterization involved developing and administering a series of tests to evaluate the performance of the wicks and test systems. Although there were some indications that the devices were operating according to loop heat pipe theory, they were transient and unstable. Performance analysis involved the construction of a transparent evaporator, which enabled the visual observation of the phenomena, which occurred in the evaporator during operation. It also involved investigating the effect of the quartz wool secondary wick on the operation of the device. Observations made during the visualization study indicated that the capillary and boiling limits were being reached at extremely low values of input power. The work was performed in a collaborative effort between the Biomedical Nanotechnology Research Laboratory at the University of Toledo, the Center for Microelectronics and Sensors and MEMS at the University of Cincinnati and the Thermo-Mechanical Systems Branch of the Power and On-Board Propulsion Division at the John H. Glenn Research Center of the National Aeronautics and Space Administration in Cleveland, Ohio. Work on the project produced six publications, which presented various details on component fabrication, tests system construction and characterization and thermal modeling.

Electronics Thermal Management Using Advanced Hybrid Two-Phase Loop Technology

DTIC Science & Technology

2007-07-08

high heat flux cooling systems [Kawaji and Chung, 2003; Estes and Mudawar , 1995]. The successful integration of mechanical pumps into the heat...1st International Conference on Microchannels and Minichannels, Rochester, New York, April 24~25, 2003. Estes, K. and Mudawar , I., “Comparison of

Spacecraft Thermal Management using Advanced Hybrid Two-Phase Loop Technology

DTIC Science & Technology

2007-02-01

Estes and Mudawar , 1995]. The successful implementation of mechanical pumps used in the heat rejection system of the NASA’s Mars Exploration Rover...Proceedings of 1st International Conference on Microchannels and Minichannels, Rochester, New York, April 24~25, 2003. Estes, K. and Mudawar , I