Wick for metal vapor laser

DOEpatents

Duncan, David B.

1992-01-01

An improved wick for a metal vapor laser is made of a refractory metal cylinder, preferably molybdenum or tungsten for a copper laser, which provides the wicking surface. Alternately, the inside surface of the ceramic laser tube can be metalized to form the wicking surface. Capillary action is enhanced by using wire screen, porous foam metal, or grooved surfaces. Graphite or carbon, in the form of chunks, strips, fibers or particles, is placed on the inside surface of the wick to reduce water, reduce metal oxides and form metal carbides.

Heat pipe wick with structural enhancement

DOEpatents

Andraka, Charles E.; Adkins, Douglas R.; Moreno, James B.; Rawlinson, K. Scott; Showalter, Steven K.; Moss, Timothy A.

2003-11-18

Heat pipe wick structure wherein a stout sheet of perforated material overlays a high performance wick material such as stainless steel felt affixed to a substrate. The inventive structure provides a good flow path for working fluid while maintaining durability and structural stability independent of the structure (or lack of structure) associated with the wick material. In one described embodiment, a wick of randomly laid .about.8 micron thickness stainless steel fibers is sintered to a metal substrate and a perforated metal overlay.

Characterization and Separation of Cancer Cells with a Wicking Fiber Device.

PubMed

Tabbaa, Suzanne M; Sharp, Julia L; Burg, Karen J L

2017-12-01

Current cancer diagnostic methods lack the ability to quickly, simply, efficiently, and inexpensively screen cancer cells from a mixed population of cancer and normal cells. Methods based on biomarkers are unreliable due to complexity of cancer cells, plasticity of markers, and lack of common tumorigenic markers. Diagnostics are time intensive, require multiple tests, and provide limited information. In this study, we developed a novel wicking fiber device that separates cancer and normal cell types. To the best of our knowledge, no previous work has used vertical wicking of cells through fibers to identify and isolate cancer cells. The device separated mouse mammary tumor cells from a cellular mixture containing normal mouse mammary cells. Further investigation showed the device separated and isolated human cancer cells from a heterogeneous mixture of normal and cancerous human cells. We report a simple, inexpensive, and rapid technique that has potential to identify and isolate cancer cells from large volumes of liquid samples that can be translated to on-site clinic diagnosis.

Heat transfer device

NASA Technical Reports Server (NTRS)

Kalkbrenner, R. W. (Inventor)

1974-01-01

A heat transfer device is characterized by an hermetically sealed tubular housing including a tubular shell terminating in spaced end plates, and a tubular mesh wick concentrically arranged and operatively supported within said housing. The invention provides an improved wicking restraint formed as an elongated and radially expanded tubular helix concentrically related to the wick and adapted to be axially foreshortened and radially expanded into engagement with the wick in response to an axially applied compressive load. The wick is continuously supported in a contiguous relationship with the internal surfaces of the shell.

Heat pipe design handbook, part 2. [digital computer code specifications

NASA Technical Reports Server (NTRS)

Skrabek, E. A.

1972-01-01

The utilization of a digital computer code for heat pipe analysis and design (HPAD) is described which calculates the steady state hydrodynamic heat transport capability of a heat pipe with a particular wick configuration, the working fluid being a function of wick cross-sectional area. Heat load, orientation, operating temperature, and heat pipe geometry are specified. Both one 'g' and zero 'g' environments are considered, and, at the user's option, the code will also perform a weight analysis and will calculate heat pipe temperature drops. The central porous slab, circumferential porous wick, arterial wick, annular wick, and axial rectangular grooves are the wick configurations which HPAD has the capability of analyzing. For Vol. 1, see N74-22569.

Method for harvesting rare earth barium copper oxide single crystals

DOEpatents

Todt, V.R.; Sengupta, S.; Shi, D.

1996-04-02

A method of preparing high temperature superconductor single crystals is disclosed. The method of preparation involves preparing precursor materials of a particular composition, heating the precursor material to achieve a peritectic mixture of peritectic liquid and crystals of the high temperature superconductor, cooling the peritectic mixture to quench directly the mixture on a porous, wettable inert substrate to wick off the peritectic liquid, leaving single crystals of the high temperature superconductor on the porous substrate. Alternatively, the peritectic mixture can be cooled to a solid mass and reheated on a porous, inert substrate to melt the matrix of peritectic fluid while leaving the crystals melted, allowing the wicking away of the peritectic liquid. 2 figs.

Method for harvesting rare earth barium copper oxide single crystals

DOEpatents

Todt, Volker R.; Sengupta, Suvankar; Shi, Donglu

1996-01-01

A method of preparing high temperature superconductor single crystals. The method of preparation involves preparing precursor materials of a particular composition, heating the precursor material to achieve a peritectic mixture of peritectic liquid and crystals of the high temperature superconductor, cooling the peritectic mixture to quench directly the mixture on a porous, wettable inert substrate to wick off the peritectic liquid, leaving single crystals of the high temperature superconductor on the porous substrate. Alternatively, the peritectic mixture can be cooled to a solid mass and reheated on a porous, inert substrate to melt the matrix of peritectic fluid while leaving the crystals melted, allowing the wicking away of the peritectic liquid.

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.

Sampling silica and ferrihydrite colloids with fiberglass wicks under unsaturated conditions.

PubMed

Shira, Jason M; Williams, Barbara C; Flury, Markus; Czigány, Szabolcs; Tuller, Markus

2006-01-01

The suitability of passive capillary samplers (PCAPS) for collection of representative colloid samples under partially saturated conditions was evaluated by investigating the transport of negatively and positively charged colloids in fiberglass wicks. A synthetic pore water solution was used to suspend silica microspheres (330 nm in diameter) and ferrihydrite (172 nm in diameter) for transport experiments on fiberglass wicks. Breakthrough curves were collected for three unsaturated flow rates with silica microspheres and one unsaturated flow rate with ferrihydrite colloids. A moisture characteristic curve, relating tensiometer measurements of matric potential to moisture content, was developed for the fiberglass wick. Results indicate that retention of the silica and the ferrihydrite on the wick occurred; that is, the wicks did not facilitate quantitative sampling of the colloids. For silica microspheres, 90% of the colloids were transmitted through the wicks. For ferrihydrite, 80 to 90% of the colloids were transmitted. The mechanisms responsible for the retention of the colloids on the fiberglass wicks appeared to be physicochemical attachment and not thin-film, triple-phase entrapment, or mechanical straining. Visualization of pathways by iron staining indicates that flow is preferential at the center of twisted bundles of filaments. Although axial preferential flow in PCAPS may enhance their hydraulic suitability for sampling mobile colloids, we conclude that without specific preparation to reduce attachment or retention, fiberglass wicks should only be used for qualitative sampling of pore water colloids.

Police Self-Deployment at Critical Incidents: A Wicked Problem or a Part of the Solution

DTIC Science & Technology

2017-09-01

bombings , this thesis explored police self-deployment through the lens of wicked problems. A better understanding of the definition resulted in...police, ICS, wicked problems, Boston Marathon bombings , edge of chaos, apperception, phronesis, self-initiated, Cynefin framework, after-action...manhunt and 2013 Boston Marathon bombings , this thesis explored police self-deployment through the lens of wicked problems. A better understanding of

Wicking of liquids in screens

NASA Technical Reports Server (NTRS)

Symons, E. P.

1974-01-01

An investigation was conducted to determine the magnitude of the wicking rates of liquids in various screens. Evaluation of the parameters characterizing the wicking process resulted in the development of an expression which defined the wicking velocity in terms of screen and system geometry, liquid properties, and gravitational effects. Experiment data obtained both in normal gravity and in weightlessness demonstrated that the model successfully predicted the functional relation of the liquid properties and the distance from the liquid source to the wicking velocity. Because the pore geometry in the screens was complex, several screen geometric parameters were lumped into a single constant which was determined experimentally for each screen.

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.

Hanging drop crystal growth apparatus and method

NASA Technical Reports Server (NTRS)

Carter, Daniel C. (Inventor); Smith, Robbie E. (Inventor)

1989-01-01

An apparatus (10) is constructed having a cylindrical enclosure (16) within which a disc-shaped wicking element (18) is positioned. A well or recess (22) is cut into an upper side (24) of this wicking element, and a glass cover plate or slip (28) having a protein drop disposed thereon is sealably positioned on the wicking element (18), with drop (12) being positioned over well or recess (22). A flow of control fluid is generated by a programmable gradient former (16), with this control fluid having a vapor pressure that is selectively variable. This flow of control fluid is coupled to the wicking element (18) where control fluid vapor diffusing from walls (26) of the recess (22) is exposed to the drop (12), forming a vapor pressure gradient between the drop (12) and the control fluid vapor. Initially, this gradient is adjusted to draw solvent from the drop (12) at a relatively high rate, and as the critical supersaturation point is approached (the point at which crystal nucleation occurs), the gradient is reduced to more slowly draw solvent from the drop (12). This allows discrete protein molecules more time to orient themselves into an ordered crystalline lattice, producing protein crystals which, when processed by X-ray crystallography, possess a high degree of resolution.

Vantage point - A 'wicked' problem.

PubMed

Naish, Jane

2015-10-01

SENIOR NURSES everywhere are facing a 'wicked' problem, wicked in the sense that it seems to defy resolution. The problem is this: the national shortage of nurses, particularly of those at band 5, is forcing us to use agency nurses so that we have enough staff to provide patient care safely.

Wicked Problems in Special and Inclusive Education

ERIC Educational Resources Information Center

Armstrong, David

2017-01-01

This special paper provides a critical overview of wicked problems in special and inclusive education. Practically, this paper provides a strategic framework for future special issues in the "Journal of Special Educational Needs". Critical attention is also given to the concept of a wicked problem when applied to research in special and…

Constraints on the Lee-Wick Higgs sector

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

Carone, Christopher D.; Primulando, Reinard

2009-09-01

Lee-Wick partners to the standard model Higgs doublet may appear at a mass scale that is significantly lower than that of the remaining Lee-Wick partner states. The relevant effective theory is a two-Higgs doublet model in which one doublet has wrong-sign kinetic and mass terms. We determine bounds on this effective theory, including those from neutral B-meson mixing, b{yields}X{sub s}{gamma}, and Z{yields}bb. The results differ from those of conventional two-Higgs doublet models and lead to meaningful constraints on the Lee-Wick Higgs sector.

Community Ecology and Capacity: Keys to Progressing the Environmental Communication of Wicked Problems

ERIC Educational Resources Information Center

Caron, Rosemary M.; Serrell, Nancy

2009-01-01

Wicked problems are multifactorial in nature and possess no clear resolution due to numerous community stakeholder involvement. We demonstrate childhood lead poisoning as a wicked problem and illustrate how understanding a community's ecology can build community capacity to affect local environmental management by (1) forming an academic-community…

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.

Photo-Attachment of Biomolecules for Miniaturization on Wicking Si-Nanowire Platform

PubMed Central

Cheng, He; Zheng, Han; Wu, Jia Xin; Xu, Wei; Zhou, Lihan; Leong, Kam Chew; Fitzgerald, Eugene; Rajagopalan, Raj; Too, Heng Phon; Choi, Wee Kiong

2015-01-01

We demonstrated the surface functionalization of a highly three-dimensional, superhydrophilic wicking substrate using light to immobilize functional biomolecules for sensor or microarray applications. We showed here that the three-dimensional substrate was compatible with photo-attachment and the performance of functionalization was greatly improved due to both increased surface capacity and reduced substrate reflectivity. In addition, photo-attachment circumvents the problems induced by wicking effect that was typically encountered on superhydrophilic three-dimensional substrates, thus reducing the difficulty of producing miniaturized sites on such substrate. We have investigated various aspects of photo-attachment process on the nanowire substrate, including the role of different buffers, the effect of wavelength as well as how changing probe structure may affect the functionalization process. We demonstrated that substrate fabrication and functionalization can be achieved with processes compatible with microelectronics processes, hence reducing the cost of array fabrication. Such functionalization method coupled with the high capacity surface makes the substrate an ideal candidate for sensor or microarray for sensitive detection of target analytes. PMID:25689680

Absorbent product and articles made therefrom

NASA Technical Reports Server (NTRS)

Dawn, F. S.; Correale, J. V. (Inventor)

1982-01-01

A multilayer absorbent product for use in contact with the skin to absorb fluids is described. The product has a water pervious facing layer for contacting the skin, and a first fibrous wicking layer overlaying the water pervious layer. A first container section is defined by inner and outer layers of a water pervious wicking material in between a first absorbent mass and a second container section defined by inner and outer layers of a water pervious wicking material between what is disposed a second absorbent mass, and a liquid impermeable/gas permeable layer overlaying the second fibrous wicking layer.

Cryogenic Autogenous Pressurization Testing for Robotic Refueling Mission 3

NASA Technical Reports Server (NTRS)

Boyle, R.; DiPirro, M.; Tuttle, J.; Francis, J.; Mustafi, S.; Li, X.; Barfknecht, P.; DeLee, C. H.; McGuire, J.

2015-01-01

A wick-heater system has been selected for use to pressurize the Source Dewar of the Robotic Refueling Mission Phase 3 on-orbit cryogen transfer experiment payload for the International Space Station. Experimental results of autogenous pressurization of liquid argon and liquid nitrogen using a prototype wick-heater system are presented. The wick-heater generates gas to increase the pressure in the tank while maintaining a low bulk fluid temperature. Pressurization experiments were performed in 2013 to characterize the performance of the wick heater. This paper describes the experimental setup, pressurization results, and analytical model correlations.

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.

Effect of Bamboo Viscose on the Wicking and Moisture Management Properties of Gauze

NASA Astrophysics Data System (ADS)

Akbar, Abdul R.; Su, Siwei; Amjad, Bilal; Cai, Yingjie; Lin, Lina

2017-12-01

Bamboo viscose or regenerated cellulose fibers were used to check their absorbency properties effect on the wicking and moisture management in gauzes. Bamboo viscose and cotton fibers were spun into five different yarn samples with different fiber proportion by ring spinning. Fifteen different gauze samples were made of these yarn samples. The gauze samples were subjected to wicking test to check the wicking ability. Water vapor transmission test was applied to check the vapor transmission rate. These tests were applied to measure the effectiveness of bamboo viscose, cotton and blended gauze samples in wound healing. Pure bamboo gauzes and gauzes with high content of bamboo fiber, i.e. 75B:25C and 50B:50C, shows better wicking and vapor transmission properties. It makes gauzes with high bamboo viscose suitable for wound care applications because of moisture absorbency.

One-loop renormalization of Lee-Wick gauge theory

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

Grinstein, Benjamin; O'Connell, Donal

2008-11-15

We examine the renormalization of Lee-Wick gauge theory to one-loop order. We show that only knowledge of the wave function renormalization is necessary to determine the running couplings, anomalous dimensions, and vector boson masses. In particular, the logarithmic running of the Lee-Wick vector boson mass is exactly related to the running of the coupling. In the case of an asymptotically free theory, the vector boson mass runs to infinity in the ultraviolet. Thus, the UV fixed point of the pure gauge theory is an ordinary quantum field theory. We find that the coupling runs more quickly in Lee-Wick gauge theorymore » than in ordinary gauge theory, so the Lee-Wick standard model does not naturally unify at any scale. Finally, we present results on the beta function of more general theories containing dimension six operators which differ from previous results in the literature.« less

Optimized Structures for Low-Profile Phase Change Thermal Spreaders

NASA Astrophysics Data System (ADS)

Sharratt, Stephen Andrew

Thin, low-profile phase change thermal spreaders can provide cooling solutions for some of today's most pressing heat flux dissipation issues. These thermal issues are only expected to increase as future electronic circuitry requirements lead to denser and potentially 3D chip packaging. Phase change based heat spreaders, such as heat pipes or vapor chambers, can provide a practical solution for effectively dissipating large heat fluxes. This thesis reports a comprehensive study of state-of-the-art capillary pumped wick structures using computational modeling, micro wick fabrication, and experimental analysis. Modeling efforts focus on predicting the shape of the liquid meniscus inside a complicated 3D wick structure. It is shown that this liquid shape can drastically affect the wick's thermal resistance. In addition, knowledge of the liquid meniscus shape allows for the computation of key parameters such as permeability and capillary pressure which are necessary for predicting the maximum heat flux. After the model is validated by comparison to experimental results, the wick structure is optimized so as to decrease overall wick thermal resistance and increase the maximum capillary limited heat flux before dryout. The optimized structures are then fabricated out of both silicon and copper using both traditional and novel micro-fabrication techniques. The wicks are made super-hydrophilic using chemical and thermal oxidation schemes. A sintered monolayer of Cu particles is fabricated and analyzed as well. The fabricated wick structures are experimentally tested for their heat transfer performance inside a well controlled copper vacuum chamber. Heat fluxes as high as 170 W/cm2 are realized for Cu wicks with structure heights of 100 μm. The structures optimized for both minimized thermal resistance and high liquid supply ability perform much better than their non-optimized counterparts. The super-hydrophilic oxidation scheme is found to drastically increase the maximum heat flux and decrease thermal resistance. This research provides key insights as to how to optimize heat pipe structures to minimize thermal resistance and increase maximum heat flux. These thin wick structures can also be combined with a thicker liquid supply layer so that thin, low-resistance evaporator layers can be constructed and higher heat fluxes realized. The work presented in this thesis can be used to aid in the development of high-performance phase change thermal spreaders, allowing for temperature control of a variety of powerful electronic components.

Paper diagnostic for instantaneous blood typing.

PubMed

Khan, Mohidus Samad; Thouas, George; Shen, Wei; Whyte, Gordon; Garnier, Gil

2010-05-15

Agglutinated blood transports differently onto paper than stable blood with well dispersed red cells. This difference was investigated to develop instantaneous blood typing tests using specific antibody-antigen interactions to trigger blood agglutination. Two series of experiments were performed. The first related the level of agglutination and the fluidic properties of blood on its transport in paper. Blood samples were mixed at different ratios with specific and nonspecific antibodies; a droplet of each mixture was deposited onto a filter paper strip, and the kinetics of wicking and red cell separation were measured. Agglutinated blood phase separated, with the red blood cells (RBC) forming a distinct spot upon contact with paper while the plasma wicked; in contrast, stable blood suspensions wicked uniformly. The second study analyzed the wicking and the chromatographic separation of droplets of blood deposited onto paper strips pretreated with specific and nonspecific antibodies. Drastic differences in transport occurred. Blood agglutinated by interaction with one of its specific antibodies phase separated, causing a chromatographic separation. The red cells wicked very little while the plasma wicked at a faster rate than the original blood sample. Blood agglutination and wicking in paper followed the concepts of colloids chemistry. The immunoglobin M antibodies agglutinated the red blood cells by polymer bridging, upon selective adsorption on the specific antigen at their surface. The transport kinetics was viscosity controlled, with the viscosity of red cells drastically increasing upon blood agglutination. Three arm prototypes were investigated for single-step blood typing.

Instantons re-examined: dynamical tunneling and resonant tunneling.

PubMed

Le Deunff, Jérémy; Mouchet, Amaury

2010-04-01

Starting from trace formulas for the tunneling splittings (or decay rates) analytically continued in the complex time domain, we obtain explicit semiclassical expansions in terms of complex trajectories that are selected with appropriate complex-time paths. We show how this instantonlike approach, which takes advantage of an incomplete Wick rotation, accurately reproduces tunneling effects not only in the usual double-well potential but also in situations where a pure Wick rotation is insufficient, for instance dynamical tunneling or resonant tunneling. Even though only one-dimensional autonomous Hamiltonian systems are quantitatively studied, we discuss the relevance of our method for multidimensional and/or chaotic tunneling.

Radiation bounce from the Lee-Wick construction?

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

Karouby, Johanna; Brandenberger, Robert

2010-09-15

It was recently realized that matter modeled by the scalar field sector of the Lee-Wick standard model yields, in the context of a homogeneous and isotropic cosmological background, a bouncing cosmology. However, bouncing cosmologies induced by pressureless matter are in general unstable to the addition of relativistic matter (i.e. radiation). Here we study the possibility of obtaining a bouncing cosmology if we add not only radiation, but also its Lee-Wick partner, to the matter sector. We find that, in general, no bounce occurs. The only way to obtain a bounce is to choose initial conditions with very special phases ofmore » the radiation field and its Lee-Wick partner.« less

Aircraft Thermal Management Using Loop Heat Pipes

DTIC Science & Technology

2009-03-01

flexible copper-water arterial wick heat pipe subjected to transverse acceleration using a centrifuge table. Evaporator heat loads up to Qin = 150 W and...acceleration. Yerkes and Beam (1992) examined the same flexible copper-water arterial wick heat pipe as Ponnappan et al. under transient transverse...examined the same flexible copper-water arterial wick heat pipe as Ponnappan et al. with evaporator heat loads from Qin = 75 to 150 W, condenser

Tackling wicked problems: how theories of agency can provide new insights.

PubMed

Varpio, Lara; Aschenbrener, Carol; Bates, Joanna

2017-04-01

This paper reviews why and how theories of agency can be used as analytical lenses to help health professions education (HPE) scholars address our community's wicked problems. Wicked problems are those that resist clear problem statements, defy traditional analysis approaches, and refuse definitive resolution (e.g. student remediation, assessments of professionalism, etc.). We illustrate how theories of agency can provide new insights into such challenges by examining the application of these theories to one particular wicked problem in HPE: interprofessional education (IPE). After searching the HPE literature and finding that theories of agency had received little attention, we borrowed techniques from narrative literature reviews to search databases indexing a broad scope of disciplines (i.e. ERIC, Web of Science, Scopus, MEDLINE and PubMed) for publications (1994-2014) that: (i) examined agency, or (ii) incorporated an agency-informed analytical perspective. The lead author identified the theories of agency used in these articles, and reviewed the texts on agency cited therein and the original sources of each theory. We identified 10 theories of agency that we considered to be applicable to HPE's wicked problems. To select a subset of theories for presentation in this paper, we discussed each theory in relation to some of HPE's wicked problems. Through debate and reflection, we unanimously agreed on the applicability of a subset of theories for illuminating HPE's wicked problems. This subset is described in this paper. We present four theories of agency: Butler's post-structural formulation; Giddens' sociological formulation; cultural historical activity theory's formulation, and Bandura's social cognitive psychology formulation. We introduce each theory and apply each to the challenges of engaging in IPE. Theories of agency can inform HPE scholarship in novel and generative ways. Each theory offers new insights into the roots of wicked problems and means for contending with them. © 2017 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

(Un)Earthing a Vocabulary of Values: A Discourse Analysis for Ecocomposition

ERIC Educational Resources Information Center

Walker, Paul

2010-01-01

In this article, the author aims to propose an analytic method through which composition students and others might discover and understand the ecological complexities of prevailing environmental terminology that create "wicked problems." Through this method, students engage in "discursive ecology" by exploring the connections…

Wicked problems and a 'wicked' solution.

PubMed

Walls, Helen L

2018-04-13

'Wicked' is the term used to describe some of the most challenging and complex issues of our time, many of which threaten human health. Climate change, biodiversity loss, persisting poverty, the advancing obesity epidemic, and food insecurity are all examples of such wicked problems. However there is a strong body of evidence describing the solutions for addressing many of these problems. Given that much is known about how many of these problems could be addressed - and given the risks of not acting - what will it take to create the 'tipping point' needed for effective action? A recent (2015) court ruling in The Hague held that the Dutch government's stance on climate change was illegal, ordering them to cut greenhouse gas emissions by at least 25% within 5 years (by 2020), relative to 1990 levels. The case was filed on behalf of 886 Dutch citizens, suing the government for violating human rights and climate changes treaties by failing to take adequate action to prevent the harmful impacts of climate change. This judicial ruling has the potential to provide a way forward, inspiring other civil movements and creating a template from which to address other wicked problems. This judicial strategy to address the need to lower greenhouse gas emissions in the Netherlands is not a magic bullet, and requires a particular legal and institutional setting. However it has the potential to be a game-changer - providing an example of a strategy for achieving domestic regulatory change that is likely to be replicable in some countries elsewhere, and providing an example of a particularly 'wicked' (in the positive, street-slang sense of the word) strategy to address seemingly intractable and wicked problems.

Process gg{yields}h{sub 0}{yields}{gamma}{gamma} in the Lee-Wick standard model

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

Krauss, F.; Underwood, T. E. J.; Zwicky, R.

2008-01-01

The process gg{yields}h{sub 0}{yields}{gamma}{gamma} is studied in the Lee-Wick extension of the standard model (LWSM) proposed by Grinstein, O'Connell, and Wise. In this model, negative norm partners for each SM field are introduced with the aim to cancel quadratic divergences in the Higgs mass. All sectors of the model relevant to gg{yields}h{sub 0}{yields}{gamma}{gamma} are diagonalized and results are commented on from the perspective of both the Lee-Wick and higher-derivative formalisms. Deviations from the SM rate for gg{yields}h{sub 0} are found to be of the order of 15%-5% for Lee-Wick masses in the range 500-1000 GeV. Effects on the rate formore » h{sub 0}{yields}{gamma}{gamma} are smaller, of the order of 5%-1% for Lee-Wick masses in the same range. These comparatively small changes may well provide a means of distinguishing the LWSM from other models such as universal extra dimensions where same-spin partners to standard model fields also appear. Corrections to determinations of Cabibbo-Kobayashi-Maskawa (CKM) elements |V{sub t(b,s,d)}| are also considered and are shown to be positive, allowing the possibility of measuring a CKM element larger than unity, a characteristic signature of the ghostlike nature of the Lee-Wick fields.« less

Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces

NASA Technical Reports Server (NTRS)

Dussinger, Peter M.; Lindemuth, James E.

1997-01-01

The principal objective of this Phase 2 SBIR program was to develop and demonstrate a practically insoluble coating for nickel-based superalloys for Stirling engine heat pipe applications. Specific technical objectives of the program were: (1) Determine the solubility corrosion rates for Nickel 200, Inconel 718, and Udimet 72OLI in a simulated Stirling engine heat pipe environment, (2) Develop coating processes and techniques for capillary groove and screen wick structures, (3) Evaluate the durability and solubility corrosion rates for capillary groove and screen wick structures coated with an insoluble coating in cylindrical heat pipes operating under Stirling engine conditions, and (4) Design and fabricate a coated full-scale, partial segment of the current Stirling engine heat pipe for the Stirling Space Power Convertor program. The work effort successfully demonstrated a two-step nickel aluminide coating process for groove wick structures and interior wall surfaces in contact with liquid metals; demonstrated a one-step nickel aluminide coating process for nickel screen wick structures; and developed and demonstrated a two-step aluminum-to-nickel aluminide coating process for nickel screen wick structures. In addition, the full-scale, partial segment was fabricated and the interior surfaces and wick structures were coated. The heat pipe was charged with sodium, processed, and scheduled to be life tested for up to ten years as a Phase 3 effort.

Methods for separating a fluid, and devices capable of separating a fluid

DOEpatents

TeGrotenhuis, Ward E; Humble, Paul H; Caldwell, Dustin D

2013-05-14

Methods and apparatus for separating fluids are disclosed. We have discovered that, surprisingly, providing an open pore structure between a wick and an open flow channel resulted in superior separation performance. A novel and compact integrated device components for conducting separations are also described.

Fluid leak indicator

NASA Technical Reports Server (NTRS)

Anderson, G. E.; Loo, S. (Inventor)

1985-01-01

A fluid leak indicator for detecting and indicating leaks in visually inaccessible fluid tubing joints, such as those obstructed by insulation includes a bag system and a wicking system surrounding or wrapping the joints under the visual obstructing material. Leaking fluid is collected in the bag or on the wicking material where it is conducted along the wicking material to a visily accessible capturing transparent indicator bulb for providing a visual indication of the leak without requiring a chemical change in the capturing indicator bulb.

An auto-Bäcklund transformation and exact solutions for Wick-type stochastic generalized KdV equations

NASA Astrophysics Data System (ADS)

Xie, Yingchao

2004-05-01

Wick-type stochastic generalized KdV equations are researched. By using the homogeneous balance, an auto-Bäcklund transformation to the Wick-type stochastic generalized KdV equations is derived. And stochastic single soliton and stochastic multi-soliton solutions are shown by using the Hermite transform. Research supported by the National Natural Science Foundation of China (19971072) and the Natural Science Foundation of Education Committee of Jiangsu Province of China (03KJB110135).

Phenomenology of the N = 3 Lee-Wick Standard Model

NASA Astrophysics Data System (ADS)

TerBeek, Russell Henry

With the discovery of the Higgs Boson in 2012, particle physics has decidedly moved beyond the Standard Model into a new epoch. Though the Standard Model particle content is now completely accounted for, there remain many theoretical issues about the structure of the theory in need of resolution. Among these is the hierarchy problem: since the renormalized Higgs mass receives quadratic corrections from a higher cutoff scale, what keeps the Higgs boson light? Many possible solutions to this problem have been advanced, such as supersymmetry, Randall-Sundrum models, or sub-millimeter corrections to gravity. One such solution has been advanced by the Lee-Wick Standard Model. In this theory, higher-derivative operators are added to the Lagrangian for each Standard Model field, which result in propagators that possess two physical poles and fall off more rapidly in the ultraviolet regime. It can be shown by an auxiliary field transformation that the higher-derivative theory is identical to positing a second, manifestly renormalizable theory in which new fields with opposite-sign kinetic and mass terms are found. These so-called Lee-Wick fields have opposite-sign propagators, and famously cancel off the quadratic divergences that plague the renormalized Higgs mass. The states in the Hilbert space corresponding to Lee-Wick particles have negative norm, and implications for causality and unitarity are examined. This dissertation explores a variant of the theory called the N = 3 Lee-Wick Standard Model. The Lagrangian of this theory features a yet-higher derivative operator, which produces a propagator with three physical poles and possesses even better high-energy behavior than the minimal Lee-Wick theory. An analogous auxiliary field transformation takes this higher-derivative theory into a renormalizable theory with states of alternating positive, negative, and positive norm. The phenomenology of this theory is examined in detail, with particular emphasis on the collider signatures of Lee-Wick particles, electroweak precision constraints on the masses that the new particles can take on, and scenarios in early-universe cosmology in which Lee-Wick particles can play a significant role.

Ultrasonic-assisted deacetylation of cellulose acetate nanofibers: A rapid method to produce cellulose nanofibers.

PubMed

Ahmed, Farooq; Ayoub Arbab, Alvira; Jatoi, Abdul Wahab; Khatri, Muzamil; Memon, Najma; Khatri, Zeeshan; Kim, Ick Soo

2017-05-01

Herein we report a rapid method for deacetylation of cellulose acetate (CA) nanofibers in order to produce cellulose nanofibers using ultrasonic energy. The CA nanofibers were fabricated via electrospinning thereby treated with NaOH and NaOH/EtOH solutions at various pH levels for 30, 60 and 90min assisted by ultrasonic energy. The nanofiber webs were optimized by degree of deacetylation (DD%) and wicking behavior. The resultant nanofibers were further characterized by FTIR, SEM, WAXD, DSC analysis. The DD% and FTIR results confirmed a complete conversion of CA nanofibers to cellulose nanofibers within 1h with substantial increase of wicking height. Nanofibers morphology under SEM showed slightly swelling and no damage of nanofibers observed by use of ultrasonic energy. The results of ultrasonic-assisted deacetylation are comparable with the conventional deacetylation. Our rapid method offers substantially reduced deacetylation time from 30h to just 1h, thanks to the ultrasonic energy. Copyright © 2016 Elsevier B.V. All rights reserved.

Filtration Isolation of Nucleic Acids: A Simple and Rapid DNA Extraction Method.

PubMed

McFall, Sally M; Neto, Mário F; Reed, Jennifer L; Wagner, Robin L

2016-08-06

FINA, filtration isolation of nucleic acids, is a novel extraction method which utilizes vertical filtration via a separation membrane and absorbent pad to extract cellular DNA from whole blood in less than 2 min. The blood specimen is treated with detergent, mixed briefly and applied by pipet to the separation membrane. The lysate wicks into the blotting pad due to capillary action, capturing the genomic DNA on the surface of the separation membrane. The extracted DNA is retained on the membrane during a simple wash step wherein PCR inhibitors are wicked into the absorbent blotting pad. The membrane containing the entrapped DNA is then added to the PCR reaction without further purification. This simple method does not require laboratory equipment and can be easily implemented with inexpensive laboratory supplies. Here we describe a protocol for highly sensitive detection and quantitation of HIV-1 proviral DNA from 100 µl whole blood as a model for early infant diagnosis of HIV that could readily be adapted to other genetic targets.

Titanium based flat heat pipes for computer chip cooling

NASA Astrophysics Data System (ADS)

Soni, Gaurav; Ding, Changsong; Sigurdson, Marin; Bozorgi, Payam; Piorek, Brian; MacDonald, Noel; Meinhart, Carl

2008-11-01

We are developing a highly conductive flat heat pipe (called Thermal Ground Plane or TGP) for cooling computer chips. Conventional heat pipes have circular cross sections and thus can't make good contact with chip surface. The flatness of our TGP will enable conformal contact with the chip surface and thus enhance cooling efficiency. Another limiting factor in conventional heat pipes is the capillary flow of the working fluid through a wick structure. In order to overcome this limitation we have created a highly porous wick structure on a flat titanium substrate by using micro fabrication technology. We first etch titanium to create very tall micro pillars with a diameter of 5 μm, a height of 40 μm and a pitch of 10 μm. We then grow a very fine nano structured titania (NST) hairs on all surfaces of the pillars by oxidation in H202. In this way we achieve a wick structure which utilizes multiple length scales to yield high performance wicking of water. It's capable of wicking water at an average velocity of 1 cm/s over a distance of several cm. A titanium cavity is laser-welded onto the wicking substrate and a small quantity of water is hermetically sealed inside the cavity to achieve a TGP. The thermal conductivity of our preliminary TGP was measured to be 350 W/m-K, but has the potential to be several orders of magnitude higher.

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.

Fluid leak indicator

NASA Technical Reports Server (NTRS)

Anderson, George E. (Inventor); Loo, Shu (Inventor)

1989-01-01

A fluid leak indicator (30) for detecting and indicating leaks in visually inaccessible fluid tubing joints (20, 21), such as those obstructed by insulation (24), includes a bag system (25) and a wicking system (30) surrounding or wrapping the joints (20, 21) under the visual obstructing material (24). Leaking fluid is collected in the bag (25) or on the wicking material (34) where it is conducted along the wicking material (34) to a visibly accessible capturing transparent indicator bulb (35) for providing a visual indication of the leak without requiring a chemical change in the capturing indicator bulb (35).

Wick-and-pool electrodes for electrochemical cell

DOEpatents

Roche, Michael F.; Faist, Suzan M.; Eberhart, James G.; Ross, Laurids E.

1977-01-01

An electrode system includes a reservoir of liquid-metal reactant, and a wick extending from a submersed location within the reservoir into the molten electrolyte of an electrochemical cell structure. The wick is flooded with the liquid metal and thereby serves as one electrode within the cell. This electrode system has application in high-temperature batteries employing molten alkali metals or their alloys as active material within an electrode submersed within a molten salt electrolyte. It also can be used in electrochemical cells where the purification, separation or electrowinning of liquid metals is accomplished.

Wick-and-pool electrodes for electrochemical cell

DOEpatents

Roche, Michael F.; Faist, Suzan M.; Eberhart, James G.; Ross, Laurids E.

1980-01-01

An electrode system includes a reservoir of liquid-metal reactant, and a wick extending from a submersed location within the reservoir into the molten electrolyte of an electrochemical cell structure. The wick is flooded with the liquid metal and thereby serves as one electrode within the cell. This electrode system has application in high-temperature batteries employing molten alkali metals or their alloys as active material within an electrode submersed within a molten salt electrolyte. It also can be used in electrochemical cells where the purification, separation or electrowinning of liquid metals is accomplished.

Causality as an emergent macroscopic phenomenon: The Lee-Wick O(N) model

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

Grinstein, Benjamin; O'Connell, Donal; Wise, Mark B.

2009-05-15

In quantum mechanics the deterministic property of classical physics is an emergent phenomenon appropriate only on macroscopic scales. Lee and Wick introduced Lorentz invariant quantum theories where causality is an emergent phenomenon appropriate for macroscopic time scales. In this paper we analyze a Lee-Wick version of the O(N) model. We argue that in the large-N limit this theory has a unitary and Lorentz invariant S matrix and is therefore free of paradoxes in scattering experiments. We discuss some of its acausal properties.

Nanoscale wicking methods and devices

NASA Technical Reports Server (NTRS)

Zhou, Jijie (Inventor); Bronikowski, Michael (Inventor); Noca, Flavio (Inventor); Sansom, Elijah B. (Inventor)

2011-01-01

A fluid transport method and fluid transport device are disclosed. Nanoscale fibers disposed in a patterned configuration allow transport of a fluid in absence of an external power source. The device may include two or more fluid transport components having different fluid transport efficiencies. The components may be separated by additional fluid transport components, to control fluid flow.

No Lee-Wick fields out of gravity

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

Rodigast, Andreas; Schuster, Theodor

2009-06-15

We investigate the gravitational one-loop divergences of the standard model in large extra dimensions, with gravitons propagating in the (4+{delta})-dimensional bulk and gauge fields as well as scalar and fermionic multiplets confined to a three-brane. To determine the divergences we establish a cutoff regularization which allows us to extract gauge-invariant counterterms. In contrast to the claim of a recent paper [F. Wu and M. Zhong, Phys. Rev. D 78, 085010 (2008).], we show that the fermionic and scalar higher derivative counterterms do not coincide with the higher derivative terms in the Lee-Wick standard model. We argue that even if themore » exact Lee-Wick higher derivative terms were found, as in the case of the pure gauge sector, this would not allow to conclude the existence of the massive ghost fields corresponding to these higher derivative terms in the Lee-Wick standard model.« less

Hybrid Heat Pipes for Lunar and Martian Surface and High Heat Flux Space Applications

NASA Technical Reports Server (NTRS)

Ababneh, Mohammed T.; Tarau, Calin; Anderson, William G.; Farmer, Jeffery T.; Alvarez-Hernandez, Angel R.

2016-01-01

Novel hybrid wick heat pipes are developed to operate against gravity on planetary surfaces, operate in space carrying power over long distances and act as thermosyphons on the planetary surface for Lunar and Martian landers and rovers. These hybrid heat pipes will be capable of operating at the higher heat flux requirements expected in NASA's future spacecraft and on the next generation of polar rovers and equatorial landers. In addition, the sintered evaporator wicks mitigate the start-up problems in vertical gravity aided heat pipes because of large number of nucleation sites in wicks which will allow easy boiling initiation. ACT, NASA Marshall Space Flight Center, and NASA Johnson Space Center, are working together on the Advanced Passive Thermal experiment (APTx) to test and validate the operation of a hybrid wick VCHP with warm reservoir and HiK"TM" plates in microgravity environment on the ISS.

Heat pipe development

NASA Technical Reports Server (NTRS)

Bienart, W. B.

1973-01-01

The objective of this program was to investigate analytically and experimentally the performance of heat pipes with composite wicks--specifically, those having pedestal arteries and screwthread circumferential grooves. An analytical model was developed to describe the effects of screwthreads and screen secondary wicks on the transport capability of the artery. The model describes the hydrodynamics of the circumferential flow in triangular grooves with azimuthally varying capillary menisci and liquid cross-sections. Normalized results were obtained which give the influence of evaporator heat flux on the axial heat transport capability of the arterial wick. In order to evaluate the priming behavior of composite wicks under actual load conditions, an 'inverted' glass heat pipe was designed and constructed. The results obtained from the analysis and from the tests with the glass heat pipe were applied to the OAO-C Level 5 heat pipe, and an improved correlation between predicted and measured evaporator and transport performance were obtained.

Four-man rated dual catalyst system for the recovery of water from urine

NASA Technical Reports Server (NTRS)

Budininkas, P.

1978-01-01

The catalytic system was integrated with a 4-man rated urine wick evaporator. During operation, urine vapor produced by the wick-evaporator was treated in the catalytic system to remove ammonia and volatile hydrocarbons, and water was recovered by condensation in a water cooled condenser. The system operated completely automatically and required no manual adjustments, except periodic supply of urine and removal of the recovered water. Although the system was designed for treating 0.325 kg urine per hour, this rate could be achieved only with a fresh wick, then gradually decreased as the wick became saturated with urine solids. The average urine treatment rates achieved during each of the three endurance tests were 0.137, 0.217, and 0.235 kg/hr. The quality of the recovered water meets drinking water standards, with the exception of a generally low pH.

Evaluation of wick drain performance in Virginia soils.

DOT National Transportation Integrated Search

2003-01-01

Prefabricated vertical drains (PVD), also known as wick drains, are commonly used to accelerate the consolidation of fine-grained soils in order to reduce future settlements and increase shear strength. Various drain designs are currently on the mark...

Partially Acetylated Sugarcane Bagasse For Wicking Oil From Contaminated Wetlands

EPA Science Inventory

Sugarcane bagasse was partially acetylated to enhance its oil-wicking ability in saturated environments while holding moisture for hydrocarbon biodegradation. The water sorption capacity of raw bagasse was reduced fourfold after treatment, which indicated considerably increased ...

Tungsten-yttria carbide coating for conveying copper

DOEpatents

Rothman, Albert J.

1993-01-01

A method is provided for providing a carbided-tungsten-yttria coating on the interior surface of a copper vapor laser. The surface serves as a wick for the condensation of liquid copper to return the condensate to the interior of the laser for revolatilization.

Solving the 10 Most Common Carpet Problems.

ERIC Educational Resources Information Center

Hilton, Michael

1998-01-01

Identifies the 10 most common carpet problems in school facilities and offers solutions. These include: transition areas, moisture, spot removal, recurring spots, cleaning agents, allergens, wicking, biological contamination, equipment selection, and cleaning methods. Ensuring a successful maintenance program results in satisfactory appearance,…

Synthetic biology and conservation of nature: wicked problems and wicked solutions.

PubMed

Redford, Kent H; Adams, William; Mace, Georgina M

2013-01-01

So far, conservation scientists have paid little attention to synthetic biology; this is unfortunate as the technology is likely to transform the operating space within which conservation functions, and therefore the prospects for maintaining biodiversity into the future.

Heat pipe with improved wick structures

DOEpatents

Benson, David A.; Robino, Charles V.; Palmer, David W.; Kravitz, Stanley H.

2000-01-01

An improved planar heat pipe wick structure having projections formed by micromachining processes. The projections form arrays of interlocking, semi-closed structures with multiple flow paths on the substrate. The projections also include overhanging caps at their tops to increase the capillary pumping action of the wick structure. The capped projections can be formed in stacked layers. Another layer of smaller, more closely spaced projections without caps can also be formed on the substrate in between the capped projections. Inexpensive materials such as Kovar can be used as substrates, and the projections can be formed by electrodepositing nickel through photoresist masks.

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.

Two-ply channels for faster wicking in paper-based microfluidic devices.

PubMed

Camplisson, Conor K; Schilling, Kevin M; Pedrotti, William L; Stone, Howard A; Martinez, Andres W

2015-12-07

This article describes the development of porous two-ply channels for paper-based microfluidic devices that wick fluids significantly faster than conventional, porous, single-ply channels. The two-ply channels were made by stacking two single-ply channels on top of each other and were fabricated entirely out of paper, wax and toner using two commercially available printers, a convection oven and a thermal laminator. The wicking in paper-based channels was studied and modeled using a modified Lucas-Washburn equation to account for the effect of evaporation, and a paper-based titration device incorporating two-ply channels was demonstrated.

HPTAM, a two-dimensional Heat Pipe Transient Analysis Model, including the startup from a frozen state

NASA Technical Reports Server (NTRS)

Tournier, Jean-Michel; El-Genk, Mohamed S.

1995-01-01

A two-dimensional Heat Pipe Transient Analysis Model, 'HPTAM,' was developed to simulate the transient operation of fully-thawed heat pipes and the startup of heat pipes from a frozen state. The model incorporates: (a) sublimation and resolidification of working fluid; (b) melting and freezing of the working fluid in the porous wick; (c) evaporation of thawed working fluid and condensation as a thin liquid film on a frozen substrate; (d) free-molecule, transition, and continuum vapor flow regimes, using the Dusty Gas Model; (e) liquid flow and heat transfer in the porous wick; and (f) thermal and hydrodynamic couplings of phases at their respective interfaces. HPTAM predicts the radius of curvature of the liquid meniscus at the liquid-vapor interface and the radial location of the working fluid level (liquid or solid) in the wick. It also includes the transverse momentum jump condition (capillary relationship of Pascal) at the liquid-vapor interface and geometrically relates the radius of curvature of the liquid meniscus to the volume fraction of vapor in the wick. The present model predicts the capillary limit and partial liquid recess (dryout) in the evaporator wick, and incorporates a liquid pooling submodel, which simulates accumulation of the excess liquid in the vapor core at the condenser end.

Wicking Tests for Unidirectional Fabrics: Measurements of Capillary Parameters to Evaluate Capillary Pressure in Liquid Composite Molding Processes.

PubMed

Pucci, Monica Francesca; Liotier, Pierre-Jacques; Drapier, Sylvain

2017-01-27

During impregnation of a fibrous reinforcement in liquid composite molding (LCM) processes, capillary effects have to be understood in order to identify their influence on void formation in composite parts. Wicking in a fibrous medium described by the Washburn equation was considered equivalent to a flow under the effect of capillary pressure according to the Darcy law. Experimental tests for the characterization of wicking were conducted with both carbon and flax fiber reinforcement. Quasi-unidirectional fabrics were then tested by means of a tensiometer to determine the morphological and wetting parameters along the fiber direction. The procedure was shown to be promising when the morphology of the fabric is unchanged during capillary wicking. In the case of carbon fabrics, the capillary pressure can be calculated. Flax fibers are sensitive to moisture sorption and swell in water. This phenomenon has to be taken into account to assess the wetting parameters. In order to make fibers less sensitive to water sorption, a thermal treatment was carried out on flax reinforcements. This treatment enhances fiber morphological stability and prevents swelling in water. It was shown that treated fabrics have a linear wicking trend similar to those found in carbon fabrics, allowing for the determination of capillary pressure.

Conditions for fluid separations in microchannels, capillary-driven fluid separations, and laminated devices capable of separating fluids

DOEpatents

TeGrotenhuis, Ward E [Kennewick, WA; Stenkamp, Victoria S [Richland, WA

2005-04-05

Methods of separating fluids using capillary forces and/or improved conditions for are disclosed. The improved methods may include control of the ratio of gas and liquid Reynolds numbers relative to the Suratman number. Also disclosed are wick-containing, laminated devices that are capable of separating fluids.

Conditions for fluid separations in microchannels, capillary-driven fluid separations, and laminated devices capable of separating fluids

DOEpatents

TeGrotenhuis, Ward E [Kennewick, WA; Stenkamp, Victoria S [Richland, WA

2008-03-18

Methods of separating fluids using capillary forces and/or improved conditions for are disclosed. The improved methods may include control of the ratio of gas and liquid Reynolds numbers relative to the Suratman number. Also disclosed are wick-containing, laminated devices that are capable of separating fluids.

Tackling 'wicked' health promotion problems: a New Zealand case study.

PubMed

Signal, Louise N; Walton, Mat D; Ni Mhurchu, Cliona; Maddison, Ralph; Bowers, Sharron G; Carter, Kristie N; Gorton, Delvina; Heta, Craig; Lanumata, Tolotea S; McKerchar, Christina W; O'Dea, Des; Pearce, Jamie

2013-03-01

This paper reports on a complex environmental approach to addressing 'wicked' health promotion problems devised to inform policy for enhancing food security and physical activity among Māori, Pacific and low-income people in New Zealand. This multi-phase research utilized literature reviews, focus groups, stakeholder workshops and key informant interviews. Participants included members of affected communities, policy-makers and academics. Results suggest that food security and physical activity 'emerge' from complex systems. Key areas for intervention include availability of money within households; the cost of food; improvements in urban design and culturally specific physical activity programmes. Seventeen prioritized intervention areas were explored in-depth and recommendations for action identified. These include healthy food subsidies, increasing the statutory minimum wage rate and enhancing open space and connectivity in communities. This approach has moved away from seeking individual solutions to complex social problems. In doing so, it has enabled the mapping of the relevant systems and the identification of a range of interventions while taking account of the views of affected communities and the concerns of policy-makers. The complex environmental approach used in this research provides a method to identify how to intervene in complex systems that may be relevant to other 'wicked' health promotion problems.

Preparing for Complexity and Wicked Problems through Transformational Learning Approaches

ERIC Educational Resources Information Center

Yukawa, Joyce

2015-01-01

As the information environment becomes increasingly complex and challenging, Library and Information Studies (LIS) education is called upon to nurture innovative leaders capable of managing complex situations and "wicked problems." While disciplinary expertise remains essential, higher levels of mental complexity and adaptive…

MOOCs, Wicked Problems, and the Spirit of the Liberal Arts

ERIC Educational Resources Information Center

McClure, Maureen W.

2014-01-01

Higher education institutions today are increasingly considered to be "means," serving as suppliers for employers, not "ends" that address "wicked" problems. This disregards their role in the generational succession of civil societies. Massive open online courses can strengthen higher education institutions by working…

Principles for Framing a Healthy Food System.

PubMed

Hamm, Michael W

2009-07-01

Wicked problems are most simply defined as ones that are impossible to solve. In other words, the range of complex interacting influences and effects; the influence of human values in all their range; and the constantly changing conditions in which the problem exists guarantee that what we strive to do is improve the situation rather than solve the wicked problem. This does not mean that we cannot move a long way toward resolving the problem but simply that there is no clean endpoint. This commentary outlines principles that could be used in moving us toward a healthy food system within the framework of it presenting as a wicked problem.

Metal vapor laser including hot electrodes and integral wick

DOEpatents

Ault, Earl R.; Alger, Terry W.

1995-01-01

A metal vapor laser, specifically one utilizing copper vapor, is disclosed herein. This laser utilizes a plasma tube assembly including a thermally insulated plasma tube containing a specific metal, e.g., copper, and a buffer gas therein. The laser also utilizes means including hot electrodes located at opposite ends of the plasma tube for electrically exciting the metal vapor and heating its interior to a sufficiently high temperature to cause the metal contained therein to vaporize and for subjecting the vapor to an electrical discharge excitation in order to lase. The laser also utilizes external wicking arrangements, that is, wicking arrangements located outside the plasma tube.

Metal vapor laser including hot electrodes and integral wick

DOEpatents

Ault, E.R.; Alger, T.W.

1995-03-07

A metal vapor laser, specifically one utilizing copper vapor, is disclosed herein. This laser utilizes a plasma tube assembly including a thermally insulated plasma tube containing a specific metal, e.g., copper, and a buffer gas therein. The laser also utilizes means including hot electrodes located at opposite ends of the plasma tube for electrically exciting the metal vapor and heating its interior to a sufficiently high temperature to cause the metal contained therein to vaporize and for subjecting the vapor to an electrical discharge excitation in order to lase. The laser also utilizes external wicking arrangements, that is, wicking arrangements located outside the plasma tube. 5 figs.

Multilead, Vaporization-Cooled Soldering Heat Sink

NASA Technical Reports Server (NTRS)

Rice, John

1995-01-01

Vaporization-cooled heat sink proposed for use during soldering of multiple electrical leads of packaged electronic devices to circuit boards. Heat sink includes compliant wicks held in grooves on edges of metal fixture. Wicks saturated with water. Prevents excessive increases in temperature at entrances of leads into package.

Evaporation effect on two-dimensional wicking in porous media.

PubMed

Benner, Eric M; Petsev, Dimiter N

2018-03-15

We analyze the effect of evaporation on expanding capillary flow for losses normal to the plane of a two-dimensional porous medium using the potential flow theory formulation of the Lucas-Washburn method. Evaporation induces a finite steady state liquid flux on capillary flows into fan-shaped domains which is significantly greater than the flux into media of constant cross section. We introduce the evaporation-capillary number, a new dimensionless quantity, which governs the frontal motion when multiplied by the scaled time. This governing product divides the wicking behavior into simple regimes of capillary dominated flow and evaporative steady state, as well as the intermediate regime of evaporation influenced capillary driven motion. We also show flow dimensionality and evaporation reduce the propagation rate of the wet front relative to the Lucas-Washburn law. Copyright © 2017 Elsevier Inc. All rights reserved.

New technique for installing screen wicking into Inconel 718 heat pipe

NASA Astrophysics Data System (ADS)

Giriunas, Julius A.; Watson, Gordon K.; Tower, Leonard K.

1993-01-01

The creep behavior of superalloys, including Inconel 718, in the presence of liquid sodium is not yet known. To study this problem, the NASA Lewis Research Center has initiated a program with the Energy Technology Engineering Center (ETEC) of Rockwell International Corporation to fill with sodium and creep-test three small cylindrical heat pipes of Inconel 718 for a period of 1000 hours each. This report documents the design and the construction methods that were used at NASA Lewis to fabricate these heat pipes. Of particular importance in the heat pipe construction was the installation of the screen wicking by using an expandable mandrel and differential thermal expansion. This installation technique differs from anything known to have been reported in the heat pipe literature and may be of interest to other workers in the heat pipe field.

Unlearning, Critical Action Learning and Wicked Problems

ERIC Educational Resources Information Center

Pedler, Mike; Hsu, Shih-wei

2014-01-01

This paper explores the idea of unlearning in Critical Action Learning (CAL) as applied to the wicked problems of organisations and societies. It draws on data and ideas developed during a research project conducted for "Skills for Care" by Pedler, Abbott, Brook and Burgoyne ("Skills for Care" 2014) and from experiences on…

A Relational Cultural Approach to the Broadway Musical "Wicked"

ERIC Educational Resources Information Center

Lane, Ileana

2009-01-01

Relational-Cultural Theory (Miller, 1976, 1986) is based on the tenet that people grow through and toward relationships with others, rather than through separation and individuation. In this article, the characters and song lyrics of the Broadway musical, "Wicked" (Schwartz, Holzman, Mantello, & Platt, 2003), are viewed through the lens of…

Australian NAPLAN Testing: In What Ways Is This a "Wicked" Problem?

ERIC Educational Resources Information Center

Johnston, Jenny

2017-01-01

This article employs Rittel and Webber's "wicked" problem as a heuristic device for enhancing understanding about National Assessment Program--Literacy and Numeracy (NAPLAN) testing in the Australian education context. Using a research project with seven independent schools in New South Wales, Australia, which analysed NAPLAN data from…

Designing for Quality: The Understanding Dementia MOOC

ERIC Educational Resources Information Center

King, Carolyn; Kelder, Jo-Anne; Doherty, Kathleen; Phillips, Rob; McInerney, Fran; Walls, Justin; Robinson, Andrew; Vickers, James

2014-01-01

The introduction of Massive Open Online Courses (MOOCs) as a vehicle for education delivery presents opportunities and challenges. In the context of the Wicking Dementia Research and Education Centre (Wicking Centre), the driver to develop a MOOC was the promise of addressing the international deficit in evidence-based dementia education, as well…

The Wicked Problem of the Intersection between Supervision and Evaluation

ERIC Educational Resources Information Center

Mette, Ian M.; Anderson, Jason; Nieuwenhuizen, Lisa; Range, Bret G.; Hvidston, David J.; Doty, Jon

2017-01-01

The purpose of this research was to explore how principals in eight high-functioning elementary schools in one American school district balanced teacher supervision and evaluation in their role as an instructional leader. Using the theoretical framework of "wicked problems," to unpack the circular used to problematize teacher supervision…

Wicked Waste: Helping Numeracy in the Primary Classroom

ERIC Educational Resources Information Center

Yoxon, Mark

2002-01-01

"Wicked Waste" is a powerful teaching resource and four tools in one: (1) It complements literacy and numeracy teaching for KS2/attainment levels D & E using 20 minute interactive teaching modules; (2) It manages time and, with its intelligent programming, complexity of questions; (3) It provides diagnostic information for the…

Deliberative Democracy and Adult Civic Education

ERIC Educational Resources Information Center

Carcasson, Martin; Sprain, Leah

2012-01-01

Adult education programs should turn to the deliberative democracy movement in order to help their communities better address the "wicked problems" they face. The authors contend that due to the "wicked" nature of problems in the diverse democracies, communities must develop and sustain their capacity for deliberative democracy and collaborative…

LEAD IN CANDLE EMISSIONS

EPA Science Inventory

The candle-using public should be made aware that the core of candle wicks may contain lead. Used as a stiffening agent to keep the wick out of the molten wax, lead can be emitted as particulate to the air and then deposited on indoor surfaces. To define the problem, 100 sets of ...

Computer program grade 2 for the design and analysis of heat-pipe wicks

NASA Technical Reports Server (NTRS)

Eninger, J. E.; Edwards, D. K.

1976-01-01

This user's manual describes the revised version of the computer program GRADE(1), which designs and analyzes heat pipes with graded porosity fibrous slab wicks. The revisions are: (1) automatic calculation of the minimum condenser-end stress that will not result in an excess-liquid puddle or a liquid slug in the vapor space; (2) numerical solution of the equations describing flow in the circumferential grooves to assess the burnout criterion; (3) calculation of the contribution of excess liquid in fillets and puddles to the heat-transport; (4) calculation of the effect of partial saturation on the wick performance; and (5) calculation of the effect of vapor flow, which includes viscousinertial interactions.

Absorbent product to absorb fluids. [for collection of human wastes

NASA Technical Reports Server (NTRS)

Dawn, F. S.; Correale, J. V. (Inventor)

1982-01-01

A multi-layer absorbent product for use in contact with the skin to absorb fluids is discussed. The product utilizes a water pervious facing layer for contacting the skin, overlayed by a first fibrous wicking layer, the wicking layer preferably being of the one-way variety in which fluid or liquid is moved away from the facing layer. The product further includes a first container section defined by inner and outer layer of a water pervious wicking material between which is disposed a first absorbent mass. A second container section defined by inner and outer layers between which is disposed a second absorbent mass and a liquid impermeable/gas permeable layer. Spacesuit applications are discussed.

Leadership Development in Governments of the United Arab Emirates: Re-Framing a Wicked Problem

ERIC Educational Resources Information Center

Mathias, Megan

2017-01-01

Developing the next generation of leaders in government is seen as a strategic challenge of national importance in the United Arab Emirates (UAE). This article examines the wicked nature of the UAE's leadership development challenge, identifying patterns of complexity, uncertainty, and divergence in the strategic intentions underlying current…

Wicked Learning: Reflecting on "Learning to Be Drier"

ERIC Educational Resources Information Center

Golding, Barry; Brown, Mike; Foley, Annette; Smith, Erica; Campbell, Coral; Schulz, Christine; Angwin, Jennifer; Grace, Lauri

2009-01-01

In this final, collaborative paper in the "Learning to be drier" edition, we reflect on and draw together some of the key threads from the diverse narratives in our four site papers from across the southern Murray-Darling Basin. Our paper title, "Wicked learning", draws on a recent body literature (Rittel & Webber 1973)…

Training Interdisciplinary "Wicked Problem" Solvers: Applying Lessons from HERO in Community-Based Research Experiences for Undergraduates

ERIC Educational Resources Information Center

Cantor, Alida; DeLauer, Verna; Martin, Deborah; Rogan, John

2015-01-01

Management of "wicked problems", messy real-world problems that defy resolution, requires thinkers who can transcend disciplinary boundaries, work collaboratively, and handle complexity and obstacles. This paper explores how educators can train undergraduates in these skills through applied community-based research, using the example of…

Women, Leadership, and Power Revisiting the Wicked Witch of the West

ERIC Educational Resources Information Center

Kruse, Sharon D.; Prettyman, Sandra Spickard

2008-01-01

By examining the cultural images present in the popular musical "Wicked", cultural norms and biases toward women in leadership and women's leadership practices are explored. The discussion rests on conceptions of male and female leadership "styles", how power is obtained and utilised within organisational settings and how resistance and…

Inequality--"Wicked Problems", Labour Market Outcomes and the Search for Silver Bullets

ERIC Educational Resources Information Center

Keep, Ewart; Mayhew, Ken

2014-01-01

In recent years concerns about inequality have been growing in prominence within UK policy debates. The many causes of inequality of earnings and income are complex in their interactions and their tendency to reinforce one another. This makes inequality an intractable or "wicked" policy problem, particularly within a contemporary context…

Tangled Narratives and Wicked Problems: A Complex Case of Positioning and Politics in a Diverse School Community

ERIC Educational Resources Information Center

Nguyen, Thu Suong Thi; Scribner, Samantha M. Paredes; Crow, Gary M.

2012-01-01

The case of Allen Elementary School presents tangled narratives and wicked problems describing the multidimensionality of school community work. Using multiple converging and diverging vignettes, the case points to the distinctiveness of individual experience in schools; the ways institutionalized organizational narratives become cultural…

Understanding Wicked Problems: A Key to Advancing Environmental Health Promotion

ERIC Educational Resources Information Center

Kreuter, Marshall W.; De Rosa, Christopher; Howze, Elizabeth H.; Baldwin, Grant T.

2004-01-01

Complex environmental health problems--like air and water pollution, hazardous waste sites, and lead poisoning--are in reality a constellation of linked problems embedded in the fabric of the communities in which they occur. These kinds of complex problems have been characterized by some as "wicked problems" wherein stakeholders may have…

Exploring Essential Conditions: A Commentary on Bull et al. (2008)

ERIC Educational Resources Information Center

Borthwick, Arlene; Hansen, Randall; Gray, Lucy; Ziemann, Irina

2008-01-01

The editorial by Bull et al. (2008) on connections between informal and formal learning made explicit one element of solving what Koehler and Mishra (2008) termed a "wicked problem." This wicked (complex, ill-structured) problem involves working with teachers for effective integration of technology in support of student learning. The…

Household light makes global heat: high black carbon emissions from kerosene wick lamps.

PubMed

Lam, Nicholas L; Chen, Yanju; Weyant, Cheryl; Venkataraman, Chandra; Sadavarte, Pankaj; Johnson, Michael A; Smith, Kirk R; Brem, Benjamin T; Arineitwe, Joseph; Ellis, Justin E; Bond, Tami C

2012-12-18

Kerosene-fueled wick lamps used in millions of developing-country households are a significant but overlooked source of black carbon (BC) emissions. We present new laboratory and field measurements showing that 7-9% of kerosene consumed by widely used simple wick lamps is converted to carbonaceous particulate matter that is nearly pure BC. These high emission factors increase previous BC emission estimates from kerosene by 20-fold, to 270 Gg/year (90% uncertainty bounds: 110, 590 Gg/year). Aerosol climate forcing on atmosphere and snow from this source is estimated at 22 mW/m² (8, 48 mW/m²), or 7% of BC forcing by all other energy-related sources. Kerosene lamps have affordable alternatives that pose few clear adoption barriers and would provide immediate benefit to user welfare. The net effect on climate is definitively positive forcing as coemitted organic carbon is low. No other major BC source has such readily available alternatives, definitive climate forcing effects, and cobenefits. Replacement of kerosene-fueled wick lamps deserves strong consideration for programs that target short-lived climate forcers.

Household Light Makes Global Heat: High Black Carbon Emissions From Kerosene Wick Lamps

PubMed Central

Lam, Nicholas L.; Chen, Yanju; Weyant, Cheryl; Venkataraman, Chandra; Sadavarte, Pankaj; Johnson, Michael A.; Smith, Kirk R.; Brem, Benjamin T.; Arineitwe, Joseph; Ellis, Justin E.; Bond, Tami C.

2012-01-01

Kerosene-fueled wick lamps used in millions of developing-country households are a significant but overlooked source of black carbon (BC) emissions. We present new laboratory and field measurements showing that 7–9% of kerosene consumed by widely used simple wick lamps is converted to carbonaceous particulate matter that is nearly pure BC. These high emission factors increase previous BC emission estimates from kerosene by 20-fold, to 270 Gg/year (90% uncertainty bounds: 110, 590 Gg/year). Aerosol climate forcing on atmosphere and snow from this source is estimated at 22 mW/m2 (8, 48 mW/m2), or 7% of BC forcing by all other energy-related sources. Kerosene lamps have affordable alternatives that pose few clear adoption barriers and would provide immediate benefit to user welfare. The net effect on climate is definitively positive forcing as co-emitted organic carbon is low. No other major BC source has such readily available alternatives, definitive climate forcing effects, and co-benefits. Replacement of kerosene-fueled wick lamps deserves strong consideration for programs that target short-lived climate forcers. PMID:23163320

Study Unveils New Method for Universal Extraction and PCR Amplification of Fungal DNA

DTIC Science & Technology

2014-06-12

Wickes noted that there are methods to extract fungi from soil , for example, and "once you get down to pure DNA, everything else is the same," he said...rare or hard to identify fungal infections. The new extraction and amplification method can be universally applied to fungi , according to the...best treatments. In addition, rare fungi , or species with phenotypic doppelgangers, can stump medical mycologists, so molecular methods are critical

Recent reflux receiver developments under the US DOE program

NASA Astrophysics Data System (ADS)

Andraka, C. E.; Diver, R. B.; Moreno, J. B.; Moss, T. A.; Adkins, D. R.

The United States Department of Energy (DOE) Solar Thermal Program, through Sandia National Laboratories (SNL), is cooperating with industry to commercialize dish-Stirling technology. Sandia and the DOE have actively encouraged the use of liquid metal reflux receivers in these systems to improve efficiency and lower the levelized cost of electricity. The reflux receiver uses two-phase heat transfer as a 'thermal transformer' to transfer heat from a parabolic tracking-concentrator to the heater heads of the Stirling engine. The two-phase system leads to a higher available input temperature, lower thermal stresses, longer life, and independent design of the absorber and engine sections. Two embodiments of reflux receivers have been investigated: Pool boilers and heat pipes. Several pool-boiler reflux receivers have been successfully demonstrated on sun at up to 64 kWt throughput at SNL. In addition, a bench-scale device was operated for 7500 hours to investigate materials compatibility and boiling stability. Significant progress has also been made on heat pipe receiver technology. Sintered metal wick heat pipes have been investigated extensively for application to 7.5 kWe and 25 kWe systems. One test article has amassed over 1800 hours of on-sun operation. Another was limit tested at Sandia to 65 kWt throughput. These devices incorporate a nickel-powder thick wick structure with condensate return directly to the wick surface. Circumferential tubular arteries are optionally employed to improve the operating margin. In addition, DOE has begun a development program for advanced wick structures capable of supporting the Utility Scale Joint Venture Program, requiring up to 100 kWt throughput. Promising technologies include a brazed stainless steel powdered metal wick and a stainless steel metal felt wick. Bench-scale testing has been encouraging, and on-sun testing is expected this fall. Prototype gas-fired hybrid solar receivers have also been demonstrated.

Recent reflux receiver developments under the US DOE program

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

Andraka, C.E.; Diver, R.B.; Moreno, J.B.

1994-10-01

The United States Department of Energy (DOE) Solar Thermal Program, through Sandia National Laboratories (SNL), is cooperating with industry to commercialize dish-Stirling technology. Sandia and the DOE have actively encouraged the use of liquid metal reflux receivers in these systems to improve efficiency and lower the levelized cost of electricity. The reflux receiver uses two-phase heat transfer as a {open_quotes}thermal transformer{close_quotes} to transfer heat from a parabolic tracking-concentrator to the heater heads of the Stirling engine. The two-phase system leads to a higher available input temperature, lower thermal stresses, longer life, and independent design of the absorber and engine sections.more » Two embodiments of reflux receivers have been investigated: Pool boilers and heat pipes. Several pool-boiler reflux receivers have been successfully demonstrated on sun at up to 64 kWt throughput at SNL. In addition, a bench-scale device was operated for 7500 hours to investigate materials compatibility and boiling stability. Significant progress has also been made on heat pipe receiver technology. Sintered metal wick heat pipes have been investigated extensively for application to 7.5 kWe and 25 kWe systems. One test article has a massed over 1800 hours of on-sun operation. Another was limit tested at Sandia to 65 kWt throughput. These devices incorporate a nickel-powder thick wick structure with condensate return directly to the wick surface. Circumferential tubular arteries are optionally employed to improve the operating margin. In addition, DOE has begun a development program for advanced wick structures capable of supporting the Utility Scale Joint Venture Program, requiring up to 100 kWt throughput. Promising technologies include a brazed stainless steel powdered metal wick and a stainless steel metal felt wick. Bench-scale testing has been encouraging, and on-sun testing is expected this fall. Prototype gas-fired hybrid solar receivers have also been.« less

High efficiency vapor-fed AMTEC system for direct conversion. Final report

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

Anderson, W.G.; Bland, J.J.

1997-05-23

The Alkali Metal Thermal to Electric Converter (AMTEC) is a high temperature, high efficiency system for converting thermal to electrical energy, with no moving parts. It is based on the unique properties of {beta}{double_prime}-alumina solid electrolyte (BASE), which is an excellent conductor of sodium ions, but an extremely poor conductor of electrons. When the inside of the BASE is maintained at a higher temperature and pressure, a concentration gradient is created across the BASE. Electrons and sodium atoms cannot pass through the BASE. However, the sodium atoms are ionized, and the sodium ions move through the BASE to the lowermore » potential (temperature) region. The electrons travel externally to the AMTEC cell, providing power. There are a number of potential advantages to a wick-pumped, vapor-fed AMTEC system when compared with other designs. A wick-pumped system uses capillary forces to passively return liquid to the evaporator, and to distribute the liquid in the evaporator. Since the fluid return is self-regulating, multiple BASE tubes can use a single remote condenser, potentially improving efficiency in advanced AMTEC designs. Since the system is vapor-fed, sodium vapor is supplied at a uniform temperature and flux to the BASE tube, even with non-uniform heat fluxes and temperatures at the evaporator. The primary objective of the Phase 2 program was to develop wick-pumped AMTEC cells. During the program, procedures to fabricate wicks with smaller pore sizes were developed, to allow operation of an AMTEC cell at 800 C. A revised design was made for a High-Temperature, Wick-Fed AMTEC cell. In addition to the smaller wick pore size, several other changes were made to increase the cell efficiency: (1) internal artery return of condensate; (2) high temperature electrical feedthrough; and (3) separate heat pipe for providing heat to the BASE.« less

Drop Impingement on Highly Wetting Micro/Nano Porous Surfaces

NASA Astrophysics Data System (ADS)

Buie, Cullen; Joung, Youngsoo

2011-11-01

Recently, we developed a novel fabrication method using a combination of electrophoretic deposition (EPD) and break down anodization (BDA) to achieve highly wetting nanoporous surfaces with microscale features. In this study we investigate droplet impingement behavior on these surfaces as a function of impact velocity, droplet size, and liquid properties. We observe impingement modes we denote as ``necking'' (droplet breaks before full penetration in the porous surface), ``spreading'' (continuous wicking into the porous surface), and ``jetting'' (jets of liquid emanate from the edges of the wicking liquid). To predict the droplet impingement modes, we've developed a non-dimensional parameter that is a function of droplet velocity, dynamic viscosity, effective pore radius and contact angle. The novel dimensionless parameter successfully predicts drop impingement modes across multiple fluids. Results of this study will inform the design of spray impingement cooling systems for electronics applications where the ``spreading'' mode is preferred.

Addressing the Wicked Problem of Quality in Higher Education: Theoretical Approaches and Implications

ERIC Educational Resources Information Center

Krause, Kerri-Lee

2012-01-01

This article explores the wicked problem of quality in higher education, arguing for a more robust theorising of the subject at national, institutional and local department level. The focus of the discussion rests on principles for theorising in more rigorous ways about the multidimensional issue of quality. Quality in higher education is proposed…

Solving Wicked Problems through Action Learning

ERIC Educational Resources Information Center

Crul, Liselore

2014-01-01

This account of practice outlines the Oxyme Action Learning Program which was conducted as part of the Management Challenge in my final year of the MSc in Coaching and Behavioral Change at Henley Business School. The central research questions were: (1) how action learning can help to solve wicked problems and (2) what the effect of an action…

Laboratory performance of wicking fabric H2Ri in silty gravel, sand and organic silt.

DOT National Transportation Integrated Search

2016-05-01

The use of wicking fabric, H2Ri, is growing in its use to remove water from roadway and airport embankments. Past research has shown H2Ri to be effective in sands : and fine grained materials in roadways up to 32 feet in width. However, there is a de...

Hydrophilic structures for condensation management in appliances

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

Kuehl, Steven John; Vonderhaar, John J.; Wu, Guolian

2016-02-02

An appliance that includes a cabinet having an exterior surface; a refrigeration compartment located within the cabinet; and a hydrophilic structure disposed on the exterior surface. The hydrophilic structure is configured to spread condensation. The appliance further includes a wicking structure located in proximity to the hydrophilic structure, and the wicking structure is configured to receive the condensation.

Small Schools in a Big World: Thinking about a Wicked Problem

ERIC Educational Resources Information Center

Corbett, Michael; Tinkham, Jennifer

2014-01-01

The position of small rural schools is precarious in much of rural Canada today. What is to be done about small schools in rural communities which are often experiencing population decline and aging, economic restructuring, and the loss of employment and services? We argue this issue is a classic "wicked" policy problem. Small schools…

Avoid, Control, Succumb, or Balance: Engineering Students' Approaches to a Wicked Sustainability Problem

ERIC Educational Resources Information Center

Lönngren, Johanna; Ingerman, Åke; Svanström, Magdalena

2017-01-01

Wicked sustainability problems (WSPs) are an important and particularly challenging type of problem. Science and engineering education can play an important role in preparing students to deal with such problems, but current educational practice may not adequately prepare students to do so. We address this gap by providing insights related to…

Two Steps Forward, One Step Backward: Must This Be the Future of Diversity?

ERIC Educational Resources Information Center

Butler, Johnnella E.

2013-01-01

Johnnella Butler writes here that the title of this article "Two Steps Forward, One Step Backward," expresses the "wicked problem" of diversity as a concrete goal in higher education. The concept of the "wicked problem," is a term coined in the late 1960s by social planners. Consulting Wikipedia, as so many of our…

Embracing Wicked Problems: The Turn to Design in Composition Studies

ERIC Educational Resources Information Center

Marback, Richard

2009-01-01

Recent appeal to the concept of design in composition studies benefits teaching writing in digital media. Yet the concept of design has not been developed enough to fully benefit composition instruction. This article develops an understanding of design as a matter of resolving wicked problems and makes a case for the advantages of this…

Nonorthogonal orbital based N-body reduced density matrices and their applications to valence bond theory. I. Hamiltonian matrix elements between internally contracted excited valence bond wave functions

NASA Astrophysics Data System (ADS)

Chen, Zhenhua; Chen, Xun; Wu, Wei

2013-04-01

In this series, the n-body reduced density matrix (n-RDM) approach for nonorthogonal orbitals and their applications to ab initio valence bond (VB) methods are presented. As the first paper of this series, Hamiltonian matrix elements between internally contracted VB wave functions are explicitly provided by means of nonorthogonal orbital based RDM approach. To this end, a more generalized Wick's theorem, called enhanced Wick's theorem, is presented both in arithmetical and in graphical forms, by which the deduction of expressions for the matrix elements between internally contracted VB wave functions is dramatically simplified, and the matrix elements are finally expressed in terms of tensor contractions of electronic integrals and n-RDMs of the reference VB self-consistent field wave function. A string-based algorithm is developed for the purpose of evaluating n-RDMs in an efficient way. Using the techniques presented in this paper, one is able to develop new methods and efficient algorithms for nonorthogonal orbital based many-electron theory much easier than by use of the first quantized formulism.

Dynamic Testing of In-Situ Composite Floors and Evaluation of Vibration Serviceability Using the Finite Element Method

DTIC Science & Technology

2006-08-21

Dynamic Testing of In-Situ Composite Floors and Evaluation of Vibration Serviceability Using the Finite Element Method By Anthony R. Barrett...Setareh Alfred L. Wicks 21 August 2006 Blacksburg, VA Keywords: vibration, floor, serviceability , walking, modal analysis, fundamental frequency...burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services

Collaborative Visual Analytics: A Health Analytics Approach to Injury Prevention

PubMed Central

Fisher, Brian; Smith, Jennifer; Pike, Ian

2017-01-01

Background: Accurate understanding of complex health data is critical in order to deal with wicked health problems and make timely decisions. Wicked problems refer to ill-structured and dynamic problems that combine multidimensional elements, which often preclude the conventional problem solving approach. This pilot study introduces visual analytics (VA) methods to multi-stakeholder decision-making sessions about child injury prevention; Methods: Inspired by the Delphi method, we introduced a novel methodology—group analytics (GA). GA was pilot-tested to evaluate the impact of collaborative visual analytics on facilitating problem solving and supporting decision-making. We conducted two GA sessions. Collected data included stakeholders’ observations, audio and video recordings, questionnaires, and follow up interviews. The GA sessions were analyzed using the Joint Activity Theory protocol analysis methods; Results: The GA methodology triggered the emergence of ‘common ground’ among stakeholders. This common ground evolved throughout the sessions to enhance stakeholders’ verbal and non-verbal communication, as well as coordination of joint activities and ultimately collaboration on problem solving and decision-making; Conclusions: Understanding complex health data is necessary for informed decisions. Equally important, in this case, is the use of the group analytics methodology to achieve ‘common ground’ among diverse stakeholders about health data and their implications. PMID:28895928

Collaborative Visual Analytics: A Health Analytics Approach to Injury Prevention.

PubMed

Al-Hajj, Samar; Fisher, Brian; Smith, Jennifer; Pike, Ian

2017-09-12

Background : Accurate understanding of complex health data is critical in order to deal with wicked health problems and make timely decisions. Wicked problems refer to ill-structured and dynamic problems that combine multidimensional elements, which often preclude the conventional problem solving approach. This pilot study introduces visual analytics (VA) methods to multi-stakeholder decision-making sessions about child injury prevention; Methods : Inspired by the Delphi method, we introduced a novel methodology-group analytics (GA). GA was pilot-tested to evaluate the impact of collaborative visual analytics on facilitating problem solving and supporting decision-making. We conducted two GA sessions. Collected data included stakeholders' observations, audio and video recordings, questionnaires, and follow up interviews. The GA sessions were analyzed using the Joint Activity Theory protocol analysis methods; Results : The GA methodology triggered the emergence of ' common g round ' among stakeholders. This common ground evolved throughout the sessions to enhance stakeholders' verbal and non-verbal communication, as well as coordination of joint activities and ultimately collaboration on problem solving and decision-making; Conclusion s : Understanding complex health data is necessary for informed decisions. Equally important, in this case, is the use of the group analytics methodology to achieve ' common ground' among diverse stakeholders about health data and their implications.

Molecular Identification of Human Fungal Pathogens

DTIC Science & Technology

2008-03-01

reported this period: Drees M, Wickes BL, Gupta M, Hadley S. Lecythophora mutabilis prosthetic valve endocarditis in a diabetic patient. Med Mycol. (2007...Wickes BL, Gupta M, Hadley S. 2007. Lecythophora mutabilis prosthetic valve endocarditis in a diabetic patient. Med Mycol. 45:463-467. 9...information: http://www.informaworld.com/smpp/title~content=t713694156 Lecythophora mutabilis prosthetic valve endocarditis in a diabetic patient Marci

Yes, and … : Continuing the Scholarly Conversation about Mental Health Stigma in Higher Education. Wicked Problems Forum: Mental Health Stigma

ERIC Educational Resources Information Center

Rudick, C. Kyle; Dannels, Deanna P.

2018-01-01

The issues surrounding mental health stigma in higher education are complex and multipronged; perfectly classifying the topic as a "wicked problem" Approximately 55% of students stated they have been diagnosed or treated by a professional for some form of mental illness while in college (American College Health Association, 2017a). The…

Sintered Lining for Heat-Pipe Evaporator

NASA Technical Reports Server (NTRS)

Ernst, D. M.; Eastman, G. Y.

1985-01-01

Hotspots eliminated by lining inner wall. Distribution of heat transfer liquid in heat-pipe evaporator improved by lining inner wall with layer of sintered metal. Sintered layer takes place of layer of screen wick formerly sintered or bonded to wall. Since sintered layer always full of liquid, no hotspot of type that previously arose where former screen wick did not fit properly against wall.

Poro-elasto-capillary wicking of cellulose sponges

PubMed Central

Kim, Do-Nyun

2018-01-01

We mundanely observe cellulose (kitchen) sponges swell while absorbing water. Fluid flows in deformable porous media, such as soils and hydrogels, are classically described on the basis of the theories of Darcy and poroelasticity, where the expansion of media arises due to increased pore pressure. However, the situation is qualitatively different in cellulosic porous materials like sponges because the pore expansion is driven by wetting of the surrounding cellulose walls rather than by increase of the internal pore pressure. We address a seemingly so simple but hitherto unanswered question of how fast water wicks into the swelling sponge. Our experiments uncover a power law of the wicking height versus time distinct from that for nonswelling materials. The observation using environmental scanning electron microscopy reveals the coalescence of microscale wall pores with wetting, which allows us to build a mathematical model for pore size evolution and the consequent wicking dynamics. Our study sheds light on the physics of water absorption in hygroscopically responsive multiscale porous materials, which have far more implications than everyday activities (for example, cleaning, writing, and painting) carried out with cellulosic materials (paper and sponge), including absorbent hygiene products, biomedical cell cultures, building safety, and cooking. PMID:29682606

Validation test of 125 Ah advanced design IPV nickel-hydrogen flight cells

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1993-01-01

An update of validation test results confirming the advanced design nickel-hydrogen cell is presented. An advanced 125 Ah individual pressure vessel Ni-H cell was designed. The primary function of the advanced cell is to store and deliver energy for long-term LEO spacecraft missions. The new features of this design are: (1) use of 26 percent rather than 31 percent KOH electrolyte; (2) use of a patented catalyzed wall wick; (3) use of serrated-edge separators to facilitate gaseous O and H flow within the cell, while maintaining physical contact with the wall wick for electrolyte management; and (4) use of a floating rather than a fixed stack to accommodate Ni electrode expansion due to charge/discharge cycling. The significant improvements resulting from these innovations are extended cycle life; enhanced thermal, electrolyte, and oxygen management; and accommodation of Ni electrode expansion. Six 125 Ah flight cells based on this design were fabricated; the catalyzed wall wick cells have been cycled for over 19,000 cycles with no cell failures in the continuing test. Two of the noncatalyzed wall wick cells failed (cycles 9588 and 13,900).

Comparison of clinical outcomes of three different packing materials in the treatment of severe acute otitis externa.

PubMed

Demir, D; Yılmaz, M S; Güven, M; Kara, A; Elden, H; Erkorkmaz, Ü

2018-06-13

To analyse the clinical outcomes of biodegradable synthetic polyurethane foam versus ribbon gauze and ear wick in the treatment of severe acute otitis externa. Ninety-two adults with severe acute otitis externa were randomly assigned to groups receiving ear wick (n = 28), ribbon gauze (n = 34) or biodegradable synthetic polyurethane foam (n = 30). Clinical efficacy, in terms of otalgia, oedema, erythema and tenderness of the external auditory canal, was assessed before packing was applied and at follow up on the 3rd and 7th days of presentation. All packing materials were associated with improved otalgia and oedema on the 3rd day; however, there were significant differences between biodegradable synthetic polyurethane foam and the other packing materials, and there was no significant reduction in tenderness in the biodegradable synthetic polyurethane foam group on the 3rd day. In the ribbon gauze and ear wick groups, improvements in all clinical efficacy scores were statistically significant for all pairwise comparisons. The three packing materials were all quite effective in treating severe acute otitis externa, but ear wick and ribbon gauze were superior to biodegradable synthetic polyurethane foam for relieving signs and symptoms, especially on the 3rd day.

An Alternative View of the Thirties: The Industrial Photographs of Lewis Wickes Hine and Margaret Bourke-White.

ERIC Educational Resources Information Center

Smith, C. Zoe

The photographs of Margaret Bourke-White and Lewis Wickes Hine are graphic accounts of the urban industrial United States during the Depression of the 1930s. Hine was a sociologist who initially used his camera to promote social reform and is best remembered for his photographs of immigrants at Ellis Island, New York, and of children laboring in…

If All You Have Is a Hammer, Everything Begins to Look Like a Nail--How Wicked Is the Problem of Measuring Productivity in Higher Education?

ERIC Educational Resources Information Center

Drengenberg, Nicholas; Bain, Alan

2017-01-01

This paper addresses the wicked problem of measuring the productivity of learning and teaching in higher education. We show how fundamental validity issues and difficulties identified in educational productivity research point to the need for a qualitatively different framework when considering the entire question. We describe the work that needs…

A Communications Strategy for Disaster Relief

DTIC Science & Technology

2015-03-01

there were “ pockets ” of cellular coverage in the immediate aftermath of the earthquake, thus enabling some critical life-saving SMS traffic.105 4...Accessed 30 October 2014. http://www.oxfam.org/en/haiti-earthquake-our-response. Oxford Learners Dictionary . “Definition of Wicked.” Oxford University...Press. Assessed 02 September 2014. http://www.oxfordlearnersdictionaries.com/ definition/ english /wicked_1. Pacific Disaster Center. “Disaster Response

Validation test of 125 Ah advanced design IPV nickel-hydrogen flight cells

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1993-01-01

An update of validation test results confirming the advanced design nickel-hydrogen cell is presented. An advanced 125 Ah individual pressure vessel (IPV) nickel-hydrogen cell was designed. The primary function of the advanced cell is to store and deliver energy for long-term, Low-Earth-Orbit (LEO) spacecraft missions. The new features of this design, which are not incorporated in state-of-the-art design cells, are: (1) use of 26 percent rather than 31 percent potassium hydroxide (KOH) electrolyte; (2) use of a patented catalyzed wall wick; (3) use of serrated-edge separators to facilitate gaseous oxygen and hydrogen flow within the cell, while still maintaining physical contact with the wall wick for electrolyte management; and (4) use of a floating rather than a fixed stack (state-of-the-art) to accommodate nickel electrode expansion due to charge/discharge cycling. The significant improvements resulting from these innovations are extended cycle life; enhanced thermal, electrolyte, and oxygen management; and accommodation of nickel electrode expansion. Six 125 Ah flight cells based on this design were fabricated by Eagle-Picher. Three of the cells contain all of the advanced features (test cells) and three are the same as the test cells except they do not have catalyst on the wall wick (control cells). All six cells are in the process of being evaluated in a LEO cycle life test at the Naval Weapons Support Center, Crane, IN, under a NASA Lewis Research Center contract. The catalyzed wall wick cells have been cycled for over 19000 cycles with no cell failures in the continuing test. Two of the noncatalyzed wall wick cells failed (cycles 9588 and 13,900).

Gas-Liquid Processing in Microchannels

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

TeGrotenhuis, Ward E.; Stenkamp, Victoria S.; Twitchell, Alvin

Processing gases and liquids together in microchannels having at least one dimension <1 mm has unique advantages for rapid heat and mass transfer. One approach for managing the two phases is to use porous structures as wicks within microchannels to segregate the liquid phase from the gas phase. Gas-liquid processing is accomplished by providing a gas flow path and inducing flow of the liquid phase through or along the wick under an induced pressure gradient. A variety of unit operations are enabled, including phase separation, partial condensation, absorption, desorption, and distillation. Results are reported of an investigation of microchannel phasemore » separation in a transparent, single-channel device. Next, heat exchange is integrated with the microchannel wick approach to create a partial condenser that also separates the condensate. Finally, the scale-up to a multi-channel phase separator is described.« less

Investigation of an inverted meniscus heat pipe wick concept

NASA Technical Reports Server (NTRS)

Saaski, E. W.

1975-01-01

A wicking concept is described for efficient evaporation of heat pipe working fluids under diverse conditions. It embodies the high heat transfer coefficient of the circumferential groove while retaining the circumferential fluid transport capability of a thick porous wick or screen. Experimental tests are described which substantiate the efficacy of the evaporation technique for a circumferentially-grooved heat pipe charged alternately with ammonia and R-ll (CCl3F). With ammonia, heat transfer coefficients in the range of 2 to 2.7 W/sq cm K were measured at heat flux densities up to 20 W/sq cm while, with R-ll, a heat transfer coefficient of l.0 W/sq cm K was measured with flux densities up to 5 W/sq cm. Heat transfer coefficients and flux densities were unusually high compared to literature data for other nonboiling evaporative surfaces.

Measurement of Coolant in a Flat Heat Pipe Using Neutron Radiography

NASA Astrophysics Data System (ADS)

Mizuta, Kei; Saito, Yasushi; Goshima, Takashi; Tsutsui, Toshio

A newly developed flat heat pipe FGHPTM (Morex Kiire Co.) was experimentally investigated by using neutron radiography. The test sample of the FGHP heat spreader was 65 × 65 × 2 mm3 composed of several etched copper plates and pure water was used as the coolant. Neutron radiography was performed at the E-2 port of the Kyoto University Research Reactor (KUR). The coolant distributions in the wick area of the FGHP and its heat transfer characteristics were measured at heating conditions. Experimental results show that the coolant distributions depend slightly on its installation posture and that the liquid thickness in the wick region remains constant with increasing heat input to the FGHP. In addition, it is found that the wick surface does not dry out even in the vertical posture at present experimental conditions.

Alternate high capacity heat pipe

NASA Technical Reports Server (NTRS)

Voss, F. E.

1986-01-01

The performance predictions for a fifty foot heat pipe (4 foot evaporator - 46 foot condensor) are discussed. These performance predictions are supported by experimental data for a four foot heat pipe. Both heat pipes have evaporators with axial groove wick structures and condensers with powder metal external artery wick structures. The predicted performance of a rectangular axial groove/external artery heat pipe operating in space is given. Heat transport versus groove width is plotted for 100, 200 and 300 grooves in the evaporator. The curves show that maximum power is achieved for groove widths from 0.040 to 0.053 as the number of grooves varies from 300 to 100. The corresponding range of maximum power is 3150 to 2400 watts. The relationships between groove width and heat pipe evaporate diameter for 100, 200 and 300 grooves in the evaporator are given. A four foot heat pipe having a three foot condenser and one foot evaporator was built and tested. The evaporator wick structure used axial grooves with rectangular cross sections, and the condenser wick structure used powder metal with an external artery configuration. Fabrication drawings are enclosed. The predicted and measured performance for this heat pipe is shown. The agreement between predicted and measured performance is good and therefore substantiates the predicted performance for a fifty foot heat pipe.

Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen battery cells

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1990-01-01

An advanced 125 Ah individual pressure vessel (IPV) nickel-hydrogen cell was designed. The primary function of the advanced cell, is to store and deliver energy for long term, low earth-orbit (LEO) spacecraft missions. The new features of this design are: (1) use of 26 percent rather than 31 percent potassium hydroxide (KOH) electrolyte, (2) use of a patented catalyzed wall wick, (3) use of serrated edge separators to facilitate gaseous oxygen and hydrogen flow within the cell, while still maintaining physical contact with the wall wick for electrolyte management, and (4) use of a floating rather than a fixed stack (state-of-the-art) to accommodate nickel electrode expansion. Six 125 Ah flight cells based on this design were fabricated by Eagle-Picher. Three of the cells contain all of the advanced features (test cells) and three are the same as the test cells except they don't have catalyst on the wall wick (control cells). All six cells are in the process of being evaluated in a LEO cycle life test. The cells have accumulated about 4700 LEO cycles (60 percent DOD 10 C). There have been no cell failures, the catalyzed wall wick cells however, are performing better.

Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen battery cells

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1990-01-01

An advanced 125 Ah individual pressure vessel (IPV) nickel-hydrogen cell was designed. The primary function of the advanced cell is to store and deliver energy for long-term, low earth-orbit (LEO) spacecraft missions. The new features of this design are: (1) use of 26 percent rather than 31 percent potassium hydroxide (KOH) electrolyte, (2) use of a patented catalyzed wall wick, (3) use of serrated-edge separators to facilitate gaseous oxygen and hydrogen flow within the cell, while still maintaining physical contact with the wall wick for electrolyte management, and (4) use of a floating rather than a fixed stack (state-of-the-art) to accommodate nickel electrode expansion. Six 125-Ah flight cells based on this design were fabricated by Eagle-Picher. Three of the cells contain all of the advanced features (test cells) and three are the same as the test cells except they don't have catalyst on the wall wick (control cells). All six cells are in the process of being evaluated in a LEO cycle life test. The cells have accumulated about 4700 LEO cycles (60 percent DOD 10 C). There have been no cell failures; the catalyzed wall wick cells, however, are performing better.

Transport of europium colloids in vadose zone lysimeters at the semiarid Hanford site.

PubMed

Liu, Ziru; Flury, Markus; Zhang, Z Fred; Harsh, James B; Gee, Glendon W; Strickland, Chris E; Clayton, Ray E

2013-03-05

The objective of this study was to quantify transport of Eu colloids in the vadose zone at the semiarid Hanford site. Eu-hydroxy-carbonate colloids, Eu(OH)(CO3), were applied to the surface of field lysimeters, and migration of the colloids through the sediments was monitored using wick samplers. The lysimeters were exposed to natural precipitation (145-231 mm/year) or artificial irrigation (124-348 mm/year). Wick outflow was analyzed for Eu concentrations, supplemented by electron microscopy and energy-dispersive X-ray analysis. Small amounts of Eu colloids (<1%) were detected in the deepest wick sampler (2.14 m depth) 2.5 months after application and cumulative precipitation of only 20 mm. We observed rapid transport of Eu colloids under both natural precipitation and artificial irrigation; that is, the leading edge of the Eu colloids moved at a velocity of 3 cm/day within the first 2 months after application. Episodic infiltration (e.g., Chinook snowmelt events) caused peaks of Eu in the wick outflow. While a fraction of Eu moved consistent with long-term recharge estimates at the site, the main mass of Eu remained in the top 30 cm of the sediments. This study illustrates that, under field conditions, near-surface colloid mobilization and transport occurred in Hanford sediments.

Advanced Stirling receiver development program, phase 1

NASA Technical Reports Server (NTRS)

Lurio, Charles A.

1990-01-01

Critical technology experiments were designed and developed to evaluate the Stirling cavity heat pipe receiver for a space solar power system. Theoretical criteria were applied to the design of a module for containing energy storage phase change material while avoiding thermal ratcheting. Zero-g drop tower tests, without phase change, were conducted to affirm that the bubble location required to avoid ratcheting could be achieved without the use of container materials that are wetted by the phase change material. A full scale module was fabricated, but not tested. A fabrication method was successfully developed for the sodium evaporator dome, with a sintered screen wick, to be used as the focal point for the receiver. Crushing of the screen during hydroforming was substantially reduced over the results of other researchers by using wax impregnation. Superheating of the sodium in the wick under average flux conditions is expected to be under 10K. A 2000K furnace which will simulate solar flux conditions for testing the evaporator dome was successfully built and tested.

Intersectoral action for health equity as it relates to climate change in Canada: contributions from critical systems heuristics.

PubMed

Buse, Chris

2013-12-01

Intersectoral action (ISA) has been at the forefront of public health policy discussions since the 1970s. ISA incorporates a broader perspective of public health issues and coordinates efforts to address the social, political, economic and environmental contexts from which health determinants operate and are created. Despite being forwarded as a useful way to address and treat complex or 'wicked' problems, such policy issues are still often addressed within, rather than across, disciplinary silos and ISA has been documented to fail more often than it succeeds. This paper contributes to an understanding of ISA by outlining and applying critical systems heuristics (CSH) theory and methods. CSH theory and methods are described and discussed before applying them to the example of addressing climate change and health equity through public health practice. CSH thinking provides useful tools to engage stakeholders, question relations of power that may exist between collaborating partners, and move beyond power inequalities that guide ISA initiatives. CSH is a compelling framing that can improve an understanding of the collaborative relationships that are a prerequisite for engaging in ISA to address complex or 'wicked' policy problems such as climate change. © 2013 John Wiley & Sons Ltd.

Properties of natural and synthetic hydroxyapatite and their surface free energy determined by the thin-layer wicking method

NASA Astrophysics Data System (ADS)

Szcześ, Aleksandra; Yan, Yingdi; Chibowski, Emil; Hołysz, Lucyna; Banach, Marcin

2018-03-01

Surface free energy is one of the parameters accompanying interfacial phenomena, occurring also in the biological systems. In this study the thin layer wicking method was used to determine surface free energy and its components for synthetic hydroxyapatite (HA) and natural one obtained from pig bones. The Raman, FTIR and X-Ray photoelectron spectroscopy, X-ray diffraction techniques and thermal analysis showed that both samples consist of carbonated hydroxyapatite without any organic components. Surface free energy and its apolar and polar components were found to be similar for both investigated samples and equalled γSTOT = 52.4 mJ/m2, γSLW = 40.2 mJ/m2 and γSAB = 12.3 mJ/m2 for the synthetic HA and γSTOT = 54.6 mJ/m2, γSLW = 40.3 mJ/m2 and γSAB = 14.3 mJ/m2 for the natural one. Both HA samples had different electron acceptor (γs+) and electron donor (γs-) parameters. The higher value of the electron acceptor was found for the natural HA whereas the electron donor one was higher for the synthetic HA

Development of optimized, graded-permeability axial groove heat pipes

NASA Technical Reports Server (NTRS)

Kapolnek, Michael R.; Holmes, H. Rolland

1988-01-01

Heat pipe performance can usually be improved by uniformly varying or grading wick permeability from end to end. A unique and cost effective method for grading the permeability of an axial groove heat pipe is described - selective chemical etching of the pipe casing. This method was developed and demonstrated on a proof-of-concept test article. The process improved the test article's performance by 50 percent. Further improvement is possible through the use of optimally etched grooves.

Co-electrospun poly(ɛ-caprolactone)/cellulose nanofibers-fabrication and characterization.

PubMed

Ahmed, Farooq; Saleemi, Sidra; Khatri, Zeeshan; Abro, Muhammad Ishaque; Kim, Ick-Soo

2015-01-22

We report fabrication of poly (ɛ-caprolactone) (PCL)/cellulose (CEL) nanofiber blends via co-electrospinning for the possible use as biofilters and biosensor strips. Five different ratios of PCL to CEL were fabricated to investigate the wicking behavior. The cellulose acetate (CA) was taken as precursor to make cellulose nanofibers. Double nozzles were employed for jetting constituent polymers toward collector drum independently and resultant nanofibers webs were deacetylated in aqueous alkaline solution to convert CA into CEL as confirmed by FTIR spectra. FTIR further revealed that there is no effect of deacetylation on PCL nanofiber. The morphology of each blend webs under SEM showed uniform and bead-free nanofibers. Wicking behavior for five different ratios of PCL/CEL suggested that increasing CEL ratio in the blend enhanced the wicking front height; however, X-ray diffraction patterns of PCL/CEL showed a slight decrease in crystallinity. Copyright © 2014 Elsevier Ltd. All rights reserved.

A relation between deformed superspace and Lee-Wick higher-derivative theories

NASA Astrophysics Data System (ADS)

Dias, M.; Ferrari, A. F.; Palechor, C. A.; Senise, C. R., Jr.

2015-07-01

We propose a non-anticommutative superspace that relates to the Lee-Wick type of higher-derivative theories, which are known for their interesting properties and have led to proposals of phenomenologically viable higher-derivative extensions of the Standard Model. The deformation of superspace we consider does not preserve supersymmetry or associativity in general, but, we show that a non-anticommutative version of the Wess-Zumino model can be properly defined. In fact, the definition of chiral and antichiral superfields turns out to be simpler in our case than in the well known N=1/2 supersymmetric case. We show that when the theory is truncated at the first nontrivial order in the deformation parameter, supersymmetry is restored, and we end up with a well-known Lee-Wick type of higher-derivative extension of the Wess-Zumino model. Thus, we show how non-anticommutativity could provide an alternative mechanism for generating these higher-derivative theories.

Catalyzing Transdisciplinarity: A Systems Ethnography of Cancer-Obesity Comorbidity and Risk Coincidence.

PubMed

Graham, S Scott; Harley, Amy; Kessler, Molly M; Roberts, Laura; DeVasto, Dannielle; Card, Daniel J; Neuner, Joan M; Kim, Sang-Yeon

2017-05-01

Effectively addressing wicked health problems, that is, those arising from complex multifactorial biological and socio-economic causes, requires transdisciplinary action. However, a significant body of research points toward substantial difficulties in cultivating transdisciplinary collaboration. Accordingly, this article presents the results of a study that adapts Systems Ethnography and Qualitative Modeling (SEQM) in response to wicked health problems. SEQM protocols were designed to catalyze transdisciplinary responses to national defense concerns. We adapted these protocols to address cancer-obesity comorbidity and risk coincidence. In so doing, we conducted participant-observations and interviews with a diverse range of health care providers, community health educators, and health advocacy professionals who target either cancer or obesity. We then convened a transdisciplinary conference designed to catalyze a coordinated response. The findings offer productive insights into effective ways of catalyzing transdisciplinarity in addressing wicked health problems action and demonstrate the promise of SEQM for continued use in health care contexts.

Device for equalizing molten electrolyte content in a fuel cell stack

DOEpatents

Smith, J.L.

1985-12-23

A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

Device for equalizing molten electrolyte content in a fuel cell stack

DOEpatents

Smith, James L.

1987-01-01

A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

Gravitationally Driven Wicking for Enhanced Condensation Heat Transfer.

PubMed

Preston, Daniel J; Wilke, Kyle L; Lu, Zhengmao; Cruz, Samuel S; Zhao, Yajing; Becerra, Laura L; Wang, Evelyn N

2018-04-17

Vapor condensation is routinely used as an effective means of transferring heat or separating fluids. Filmwise condensation is prevalent in typical industrial-scale systems, where the condensed fluid forms a thin liquid film due to the high surface energy associated with many industrial materials. Conversely, dropwise condensation, where the condensate forms discrete liquid droplets which grow, coalesce, and shed, results in an improvement in heat transfer performance of an order of magnitude compared to filmwise condensation. However, current state-of-the-art dropwise technology relies on functional hydrophobic coatings, for example, long chain fatty acids or polymers, which are often not robust and therefore undesirable in industrial conditions. In addition, low surface tension fluid condensates, such as hydrocarbons, pose a unique challenge because common hydrophobic condenser coatings used to shed water (with a surface tension of 73 mN/m) often do not repel fluids with lower surface tensions (<25 mN/m). We demonstrate a method to enhance condensation heat transfer using gravitationally driven flow through a porous metal wick, which takes advantage of the condensate's affinity to wet the surface and also eliminates the need for condensate-phobic coatings. The condensate-filled wick has a lower thermal resistance than the fluid film observed during filmwise condensation, resulting in an improved heat transfer coefficient of up to an order of magnitude and comparable to that observed during dropwise condensation. The improved heat transfer realized by this design presents the opportunity for significant energy savings in natural gas processing, thermal management, heating and cooling, and power generation.

Method for joining carbon-carbon composites to metals

DOEpatents

Lauf, Robert J.; McMillan, April D.; Moorhead, Arthur J.

1997-01-01

A method for joining carbon-carbon composites to metals by brazing. Conventional brazing of recently developed carbon-bonded carbon fiber (CBCF) material to a metal substrate is limited by the tendency of the braze alloy to "wick" into the CBCF composite rather than to form a strong bond. The surface of the CBCF composite that is to be bonded is first sealed with a fairly dense carbonaceous layer achieved by any of several methods. The sealed surface is then brazed to the metal substrate by vacuum brazing with a Ti-Cu-Be alloy.

Method for joining carbon-carbon composites to metals

DOEpatents

Lauf, R.J.; McMillan, A.D.; Moorhead, A.J.

1997-07-15

A method for joining carbon-carbon composites to metals by brazing. Conventional brazing of recently developed carbon-bonded carbon fiber (CBCF) material to a metal substrate is limited by the tendency of the braze alloy to ``wick`` into the CBCF composite rather than to form a strong bond. The surface of the CBCF composite that is to be bonded is first sealed with a fairly dense carbonaceous layer achieved by any of several methods. The sealed surface is then brazed to the metal substrate by vacuum brazing with a Ti-Cu-Be alloy. 1 fig.

Percolated microstructures for multi-modal transport enhancement in porous active materials

DOEpatents

McKay, Ian Salmon; Yang, Sungwoo; Wang, Evelyn N.; Kim, Hyunho

2018-03-13

A method of forming a composite material for use in multi-modal transport includes providing three-dimensional graphene having hollow channels, enabling a polymer to wick into the hollow channels of the three-dimensional graphene, curing the polymer to form a cured three-dimensional graphene, adding an active material to the cured three-dimensional graphene to form a composite material, and removing the polymer from within the hollow channels. A composite material formed according to the method is also provided.

Comparative Investigation and Operational Performance Characteristics of a Wick Assisted and Axially Square Grooved Heat Pipe

NASA Astrophysics Data System (ADS)

Naik, Rudra, Dr.; Rama Narasihma, K., Dr.; Anikivi, Atmanand

2018-04-01

The present work reported here involves the experimental investigation and performance evaluation of wick assisted and axially square grooved heat pipes of outer diameter 8mm, inner diameter 4mm with a length of 150mm.The objective of this work is to design, fabricate and test the heat pipes with and without an axial square groove for horizontal and gravity assisted conditions. The performance of the heat pipes was measured in terms of thermal resistance and heat transfer coefficients. In the present investigation four different working fluids were chosen namely acetone, ethanol, methanol and distilled water. Experiments were conducted by varying the heat load from 2 W to 10 W for different fill charge ratios in the range of 25% to 75% of evaporator volume for wick assisted heat pipe and 8 W to 18 W for axially square grooved heat pipe. From the experiments, it was found that there is a steady increase in temperature with the increase in heat input. The overall heat transfer coefficient was found to increase with the increase heat load for wick assisted heat pipe. In case of axially square grooved heat pipe, an attempt was made to experiment the heat pipe in different orientations. The maximum heat transfer coefficient of 7000 W/m2 °C is found for Acetone at 180° orientation.

Wicking Performance of Profiled Fibre Part B: Assessment of Fabric

NASA Astrophysics Data System (ADS)

Datta Roy, M.; Chattopadhyay, R.; Sinha, S. K.

2018-06-01

For moisture regulation, careful selection of fibre, fibre packing in yarns and fabric structure are necessary. Introducing selective porosity in yarn can significantly influence moisture transport properties in fabrics made out of profiled fibre yarn. The arrangement of fibres in the yarn and that of yarn in fabric provide wide variability in the size and shape of the passage of liquid to flow. A change in the cross sectional diameter of the capillary leads to a change in interfacial speed for liquid. The mechanism of liquid transmission in fabric is expected to be different from that in yarn in isolated state. Generally, openness in fabric offers least resistance to flow. However, at each cross over points of threads the pressure exerted by one set of yarn on another can influence the capillary geometry affecting flow of liquid. The present work reports on the investigation made to study the wicking performance of five sets of fabrics made out of five homogeneous profiled fibre yarns as weft and respective double yarns as warp. It was observed that the wicking time and height in the weft direction were different than that in the corresponding yarns. Interestingly, wicking height attained in warp direction and individual yarn in isolation does not show any significant difference. It was observed that the points of interlacements between warps and wefts were constantly splitting the fluid flow both in horizontal and vertical directions.

Pump, and earth-testable spacecraft capillary heat transport loop using augmentation pump and check valves

NASA Technical Reports Server (NTRS)

Baker, David (Inventor)

1998-01-01

A spacecraft includes heat-generating payload equipment, and a heat transport system with a cold plate thermally coupled to the equipment and a capillary-wick evaporator, for evaporating coolant liquid to cool the equipment. The coolant vapor is coupled to a condenser and in a loop back to the evaporator. A heated coolant reservoir is coupled to the loop for pressure control. If the wick is not wetted, heat transfer will not begin or continue. A pair of check valves are coupled in the loop, and the heater is cycled for augmentation pumping of coolant to and from the reservoir. This augmentation pumping, in conjunction with the check valves, wets the wick. The wick liquid storage capacity allows the augmentation pump to provide continuous pulsed liquid flow to assure continuous vapor transport and a continuously operating heat transport system. The check valves are of the ball type to assure maximum reliability. However, any type of check valve can be used, including designs which are preloaded in the closed position. The check valve may use any ball or poppet material which resists corrosion. For optimum performance during testing on Earth, the ball or poppet would have neutral buoyancy or be configured in a closed position when the heat transport system is not operating. The ball may be porous to allow passage of coolant vapor.

Investigating the Wicked Problems of (Un)sustainability Through Three Case Studies Around the Water-Energy-Food Nexus

NASA Astrophysics Data System (ADS)

Metzger, E. P.; Curren, R. R.

2016-12-01

Effective engagement with the problems of sustainability begins with an understanding of the nature of the challenges. The entanglement of interacting human and Earth systems produces solution-resistant dilemmas that are often portrayed as wicked problems. As introduced by urban planners Rittel and Webber (1973), wicked problems are "dynamically complex, ill-structured, public problems" arising from complexity in both biophysical and socio-economic systems. The wicked problem construct is still in wide use across diverse contexts, disciplines, and sectors. Discourse about wicked problems as related to sustainability is often connected to discussion of complexity or complex systems. In preparation for life and work in an uncertain, dynamic and hyperconnected world, students need opportunities to investigate real problems that cross social, political and disciplinary divides. They need to grapple with diverse perspectives and values, and collaborate with others to devise potential solutions. Such problems are typically multi-casual and so intertangled with other problems that they cannot be resolved using the expertise and analytical tools of any single discipline, individual, or organization. We have developed a trio of illustrative case studies that focus on energy, water and food, because these resources are foundational, interacting, and causally connected in a variety of ways with climate destabilization. The three interrelated case studies progress in scale from the local and regional, to the national and international and include: 1) the 2010 Gulf of Mexico oil spill with examination of the multiple immediate and root causes of the disaster, its ecological, social, and economic impacts, and the increasing risk and declining energy return on investment associated with the relentless quest for fossil fuels; 2) development of Australia's innovative National Water Management System; and 3) changing patterns of food production and the intertwined challenge of managing transnational water resources in the rapidly growing Mekong Region of Southeast Asia. .

Emission factors of gaseous pollutants from recent kerosene space heaters and fuels available in France in 2010.

PubMed

Carteret, M; Pauwels, J-F; Hanoune, B

2012-08-01

Laboratory measurements of the gaseous emission factors (EF) from two recent kerosene space heaters (wick and injector) with five different fuels have been conducted in an 8-m(3) environmental chamber. The two heaters tested were found to emit mainly CO(2), CO, NO, NO(2), and some volatile organic compounds (VOCs). NO(2) is continuously emitted during use, with an EF of 100-450 μg per g of consumed fuel. CO is normally emitted mainly during the first minutes of use (up to 3 mg/g). Formaldehyde and benzene EFs were quantified at 15 and 16 μg/g, respectively, for the wick heater. Some other VOCs, such as 1,3-butadiene, were detected with lower EFs. We demonstrated the unsuitability of a 'biofuel' containing fatty acid methyl esters for use with the wick heater, and that the accumulation of soot on the same heater, whatever the fuel, leads to a dramatic increase in the CO EF, up to 16 mg/g, which could be responsible for chronic and acute CO intoxications. Our results show that in spite of new technologies and emission standards for unvented kerosene space heaters, as well as for the fuels, the use of these heaters in indoor environments still leads to NO(x) levels in excess of current health recommendations. Whereas injection heaters generate more nitrogen oxides than wick heaters, prolonged use of the latter leads to a soot buildup, concomitant with high CO emissions, which could be responsible for acute and chronic intoxications. The use of a biofuel in a wick heater is also of concern. Maintenance of the heaters and adequate ventilation of the room during use of kerosene space heaters are therefore of prime importance to reduce personal exposure. © 2011 John Wiley & Sons A/S.

Lysimeter study to investigate the effect of rainfall patterns on leaching of isoproturon.

PubMed

Beulke, Sabine; Brown, Colin D; Fryer, Christopher J; Walker, Allan

2002-01-01

The influence of five rainfall treatments on water and solute leaching through two contrasting soil types was investigated. Undisturbed lysimeters (diameter 0.25 m, length 0.5 m) from a sandy loam (Wick series) and a moderately structured clay loam (Hodnet series) received autumn applications of the radio-labelled pesticide isoproturon and bromide tracer. Target rainfall plus irrigation from the end of November 1997 to May 1998 ranged from drier to wetter than average (235 to 414 mm); monthly rainfall was varied according to a pre-selected pattern or kept constant (triplicate lysimeters per regime). Leachate was collected at intervals and concentrations of the solutes were determined. Total flow (0.27-0.94 pore volumes) and losses of bromide (3-80% of applied) increased with increasing inputs of water and were larger from the Wick sandy loam than from the Hodnet clay loam soil. Matrix flow appeared to be the main mechanism for transport of isoproturon through the Wick soil whereas there was a greater influence of preferential flow for the Hodnet lysimeters. The total leached load of isoproturon from the Wick lysimeters was 0.02-0.26% of that applied. There was no clear variation in transport processes between the rainfall treatments investigated for this soil and there was an approximately linear relationship (r2 = 0.81) between leached load and total flow. Losses of isoproturon from the Hodnet soil were 0.03-0.39% of applied and there was evidence of enhanced preferential flow in the driest and wettest treatments. Leaching of isoproturon was best described by an exponential relationship between load and total flow (r2 = 0.62). A 45% increase in flow between the two wettest treatments gave a 100% increase in leaching of isoproturon from the Wick soil. For the Hodnet lysimeters, a 35% increase in flow between the same treatments increased herbicide loss by 325%.

Definition and use of Solution-focused Sustainability Assessment: A novel approach to generate, explore and decide on sustainable solutions for wicked problems.

PubMed

Zijp, Michiel C; Posthuma, Leo; Wintersen, Arjen; Devilee, Jeroen; Swartjes, Frank A

2016-05-01

This paper introduces Solution-focused Sustainability Assessment (SfSA), provides practical guidance formatted as a versatile process framework, and illustrates its utility for solving a wicked environmental management problem. Society faces complex and increasingly wicked environmental problems for which sustainable solutions are sought. Wicked problems are multi-faceted, and deriving of a management solution requires an approach that is participative, iterative, innovative, and transparent in its definition of sustainability and translation to sustainability metrics. We suggest to add the use of a solution-focused approach. The SfSA framework is collated from elements from risk assessment, risk governance, adaptive management and sustainability assessment frameworks, expanded with the 'solution-focused' paradigm as recently proposed in the context of risk assessment. The main innovation of this approach is the broad exploration of solutions upfront in assessment projects. The case study concerns the sustainable management of slightly contaminated sediments continuously formed in ditches in rural, agricultural areas. This problem is wicked, as disposal of contaminated sediment on adjacent land is potentially hazardous to humans, ecosystems and agricultural products. Non-removal would however reduce drainage capacity followed by increased risks of flooding, while contaminated sediment removal followed by offsite treatment implies high budget costs and soil subsidence. Application of the steps in the SfSA-framework served in solving this problem. Important elements were early exploration of a wide 'solution-space', stakeholder involvement from the onset of the assessment, clear agreements on the risk and sustainability metrics of the problem and on the interpretation and decision procedures, and adaptive management. Application of the key elements of the SfSA approach eventually resulted in adoption of a novel sediment management policy. The stakeholder participation and the intensive communication throughout the project resulted in broad support for both the scientific approaches and results, as well as for policy implementation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Thermal Performance of Surface Wick Structures.

NASA Astrophysics Data System (ADS)

Chen, Yongkang; Tavan, Noel; Baker, John; Melvin, Lawrence; Weislogel, Mark

2010-03-01

Microscale surface wick structures that exploit capillary driven flow in interior corners have been designed. In this study we examine the interplay between capillary flow and evaporative heat transfer that effectively reduces the surface temperature. The tests are performed by raising the surface temperature to various levels before the flow is introduced to the surfaces. Certainly heat transfer weakens the capillary driven flow. It is observed, however, the surface temperature can be reduced significantly. The effects of geometric parameters and interconnectivity are to be characterized to identify optimal configurations.

Scalar perturbation in symmetric Lee-Wick bouncing universe

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

Cho, Inyong; Kwon, O-Kab, E-mail: iycho@seoultech.ac.kr, E-mail: okab@skku.edu

2011-11-01

We investigate the scalar perturbation in the Lee-Wick bouncing universe driven by an ordinary scalar field plus a ghost field. We consider only a symmetric evolution of the universe and the scalar fields about the bouncing point. The gauge invariant Sasaki-Mukhanov variable is numerically solved in the spatially flat gauge. We find a new form of the initial perturbation growing during the contracting phase. After the bouncing, this growing mode stabilizes to a constant mode which is responsible for the late-time power spectrum.

Command and Control in a Complex World

DTIC Science & Technology

2012-05-22

definition of command and control does not adequately address changes introduced through technology trends, our understanding of the global operating...processes. The current joint definition of command and control does not adequately address changes introduced through technology trends, our...the problem is actually solved.  There are no  definitive ,  objective solutions to wicked problems.  For a complete  definition  of wicked problems, see

Multileg Heat-Pipe Evaporator

NASA Technical Reports Server (NTRS)

Alario, J. P.; Haslett, R. A.

1986-01-01

Parallel pipes provide high heat flow from small heat exchanger. Six parallel heat pipes extract heat from overlying heat exchanger, forming evaporator. Vapor channel in pipe contains wick that extends into screen tube in liquid channel. Rods in each channel hold wick and screen tube in place. Evaporator compact rather than extended and more compatible with existing heat-exchanger geometries. Prototype six-pipe evaporator only 0.3 m wide and 0.71 m long. With ammonia as working fluid, transports heat to finned condenser at rate of 1,200 W.

Navigating systems ideas for health practice: Towards a common learning device.

PubMed

Reynolds, Martin; Sarriot, Eric; Swanson, Robert Chad; Rusoja, Evan

2018-06-01

Systems thinking and reference to complexity science have gained currency in health sector practice and research. The extent to which such ideas might represent a mere passing fad or might more usefully be mobilized to tackle wicked problems in health systems is a concern underpinning this paper. Developing the usefulness of the systems idea requires appreciating how systems ideas are used essentially as constructs conceptually bounded by practitioners. Systems are used for purposes of understanding and engaging the reality of health issues, with the intent of transforming the reality into one that is more manageable, equitable, and sustainable. We examine some manifestations of the systems idea in health practice and the traditions of systems practice that variously make use of them. This provides a platform for proposing a systems thinking in (health) practice heuristic: a learning device supporting how different tools and methods can address "wicked problems" in health praxis. The device is built on the use of "conversation" as a metaphor to help practitioners use systems ideas in tandem with existing disciplinary and professional skills and methods. We consider how the application of the heuristic requires, and helps to develop, human characteristics of humility, empathy, and recognition of fallibility. © 2018 John Wiley & Sons, Ltd.

Porous Foam Based Wick Structures for Loop Heat Pipes

NASA Technical Reports Server (NTRS)

Silk, Eric A.

2012-01-01

As part of an effort to identify cost efficient fabrication techniques for Loop Heat Pipe (LHP) construction, NASA Goddard Space Flight Center's Cryogenics and Fluids Branch collaborated with the U.S. Naval Academy s Aerospace Engineering Department in Spring 2012 to investigate the viability of carbon foam as a wick material within LHPs. The carbon foam was manufactured by ERG Aerospace and machined to geometric specifications at the U.S. Naval Academy s Materials, Mechanics and Structures Machine Shop. NASA GSFC s Fractal Loop Heat Pipe (developed under SBIR contract #NAS5-02112) was used as the validation LHP platform. In a horizontal orientation, the FLHP system demonstrated a heat flux of 75 Watts per square centimeter with deionized water as the working fluid. Also, no failed start-ups occurred during the 6 week performance testing period. The success of this study validated that foam can be used as a wick structure. Furthermore, given the COTS status of foam materials this study is one more step towards development of a low cost LHP.

Neutrino masses in the Lee-Wick standard model

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

Espinosa, Jose Ramon; Grinstein, Benjamin; O'Connell, Donal

2008-04-15

Recently, an extension of the standard model based on ideas of Lee and Wick has been discussed. This theory is free of quadratic divergences and hence has a Higgs mass that is stable against radiative corrections. Here, we address the question of whether or not it is possible to couple very heavy particles, with masses much greater than the weak scale, to the Lee-Wick standard model degrees of freedom and still preserve the stability of the weak scale. We show that in the LW-standard model the familiar seesaw mechanism for generating neutrino masses preserves the solution to the hierarchy puzzlemore » provided by the higher derivative terms. The very heavy right-handed neutrinos do not destabilize the Higgs mass. We give an example of new heavy degrees of freedom that would destabilize the hierarchy, and discuss a general mechanism for coupling other heavy degrees of freedom to the Higgs doublet while preserving the hierarchy.« 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

A sampling method to determine insecticide residues on surfaces and its application to food-handling establishments.

PubMed

Leidy, R B; Wright, C G; Dupree, H E

1987-07-01

Known amounts of acephate, chlorpyrifos, and diazinon were applied to Formica, unfinished plywood, stainless steel, and vinyl tile. Cotton-ball and dental wick materials were dipped in 2-propanol and "swiped" over the treated surface area two time. More acephate was found on the second swipe compared to the first from vinyl tile, similar amounts on both swipes from plywood, and less on the second swipe from formica and stainless steel. The ratio of chlorpyrifos on Swipe 1 compared to Swipe 2 found with cotton-ball on both formica and stainless steel surfaces was equivalent (6:1), but a considerable difference was seen when two dental wick swipes were used. Residues of diazinon removed from formica and stainless steel were equivalent, regardless of the swiping material used. Residues of chlorpyrifos were detected by taking swipes of surfaces in two restaurants and a supermarket up to 6 mo after a prescribed application by a commercial pest control firm. The data show that measurable amounts of chloropyrifos can be detected on surfaces not treated with the insecticide for at least 6 mo.

Effects of Surface Wettability on the Porosity and Wickability of Frost

NASA Astrophysics Data System (ADS)

Witt, Katherine; Ahmadi, Farzad; Boreyko, Jonathan

2017-11-01

The wicking of liquids through porous media has been studied for many materials, but never for frost, despite its implications for arctic oil spills and oil-infused surfaces. Here, we characterize silicone oils wicking up frost sheets. A layer of frost was grown on aluminum plates of varying surface wettability: superhydrophilic, hydrophilic, hydrophobic, and superhydrophobic. Once the desired frost thickness was grown, a humidity chamber was used to maintain the frost at the dew point and the bottom of the plate was dipped in a reservoir of fluorescent silicone oil. For all surfaces, the wicking rate of the oil increased with increasing wettability. For the wetting surfaces, this is manifested in the length vs. time data following the classical Washburn equation, exhibiting a power slope of about 1/2 and resulting in a larger effective pore radius with increasing wettability. However, we observed that on the non-wetting surfaces, the discrete distribution of the frosted dew droplets resulted in a new scaling law with a slope much less than 1/2, especially for the superhydrophobic surface which promoted jumping-droplet condensation. This research shows that the wicking of oil up a layer of frost can give insight into the morphology of frost. Conversely, if the underlying wettability of a frost sheet can be controlled, the spread of oil can be widely tuned. This work was supported by a Virginia Space Grant Consortium Undergraduate Research Scholarship (PMPTX7EP).

A Novel Silicon Micromachined Integrated MCM Thermal Management System

NASA Technical Reports Server (NTRS)

Kazmierczak, M. J.; Henderson, H. T.; Gerner, F. M.

1999-01-01

This research concerned the development of a novel porous wick, fabricated totally out of silicon, using state-of-the-art MEMS technology. A comprehensive summary of results, as well as additional fabrication details, can be found in the following three documents located in the attached Appendices: A) Selected pages and excerpts from Year 2 progress report of the principal NASA Grant awarded from NASA Lewis Research Center, Grant Number NAG3-1706 entitled "A Novel Silicon Nficromachined Integrated MCM Thermal Management System" submitted to NASA LRC on 4/4/98. B) Selected viewgraphs from the joint NASA, TEES, and UC meeting held at the University of Cincinnati on April 24, 1998. C) Pre-print of the paper entitled "Coherent Macro Porous Silicon as a Wick Structure in an Integrated Nficrofluidic Two-Phase Cooling System" to be presented September 20-25, 1998 at the SPIE conference held in Santa Clara, Ca. To summarize,. nearly all of the proposed work was successfully accomplished (albeit a 3-month time extension was required), proving that micromachining can indeed be used to fabricate porous silicon wick structures with precise hole sizes and patterning control, thus permitting a substantial improvement in future wick designs. In addition, the appropriate range of thermal conductivities of the porous samples were theoretically predicted (see Appendix A). Although not part of the scope of work, the permeability of the test samples were measured (see results sections of Appendices B and C).

Kerosene lighting contributes to household air pollution in rural Uganda.

PubMed

Muyanja, D; Allen, J G; Vallarino, J; Valeri, L; Kakuhikire, B; Bangsberg, D R; Christiani, D C; Tsai, A C; Lai, P S

2017-09-01

The literature on the contribution of kerosene lighting to indoor air particulate concentrations is sparse. In rural Uganda, kitchens are almost universally located outside the main home, and kerosene is often used for lighting. In this study, we obtained longitudinal measures of particulate matter 2.5 microns or smaller in size (PM 2.5 ) from living rooms and kitchens of 88 households in rural Uganda. Linear mixed-effects models with a random intercept for household were used to test the hypotheses that primary reported lighting source and kitchen location (indoor vs outdoor) are associated with PM 2.5 levels. During initial testing, households reported using the following sources of lighting: open-wick kerosene (19.3%), hurricane kerosene (45.5%), battery-powered (33.0%), and solar (1.1%) lamps. During follow-up testing, these proportions changed to 29.5%, 35.2%, 18.2%, and 9.1%, respectively. Average ambient, living room, and kitchen PM 2.5 levels were 20.2, 35.2, and 270.0 μg/m 3 . Living rooms using open-wick kerosene lamps had the highest PM 2.5 levels (55.3 μg/m 3 ) compared to those using solar lighting (19.4 μg/m 3 ; open wick vs solar, P=.01); 27.6% of homes using open-wick kerosene lamps met World Health Organization indoor air quality standards compared to 75.0% in homes using solar lighting. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Measurement of heating coil temperature for e-cigarettes with a “top-coil” clearomizer

PubMed Central

Wang, Ping; Ito, Kazuhide; Fowles, Jeff; Shusterman, Dennis; Jaques, Peter A.; Kumagai, Kazukiyo

2018-01-01

Objectives To determine the effect of applied power settings, coil wetness conditions, and e-liquid compositions on the coil heating temperature for e-cigarettes with a “top-coil” clearomizer, and to make associations of coil conditions with emission of toxic carbonyl compounds by combining results herein with the literature. Methods The coil temperature of a second generation e-cigarette was measured at various applied power levels, coil conditions, and e-liquid compositions, including (1) measurements by thermocouple at three e-liquid fill levels (dry, wet-through-wick, and full-wet), three coil resistances (low, standard, and high), and four voltage settings (3–6 V) for multiple coils using propylene glycol (PG) as a test liquid; (2) measurements by thermocouple at additional degrees of coil wetness for a high resistance coil using PG; and (3) measurements by both thermocouple and infrared (IR) camera for high resistance coils using PG alone and a 1:1 (wt/wt) mixture of PG and glycerol (PG/GL). Results For single point thermocouple measurements with PG, coil temperatures ranged from 322 ‒ 1008°C, 145 ‒ 334°C, and 110 ‒ 185°C under dry, wet-through-wick, and full-wet conditions, respectively, for the total of 13 replaceable coil heads. For conditions measured with both a thermocouple and an IR camera, all thermocouple measurements were between the minimum and maximum across-coil IR camera measurements and equal to 74% ‒ 115% of the across-coil mean, depending on test conditions. The IR camera showed details of the non-uniform temperature distribution across heating coils. The large temperature variations under wet-through-wick conditions may explain the large variations in formaldehyde formation rate reported in the literature for such “top-coil” clearomizers. Conclusions This study established a simple and straight-forward protocol to systematically measure e-cigarette coil heating temperature under dry, wet-through-wick, and full-wet conditions. In addition to applied power, the composition of e-liquid, and the devices’ ability to efficiently deliver e-liquid to the heating coil are important product design factors effecting coil operating temperature. Precautionary temperature checks on e-cigarettes under manufacturer-recommended normal use conditions may help to reduce the health risks from exposure to toxic carbonyl emissions associated with coil overheating. PMID:29672571

A Reactive-Heat-Pipe for Combined Heat Generation and Transport

DTIC Science & Technology

1977-12-01

The Lennard - Jones potential parameters a and F-1 can be found in Ar Ar Table 2.3 of Reference [26]. They are a Ar =3.542 A ~Ar -=93.3 K The above...Specific Heat Ratio Wire Spacing of Screen S Volume Fraction of Solid Phase in Wick or Lennard Jones Force Constant e’ Wick Void Fraction 1Viscusity p...Density a Surface Tension G Condensation Coefficient c e Evaporation Coefficient*e U Lennard - Jones Force Constant Subscripts A Position A in Figure 13 Ar

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).

Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen flight cells. An update

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1991-01-01

Validation testing of the NASA Lewis 125 Ah advanced design individual pressure vessel (IPV) nickel-hydrogen flight cells was conducted. Work consisted of characterization, storage, and cycle life testing. There was no capacity degradation after 52 days of storage with the cells in the discharged state, an open circuit, 0 C, and a hydrogen pressure of 14.5 psia. The catalyzed wall wick cells were cycled for over 11,000 cycles with no cell failures in the continuing test. One of the noncatalyzed wall wick cells failed.

Potable water recovery for spacecraft application by electrolytic pretreatment/air evaporation

NASA Technical Reports Server (NTRS)

Wells, G. W.

1975-01-01

A process for the recovery of potable water from urine using electrolytic pretreatment followed by distillation in a closed-cycle air evaporator has been developed and tested. Both the electrolytic pretreatment unit and the air evaporation unit are six-person, flight-concept prototype, automated units. Significantly extended wick lifetimes have been achieved in the air evaporation unit using electrolytically pretreated, as opposed to chemically pretreated, urine feed. Parametric test data are presented on product water quality, wick life, process power, maintenance requirements, and expendable requirements.

Modeling Candle Flame Behavior In Variable Gravity

NASA Technical Reports Server (NTRS)

Alsairafi, A.; Tien, J. S.; Lee, S. T.; Dietrich, D. L.; Ross, H. D.

2003-01-01

The burning of a candle, as typical non-propagating diffusion flame, has been used by a number of researchers to study the effects of electric fields on flame, spontaneous flame oscillation and flickering phenomena, and flame extinction. In normal gravity, the heat released from combustion creates buoyant convection that draws oxygen into the flame. The strength of the buoyant flow depends on the gravitational level and it is expected that the flame shape, size and candle burning rate will vary with gravity. Experimentally, there exist studies of candle burning in enhanced gravity (i.e. higher than normal earth gravity, g(sub e)), and in microgravity in drop towers and space-based facilities. There are, however, no reported experimental data on candle burning in partial gravity (g < g(sub e)). In a previous numerical model of the candle flame, buoyant forces were neglected. The treatment of momentum equation was simplified using a potential flow approximation. Although the predicted flame characteristics agreed well with the experimental results, the model cannot be extended to cases with buoyant flows. In addition, because of the use of potential flow, no-slip boundary condition is not satisfied on the wick surface. So there is some uncertainty on the accuracy of the predicted flow field. In the present modeling effort, the full Navier-Stokes momentum equations with body force term is included. This enables us to study the effect of gravity on candle flames (with zero gravity as the limiting case). In addition, we consider radiation effects in more detail by solving the radiation transfer equation. In the previous study, flame radiation is treated as a simple loss term in the energy equation. Emphasis of the present model is on the gas-phase processes. Therefore, the detailed heat and mass transfer phenomena inside the porous wick are not treated. Instead, it is assumed that a thin layer of liquid fuel coated the entire wick surface during the burning process. This is the limiting case that the mass transfer process in the wick is much faster than the evaporation process at the wick surface.

Passive wick fluxmeters: Design considerations and field applications

NASA Astrophysics Data System (ADS)

Gee, G. W.; Newman, B. D.; Green, S. R.; Meissner, R.; Rupp, H.; Zhang, Z. F.; Keller, J. M.; Waugh, W. J.; van der Velde, M.; Salazar, J.

2009-04-01

Optimization of water use in agriculture and quantification of percolation from landfills and watersheds require reliable estimates of vadose zone water fluxes. Current technology is limited primarily to lysimeters, which directly measure water flux but are expensive and may in some way disrupt flow, causing errors in the measured drainage. We report on design considerations and field tests of an alternative approach, passive wick fluxmeters, which use a control tube to minimize convergent or divergent flow. Design calculations with a quasi-three-dimensional model illustrate how convergence and divergence can be minimized for a range of soil and climatic conditions under steady state and transient fluxes using control tubes of varying heights. There exists a critical recharge rate for a given wick length, where the fluxmeter collection efficiency is 100% regardless of the height of the control tube. Otherwise, convergent or divergent flow will occur, especially when the control tube height is small. While divergence is eliminated in coarse soils using control tubes, it is reduced but not eliminated in finer soils, particularly for fluxes <100 mm/a. Passive wick fluxmeters were tested in soils ranging from nonvegetated semiarid settings in the United States to grasslands in Germany and rain-fed crops in New Zealand and the South Pacific. Where side-by-side comparisons of drainage were made between passive wick fluxmeters and conventional lysimeters in the United States and Germany, agreement was very good. In semiarid settings, drainage was found to depend upon precipitation distribution, surface soil, topographic relief, and the type and amount of vegetation. In Washington State, United States, soil texture dominated all factors controlling drainage from test landfill covers. As expected, drainage was greatest (>60% annual precipitation) from gravel surfaces and least (no drainage) from silt loam soils. In Oregon and New Mexico, United States, and in New Zealand, drainage showed substantial spatial variability. The New Mexico tests were located in semiarid canyon bottom terraces, with flash flood prone locations having extremely high drainage/precipitation ratios. In the wettest environments, drainage was found to be closely linked to the rate and duration of precipitation events.

Wetting in color: colorimetric differentiation of organic liquids with high selectivity.

PubMed

Burgess, Ian B; Koay, Natalie; Raymond, Kevin P; Kolle, Mathias; Lončar, Marko; Aizenberg, Joanna

2012-02-28

Colorimetric litmus tests such as pH paper have enjoyed wide commercial success due to their inexpensive production and exceptional ease of use. Expansion of colorimetry to new sensing paradigms is challenging because macroscopic color changes are seldom coupled to arbitrary differences in the physical/chemical properties of a system. Here we present in detail the design of a "Wetting In Color Kit" (WICK), an inexpensive and highly selective colorimetric indicator for organic liquids that exploits chemically encoded inverse-opal photonic crystals to project minute differences in liquids' wettability to macroscopically distinct, easy-to-visualize structural color patterns. We show experimentally and corroborate with theoretical modeling using percolation theory that the highly symmetric structure of our large-area, defect-free SiO(2) inverse-opal films leads to sharply defined threshold wettability for liquid infiltration, occurring at intrinsic contact angles near 20° with an estimated resolution smaller than 5°. The regular structure also produces a bright iridescent color, which disappears when infiltrated with liquid, naturally coupling the optical and fluidic responses. To deterministically design a WICK that differentiates a broad range of liquids, we introduced a nondestructive quality control procedure to regulate the pore structure and developed two new surface modification protocols, both requiring only silanization and selective oxidation. The resulting tunable, built-in horizontal and vertical chemistry gradients let us tailor the wettability threshold to specific liquids across a continuous range. With patterned oxidation as a final step, we control the shape of the liquid-specific patterns displayed, making WICK easier to read. Using these techniques, we demonstrate the applicability of WICKs in several exemplary systems that colorimetrically distinguish (i) ethanol-water mixtures varying by only 2.5% in concentration; (ii) methanol, ethanol, and isopropyl alcohol; (iii) hexane, heptane, octane, nonane, and decane; and (iv) samples of gasoline (regular unleaded) and diesel. As wetting is a generic fluidic phenomenon, we envision that WICK could be suitable for applications in authentication or identification of unknown liquids across a broad range of industries.

Geospatial and machine learning techniques for wicked social science problems: analysis of crash severity on a regional highway corridor

NASA Astrophysics Data System (ADS)

Effati, Meysam; Thill, Jean-Claude; Shabani, Shahin

2015-04-01

The contention of this paper is that many social science research problems are too "wicked" to be suitably studied using conventional statistical and regression-based methods of data analysis. This paper argues that an integrated geospatial approach based on methods of machine learning is well suited to this purpose. Recognizing the intrinsic wickedness of traffic safety issues, such approach is used to unravel the complexity of traffic crash severity on highway corridors as an example of such problems. The support vector machine (SVM) and coactive neuro-fuzzy inference system (CANFIS) algorithms are tested as inferential engines to predict crash severity and uncover spatial and non-spatial factors that systematically relate to crash severity, while a sensitivity analysis is conducted to determine the relative influence of crash severity factors. Different specifications of the two methods are implemented, trained, and evaluated against crash events recorded over a 4-year period on a regional highway corridor in Northern Iran. Overall, the SVM model outperforms CANFIS by a notable margin. The combined use of spatial analysis and artificial intelligence is effective at identifying leading factors of crash severity, while explicitly accounting for spatial dependence and spatial heterogeneity effects. Thanks to the demonstrated effectiveness of a sensitivity analysis, this approach produces comprehensive results that are consistent with existing traffic safety theories and supports the prioritization of effective safety measures that are geographically targeted and behaviorally sound on regional highway corridors.

Understanding enabling capacities for managing the 'wicked problem' of nonpoint source water pollution in catchments: a conceptual framework.

PubMed

Patterson, James J; Smith, Carl; Bellamy, Jennifer

2013-10-15

Nonpoint source (NPS) water pollution in catchments is a 'wicked' problem that threatens water quality, water security, ecosystem health and biodiversity, and thus the provision of ecosystem services that support human livelihoods and wellbeing from local to global scales. However, it is a difficult problem to manage because water catchments are linked human and natural systems that are complex, dynamic, multi-actor, and multi-scalar in nature. This in turn raises questions about understanding and influencing change across multiple levels of planning, decision-making and action. A key challenge in practice is enabling implementation of local management action, which can be influenced by a range of factors across multiple levels. This paper reviews and synthesises important 'enabling' capacities that can influence implementation of local management action, and develops a conceptual framework for understanding and analysing these in practice. Important enabling capacities identified include: history and contingency; institutional arrangements; collaboration; engagement; vision and strategy; knowledge building and brokerage; resourcing; entrepreneurship and leadership; and reflection and adaptation. Furthermore, local action is embedded within multi-scalar contexts and therefore, is highly contextual. The findings highlight the need for: (1) a systemic and integrative perspective for understanding and influencing change for managing the wicked problem of NPS water pollution; and (2) 'enabling' social and institutional arenas that support emergent and adaptive management structures, processes and innovations for addressing NPS water pollution in practice. These findings also have wider relevance to other 'wicked' natural resource management issues facing similar implementation challenges. Copyright © 2013 Elsevier Ltd. All rights reserved.

How books are wet by water

NASA Astrophysics Data System (ADS)

Kim, Jungchul; Kim, Ho-Young

2013-11-01

It is well known that a sheet of paper, a hydrophilic porous medium, imbibes water via capillary action. The wicking on two-dimensional sheets has no preferred direction, in general. However, when water is spilled on a book, a number of pieces of paper fastened together on one side, we notice that corners are wet first compared to the rest of the area. This is because the wicking along the sharp corner experiences weaker resistance than that into pores within paper. We study a simple model of this wicking dynamics in the context of the surface-tension-driven vertical rise of a liquid along a corner of folded paper. We find that the liquid height at the corner follows a power law different from that at the corner formed by impermeable walls (A. Ponomarenko, D. Quere, and C. Clanet, J. Fluid Mech. 666, 146-154, 2011). The difference is caused by the fact that the Laplace pressure that drives the vertical rise is independent of the liquid height on permeable walls (paper) while it increases with height at the corner of impermeable walls. The experiments are shown to be consistent with our theory.

Active and Healthy Ageing as a Wicked Problem: The Contribution of a Multidisciplinary Research University.

PubMed

Riva, Giuseppe; Graffigna, Guendalina; Baitieri, Maddalena; Amato, Alessandra; Bonanomi, Maria Grazia; Valentini, Paolo; Castelli, Guido

2014-01-01

The quest for an active and healthy ageing can be considered a "wicked problem." It is a social and cultural problem, which is difficult to solve because of incomplete, changing, and contradictory requirements. These problems are tough to manage because of their social complexity. They are a group of linked problems embedded in the structure of the communities in which they occur. First, they require the knowledge of the social and cultural context in which they occur. They can be solved only by understanding of what people do and why they do it. Second, they require a multidisciplinary approach. Wicked problems can have different solutions, so it is critical to capture the full range of possibilities and interpretations. Thus, we suggest that Università Cattolica del Sacro Cuore (UCSC) is well suited for accepting and managing this challenge because of its applied research orientation, multidisciplinary approach, and integrated vision. After presenting the research activity of UCSC, we describe a possible "systems thinking" strategy to consider the complexity and interdependence of active ageing and healthy living.

Nonsingular cosmology with a scale-invariant spectrum of cosmological perturbations from Lee-Wick theory

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

Cai Yifu; Qiu Taotao; Brandenberger, Robert

2009-07-15

We study the cosmology of a Lee-Wick type scalar field theory. First, we consider homogeneous and isotropic background solutions and find that they are nonsingular, leading to cosmological bounces. Next, we analyze the spectrum of cosmological perturbations which result from this model. Unless either the potential of the Lee-Wick theory or the initial conditions are finely tuned, it is impossible to obtain background solutions which have a sufficiently long period of inflation after the bounce. More interestingly, however, we find that in the generic noninflationary bouncing cosmology, perturbations created from quantum vacuum fluctuations in the contracting phase have the correctmore » form to lead to a scale-invariant spectrum of metric inhomogeneities in the expanding phase. Since the background is nonsingular, the evolution of the fluctuations is defined unambiguously through the bounce. We also analyze the evolution of fluctuations which emerge from thermal initial conditions in the contracting phase. The spectrum of gravitational waves stemming from quantum vacuum fluctuations in the contracting phase is also scale-invariant, and the tensor to scalar ratio is not suppressed.« less

Unique Identification of Lee-Wick Gauge Bosons at Linear Colliders

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

Rizzo, Thomas G.

2007-12-14

Grinstein, O'Connell and Wise have recently presented an extension of the Standard Model (SM), based on the ideas of Lee and Wick (LW), which demonstrates an interesting way to remove the quadratically divergent contributions to the Higgs mass induced by radiative corrections. This model predicts the existence of negative-norm copies of the usual SM fields at the TeV scale with ghost-like propagators and negative decay widths, but with otherwise SM-like couplings. In earlier work, it was demonstrated that the LW states in the gauge boson sector of these models, though easy to observe, cannot be uniquely identified as such atmore » the LHC. In this paper, we address the issue of whether or not this problem can be resolved at an e{sup +}e{sup -} collider with a suitable center of mass energy range. We find that measurements of the cross section and the left-right polarization asymmetry associated with Bhabha scattering can lead to a unique identification of the neutral electroweak gauge bosons of the Lee-Wick type.« less

Small farms, cash crops, agrarian ideals, and international development.

PubMed

Effland, Anne

2010-01-01

This address is an exploration of a lifetime of disparate and often conflicting observations about how different people view what is right and good for agriculture, food, and farmers around the world. The exploration utilizes the concept of wicked problems to focus on the issue of differing historical interpretations of global agricultural development. Sandra Batie defines wicked problems as "dynamically complex, ill-structured, public problems" for which "there can be radically different views and understanding of the problem by different stakeholders, with no unique 'correct' view." The wicked problem construct is applied to four core ideas in the history of agricultural development -- small farms, cash crops, agrarian ideals, and international development -- to demonstrate the potential for using this concept to approach complex problems of historical interpretation and contribute to solutions to the challenges of global agricultural development. The author suggests historians should acknowledge contradictory interpretations adn work toward reconciliation and synthesis, where it is possible and, where not, toward a clear explication of the basis for remaining differences. The author also encourages historians to seek multidisciplinary research opportunities that will help bring insights about historical context to policy deliberations.

Transforming the U.S. Immigration System After 9/11: The Impact of Organizational Change and Collaboration in the Context of Homeland Security

DTIC Science & Technology

2008-12-01

disqualifying criminal conviction from an application to become a Lawful Permanent Resident of the U.S.10 10...developing Collaborative Capacity Builders (CCBs) is another method to sustain and continue to build an effective USCIS and ICE network into the 21st...Weber and Anne M. Khademian, “Wicked Problems, Knowledge Challenges, and Collaborative Capacity Builders in Network Settings,” Public Administration

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

Bandhauer, Todd; Deri, Robert J.; Elmer, John W.

A laser diode package includes a heat pipe having a fluid chamber enclosed in part by a heat exchange wall for containing a fluid. Wicking channels in the fluid chamber is adapted to wick a liquid phase of the fluid from a condensing section of the heat pipe to an evaporating section of the heat exchanger, and a laser diode is connected to the heat exchange wall at the evaporating section of the heat exchanger so that heat produced by the laser diode is removed isothermally from the evaporating section to the condensing section by a liquid-to-vapor phase change ofmore » the fluid.« less

Advanced radiator concepts utilizing honeycomb panel heat pipes (stainless steel)

NASA Technical Reports Server (NTRS)

Fleischman, G. L.; Tanzer, H. J.

1985-01-01

The feasibility of fabricating and processing moderate temperature range heat pipes in a low mass honeycomb sandwich panel configuration for highly efficient radiator fins for the NASA space station was investigated. A variety of honeycomb panel facesheet and core-ribbon wick concepts were evaluated within constraints dictated by existing manufacturing technology and equipment. Concepts evaluated include: type of material, material and panel thicknesses, wick type and manufacturability, liquid and vapor communication among honeycomb cells, and liquid flow return from condenser to evaporator facesheet areas. In addition, the overall performance of the honeycomb panel heat pipe was evaluated analytically.

Innovative self-drying concept for thermal insulation of cold piping

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

Korsgaard, V.

1997-11-01

In the paper an innovative Self-Drying concept, the Hygro-Wick concept, for thermal insulation of cold piping is described. The concept is based on the wicking action of certain fabrics to remove by capillary suction condensed water vapor from the pipe surface to the outer surface of the insulation/jacket, from whence it will evaporate/diffuse into the ambient air. Hence the concept will prevent long term accumulation of moisture in the insulation material. Theoretical and experimental results for two different embodiments of the concept is given: The Self-Drying system and the Self-Sealing system.

Wicked problems in space technology development at NASA

NASA Astrophysics Data System (ADS)

Balint, Tibor S.; Stevens, John

2016-01-01

Technological innovation is key to enable future space exploration missions at NASA. Technology development, however, is not only driven by performance and resource considerations, but also by a broad range of directly or loosely interconnected factors. These include, among others, strategy, policy and politics at various levels, tactics and programmatics, interactions between stakeholders, resource requirements, performance goals from component to system level, mission infusion targets, portfolio execution and tracking, and technology push or mission pull. Furthermore, at NASA, these influences occur on varying timescales and at diverse geographic locations. Such a complex and interconnected system could impede space technology innovation in this examined segment of the government environment. Hence, understanding the process through NASA's Planning, Programming, Budget and Execution cycle could benefit strategic thinking, planning and execution. Insights could be gained through suitable models, for example assessing the key drivers against the framework of Wicked Problems. This paper discusses NASA specific space technology innovation and innovation barriers in the government environment through the characteristics of Wicked Problems; that is, they do not have right or wrong solutions, only improved outcomes that can be reached through authoritative, competitive, or collaborative means. We will also augment the Wicked Problems model to account for the temporally and spatially coupled, and cyclical nature of this NASA specific case, and propose how appropriate models could improve understanding of the key influencing factors. In turn, such understanding may subsequently lead to reducing innovation barriers, and stimulating technology innovation at NASA. Furthermore, our approach can be adopted for other government-directed environments to gain insights into their structures, hierarchies, operational flow, and interconnections to facilitate circular dialogs towards preferred outcomes.

High heat flux loop heat pipes

NASA Astrophysics Data System (ADS)

North, Mark T.; Sarraf, David B.; Rosenfeld, John H.; Maidanik, Yuri F.; Vershinin, Sergey

1997-01-01

Loop Heat Pipes (LHPs) can transport very large thermal power loads, over long distances, through flexible, small diameter tubes and against high gravitational heads. While recent LHPs have transported as much as 1500 W, the peak heat flux through a LHP's evaporator has been limited to about 0.07 MW/m2. This limitation is due to the arrangement of vapor passages next to the heat load which is one of the conditions necessary to ensure self priming of the device. This paper describes work aimed at raising this limit by threefold to tenfold. Two approaches were pursued. One optimized the vapor passage geometry for the high heat flux conditions. The geometry improved the heat flow into the wick and working fluid. This approach also employed a finer pored wick to support higher vapor flow losses. The second approach used a bidisperse wick material within the circumferential vapor passages. The bidisperse material increased the thermal conductivity and the evaporative surface area in the region of highest heat flux, while providing a flow path for the vapor. Proof-of-concept devices were fabricated and tested for each approach. Both devices operated as designed and both demonstrated operation at a heat flux of 0.70 MW/m2. This performance exceeded the known state of the art by a factor of more than six for both conventional heat pipes and for loop heat pipes using ammonia. In addition, the bidisperse-wick device demonstrated boiling heat transfer coefficients up to 100,000 W/m2.K, and the fine pored device demonstrated an orientation independence with its performance essentially unaffected by whether its evaporator was positioned above, below or level with the condenser.

The rebuilding imperative in fisheries: Clumsy solutions for a wicked problem?

NASA Astrophysics Data System (ADS)

Khan, Ahmed S.; Neis, Barb

2010-10-01

There is mounting evidence that global fisheries are in crisis and about 25-30% of fish stocks are over exploited, depleted or recovering. Fish landings are increasingly coming from fully-exploited and over-exploited fisheries, and from intensive aquaculture that often relies indirectly on reduction fisheries. This poses severe challenges for marine ecosystems as well as food security and the livelihoods of resource-dependent coastal communities. Growing awareness of these social, economic and ecological consequences of overfishing is reflected in an expanding literature which shows that reducing fishing effort to allow fish stocks to recover has been the main focus of management efforts, but successful examples of stock recovery are few. An alternative, less explored social-ecological approach focuses on rebuilding entire ‘fish chains’ from oceans to plate. This paper supports this alternative approach. A review and synthesis of stock rebuilding initiatives worldwide suggests effective governance is central to rebuilding, and fisheries governance is a wicked problem. Wicked problems are complex, persistent or reoccurring and hard to fix because they are linked to broader social, economic and policy issues. This review and analysis implies that, due to socioeconomic and sociopolitical concerns, fisheries governance challenges are particularly wicked when dealing with collapsed fisheries and rebuilding efforts. The paper concludes that rebuilding might benefit from experimenting with clumsy solutions. Clumsy solutions are exploratory, include inputs from a broad range of stakeholders along the fish chain, and require information sharing, knowledge synthesis, and trust building. Moreover, clumsy solutions that address power relations, collective action dilemmas, and the fundamental question of ‘rebuilding for whom’ are essential for stewardship, equity and long-term resource sustainability.

Manipulation of fluids in three-dimensional porous photonic structures with patterned surface properties

DOEpatents

Aizenberg, Joanna; Burgess, Ian B.; Mishchenko, Lidiya; Hatton, Benjamin; Loncar, Marko

2016-03-08

A three-dimensional porous photonic structure, whose internal pore surfaces can be provided with desired surface properties in a spatially selective manner with arbitrary patterns, and methods for making the same are described. When exposed to a fluid (e.g., via immersion or wicking), the fluid can selectively penetrate the regions of the structure with compatible surface properties. Broad applications, for example in security, encryption and document authentication, as well as in areas such as simple microfluidics and diagnostics, are anticipated.

Manipulation of fluids in three-dimensional porous photonic structures with patterned surface properties

DOEpatents

Aizenberg, Joanna; Burgess, Ian; Mishchenko, Lidiya; Hatton, Benjamin; Loncar, Marko

2017-12-26

A three-dimensional porous photonic structure, whose internal pore surfaces can be provided with desired surface properties in a spatially selective manner with arbitrary patterns, and methods for making the same are described. When exposed to a fluid (e.g., via immersion or wicking), the fluid can selectively penetrate the regions of the structure with compatible surface properties. Broad applications, for example in security, encryption and document authentication, as well as in areas such as simple microfluidics and diagnostics, are anticipated.

A versatile valving toolkit for automating fluidic operations in paper microfluidic devices.

PubMed

Toley, Bhushan J; Wang, Jessica A; Gupta, Mayuri; Buser, Joshua R; Lafleur, Lisa K; Lutz, Barry R; Fu, Elain; Yager, Paul

2015-03-21

Failure to utilize valving and automation techniques has restricted the complexity of fluidic operations that can be performed in paper microfluidic devices. We developed a toolkit of paper microfluidic valves and methods for automatic valve actuation using movable paper strips and fluid-triggered expanding elements. To the best of our knowledge, this is the first functional demonstration of this valving strategy in paper microfluidics. After introduction of fluids on devices, valves can actuate automatically after a) a certain period of time, or b) the passage of a certain volume of fluid. Timing of valve actuation can be tuned with greater than 8.5% accuracy by changing lengths of timing wicks, and we present timed on-valves, off-valves, and diversion (channel-switching) valves. The actuators require ~30 μl fluid to actuate and the time required to switch from one state to another ranges from ~5 s for short to ~50 s for longer wicks. For volume-metered actuation, the size of a metering pad can be adjusted to tune actuation volume, and we present two methods - both methods can achieve greater than 9% accuracy. Finally, we demonstrate the use of these valves in a device that conducts a multi-step assay for the detection of the malaria protein PfHRP2. Although slightly more complex than devices that do not have moving parts, this valving and automation toolkit considerably expands the capabilities of paper microfluidic devices. Components of this toolkit can be used to conduct arbitrarily complex, multi-step fluidic operations on paper-based devices, as demonstrated in the malaria assay device.

A versatile valving toolkit for automating fluidic operations in paper microfluidic devices

PubMed Central

Toley, Bhushan J.; Wang, Jessica A.; Gupta, Mayuri; Buser, Joshua R.; Lafleur, Lisa K.; Lutz, Barry R.; Fu, Elain; Yager, Paul

2015-01-01

Failure to utilize valving and automation techniques has restricted the complexity of fluidic operations that can be performed in paper microfluidic devices. We developed a toolkit of paper microfluidic valves and methods for automatic valve actuation using movable paper strips and fluid-triggered expanding elements. To the best of our knowledge, this is the first functional demonstration of this valving strategy in paper microfluidics. After introduction of fluids on devices, valves can actuate automatically a) after a certain period of time, or b) after the passage of a certain volume of fluid. Timing of valve actuation can be tuned with greater than 8.5% accuracy by changing lengths of timing wicks, and we present timed on-valves, off-valves, and diversion (channel-switching) valves. The actuators require ~30 μl fluid to actuate and the time required to switch from one state to another ranges from ~5 s for short to ~50s for longer wicks. For volume-metered actuation, the size of a metering pad can be adjusted to tune actuation volume, and we present two methods – both methods can achieve greater than 9% accuracy. Finally, we demonstrate the use of these valves in a device that conducts a multi-step assay for the detection of the malaria protein PfHRP2. Although slightly more complex than devices that do not have moving parts, this valving and automation toolkit considerably expands the capabilities of paper microfluidic devices. Components of this toolkit can be used to conduct arbitrarily complex, multi-step fluidic operations on paper-based devices, as demonstrated in the malaria assay device. PMID:25606810

Electrolyte-Sensing Transistor Decals Enabled by Ultrathin Microbial Nanocellulose

PubMed Central

Yuen, Jonathan D.; Walper, Scott A.; Melde, Brian J.; Daniele, Michael A.; Stenger, David A.

2017-01-01

We report an ultra-thin electronic decal that can simultaneously collect, transmit and interrogate a bio-fluid. The described technology effectively integrates a thin-film organic electrochemical transistor (sensing component) with an ultrathin microbial nanocellulose wicking membrane (sample handling component). As far as we are aware, OECTs have not been integrated in thin, permeable membrane substrates for epidermal electronics. The design of the biocompatible decal allows for the physical isolation of the electronics from the human body while enabling efficient bio-fluid delivery to the transistor via vertical wicking. High currents and ON-OFF ratios were achieved, with sensitivity as low as 1 mg·L−1. PMID:28102316

Tissue fluid pressures - From basic research tools to clinical applications

NASA Technical Reports Server (NTRS)

Hargens, Alan R.; Akeson, Wayne H.; Mubarak, Scott J.; Owen, Charles A.; Gershuni, David H.

1989-01-01

This paper describes clinical applications of two basic research tools developed and refined in the past 20 years: the wick catheter (for measuring tissue fluid pressure) and the colloid osmometer (for measuring osmotic pressure). Applications of the osmometer include estimations of the reduced osmotic pressure of sickle-cell hemoglobin with deoxygenation, and of reduced swelling pressure of human nucleus pulposus with hydration or upon action of certain enzymes. Clinical uses of the wick-catheter technique include an improvement of diagnosis and treatment of acute and chronic compartment syndromes, the elucidation of the tissue pressure thresholds for neuromuscular dysfunction, and the development of a better tourniquet for orthopedics.

Heat transfer device

NASA Technical Reports Server (NTRS)

Eaton, L. R. (Inventor)

1976-01-01

An improved heat transfer device particularly suited for use as an evaporator plate in a diffusion cloud chamber. The device is characterized by a pair of mutually spaced heat transfer plates, each being of a planar configuration, having a pair of opposed surfaces defining therebetween a heat pipe chamber. Within the heat pipe chamber, in contiguous relation with the pair of opposed surfaces, there is disposed a pair of heat pipe wicks supported in a mutually spaced relationship by a foraminous spacer of a planar configuration. A wick including a foraminous layer is contiguously related to the external surfaces of the heat transfer plates for uniformly wetting these surfaces.

An analysis of the vapor flow and the heat conduction through the liquid-wick and pipe wall in a heat pipe with single or multiple heat sources

NASA Technical Reports Server (NTRS)

Chen, Ming-Ming; Faghri, Amir

1990-01-01

A numerical analysis is presented for the overall performance of heat pipes with single or multiple heat sources. The analysis includes the heat conduction in the wall and liquid-wick regions as well as the compressibility effect of the vapor inside the heat pipe. The two-dimensional elliptic governing equations in conjunction with the thermodynamic equilibrium relation and appropriate boundary conditions are solved numerically. The solutions are in agreement with existing experimental data for the vapor and wall temperatures at both low and high operating temperatures.

A fluidic diode, valves, and a sequential-loading circuit fabricated on layered paper.

PubMed

Chen, Hong; Cogswell, Jeremy; Anagnostopoulos, Constantine; Faghri, Mohammad

2012-08-21

Current microfluidic paper-based devices lack crucial components for fluid manipulation. We created a fluidic diode fabricated entirely on a single layer of paper to control the wicking of fluids. The fluidic diode is a two-terminal component that promotes or stops wicking along a paper channel. We further constructed a trigger and a delay valve based on the fluidic diode. Furthermore, we demonstrated a high-level functional circuit, consisting of a diode and a delay valve, to manipulate two fluids in a sequential manner. Our study provides new, transformative tools to manipulate fluid in microfluidic paper-based devices.

Electrolyte-Sensing Transistor Decals Enabled by Ultrathin Microbial Nanocellulose

NASA Astrophysics Data System (ADS)

Yuen, Jonathan D.; Walper, Scott A.; Melde, Brian J.; Daniele, Michael A.; Stenger, David A.

2017-01-01

We report an ultra-thin electronic decal that can simultaneously collect, transmit and interrogate a bio-fluid. The described technology effectively integrates a thin-film organic electrochemical transistor (sensing component) with an ultrathin microbial nanocellulose wicking membrane (sample handling component). As far as we are aware, OECTs have not been integrated in thin, permeable membrane substrates for epidermal electronics. The design of the biocompatible decal allows for the physical isolation of the electronics from the human body while enabling efficient bio-fluid delivery to the transistor via vertical wicking. High currents and ON-OFF ratios were achieved, with sensitivity as low as 1 mg·L-1.

Fuel cell and system for supplying electrolyte thereto with wick feed

DOEpatents

Cohn, J. Gunther; Feigenbaum, Haim; Kaufman, Arthur

1984-01-01

An electrolyte distribution and supply system for use with a fuel cell having a means for drawing electrolyte therein is formed by a set of containers of electrolyte joined to respective fuel cells in a stack of such cells. The electrolyte is separately stored so as to provide for electrical isolation between electrolytes of the individual cells of the stack. Individual storage compartments are coupled by tubes containing wicking fibers, the ends of the respective tubes terminating on the means for drawing electrolyte in each of the respective fuel cells. Each tube is heat shrunk to tightly bind the fibers therein.

A comparison of field-line resonances observed at the Goose Bay and Wick radars

NASA Astrophysics Data System (ADS)

Provan, G.; Yeoman, T. K.

1997-02-01

Previous observations with the Goose Bay HF coherent-scatter radar have revealed structured spectral peaks at ultra-low frequencies. The frequencies of these spectral peaks have been demonstrated to be extremely consistent from day to day. The stability of these spectral peaks can be seen as evidence for the existence of global magnetospheric cavity modes whose resonant frequencies are independent of latitude. Field-line resonances occur when successive harmonics of the eigenfrequency of the magnetospheric cavity or waveguide match either the first harmonic eigenfrequency of the geomagnetic field lines or higher harmonics of this frequency. Power spectra observed at the SABRE VHF coherent-scatter radar at Wick, Scotland, during night and early morning are revealed to show similarly clearly structured spectral peaks. These spectral peaks are the result of local field-line resonances due to Alfvén waves standing on magnetospheric field lines. A comparison of the spectra observed by the Goose Bay and Wick radars demonstrate that the frequencies of the field-line resonances are, on average, almost identical, despite the different latitudinal ranges covered by the two radars. Possible explanations for the similarity of the signatures on the two radar systems are discussed.

Candle Flames in Microgravity

NASA Technical Reports Server (NTRS)

Dietrich, D. L.; Ross, H. D.; Chang, P.; T'ien, J. S.

2001-01-01

The goal of this work is to study both experimentally and numerically the behavior of a candle flame burning in a microgravity environment. Two space experiments (Shuttle and Mir) have shown the candle flame in microgravity to be small (approximately 1.5 cm diameter), dim blue, and hemispherical. Near steady flames with very long flame lifetimes (up to 45 minutes in some tests) existed for many of the tests. Most of the flames spontaneously oscillated with a period of approximately 1 Hz just prior to extinction). In a previous model of candle flame in microgravity, a porous sphere wetted with liquid fuel simulated the evaporating wick. The sphere, with a temperature equal to the boiling temperature of the fuel, was at the end of an inert cone that had a prescribed temperature. This inert cone produces the quenching effect of the candle wax in the real configuration. Although the computed flame shape resembled that observed in the microgravity experiment, the model was not able to differentiate the effect of wick geometry, e.g., a long vs. a short wick. This paper presents recent developments in the numerical model of the candle flame. The primary focus has been to more realistically account for the actual shape of the candle.

Wicked Problems in Natural Hazard Assessment and Mitigation

NASA Astrophysics Data System (ADS)

Stein, S.; Steckler, M. S.; Rundle, J. B.; Dixon, T. H.

2017-12-01

Social scientists have defined "wicked" problems that are "messy, ill-defined, more complex than we fully grasp, and open to multiple interpretations based on one's point of view... No solution to a wicked problem is permanent or wholly satisfying, which leaves every solution open to easy polemical attack." These contrast with "tame" problems in which necessary information is available and solutions - even if difficult and expensive - are straightforward to identify and execute. Updating the U.S.'s aging infrastructure is a tame problem, because what is wrong and how to fix it are clear. In contrast, addressing climate change is a wicked problem because its effects are uncertain and the best strategies to address them are unclear. An analogous approach can be taken to natural hazard problems. In tame problems, we have a good model of the process, good information about past events, and data implying that the model should predict future events. In such cases, we can make a reasonable assessment of the hazard that can be used to develop mitigation strategies. Earthquake hazard mitigation for San Francisco is a relatively tame problem. We understand how the earthquakes result from known plate motions, have information about past earthquakes, and have geodetic data implying that future similar earthquakes will occur. As a result, it is straightforward to develop and implement mitigation strategies. However, in many cases, hazard assessment and mitigation is a wicked problem. How should we prepare for a great earthquake on plate boundaries where tectonics favor such events but we have no evidence that they have occurred and hence how large they may be or how often to expect them? How should we assess the hazard within plates, for example in the New Madrid seismic zone, where large earthquakes have occurred but we do not understand their causes and geodetic data show no strain accumulating? How can we assess the hazard and make sensible policy when the recurrence of earthquakes, floods, or hurricanes seems to be changing with time or is expected to do so due to human activity? A starting approach might be to assess what we know, what we don't know, what we think, and what can be done that might improve this situation. We should draw on what is known in other areas of risk assessment including social science, meteorology, engineering, and economics.

Micro/Nano-Scale Phase Change Systems for Thermal Management and Solar Energy Conversion Applications

NASA Astrophysics Data System (ADS)

Coso, Dusan

The first part of the dissertation presents a study that implements micro and nano scale engineered surfaces for enhancement of evaporation and boiling phase change heat transfer in both capillary wick structures and pool boiling systems. Capillary wicking surfaces are integral components of heat pipes and vapor chamber thermal spreaders often used for thermal management of microelectronic devices. In addition, pool boiling systems can be encountered in immersion cooling systems which are becoming more commonly investigated for thermal management applications of microelectronic devices and even data centers. The latent heat associated with the change of state from liquid to vapor, and the small temperature differences required to drive this process yield great heat transfer characteristics. Additionally, since no external energy is required to drive the phase change process, these systems are great for portable devices and favorable for reduction of cost and energy consumption over alternate thermal management technologies. Most state of the art capillary wicks used in these devices are typically constructed from sintered copper media. These porous structures yield high surface areas of thin liquid film where evaporation occurs, thus promoting phase change heat transfer. However, thermal interfaces at particle point contacts formed during the sintering process and complex liquid/vapor flow within these wick structures yield high thermal and liquid flow resistances and limit the maximum heat flux they can dissipate. In capillary wicks the maximum heat flux is typically governed by the capillary or boiling limits and engineering surfaces that delay these limitations and yield structures with large surface areas of thin liquid film where phase change heat transfer is promoted is highly desired. In this study, biporous media consisting of microscale pin fins separated by microchannels are examined as candidate structures for the evaporator wick of a vapor chamber heat pipe. Smaller pores are used to generate high capillary suction, while larger microchannels are used to alleviate flow resistance. The heat transfer coefficient is found to depend on the area coverage of a liquid film with thickness on the order of a few microns near the meniscus of the triple phase contact line. We manipulate the area coverage and film thickness by varying the surface area-to-volume ratio through the use of microstructuring. In some samples, a transition from evaporative heat transfer to nucleate boiling is observed. While it is difficult to identify when the transition occurs, one can identify regimes where evaporation dominates over nucleate boiling and vice versa. Heat fluxes of 277.0 (+/- 9.7) W/cm2 can be dissipated by wicks with heaters of area 1 cm2, while heat fluxes up to 733.1 (+/- 103.4) W/cm2 can be dissipated by wicks with smaller heaters intended to simulate local hot-spots. In pool boiling systems that are encountered in immersion cooling applications, the heat transfer coefficient (HTC) is governed by the bubble nucleation site density and the agitation in the liquid/vapor flow these bubbles produce when they detach from the surface. The nucleation site density and release rate is usually determined by the surface morphology. Another important parameter in pool boiling systems is the maximum heat flux (CHF) that can safely be dissipated. In practice, this quantity is about two orders of magnitude smaller than limitations suggested by kinetic theory. For essentially infinite, smooth, well wetted surfaces, hydrodynamic instability theories capturing liquid/vapor interactions away from the heated surface have been successful in predicting CHF. On finite micro and nano structured surfaces where applying the hydrodynamic theory formulation is not easily justified, other effects may contribute to phase change heat transfer characteristics. Here, we also present a pool boiling study on biporous microstructured surfaces used in capillary wick experiments. Structures are manipulated by reduction of pore size to determine if increased capillary pressure can enhance rewetting from heater edges and delay CHF. A comparative study between the two experimental systems indicates that while the capillary limitation is significant in capillary wick experiments, for these well wetted microstructured surfaces used in pool boiling systems the hydrodynamic limitation defined based on heater size causes the occurrence of CHF. Other hierarchical nanowire surfaces containing periodic microscale cavities are investigated as well and are seen to yield a ˜2.4 fold increase in heat transfer coefficient characteristics while not compromising CHF compared to surfaces where cavities are not present. These studies indicate pathways for enhancement of heat transfer coefficient via implementing hierarchical structures, while no clear method in increasing CHF is determined for finite size surfaces of various morphologies. In the second part of this dissertation, solar energy storage is sought in 'phase change' of photochromic molecular systems: the storage of solar energy in the chemical bonds of photosensitive molecules (a photochemical reaction) and subsequent recovery of the energy in a back reaction in the form of heat, reversibly. These molecular systems are interesting alternatives to photovoltaic and solar thermal technologies which cannot satisfy the needs of load leveling, or for portable municipal heating applications. Typically made of organic compounds, these molecules have become known for rapid decomposition, short energy storage time scales and poor energy storing efficiencies. Thus, they have been abandoned as practical solar energy storage systems in the past several decades. On the other hand, organometallic molecular systems have not been extensively probed for these applications. Recent research has indicated that organometallic (fulvalene)diruthenium FvRu2 has demonstrated excellent energy storage characteristic and durability. Here, we report on a full cycle molecular solar thermal (MOST) microfluidic system based on a bis(1,1-dimethyltridecyl) substituted derivative of FvRu2 that allows for long term solar energy storage (110 J/g), and "on demand" energy release upon exposure to a catalyst. The microfluidic systems developed here are excellent for photoconversion characterization and scrutinizing potential catalysts and can be extended to studying many other molecular systems. The objective of the work presented here is to demonstrate that "on demand" solar energy storage and release in MOST systems is viable and motivate future research on other photochromic organometallic systems.

Characterization of electron-beam-modified surface coated clay fillers and their influence on physical properties of rubbers

NASA Astrophysics Data System (ADS)

Ray, Sudip; Bhowmick, Anil K.; Sarma, K. S. S.; Majali, A. B.; Tikku, V. K.

2002-12-01

A novel process of surface modification of clay filler has been developed by coating this with an acrylate monomer, trimethylol propane triacrylate (TMPTA) or a silane coupling agent, triethoxy vinyl silane (TEVS) followed by electron beam irradiation. Characterization of these surface modified fillers has been carried out by Fourier-transform infrared analysis (FTIR), electron spectroscopy for chemical analysis (ESCA), wettability by dynamic wicking method measuring the rise of a liquid through a filler-packed capillary tube and water flotation test, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). Presence of the acrylate and the silane coupling agent on the modified fillers has been confirmed from FTIR, ESCA, and EDX studies, which has also been supported by TGA studies. The contact angle measurement by dynamic wicking method suggests improvement in hydrophobicity of the treated fillers, which is supported by water flotation test especially in the case of silanized clay. However, XRD studies demonstrate that the entire modification process does not affect the bulk properties of the fillers. Finally, both unmodified and modified clay fillers have been incorporated in styrene butadiene rubber (SBR) and nitrile rubber (NBR). Rheometric and mechanical properties reveal that there is a definite improvement using these modified fillers specially in the case of silanized clay compared to the control sample, probably due to successful enhancement in interaction between the treated clay and the base polymer.

Chromatographic Separation and Visual Detection on Wicking Microfluidic Devices: Quantitation of Cu2+ in Surface, Ground, and Drinking Water.

PubMed

Bandara, Gayan C; Heist, Christopher A; Remcho, Vincent T

2018-02-20

Copper is widely applied in industrial and technological applications and is an essential micronutrient for humans and animals. However, exposure to high environmental levels of copper, especially through drinking water, can lead to copper toxicity, resulting in severe acute and chronic health effects. Therefore, regular monitoring of aqueous copper ions has become necessary as recent anthropogenic activities have led to elevated environmental concentrations of copper. On-site monitoring processes require an inexpensive, simple, and portable analytical approach capable of generating reliable qualitative and quantitative data efficiently. Membrane-based lateral flow microfluidic devices are ideal candidates as they facilitate rapid, inexpensive, and portable measurements. Here we present a simple, chromatographic separation approach in combination with a visual detection method for Cu 2+ quantitation, performed in a lateral flow microfluidic channel. This method appreciably minimizes interferences by incorporating a nonspecific polymer inclusion membrane (PIM) based assay with a "dot-counting" approach to quantification. In this study, hydrophobic polycaprolactone (PCL)-filled glass microfiber (GMF) membranes were used as the base substrate onto which the PIM was evenly dispensed as an array of dots. The devices thus prepared were then selectively exposed to oxygen radicals through a mask to generate a hydrophilic surface path along which the sample was wicked. Using this approach, copper concentrations from 1 to 20 ppm were quantified from 5 μL samples using only visual observation of the assay device.

Wick Product for Commutation Relations Connected with Yang-Baxter Operators and New Constructions of Factors

NASA Astrophysics Data System (ADS)

Krsolarlak, Ilona

We analyze a certain class of von Neumann algebras generated by selfadjoint elements , for satisfying the general commutation relations: Such algebras can be continuously embedded into some closure of the set of finite linear combinations of vectors , where is an orthonormal basis of a Hilbert space . The operator which represents the vector is denoted by and called the ``Wick product'' of the operators . We describe explicitly the form of this product. Also, we estimate the operator norm of for . Finally we apply these two results and prove that under the assumption all the von Neumann algebras considered are II1 factors.

Wicked problems: policy contradictions in publicly financed dental care.

PubMed

Quiñonez, Carlos

2012-01-01

To review two policy issues that define publicly financed dental care as a "wicked policy problem." Historical review. By demonstrating how governments have shifted their funding focus from direct delivery care, to public third-party financing arrangements in private dental offices, and by their willingness to fund composite restorations in public fee schedules, it is clear that the logic and sustainability of public programming needs reconsideration. The current contradictions in public dental care programs speak to the need for policy makers to reassess their goals, and ask whether decisions are based more on political necessity than on a logical evidence-informed approach to the delivery of publicly financed dental care. © 2012 American Association of Public Health Dentistry.

Effect of electrolyte on surface free energy components of feldspar minerals using thin-layer wicking method.

PubMed

Karagüzel, C; Can, M F; Sönmez, E; Celik, M S

2005-05-01

Application of the thin-layer wicking (TLW) technique on powdered minerals is useful for characterizing their surfaces. Albite (Na-feldspar) and orthoclase (K-feldspar) are feldspar minerals which are frequently found in the same matrix. Despite similarities in their physicochemical properties, separation of these minerals from each other by flotation is generally possible in the presence of monovalent salts such as NaCl. Both albite and orthoclase exhibit the same microflotation properties and rather close electrokinetic profiles in the absence of salt. In this study, contact angles of albite and orthoclase determined by the TLW technique yielded close values in the absence and presence of amine collector. While the calculated surface energies and their components determined using contact angle data reveal that the energy terms remain farther apart in the absence of the collector, the differences narrow down at collector concentrations where full flotation recoveries are obtained. However, the effect of addition of NaCl on contact angles and surface free energy components at constant amine concentration indicates that albite is significantly affected by salt addition, whereas orthoclase remains marginally affected. This interesting finding is explained on the basis of ion-exchange properties, the stability of the interface, flotation data, and zeta potential data in the presence of NaCl.

Characterizing the transplanar and in-plane water transport of textiles with gravimetric and image analysis technique: Spontaneous Uptake Water Transport Tester

PubMed Central

Tang, K. P. M.; Wu, Y. S.; Chau, K. H.; Kan, C. W.; Fan, J. T.

2015-01-01

Water absorption and transport property of textiles is important since it affects wear comfort, efficiency of treatment and functionality of product. This paper introduces an accurate and reliable measurement tester, which is based on gravimetric and image analysis technique, for characterising the transplanar and in-plane wicking property of fabrics. The uniqueness of this instrument is that it is able to directly measure the water absorption amount in real-time, monitor the direction of water transport and estimate the amount of water left on skin when sweating. Throughout the experiment, water supply is continuous which simulates profuse sweating. Testing automation could even minimise variation caused by subjective manipulation, thus enhancing testing accuracy. This instrument is versatile in terms of the fabrics could be tested. A series of shirting fabrics made by different fabric structure and yarn were investigated and the results show that the proposed method has high sensitivity in differentiating fabrics with varying geometrical differences. Fabrics with known hydrophobicity were additionally tested to examine the sensitivity of the instrument. This instrument also demonstrates the flexibility to test on high performance moisture management fabrics and these fabrics were found to have excellent transplanar and in-plane wicking properties. PMID:25875329

Deconstructing three-dimensional (3D) structure of absorptive glass mat (AGM) separator to tailor pore dimensions and amplify electrolyte uptake

NASA Astrophysics Data System (ADS)

Rawal, Amit; Rao, P. V. Kameswara; Kumar, Vijay

2018-04-01

Absorptive glass mat (AGM) separator is a vital technical component in valve regulated lead acid (VRLA) batteries that can be tailored for a desired application. To selectively design and tailor the AGM separator, the intricate three-dimensional (3D) structure needs to be unraveled. Herein, a toolkit of 3D analytical models of pore size distribution and electrolyte uptake expressed via wicking characteristics of AGM separators under unconfined and confined states is presented. 3D data of fiber orientation distributions obtained previously through X-ray micro-computed tomography (microCT) analysis are used as key set of input parameters. The predictive ability of pore size distribution model is assessed through the commonly used experimental set-up that usually apply high level of compressive stresses. Further, the existing analytical model of wicking characteristics of AGM separators has been extended to account for 3D characteristics, and subsequently, compared with the experimental results. A good agreement between the theory and experiments pave the way to simulate the realistic charge-discharge modes of the battery by applying cyclic loading condition. A threshold criterion describing the invariant behavior of pore size and wicking characteristics in terms of maximum permissible limit of key structural parameters during charge-discharge mode of the battery has also been proposed.

Modeling of the capillary wicking of flax fibers by considering the effects of fiber swelling and liquid absorption.

PubMed

Testoni, Guilherme Apolinario; Kim, Sihwan; Pisupati, Anurag; Park, Chung Hae

2018-09-01

We propose a new model for the capillary rise of liquid in flax fibers whose diameter is changed by liquid absorption. Liquid absorption into the flax fibers is taken into account in a new modified Washburn equation by considering the mass of the liquid absorbed inside the fibers as well as that imbibed between the fibers. The change of permeability and hydraulic radius of pores in a fibrous medium due to the fiber swelling is modeled by a statistical approach considering a non-uniform distribution of flax fiber diameter. By comparisons between capillary rise test results and modeling results, we prove the validity of the proposed modified Washburn model to take into account the effects from fiber swelling and liquid absorption on the decrease of capillary rise velocity. The experimental observation of long-term capillary rise tests show that the swelling behavior of the fibers highly packed in a closed volume and its influence on the capillary wicking are different from those of an individual single fiber in a free space. The current approach was useful to characterize the swelling of fibers highly packed in a closed volume and its influence of the long-term behavior of capillary wicking. Copyright © 2018 Elsevier Inc. All rights reserved.

Performance of methyl eugenol + matrix + toxicant combinations under field conditions in Hawaii and California for trapping Bactrocera dorsalis (Diptera: Tephritidae).

PubMed

Jang, Eric B; Ramsey, Amanda; Carvalho, Lori A

2013-04-01

The oriental fruit fly, Bactrocera dorsalis (Hendel) is a major pest of many fruit crops worldwide. Current detection programs by federal and state agencies in the United States use a grid of traps consisting of liquid methyl eugenol (lure) and naled (toxicant) applied to cotton wicks and hung inside the trap. In recent years efforts have been made to incorporate these chemicals into various solid-type matrices that could be individually packaged to reduce human exposure to the chemicals and improve handling. New solid formulations containing methyl eugenol and either naled or dichlorovinyl dimethyl phosphate toxicants were compared with the standard formulations on cotton wicks in large scale field evaluation in Hawaii. Two reduced risk toxicants (spinosad and Rynaxypyr) were also evaluated. In one test the solid lure-toxicant-matrix combinations were sent to California to be weathered under California climate conditions and then sent back to Hawaii for evaluation. The polymer matrices with lure and toxicant were found to be as attractive as baited wicks and have the same longevity of attraction regardless of being weathered in Hawaii or in California. The new ingestible toxicants were also effective, although further testing of these ingestible lure + toxicant + matrix products is necessary.

Quantum-field-theoretical approach to phase–space techniques: Symmetric Wick theorem and multitime Wigner representation

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

Plimak, L.I., E-mail: Lev.Plimak@mbi-berlin.de; Olsen, M.K.

2014-12-15

In this work we present the formal background used to develop the methods used in earlier works to extend the truncated Wigner representation of quantum and atom optics in order to address multi-time problems. Analogs of Wick’s theorem for the Weyl ordering are verified. Using the Bose–Hubbard chain as an example, we show how these may be applied to constructing a mapping of the system in question to phase space. Regularisation issues and the reordering problem for the Heisenberg operators are addressed.

Off-axis cooling of rotating devices using a crank-shaped heat pipe

DOEpatents

Jankowski, Todd A.; Prenger, F. Coyne; Waynert, Joseph A.

2007-01-30

The present invention is a crank-shaped heat pipe for cooling rotating machinery and a corresponding method of manufacture. The crank-shaped heat pipe comprises a sealed cylindrical tube with an enclosed inner wick structure. The crank-shaped heat pipe includes a condenser section, an adiabatic section, and an evaporator section. The crank-shape is defined by a first curve and a second curve existing in the evaporator section or the adiabatic section of the heat pipe. A working fluid within the heat pipe provides the heat transfer mechanism.

Innovative Surfaces for Controlled Flow of Liquid Metal

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

Fortini, Arthur J.

2016-03-22

The potential economic, environmental, and strategic benefits associated with the development of fusion energy are numerous. However, application of fusion technology cannot be realized until advanced materials are developed that allow operation under the high heat flux conditions necessary for cost-competitive electric energy generation. Bathing the wall of a fusion reactor plasma-facing component in a liquid metal such as lithium, gallium, or tin is a viable approach for accommodating continuous heat flux levels exceeding 10 MW/m2, and it is also the preferred approach for removing hydrogen isotopes. Stabilizing the liquid film is the key challenge, which can be addressed throughmore » the use of a microtextured surface. In previous work, Ultramet developed high temperature microtextured tungsten and rhenium coatings consisting of thousands of high aspect ratio pyramids per square millimeter that are compatible with lithium, gallium, and tin, and whose effectiveness in wicking molten lithium has been demonstrated even in the presence of strong body forces. Heat transfer and fluid flow characteristics were also modeled. Because of the safety issues surrounding lithium, the current project focused on adapting and optimizing this wicking technology for use with gallium and tin. The coatings were deposited by chemical vapor deposition (CVD), and the height, population density, and morphology of the pyramids was varied to optimize the wetting properties, which were measured and quantified by exposing the coatings to molten gallium or tin. Micron-thick films of other materials were also applied to the textured surfaces to vary the wetting characteristics. Wicking tests were performed with both gallium and tin on a variety of coatings with different textures and surface chemistries, and both metals showed excellent wicking and wettability on virtually all of the textured coatings. Extensive modeling of the interaction between the dendrites and the liquid metal, as well as additional wetting testing, was performed by Digital Materials Solutions (DMS, Carlsbad, CA).« less

An Overview of Long Duration Sodium Heat Pipe Tests

NASA Astrophysics Data System (ADS)

Rosenfeld, John H.; Ernst, Donald M.; Lindemuth, James E.; Sanzi, James L.; Geng, Steven M.; Zuo, Jon

2004-02-01

High temperature heat pipes are being evaluated for use in energy conversion applications such as fuel cells, gas turbine re-combustors, and Stirling cycle heat sources; with the resurgence of space nuclear power, additional applications include reactor heat removal elements and radiator elements. Long operating life and reliable performance are critical requirements for these applications. Accordingly long-term materials compatibility is being evaluated through the use of high temperature life test heat pipes. Thermacore, Inc. has carried out several sodium heat pipe life tests to establish long term operating reliability. Four sodium heat pipes have recently demonstrated favorable materials compatibility and heat transport characteristics at high operating temperatures in air over long time periods. A 316L stainless steel heat pipe with a sintered porous nickel wick structure and an integral brazed cartridge heater has successfully operated at 650C to 700C for over 115,000 hours without signs of failure. A second 316L stainless steel heat pipe with a specially-designed Inconel 601 rupture disk and a sintered nickel powder wick has demonstrated over 83,000 hours at 600C to 650C with similar success. A representative one-tenth segment Stirling Space Power Converter heat pipe with an Inconel 718 envelope and a stainless steel screen wick has operated for over 41,000 hours at nearly 700C. A hybrid (i.e. gas-fired and solar) heat pipe with a Haynes 230 envelope and a sintered porous nickel wick structure was operated for about 20,000 hours at nearly 700C without signs of degradation. These life test results collectively have demonstrated the potential for high temperature heat pipes to serve as reliable energy conversion system components for power applications that require long operating lifetime with high reliability. Detailed design specifications, operating history, and test results are described for each of these sodium heat pipes. Lessons learned and future life test plans are also discussed.

An Overview of Long Duration Sodium Heat Pipe Tests

NASA Technical Reports Server (NTRS)

Rosenfeld, John H.; Ernst, Donald M.; Lindemuth, James E.; Sanzi, James L.; Geng, Steven M.; Zuo, Jon

2004-01-01

High temperature heat pipes are being evaluated for use in energy conversion applications such as fuel cells, gas turbine re-combustors, and Stirling cycle heat sources; with the resurgence of space nuclear power, additional applications include reactor heat removal elements and radiator elements. Long operating life and reliable performance are critical requirements for these applications. Accordingly long-term materials compatibility is being evaluated through the use of high temperature life test heat pipes. Thermacore International, Inc., has carried out several sodium heat pipe life tests to establish long term operating reliability. Four sodium heat pipes have recently demonstrated favorable materials compatibility and heat transport characteristics at high operating temperatures in air over long time periods. A 3l6L stainless steel heat pipe with a sintered porous nickel wick structure and an integral brazed cartridge heater has successfully operated at 650 to 700 C for over 115,000 hours without signs of failure. A second 3l6L stainless steel heat pipe with a specially-designed Inconel 60 I rupture disk and a sintered nickel powder wick has demonstrated over 83,000 hours at 600 to 650 C with similar success. A representative one-tenth segment Stirling Space Power Converter heat pipe with an Inconel 718 envelope and a stainless steel screen wick has operated for over 41 ,000 hours at nearly 700 0c. A hybrid (i.e. gas-fired and solar) heat pipe with a Haynes 230 envelope and a sintered porous nickel wick structure was operated for about 20,000 hours at nearly 700 C without signs of degradation. These life test results collectively have demonstrated the potential for high temperature heat pipes to serve as reliable energy conversion system components for power applications that require long operating lifetime with high reliability, Detailed design specifications, operating hi story, and test results are described for each of these sodium heat pipes. Lessons learned and future life test plans are also discussed.

Glass heat pipe evacuated tube solar collector

DOEpatents

McConnell, Robert D.; Vansant, James H.

1984-01-01

A glass heat pipe is adapted for use as a solar energy absorber in an evacuated tube solar collector and for transferring the absorbed solar energy to a working fluid medium or heat sink for storage or practical use. A capillary wick is formed of granular glass particles fused together by heat on the inside surface of the heat pipe with a water glass binder solution to enhance capillary drive distribution of the thermal transfer fluid in the heat pipe throughout the entire inside surface of the evaporator portion of the heat pipe. Selective coatings are used on the heat pipe surface to maximize solar absorption and minimize energy radiation, and the glass wick can alternatively be fabricated with granular particles of black glass or obsidian.

Heat pipe manufacturing study

NASA Technical Reports Server (NTRS)

Edelstein, F.

1974-01-01

Heat pipe manufacturing methods are examined with the goal of establishing cost effective procedures that will ultimately result in cheaper more reliable heat pipes. Those methods which are commonly used by all heat pipe manufacturers have been considered, including: (1) envelope and wick cleaning, (2) end closure and welding, (3) mechanical verification, (4) evacuation and charging, (5) working fluid purity, and (6) charge tube pinch off. The study is limited to moderate temperature aluminum and stainless steel heat pipes with ammonia, Freon-21 and methanol working fluids. Review and evaluation of available manufacturers techniques and procedures together with the results of specific manufacturing oriented tests have yielded a set of recommended cost-effective specifications which can be used by all manufacturers.

A vadose zone water fluxmeter with divergence control

NASA Astrophysics Data System (ADS)

Gee, G. W.; Ward, A. L.; Caldwell, T. G.; Ritter, J. C.

2002-08-01

Unsaturated water flux densities are needed to quantify water and contaminant transfer within the vadose zone. However, water flux densities are seldom measured directly and often are predicted with uncertainties of an order or magnitude or more. A water fluxmeter was designed, constructed, and tested to directly measure drainage fluxes in field soils. The fluxmeter was designed to minimize divergence. It concentrates flow into a narrow sensing region filled with a fiberglass wick. The wick applies suction, proportional to its length, and passively drains the meter. The meter can be installed in an augured borehole at almost any depth below the root zone. Water flux through the meter is measured with a self-calibrating tipping bucket, with a sensitivity of ~4 mL tip-1. For our meter this is equivalent to detection limit of ~0.1 mm. Passive-wick devices previously have not properly corrected for flow divergence. Laboratory measurements supported predictions of a two-dimensional (2-D) numerical model, which showed that control of the collector height H and knowledge of soil hydraulic properties are required for improving divergence control, particularly at fluxes below 1000 mm yr-1. The water fluxmeter is simple in concept, is inexpensive, and has the capability of providing continuous and reliable monitoring of unsaturated water fluxes ranging from less than 1 mm yr-1 to more than 1000 mm yr-1.

A vadose zone water fluxmeter with divergence control

USGS Publications Warehouse

Gee, G.W.; Ward, A.L.; Caldwell, T.G.; Ritter, J.C.

2002-01-01

Unsaturated water flux densities are needed to quantify water and contaminant transfer within the vadose zone. However, water flux densities are seldom measured directly and often are predicted with uncertainties of an order or magnitude or more. A water fluxmeter was designed, constructed, and tested to directly measure drainage fluxes in field soils. The fluxmeter was designed to minimize divergence. It concentrates flow into a narrow sensing region filled with a fiberglass wick. The wick applies suction, proportional to its length, and passively drains the meter. The meter can be installed in an augured borehole at almost any depth below the root zone. Water flux through the meter is measured with a self‐calibrating tipping bucket, with a sensitivity of ∼4 mL tip−1. For our meter this is equivalent to detection limit of ∼0.1 mm. Passive‐wick devices previously have not properly corrected for flow divergence. Laboratory measurements supported predictions of a two‐dimensional (2‐D) numerical model, which showed that control of the collector height H and knowledge of soil hydraulic properties are required for improving divergence control, particularly at fluxes below 1000 mm yr−1. The water fluxmeter is simple in concept, is inexpensive, and has the capability of providing continuous and reliable monitoring of unsaturated water fluxes ranging from less than 1 mm yr−1 to more than 1000 mm yr−1.

Physics of microstructures enhancement of thin film evaporation heat transfer in microchannels flow boiling

PubMed Central

Bigham, Sajjad; Fazeli, Abdolreza; Moghaddam, Saeed

2017-01-01

Performance enhancement of the two-phase flow boiling heat transfer process in microchannels through implementation of surface micro- and nanostructures has gained substantial interest in recent years. However, the reported results range widely from a decline to improvements in performance depending on the test conditions and fluid properties, without a consensus on the physical mechanisms responsible for the observed behavior. This gap in knowledge stems from a lack of understanding of the physics of surface structures interactions with microscale heat and mass transfer events involved in the microchannel flow boiling process. Here, using a novel measurement technique, the heat and mass transfer process is analyzed within surface structures with unprecedented detail. The local heat flux and dryout time scale are measured as the liquid wicks through surface structures and evaporates. The physics governing heat transfer enhancement on textured surfaces is explained by a deterministic model that involves three key parameters: the drying time scale of the liquid film wicking into the surface structures (τd), the heating length scale of the liquid film (δH) and the area fraction of the evaporating liquid film (Ar). It is shown that the model accurately predicts the optimum spacing between surface structures (i.e. pillars fabricated on the microchannel wall) in boiling of two fluids FC-72 and water with fundamentally different wicking characteristics. PMID:28303952

Highly Absorbent Antibacterial Hemostatic Dressing for Healing Severe Hemorrhagic Wounds

PubMed Central

Li, Ting-Ting; Lou, Ching-Wen; Chen, An-Pang; Lee, Mong-Chuan; Ho, Tsing-Fen; Chen, Yueh-Sheng; Lin, Jia-Horng

2016-01-01

To accelerate healing of severe hemorrhagic wounds, a novel highly absorbent hemostatic dressing composed of a Tencel®/absorbent-cotton/polylactic acid nonwoven base and chitosan/nanosilver antibacterial agent was fabricated by using a nonwoven processing technique and a freeze-drying technique. This study is the first to investigate the wicking and water-absorbing properties of a nonwoven base by measuring the vertical wicking height and water absorption ratio. Moreover, blood agglutination and hemostatic second tests were conducted to evaluate the hemostatic performance of the resultant wound dressing. The blending ratio of fibers, areal weight, punching density, and fiber orientation, all significantly influenced the vertical moisture wicking property. However, only the first two parameters markedly affected the water absorption ratio. After the nonwoven base absorbed blood, scanning electron microscope (SEM) observation showed that erythrocytes were trapped between the fibrin/clot network and nonwoven fibers when coagulation pathways were activated. Prothrombin time (PT) and activated partial thromboplastin time (APTT) blood agglutination of the resultant dressing decreased to 14.34 and 50.94 s, respectively. In the femoral artery of the rate bleeding model, hemostatic time was saved by 87.2% compared with that of cotton cloth. Therefore, the resultant antibacterial wound dressing demonstrated greater water and blood absorption, as well as hemostatic performance, than the commercially available cotton cloth, especially for healing severe hemorrhagic wounds. PMID:28773912

Frostbite

MedlinePlus

... trapped between the layers of clothing acts as insulation against the cold. Wear windproof and waterproof outer ... liners that fit well, wick moisture and provide insulation. You might also try hand and foot warmers. ...

Wicked Problem Solvers.

PubMed

Edmondson, Amy C

2016-06-01

Companies today increasingly rely on teams that span many industries for radical innovation, especially to solve "wicked problems." So leaders have to understand how to promote collaboration when roles are uncertain, goals are shifting, expertise and organizational cultures are varied, and participants have clashing or even antagonistic perspectives. HBS professor Amy Edmondson has studied more than a dozen cross-industry innovation projects, among them the creation of a new city, a mango supply-chain transformation, and the design and construction of leading-edge buildings. She has identified the leadership practices that make successful cross-industry teams work: fostering an adaptable vision, promoting psychological safety, enabling knowledge sharing, and encouraging collaborative innovation. Though these practices are broadly familiar, their application within cross-industry teams calls for unique leadership approaches that combine flexibility, open-mindedness, humility, and fierce resolve.

User's Manual for HPTAM: a Two-Dimensional Heat Pipe Transient Analysis Model, Including the Startup from a Frozen State

NASA Technical Reports Server (NTRS)

Tournier, Jean-Michel; El-Genk, Mohamed S.

1995-01-01

This report describes the user's manual for 'HPTAM,' a two-dimensional Heat Pipe Transient Analysis Model. HPTAM is described in detail in the UNM-ISNPS-3-1995 report which accompanies the present manual. The model offers a menu that lists a number of working fluids and wall and wick materials from which the user can choose. HPTAM is capable of simulating the startup of heat pipes from either a fully-thawed or frozen condition of the working fluid in the wick structure. The manual includes instructions for installing and running HPTAM on either a UNIX, MS-DOS or VMS operating system. Samples for input and output files are also provided to help the user with the code.

A Wicked Problem: Early Childhood Safety in the Dynamic, Interactive Environment of Home

PubMed Central

Simpson, Jean; Fougere, Geoff; McGee, Rob

2013-01-01

Young children being injured at home is a perennial problem. When parents of young children and family workers discussed what influenced parents’ perceptions and responses to child injury risk at home, both “upstream” and “downstream” causal factors were identified. Among the former, complex and interactive facets of society and contemporary living emerged as potentially critical features. The “wicked problems” model arose from the need to find resolutions for complex problems in multidimensional environments and it proved a useful analogy for child injury. Designing dynamic strategies to provide resolutions to childhood injury, may address our over-dependence on ‘tame solutions’ that only deal with physical cause-and-effect relationships and which cannot address the complex interactive contexts in which young children are often injured. PMID:23615453

A dynamic wicking technique for determining the effective pore radius of pregelatinized starch sheets.

PubMed

Kalogianni, E P; Savopoulos, T; Karapantsios, T D; Raphaelides, S N

2004-06-01

A dynamic wicking technique is employed for the first time for the determination of the effective mean pore radius of a thin-layer porous food: drum dried pregelatinized starch sheets. The technique consists of measuring the penetration rate of various n-alkanes in the porous matrix of the starch sheets and using this data to calculate the effective pore radius via the Washburn equation. Pore sizes in the order of a few nanometers have been determined in the starch sheets depending on the drum dryer's operating variables (drum rotation speed, steam pressure and starch feed concentration). The conditions for the application of the technique in porous foods are discussed as compared to the conditions for single capillaries and inorganic porous material measured in other studies.

Asymmetric finite size of ions and orientational ordering of water in electric double layer theory within lattice model.

PubMed

Gongadze, Ekaterina; Kralj-Iglic, Veronika; Iglic, Ales

2018-06-25

In the present short communication, a brief historical survey of the mean-field theoretical description of electric double layer (EDL) is presented. A special attention is devoted to asymmetric finite size of ions and orientational ordering of water dipoles. A model of Wicke and Eigen, who were first to explicitly derive the ion distribution functions for finite size of ions, is discussed. Arguments are given in favour of changing the recently adopted name of the mean-field EDL model for finite size of ions from Bikerman model to Bikerman-Wicke-Eigen model. Theoretically predicted asymmetric and symmetric camel-like shape of the voltage dependence of the differential capacitance is also discussed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

The other Higgses, at resonance, in the Lee-Wick extension of the Standard Model

NASA Astrophysics Data System (ADS)

Figy, Terrance; Zwicky, Roman

2011-10-01

Within the framework of the Lee-Wick Standard Model (LWSM) we investigate Higgs pair production gg → h 0 h 0, gg to {h_0}{tilde{p}_0} and top pair production gg to bar{t}t at the Large Hadron Collider (LHC), where the neutral particles from the Higgs sector ( h 0, {tilde{h}_0} and {tilde{p}_0} ) appear as possible resonant intermediate states. Depending on whether the LW Higgs state is below or above the top pair threshold either the hh or tt-channel are dominant and therefore of main interest. We investigate the signal gg to {h_0}{h_0} to bar{b}bγ γ and we find that the LW Higgs, depending on its mass-range, can be seen not long after the LHC upgrade in 2012. In gg to bar{t}t the LW states, due to the wrong-sign propagator and negative width, lead to a dip-peak structure instead of the usual peak-dip structure which gives a characteristic signal especially for low-lying LW Higgs states. We comment on the LWSM and the forward-backward asymmetry in view of the measurement at the TeVatron. Furthermore, we present a technique which reduces the hyperbolic diagonalization to standard diagonalization methods. We clarify issues of spurious phases in the Yukawa sector.

Technology Solutions Case Study: Capillary Break Beneath a Slab: Polyethylene Sheeting over Aggregate, Southwestern Pennsylvania

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

None

2014-07-01

In this project, Building America team IBACOS worked with a builder of single- and multifamily homes in southwestern Pennsylvania (climate zone 5) to understand its methods of successfully using polyethylene sheeting over aggregate as a capillary break beneath the slab in new construction. This builder’s homes vary in terms of whether they have crawlspaces or basements. However, in both cases, the strategy protects the home from water intrusion via capillary action (e.g., water wicking into cracks and spaces in the slab), thereby helping to preserve the durability of the home.

Childhood Asthma Disparities in Chicago: Developing Approaches to Health Inequities.

PubMed

Martin, Molly A; Kapheim, Melissa Gutierrez; Erwin, Kim; Ignoffo, Stacy; McMahon, Kate; OʼRourke, Amy; Gerald, Lynn B; Barrett, Meredith; Press, Valerie G; Darabi, Houshang; Krishnan, Jerry A

We conducted a needs assessment to develop an evidence-based, locally tailored asthma care implementation plan for high-risk children with asthma in Chicago. Our team of health policy experts, clinicians, researchers, and designers included extensive stakeholder engagement (N = 162) in a mixed-methods community needs assessment. Results showed the lines of communication and collaboration across sectors were weak; caregivers were the only consistent force and could not always manage this burden. A series of recommendations for interventions and how to implement and measure them were generated. Cooperative, multidisciplinary efforts grounded in the community can target wicked problems such as asthma.

Detergent-Fearing Milk.

ERIC Educational Resources Information Center

Hill, Diane

1997-01-01

Describes an activity that demonstrates among the following: diffusion; cohesion and adhesion; properties of surface tension which include wicking, hydrophilic, and hydrophobic molecular behaviors; and break up of fat clusters by liquid dishwashing detergent. (DDR)

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.

Analytical study of the liquid phase transient behavior of a high temperature heat pipe. M.S. Thesis

NASA Technical Reports Server (NTRS)

Roche, Gregory Lawrence

1988-01-01

The transient operation of the liquid phase of a high temperature heat pipe is studied. The study was conducted in support of advanced heat pipe applications that require reliable transport of high temperature drops and significant distances under a broad spectrum of operating conditions. The heat pipe configuration studied consists of a sealed cylindrical enclosure containing a capillary wick structure and sodium working fluid. The wick is an annular flow channel configuration formed between the enclosure interior wall and a concentric cylindrical tube of fine pore screen. The study approach is analytical through the solution of the governing equations. The energy equation is solved over the pipe wall and liquid region using the finite difference Peaceman-Rachford alternating direction implicit numerical method. The continuity and momentum equations are solved over the liquid region by the integral method. The energy equation and liquid dynamics equation are tightly coupled due to the phase change process at the liquid-vapor interface. A kinetic theory model is used to define the phase change process in terms of the temperature jump between the liquid-vapor surface and the bulk vapor. Extensive auxiliary relations, including sodium properties as functions of temperature, are used to close the analytical system. The solution procedure is implemented in a FORTRAN algorithm with some optimization features to take advantage of the IBM System/370 Model 3090 vectorization facility. The code was intended for coupling to a vapor phase algorithm so that the entire heat pipe problem could be solved. As a test of code capabilities, the vapor phase was approximated in a simple manner.

Humidifiers: Air Moisture Eases Skin, Breathing Symptoms

MedlinePlus

... fan to blow air through a wet wick, filter or belt. Steam vaporizers use electricity to create ... help dry out damp basements. Dirty reservoirs and filters in humidifiers can quickly breed bacteria and mold. ...

Testing of a high capacity research heat pipe

NASA Technical Reports Server (NTRS)

1982-01-01

Tests were performed on a high-capacity channel-wick heat pipe to assess the transport limitations of v-grooves and the effects of boiling. The results showed that transport can vary significantly (less than 50 W) under similar conditions and the continuous boiling was observed at power levels as low as 40 W. In addition, some evidence was found to support the predictions using a groove transport model which shows that transport increases with lower groove densities and longer evaporators. However, due to transport variations, these results were not consistent throughout the program. When a glass fiber wick was installed over the grooves, a relatively low transport level was achieved (80 to 140 W). Based on these results and the identification of some potential causes for them, several design suggestions were recommended for reducing the possibility of boiling and improving groove transport.

Optimizing "self-wicking" nanowire grids.

PubMed

Wei, Hui; Dandey, Venkata P; Zhang, Zhening; Raczkowski, Ashleigh; Rice, Willam J; Carragher, Bridget; Potter, Clinton S

2018-05-01

We have developed a self-blotting TEM grid for use with a novel instrument for vitrifying samples for cryo-electron microscopy (cryoEM). Nanowires are grown on the copper surface of the grid using a simple chemical reaction and the opposite smooth side is used to adhere to a holey sample substrate support, for example carbon or gold. When small volumes of sample are applied to the nanowire grids the wires effectively act as blotting paper to rapidly wick away the liquid, leaving behind a thin film. In this technical note, we present a detailed description of how we make these grids using a variety of substrates fenestrated with either lacey or regularly spaced holes. We explain how we characterize the quality of the grids and we describe their behavior under a variety of conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

Global symmetries and renormalizability of Lee-Wick theories

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

Chivukula, R. Sekhar; Farzinnia, Arsham; Foadi, Roshan

2010-08-01

In this paper we discuss the global symmetries and the renormalizability of Lee-Wick (LW) scalar QED. In particular, in the ''auxiliary-field'' formalism we identify softly broken SO(1,1) global symmetries of the theory. We introduce SO(1,1) invariant gauge-fixing conditions that allow us to show in the auxiliary-field formalism directly that the number of superficially divergent amplitudes in a LW Abelian gauge theory is finite. To illustrate the renormalizability of the theory, we explicitly carry out the one-loop renormalization program in LW scalar QED and demonstrate how the counterterms required are constrained by the joint conditions of gauge and SO(1,1) invariance. Wemore » also compute the one-loop beta functions in LW scalar QED and contrast them with those of ordinary scalar QED.« less

Lee-Wick black holes

NASA Astrophysics Data System (ADS)

Bambi, Cosimo; Modesto, Leonardo; Wang, Yixu

2017-01-01

We derive and study an approximate static vacuum solution generated by a point-like source in a higher derivative gravitational theory with a pair of complex conjugate ghosts. The gravitational theory is local and characterized by a high derivative operator compatible with Lee-Wick unitarity. In particular, the tree-level two-point function only shows a pair of complex conjugate poles besides the massless spin two graviton. We show that singularity-free black holes exist when the mass of the source M exceeds a critical value Mcrit. For M >Mcrit the spacetime structure is characterized by an outer event horizon and an inner Cauchy horizon, while for M =Mcrit we have an extremal black hole with vanishing Hawking temperature. The evaporation process leads to a remnant that approaches the zero-temperature extremal black hole state in an infinite amount of time.

Characterization of a high performance ultra-thin heat pipe cooling module for mobile hand held electronic devices

NASA Astrophysics Data System (ADS)

Ahamed, Mohammad Shahed; Saito, Yuji; Mashiko, Koichi; Mochizuki, Masataka

2017-11-01

In recent years, heat pipes have been widely used in various hand held mobile electronic devices such as smart phones, tablet PCs, digital cameras. With the development of technology these devices have different user friendly features and applications; which require very high clock speeds of the processor. In general, a high clock speed generates a lot of heat, which needs to be spreaded or removed to eliminate the hot spot on the processor surface. However, it is a challenging task to achieve proper cooling of such electronic devices mentioned above because of their confined spaces and concentrated heat sources. Regarding this challenge, we introduced an ultra-thin heat pipe; this heat pipe consists of a special fiber wick structure named as "Center Fiber Wick" which can provide sufficient vapor space on the both sides of the wick structure. We also developed a cooling module that uses this kind of ultra-thin heat pipe to eliminate the hot spot issue. This cooling module consists of an ultra-thin heat pipe and a metal plate. By changing the width, the flattened thickness and the effective length of the ultra-thin heat pipe, several experiments have been conducted to characterize the thermal properties of the developed cooling module. In addition, other experiments were also conducted to determine the effects of changes in the number of heat pipes in a single module. Characterization and comparison of the module have also been conducted both experimentally and theoretically.

A method for the imbibition and germination of wheat seeds in space

NASA Technical Reports Server (NTRS)

Levine, H. G.; Piastuch, W. C.; Sager, J. C. (Principal Investigator)

1999-01-01

A method was developed for the reliable germination in space of wheat seeds on porous tube nutrient delivery systems. Germination paper strips were loosely rolled into cylinders and two seeds inserted close to the outer edges of each cylinder. This configuration: 1) directed the emerging shoots upward and roots downward, 2) was efficient in wicking moisture from the porous tubes, and 3) provided open areas for oxygen diffusion. Cotton tufts were inserted into the bottom crevices of the cylinders to fix the seeds in a mid-level position and cylinders were then storable (indefinitely) prior to the preprogrammed (on-orbit) initiation of imbibition. This method extends both the upper and lower ends of acceptable moisture levels for successful seed germination, increasing the probability of success for spaceflight applications where moisture availability is more variable than on Earth.

The effectiveness of isometric exercises as compared to general exercises in the management of chronic non-specific neck pain.

PubMed

Khan, Muhammad; Soomro, Rabail Rani; Ali, Syed Shahzad

2014-09-01

To evaluate the effectiveness of isometric exercises as compared to general exercises in chronic non-specific neck pain. For this randomised controlled trial total 68 patients (34 each group) with chronic non-specific neck pain were recruited from Alain Poly Clinic and Institute of Physical Medicine & Rehabilitation Dow University of Health Sciences, Karachi between May, 2012 and August, 2012. Simple randomisation method was used to assign participants into isometric exercise group and general exercise groups. The isometric exercise group performed exercises for neck muscle groups with a rubber band and general exercises group performed active range of movement exercises for all neck movements. Patients in both groups received 3 supervised treatment sessions per week for 12 weeks. Visual Analogue Scale (VAS), North wick Park Neck Pain Questionnaire and goniometer were used to assess pain, disability and neck range of movements at baseline and after 12 weeks. Both interventions showed statistically significant improvements in pain, function and range of movement p = 0.001f or isometric exercise group, p = 0.04 for general exercises group and p = 0.001 for range of movement. However, mean improvements in post intervention VAS score and North wick Park Neck Pain Questionnaire score was better in isometric exercises group as compared to general exercise group. In conclusion, both interventions are effective in the treatment of chronic non-specific neck pain however; isometric exercises are clinically more effective than general exercises.

Using Structured e-Forum to Support the Legislation Formation Process

NASA Astrophysics Data System (ADS)

Xenakis, Alexandros; Loukis, Euripides

Many public policy problems are 'wicked', being characterised by high complexity, many heterogeneous views and conflicts among various stakeholders, and also lack of mathematically 'optimal' solutions and predefined algorithms for calculating them. The best approach for addressing such problems is through consultation and argumentation among stakeholders. The e-participation research has investigated and suggested several ICT tools for this purpose, such as e-forum, e-petition and e-community tools. This paper investigates the use of an advanced ICT tool, the structured e-forum, for addressing such wicked problems associated with the legislation formation. For this purpose we designed, implemented and evaluated two pilot e-consultations on legislation under formation in the Parliaments of Austria and Greece using a structured e-forum tool based on the Issue Based Information Systems (IBIS) framework. The conclusions drawn reveal the advantages offered by the structured e-forum, but also its difficulties as well.

Wicked problems: a value chain approach from Vietnam's dairy product.

PubMed

Khoi, Nguyen Viet

2013-12-01

In the past few years, dairy industry has become one of the fastest growing sectors in the packaged food industry of Vietnam. However, the value-added creation among different activities in the value chain of Vietnam dairy sector is distributed unequally. In the production activities, the dairy farmers gain low value-added rate due to high input cost. Whereas the processing activities, which managed by big companies, generates high profitability and Vietnamese consumers seem to have few choices due to the lack of dairy companies in the market. These wicked problems caused an unsustainable development to the dairy value chain of Vietnam. This paper, therefore, will map and analyze the value chain of the dairy industry in Vietnam. It will also assess the value created in each activity in order to imply solutions for a sustainable development of Vietnam's dairy industry. M10, M11.

Fuel cell and system for supplying electrolyte thereto utilizing cascade feed

DOEpatents

Feigenbaum, Haim

1984-01-01

An electrolyte distribution supply system for use with a fuel cell having a wicking medium for drawing electrolyte therein is formed by a set of containers of electrolyte joined to respective fuel cells or groups thereof in a stack of such cells. The electrolyte is separately stored so as to provide for electrical isolation between electrolytes of the individual cells or groups of cells of the stack. Individual storage compartments are coupled by individual tubes, the ends of the respective tubes terminating on the wicking medium in each of the respective fuel cells. The individual compartments are filled with electrolyte by allowing the compartments to overflow such as in a cascading fashion thereby maintaining the requisite depth of electrolyte in each of the storage compartments. The individual compartments can also contain packed carbon fibers to provide a three stage electrolyte distribution system.

NASA Lewis Steady-State Heat Pipe Code Architecture

NASA Technical Reports Server (NTRS)

Mi, Ye; Tower, Leonard K.

2013-01-01

NASA Glenn Research Center (GRC) has developed the LERCHP code. The PC-based LERCHP code can be used to predict the steady-state performance of heat pipes, including the determination of operating temperature and operating limits which might be encountered under specified conditions. The code contains a vapor flow algorithm which incorporates vapor compressibility and axially varying heat input. For the liquid flow in the wick, Darcy s formula is employed. Thermal boundary conditions and geometric structures can be defined through an interactive input interface. A variety of fluid and material options as well as user defined options can be chosen for the working fluid, wick, and pipe materials. This report documents the current effort at GRC to update the LERCHP code for operating in a Microsoft Windows (Microsoft Corporation) environment. A detailed analysis of the model is presented. The programming architecture for the numerical calculations is explained and flowcharts of the key subroutines are given

Centaur Propellant Thermal Conditioning Study

NASA Technical Reports Server (NTRS)

Blatt, M. H.; Pleasant, R. L.; Erickson, R. C.

1976-01-01

A wicking investigation revealed that passive thermal conditioning was feasible and provided considerable weight advantage over active systems using throttled vent fluid in a Centaur D-1s launch vehicle. Experimental wicking correlations were obtained using empirical revisions to the analytical flow model. Thermal subcoolers were evaluated parametrically as a function of tank pressure and NPSP. Results showed that the RL10 category I engine was the best candidate for boost pump replacement and the option showing the lowest weight penalty employed passively cooled acquisition devices, thermal subcoolers, dry ducts between burns and pumping of subcooler coolant back into the tank. A mixing correlation was identified for sizing the thermodynamic vent system mixer. Worst case mixing requirements were determined by surveying Centaur D-1T, D-1S, IUS, and space tug vehicles. Vent system sizing was based upon worst case requirements. Thermodynamic vent system/mixer weights were determined for each vehicle.

Heat pipe heat rejection system and demonstration model for the nuclear electric propulsion (NEP) spacecraft

NASA Technical Reports Server (NTRS)

Ernst, D. M.

1981-01-01

The critical evaluation and subsequent redesign of the power conversion subsystem of the spacecraft are covered. As part of that evaluation and redesign, prototype heat pipe components for the heat rejection system were designed fabricated and tested. Based on the results of these tests in conjunction with changing mission requirements and changing energy conversion devices, new system designs were investigated. The initial evaluation and redesign was based on state-of-the-art fabrication and assembly techniques for high temperature liquid metal heat pipes and energy conversion devices. The hardware evaluation demonstrated the validity of several complicated heat pipe geometries and wick structures, including an annular-to-circular transition, bends in the heat pipe, long heat pipe condensers and arterial wicks. Additionally, a heat pipe computer model was developed which describes the end point temperature profile of long radiator heat pipes to within several degrees celsius.

Carbon Nanotube Bonding Strength Enhancement Using Metal "Wicking" Process

NASA Technical Reports Server (NTRS)

Lamb, James L.; Dickie, Matthew R.; Kowalczyk, Robert S.; Liao, Anna; Bronikowski, Michael J.

2012-01-01

Carbon nanotubes grown from a surface typically have poor bonding strength at the interface. A process has been developed for adding a metal coat to the surface of carbon nano tubes (CNTs) through a wicking process, which could lead to an enhanced bonding strength at the interface. This process involves merging CNTs with indium as a bump-bonding enhancement. Classical capillary theory would not normally allow materials that do not wet carbon or graphite to be drawn into the spacings by capillary action because the contact angle is greater than 90 degrees. However, capillary action can be induced through JPL's ability to fabricate oriented CNT bundles to desired spacings, and through the use of deposition techniques and temperature to control the size and mobility of the liquid metal streams and associated reservoirs. A reflow and plasma cleaning process has also been developed and demonstrated to remove indium oxide, and to obtain smooth coatings on the CNT bundles.

Assessing and managing stressors in a changing marine environment.

PubMed

Chapman, Peter M

2017-11-30

We are facing a dynamic future in the face of multiple stressors acting individually and in combination: climate change; habitat change/loss; overfishing; invasive species; harmful algal blooms/eutrophication; and, chemical contaminants. Historic assessment and management approaches will be inadequate for addressing risks from climate change and other stressors. Wicked problems (non-linear, complex, competing risks and benefits, not easily solvable), will become increasingly common. We are facing irreversible changes to our planetary living conditions. Agreed protection goals and considering both the negatives (risks) and the positives (benefits) of all any and all actions are required, as is judicious and appropriate use of the Precautionary Principle. Researchers and managers need to focus on: determining tipping points (alternative stable points); maintaining ecosystem services; and, managing competing ecosystem services. Marine (and other) scientists are urged to focus their research on wicked problems to allow for informed decision-making on a planetary basis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Does it always feel good to get what you want? Young children differentiate between material and wicked desires.

PubMed

Smith, Craig E; Warneken, Felix

2014-03-01

One line of research on children's attributions of guilt suggests that 3-year-olds attribute negative emotion to self-serving victimizers, slightly older children attribute happiness, and with increasing age, attributions become negative again (i.e., a three-step model; Yuill et al., 1996, Br. J. Dev. Psychol., 14, 457). Another line of research provides reason to expect that 3-year-olds may be predisposed to view self-serving moral transgression as leading to positive emotion; this is a linear developmental model in which emotion attributions to transgressors become increasingly negative over the course of childhood (e.g., Nunner-Winkler & Sodian, 1988, Child Dev., 59, 1323). However, key differences in methodology make it difficult to compare across these findings. The present study was designed to address this problem. We asked how 3- to 9-year-old children (n = 111) reason about transgression scenarios that involve satisfying wicked desires (wanting to cause harm and doing so successfully) versus material desires (wanting an object and getting it successfully via harmful behaviour). Three-year-old children reasoned differently about desire and emotion across these two types of transgressions, attributing negative emotion in the case of wicked desires and positive emotion in the case of material desires. This pattern of emotion attribution by young children provides new information about how young children process information about desires and emotions in the moral domain, and it bridges a gap in the existing literature on this topic. © 2013 The British Psychological Society.

Life Test Results for Water Heat Pipes Operating at 200 °C to 300 °C

NASA Astrophysics Data System (ADS)

Rosenfeld, John H.; Gernert, Nelson J.

2008-01-01

For lunar or planetary bases to be viable, a robust electric generating system will be required for powering the habitat. Water heat pipes offer an attractive solution for lunar base heat rejection, and would serve as a qualification for them on other long duration missions. Successful operation near the upper end of water operating range is a requirement for the application. Results are reported for life tests on water heat pipes that were operated at various temperatures between 200 °C and 300 °C. Tests were conducted on twenty three gravity-assisted water heat pipes. Eleven titanium/water heat pipes and ten Monel/water heat pipes were tested at temperatures above 200 °C. Two cupronickel heat pipes were also assembled and tested. Titanium alloys tested included CP-2 titanium, as well as two beta-titanium alloys, namely 15-3 and Nitinol alloys. Some of the titanium alloy life tests used wicks fabricated from CP-2 titanium screen or porous felt. Monel alloys tested included 400 and K-500 alloys. Some of the Monel heat pipes contained copper/nickel wicks that were fabricated by brazing nickel-plated copper felt metal wicks. Although most of the envelope/material combinations exhibit favorable results at 200 °C, some of the combinations failed at higher temperatures. Causes of failure included stress-creep of envelopes and corrosion at axial or end cap welds. This information represents a significant advance in selection of materials for 200 °C to 300 °C water heat pipes. Life testing work is being continued.

Enabling and enacting 'practical action' in catchments: responding to the 'wicked problem' of nonpoint source pollution in coastal subtropical Australia.

PubMed

Patterson, James J; Smith, Carl; Bellamy, Jennifer

2015-02-01

Enabling and enacting 'practical action' (i.e., purposeful and concerted collective action) in catchments is a key challenge in responding to a wide range of pressing catchment and natural resource management (NRM) issues. It is particularly a challenge in responding to 'wicked problems,' where generating action is not straightforward and cannot be brought about solely by any single actor, policy or intervention. This paper responds to the critical need to better understand how practical action can be generated in catchments, by conducting an in-depth empirical case study of efforts to manage nonpoint source (NPS) pollution in South East Queensland (SEQ), Australia. SEQ has seen substantial concerted efforts to manage waterway and catchment issues over two decades, yet NPS pollution remains a major problem for waterway health. A novel framework was applied to empirically analyze practical action in three local catchment cases embedded within the broader SEQ region. The analysis focuses on 'enabling capacities' underpinning practical action in catchments. Findings reveal that capacities manifested in different ways in different cases, yet many commonalities also occurred across cases. Interplay between capacities was critical to the emergence of adaptive and contextual forms of practical action in all cases. These findings imply that in order to enable and enact practical action in catchments, it is vital to recognize and support a diversity of enabling capacities across both local and regional levels of decision making and action. This is likely to have relevance for other 'wicked' catchment and NRM problems requiring local responses within broader multiscalar regional problem situations.

MOISTURE MOVEMENT (WICKING) WITHIN GYPSUM WALLBOARD

EPA Science Inventory

Gypsum wallboard with repeated or prolonged exposure to water or excess moisture can lose its structural integrity and provide a growth medium for biological contaminants. Poorly sealed buildings, leaking or failed plumbing systems, or improperly constructed HVAC systems can all ...

Measurement of heating coil temperature for e-cigarettes with a "top-coil" clearomizer.

PubMed

Chen, Wenhao; Wang, Ping; Ito, Kazuhide; Fowles, Jeff; Shusterman, Dennis; Jaques, Peter A; Kumagai, Kazukiyo

2018-01-01

To determine the effect of applied power settings, coil wetness conditions, and e-liquid compositions on the coil heating temperature for e-cigarettes with a "top-coil" clearomizer, and to make associations of coil conditions with emission of toxic carbonyl compounds by combining results herein with the literature. The coil temperature of a second generation e-cigarette was measured at various applied power levels, coil conditions, and e-liquid compositions, including (1) measurements by thermocouple at three e-liquid fill levels (dry, wet-through-wick, and full-wet), three coil resistances (low, standard, and high), and four voltage settings (3-6 V) for multiple coils using propylene glycol (PG) as a test liquid; (2) measurements by thermocouple at additional degrees of coil wetness for a high resistance coil using PG; and (3) measurements by both thermocouple and infrared (IR) camera for high resistance coils using PG alone and a 1:1 (wt/wt) mixture of PG and glycerol (PG/GL). For single point thermocouple measurements with PG, coil temperatures ranged from 322 ‒ 1008°C, 145 ‒ 334°C, and 110 ‒ 185°C under dry, wet-through-wick, and full-wet conditions, respectively, for the total of 13 replaceable coil heads. For conditions measured with both a thermocouple and an IR camera, all thermocouple measurements were between the minimum and maximum across-coil IR camera measurements and equal to 74% ‒ 115% of the across-coil mean, depending on test conditions. The IR camera showed details of the non-uniform temperature distribution across heating coils. The large temperature variations under wet-through-wick conditions may explain the large variations in formaldehyde formation rate reported in the literature for such "top-coil" clearomizers. This study established a simple and straight-forward protocol to systematically measure e-cigarette coil heating temperature under dry, wet-through-wick, and full-wet conditions. In addition to applied power, the composition of e-liquid, and the devices' ability to efficiently deliver e-liquid to the heating coil are important product design factors effecting coil operating temperature. Precautionary temperature checks on e-cigarettes under manufacturer-recommended normal use conditions may help to reduce the health risks from exposure to toxic carbonyl emissions associated with coil overheating.

Bottom-up fabrication of paper-based microchips by blade coating of cellulose microfibers on a patterned surface.

PubMed

Gao, Bingbing; Liu, Hong; Gu, Zhongze

2014-12-23

We report a method for the bottom-up fabrication of paper-based capillary microchips by the blade coating of cellulose microfibers on a patterned surface. The fabrication process is similar to the paper-making process in which an aqueous suspension of cellulose microfibers is used as the starting material and is blade-coated onto a polypropylene substrate patterned using an inkjet printer. After water evaporation, the cellulose microfibers form a porous, hydrophilic, paperlike pattern that wicks aqueous solution by capillary action. This method enables simple, fast, inexpensive fabrication of paper-based capillary channels with both width and height down to about 10 μm. When this method is used, the capillary microfluidic chip for the colorimetric detection of glucose and total protein is fabricated, and the assay requires only 0.30 μL of sample, which is 240 times smaller than for paper devices fabricated using photolithography.

Reduction in wick drain effectiveness with spacing for Utah silts and clays.

DOT National Transportation Integrated Search

2012-04-01

Although decreasing the spacing of vertical drains usually decreases the time for consolidation, previous field tests have shown that there is a critical drain spacing for which tighter spacing does not decrease the time for consolidation. This...

A bio-wicking system to mitigate capillary water in base course : final project report.

DOT National Transportation Integrated Search

2016-11-01

Water within pavement layers is the major cause of pavement deteriorations. High water content results in significant reduction in soils resilient behavior and increase in permanent deformation. Conventional drainage systems can only drain gravity...

Operational Evaluation of the Root Modules of the Advanced Plant Habitat

NASA Technical Reports Server (NTRS)

Monje, O.

2014-01-01

Photosynthetic and growth data were collected on APH Root Module. Described Stand pipe system for active moisture control. Tested germination in wicks. Evaluated EC-5 moisture sensors. Demonstrated that Wheat plants can grow in the APH Root Module.

Advanced designs for IPV nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Smithrick, J. J.; Manzo, M. A.; Gonzalez-Sanabria, O. D.

1984-01-01

Advanced designs for individual pressure vessel nickel-hydrogen cells have been concieved which should improve the cycle life at deep depths-of-discharge. Features of the designs which are new and not incorporated in either of the contemporary cells (Air Force/Hughes, Comsat) are: (1) use of alternate methods of oxygen recombination, (2) use of serrated edge separators to facilitate movement of gas within the cell while still maintaining required physical contact with the wall wick, and (3) use of an expandable stack to accommodate some of the nickel electrode expansion. The designs also consider electrolyte volume requirements over the life of the cells, and are fully compatible with the Air Force/Hughes design.

Paper-based microfluidics with an erodible polymeric bridge giving controlled release and timed flow shutoff.

PubMed

Jahanshahi-Anbuhi, Sana; Henry, Aleah; Leung, Vincent; Sicard, Clémence; Pennings, Kevin; Pelton, Robert; Brennan, John D; Filipe, Carlos D M

2014-01-07

Water soluble pullulan films were formatted into paper-based microfluidic devices, serving as a controlled time shutoff valve. The utility of the valve was demonstrated by a one-step, fully automatic implementation of a complex pesticide assay requiring timed, sequential exposure of an immobilized enzyme layer to separate liquid streams. Pullulan film dissolution and the capillary wicking of aqueous solutions through the device were measured and modeled providing valve design criteria. The films dissolve mainly by surface erosion, meaning the film thickness mainly controls the shutoff time. This method can also provide time-dependent sequential release of reagents without compromising the simplicity and low cost of paper-based devices.

Reinforced-soil embankment on soft foundation.

DOT National Transportation Integrated Search

2001-01-01

A section of I-670 in Columbus, OH, constructed during 1997-1998, includes a 33 ft. (l0 m) high embankment over a deposit of very soft sludge. The design used geosynthetics for reinforcement of the embankment and wick drains to accelerate the consoli...

Software for Scientists Facing Wicked Problems: Lessons from the VISTAS Project

EPA Science Inventory

The Visualization for Terrestrial and Aquatic Systems project (VISTAS) aims to help scientists produce effective environmental science visualizations for their own use and for use in presenting their work to a wide range of stakeholders (including other scientists, decision maker...

Teaching "with" Rather than "about" Geographic Information Systems

ERIC Educational Resources Information Center

Hammond, Thomas C.; Bodzin, Alec M.

2009-01-01

Both "teaching" and "teaching" with Geographic Information Systems (GIS) are "wicked problems," in the sense that they involve multiple variables that interact with one another. Effective teaching calls for both learning with understanding and transfer. The authors' own experience implementing a geography and…

4. EXTERIOR VIEW LOOKING EAST. WATER IN THE AQUEDUCT CAN ...

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

4. EXTERIOR VIEW LOOKING EAST. WATER IN THE AQUEDUCT CAN CAN BE DIVERTED AT THE WASTE WEIR TO BE DISCHARGED INTO THE CULVERT IN FOREGROUND. - Old Croton Aqueduct, Northern Waste Weir, Snowden Avenue & Van Wick Street, Ossining, Westchester County, NY

Validation of paper-based assay for rapid blood typing.

PubMed

Al-Tamimi, Mohammad; Shen, Wei; Zeineddine, Rania; Tran, Huy; Garnier, Gil

2012-02-07

We developed and validated a new paper-based assay for the detection of human blood type. Our method involves spotting a 3 μL blood sample on a paper surface where grouping antibodies have already been introduced. A thin film chromatograph tank was used to chromatographically elute the blood spot with 0.9% NaCl buffer for 10 min by capillary absorption. Agglutinated red blood cells (RBCs) were fixed on the paper substrate, resulting in a high optical density of the spot, with no visual trace in the buffer wicking path. Conversely, nonagglutinated RBCs could easily be eluted by the buffer and had low optical density of the spot and clearly visible trace of RBCs in the buffer wicking path. Different paper substrates had comparable ability to fix agglutinated blood, while a more porous substrate like Kleenex paper had enhanced ability to elute nonagglutinated blood. Using optimized conditions, a rapid assay for detection of blood groups was developed by spotting blood to antibodies absorbed to paper and eluted with 200 μL of 0.9% NaCl buffer directly by pipetting. RBCs fixation on paper accurately detected blood groups (ABO and RhD) using ascending buffer for 10 min or using a rapid elution step in 100/100 blood samples including 4 weak AB and 4 weak RhD samples. The assay has excellent reproducibility where the same blood group was obtained in 26 samples assessed in 2 different days. Agglutinated blood fixation on porous paper substrate provides a new, simple, and sensitive assay for rapid detection of blood group for point-of-care applications. © 2011 American Chemical Society

Perspectives of Light-Front Quantized Field Theory: Some New Results

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

Srivastava, Prem P.

1999-08-13

A review of some basic topics in the light-front (LF) quantization of relativistic field theory is made. It is argued that the LF quantization is equally appropriate as the conventional one and that they lead, assuming the microcausality principle, to the same physical content. This is confirmed in the studies on the LF of the spontaneous symmetry breaking (SSB), of the degenerate vacua in Schwinger model (SM) and Chiral SM (CSM), of the chiral boson theory, and of the QCD in covariant gauges among others. The discussion on the LF is more economical and more transparent than that found inmore » the conventional equal-time quantized theory. The removal of the constraints on the LF phase space by following the Dirac method, in fact, results in a substantially reduced number of independent dynamical variables. Consequently, the descriptions of the physical Hilbert space and the vacuum structure, for example, become more tractable. In the context of the Dyson-Wick perturbation theory the relevant propagators in the front form theory are causal. The Wick rotation can then be performed to employ the Euclidean space integrals in momentum space. The lack of manifest covariance becomes tractable, and still more so if we employ, as discussed in the text, the Fourier transform of the fermionic field based on a special construction of the LF spinor. The fact that the hyperplanes x{sup {+-}} = 0 constitute characteristic surfaces of the hyperbolic partial differential equation is found irrelevant in the quantized theory; it seems sufficient to quantize the theory on one of the characteristic hyperplanes.« less

Colon targeted delivery systems of metronidazole based on osmotic technology: development and evaluation.

PubMed

Kumar, Pramod; Singh, Sanjay; Mishra, Brahmeshwar

2008-09-01

Colon targeted delivery systems of metronidazole (MTZ) based on osmotic technology were developed. The developed systems consisted of osmotic core (drug, osmotic agent and wicking agent), coated with semipermeable membrane (SPM) containing guar gum as pore former, coated core were then further coated with enteric coating to protect the system from acidic environment of stomach. The effect of various formulation variables namely the level of wicking agent (sodium lauryl sulphate), osmotic agent in the osmotic core, the level of pore former (guar gum) in SPM, and the thickness of SPM, were studied on physical parameters and drug release characteristics of developed formulations. MTZ release was inversely proportional to SPM thickness, but directly related to the level of pore former, wicking agent and osmotic agent. On the other hand burst strength of the exhausted shells was decreased with the increase in level of pore former in the membrane but increased with the increase in the thickness of SPM. The drug release from the developed formulations was independent of pH, and agitation intensity, but dependent on the osmotic pressure of the release media. The thickness of enteric coating could prevent formation of delivery pores before contact with simulated colonic fluid, but had no effect on drug release. Result of SEM studies showed the formation of in-situ delivery pores in the membrane from where the drug release occurred, and the number of pores formed were directly related to the initial level of pore former (guar gum) in SPM. The manufacturing procedure was found to be reproducible and formulations were found to be stable during 3 months of accelerated stability studies.

Computer Supported Argument Visualisation: Modelling in Consultative Democracy Around Wicked Problems

NASA Astrophysics Data System (ADS)

Ohl, Ricky

In this case study, computer supported argument visualisation has been applied to the analysis and representation of the draft South East Queensland Regional Plan Consultation discourse, demonstrating how argument mapping can help deliver the transparency and accountability required in participatory democracy. Consultative democracy for regional planning falls into a category of problems known as “wicked problems”. Inherent in this environment is heterogeneous viewpoints, agendas and voices, built on disparate and often contradictory logic. An argument ontology and notation that was designed specifically to deal with consultative urban planning around wicked problems is the Issue Based Information System (IBIS) and IBIS notation (Rittel & Webber, 1984). The software used for argument visualisation in this case was Compendium, a derivative of IBIS. The high volume of stakeholders and discourse heterogeneity in this environment calls for a unique approach to argument mapping. The map design model developed from this research has been titled a “Consultation Map”. The design incorporates the IBIS ontology within a hybrid of mapping approaches, amalgamating elements from concept, dialogue, argument, debate, thematic and tree-mapping. The consultation maps developed from the draft South East Queensland Regional Plan Consultation provide a transparent visual record to give evidence of the themes of citizen issues within the consultation discourse. The consultation maps also link the elicited discourse themes to related policies from the SEQ Regional Plan providing explicit evidence of SEQ Regional Plan policy-decisions matching citizen concerns. The final consultation map in the series provides explicit links between SEQ Regional Plan policy items and monitoring activities reporting on the ongoing implementation of the SEQ Regional Plan. This map provides updatable evidence of and accountability for SEQ Regional Plan policy implementation and developments.

Characterization of particulate matter size distributions and indoor concentrations from kerosene and diesel lamps.

PubMed

Apple, J; Vicente, R; Yarberry, A; Lohse, N; Mills, E; Jacobson, A; Poppendieck, D

2010-10-01

Over one-quarter of the world's population relies on fuel-based lighting. Kerosene lamps are often located in close proximity to users, potentially increasing the risk for respiratory illnesses and lung cancer. Particulate matter concentrations resulting from cook stoves have been extensively studied in the literature. However, characterization of particulate concentrations from fuel-based lighting has received minimal attention. This research demonstrates that vendors who use a single simple wick lamp in high-air-exchange market kiosks will likely be exposed to PM(2.5) concentrations that are an order of magnitude greater than ambient health guidelines. Using a hurricane lamp will reduce exposure to PM(2.5) and PM(10) concentrations by an order of magnitude compared to using a simple wick lamp. Vendors using a single hurricane or pressure lamp may not exceed health standards or guidelines for PM(2.5) and PM(10), but will be exposed to elevated 0.02-0.3 μm particle concentrations. Vendors who change from fuel-based lighting to electric lighting technology for enhanced illumination will likely gain the ancillary health benefit of reduced particulate matter exposure. Vendors exposed only to ambient and fuel-based lighting particulate matter would see over an 80% reduction in inhaled PM(2.5) mass if they switched from a simple wick lamp to an electric lighting technology. Changing lighting technologies to achieve increased efficiency and energy service levels can provide ancillary health benefits. The cheapest, crudest kerosene lamps emit the largest amounts of PM(2.5). Improving affordability and access to better lighting options (hurricane or pressure lamps and lighting using grid or off-grid electricity) can deliver health benefits for a large fraction of the world's population, while reducing the economic and environmental burden of the current fuel-based lighting technologies.

Reinforced-soil embankment on soft foundation : executive summary.

DOT National Transportation Integrated Search

2000-01-01

A section of I-670 in Columbus, OH, constructed during 1997-1998, includes a 33 ft. (l0 m) high embankment over a deposit of very soft sludge. The design used geosynthetics for reinforcement of the embankment and wick drains to accelerate the consoli...

Sequentially Simulated Outcomes: Kind Experience versus Nontransparent Description

ERIC Educational Resources Information Center

Hogarth, Robin M.; Soyer, Emre

2011-01-01

Recently, researchers have investigated differences in decision making based on description and experience. We address the issue of when experience-based judgments of probability are more accurate than are those based on description. If description is well understood ("transparent") and experience is misleading ("wicked"), it…

Heat pipe technology for advanced rocket thrust chambers

NASA Technical Reports Server (NTRS)

Rousar, D. C.

1971-01-01

The application of heat pipe technology to the design of rocket engine thrust chambers is discussed. Subjects presented are: (1) evaporator wick development, (2) specific heat pipe designs and test results, (3) injector design, fabrication, and cold flow testing, and (4) preliminary thrust chamber design.

"In Honor of Excellence."

ERIC Educational Resources Information Center

Hughes, Anna May

1983-01-01

Spotlights seven outstanding secondary school theatre programs and their directors: Frank Bluestein, Germantown, TN; John Steele, Plano, TX; Joe Juliano, Hamden, CT; Jack Parkhurst, Ralston, NE; Robert Geuder (Thomas Jefferson High School) Cedar Rapids, IA; Judith Rethwisch (Affton High School) St. Louis, MO; and Henry Wicke (Packer Collegiate…

Boundary Spanning: Engagement across Disciplines, Communities, and Geography

ERIC Educational Resources Information Center

Paton, Valerie O.; Reith Charles C.; Harden, Karon K.; Abaurre, Rogério; Tremblay, Crystal

2014-01-01

Narratives from 3 presenters at the closing session of the 2013 Engagement Scholarship Consortium Conference demonstrate that higher education institutions and communities can forge deep and sustainable relationships to address the "wicked problems" in their countries and communities. University leaders in Nigeria described how students…

Heat driven pulse pump

NASA Technical Reports Server (NTRS)

Benner, Steve M (Inventor); Martins, Mario S. (Inventor)

2000-01-01

A heat driven pulse pump includes a chamber having an inlet port, an outlet port, two check valves, a wick, and a heater. The chamber may include a plurality of grooves inside wall of the chamber. When heated within the chamber, a liquid to be pumped vaporizes and creates pressure head that expels the liquid through the outlet port. As liquid separating means, the wick, disposed within the chamber, is to allow, when saturated with the liquid, the passage of only liquid being forced by the pressure head in the chamber, preventing the vapor from exiting from the chamber through the outlet port. A plurality of grooves along the inside surface wall of the chamber can sustain the liquid, which is amount enough to produce vapor for the pressure head in the chamber. With only two simple moving parts, two check valves, the heat driven pulse pump can effectively function over the long lifetimes without maintenance or replacement. For continuous flow of the liquid to be pumped a plurality of pumps may be connected in parallel.

Black Carbon and Kerosene Lighting: An Opportunity for Rapid Action on Climate Change and Clean Energy for Development

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

Jacobson, Arne; Bond, Tami C.; Lam, Nicholoas L.

2013-04-15

Replacing inefficient kerosene lighting with electric lighting or other clean alternatives can rapidly achieve development and energy access goals, save money and reduce climate warming. Many of the 250 million households that lack reliable access to electricity rely on inefficient and dangerous simple wick lamps and other kerosene-fueled light sources, using 4 to 25 billion liters of kerosene annually to meet basic lighting needs. Kerosene costs can be a significant household expense and subsidies are expensive. New information on kerosene lamp emissions reveals that their climate impacts are substantial. Eliminating current annual black carbon emissions would provide a climate benefitmore » equivalent to 5 gigatons of carbon dioxide reductions over the next 20 years. Robust and low-cost technologies for supplanting simple wick and other kerosene-fueled lamps exist and are easily distributed and scalable. Improving household lighting offers a low-cost opportunity to improve development, cool the climate and reduce costs.« less

Advanced thermal energy management: A thermal test bed and heat pipe simulation

NASA Technical Reports Server (NTRS)

Barile, Ronald G.

1986-01-01

Work initiated on a common-module thermal test simulation was continued, and a second project on heat pipe simulation was begun. The test bed, constructed from surplus Skylab equipment, was modeled and solved for various thermal load and flow conditions. Low thermal load caused the radiator fluid, Coolanol 25, to thicken due to its temperature avoided by using a regenerator-heat-exchanger. Other possible solutions modeled include a radiator heater and shunting heat from the central thermal bus to the radiator. Also, module air temperature can become excessive with high avionics load. A second preoject concerning advanced heat pipe concepts was initiated. A program was written which calculates fluid physical properties, liquid and vapor pressure in the evaporator and condenser, fluid flow rates, and thermal flux. The program is directed to evaluating newer heat pipe wicks and geometries, especially water in an artery surrounded by six vapor channels. Effects of temperature, groove and slot dimensions, and wick properties are reported.

Wetting in Color: Designing a colorometric indicator for wettability

NASA Astrophysics Data System (ADS)

Raymond, Kevin; Burgess, Ian B.; Koay, Natalie; Kolle, Mathias; Loncar, Marko; Aizenberg, Joanna

2012-02-01

Colorimetric litmus tests such as pH paper have enjoyed wide commercial success due to their inexpensive production and exceptional ease of use. While such indicators commonly rely on a specific photochemical response to an analyte, we exploit structural color, derived from coherent scattering from wavelength-scale porosity rather than molecular absorption or luminescence, to create a Wetting-in-Color-Kit (WICK). This inexpensive and highly selective colorimetric indicator for organic liquids employs chemically encoded inverse-opal photonic crystals to translate minute differences in liquids' wettability to macroscopically distinct, easy-to-visualize color patterns. The highly symmetric re-entrant inter-pore geometry imparts a highly specific wetting threshold for liquids. We developed surface modification techniques to generate built-in chemistry gradients within the porous network. These let us tailor the wettability threshold to specific liquids across a continuous range. As wetting is a generic fluidic phenomenon, we envision that WICK could be suitable for applications in authentication or identification of unknown liquids across a broad range of industries.

Heat pipe fatigue test specimen: Metallurgical evaluation

NASA Technical Reports Server (NTRS)

Walak, Steven E.; Cronin, Michael J.; Grobstein, Toni

1992-01-01

An innovative creep/fatigue test was run to simulate the temperature, mechanical load, and sodium corrosion conditions expected in a heat pipe designed to supply thermal energy to a Stirling cycle power converter. A sodium-charged Inconel 718 heat pipe with a Nickel 200 screen wick was operated for 1090 hr at temperatures between 950 K (1250 F) and 1050 K (1430 F) while being subjected to creep and fatigue loads in a servo-hydraulic testing machine. After testing, the heat pipe was sectioned and examined using optical microscopy, scanning electron microscopy, and electron microprobe analysis with wavelength dispersive x-ray spectroscopy. The analysis concentrated on evaluating topographic, microstructural, and chemical changes in the sodium exposed surfaces of the heat pipe wall and wick. Surface changes in the evaporator, condenser, and adiabatic sections of the heat pipe were examined in an effort to correlate the changes with the expected sodium environment in the heat pipe. This report describes the setup, operating conditions, and analytical results of the sodium heat pipe fatigue test.

Fuel cell elements with improved water handling capacity

NASA Technical Reports Server (NTRS)

Kindler, Andrew (Inventor); Lee, Albany (Inventor)

2001-01-01

New fuel cell components for use in liquid feed fuel cell systems are provided. The components include biplates and endplates, having a hydrophilic surface and allow high efficiency operation. Conductive elements and a wicking device also form a part of the fuel cell components of the invention.

Second quantization techniques in the scattering of nonidentical composite bodies

NASA Technical Reports Server (NTRS)

Norbury, J. W.; Townsend, L. W.; Deutchman, P. A.

1986-01-01

Second quantization techniques for describing elastic and inelastic interactions between nonidentical composite bodies are presented and are applied to nucleus-nucleus collisions involving ground-state and one-particle-one-hole excitations. Evaluations of the resultant collision matrix elements are made through use of Wick's theorem.

Corrosion free phosphoric acid fuel cell

DOEpatents

Wright, Maynard K.

1990-01-01

A phosphoric acid fuel cell with an electrolyte fuel system which supplies electrolyte via a wick disposed adjacent a cathode to an absorbent matrix which transports the electrolyte to portions of the cathode and an anode which overlaps the cathode on all sides to prevent corrosion within the cell.

Performance evaluation and accuracy of passive capillary samplers (PCAPs) for estimating real-time drainage water fluxes

USDA-ARS?s Scientific Manuscript database

Successful monitoring of pollutant transport through the soil profile requires accurate, reliable, and appropriate instrumentation to measure amount of drainage water or flux within the vadose layer. We evaluated the performance and accuracy of automated passive capillary wick samplers (PCAPs) for ...

Operationalizing Counter Threat Finance Strategies

DTIC Science & Technology

2014-12-01

paying with cash, check, or credit cards, a consumer can use a mobile phone to pay for a wide range of services, as well as for digital or hard...archive/publications-archive/tackling-wicked- problems, accessed on March 3, 2014. 3. Huns were a nomadic horse people migrating from Cen- tral Asia

Literacy Geography and Pedagogy: Imagining Translocal Research Alliances for Educational Justice

ERIC Educational Resources Information Center

Comber, Barbara

2017-01-01

This article explores the possible relationships between geography, literacy, pedagogy, and poverty. It characterizes poverty as a wicked problem, which sees economic inequality escalating in a number of neoliberal democracies. Key insights from theorists of economic inequality are summarized. The enduring nature of poverty in particular places is…

Wireless lysimeters for real-time online soil water monitoring

USDA-ARS?s Scientific Manuscript database

Identification of nitrate-nitrogen (NO3-N) in drainage water allows accessing the effectiveness of water quality management. A passive capillary wick-type lysimeter (PCAPs) was used to monitor water flux and NO3-N leached below the root zone under an irrigated cropping system. Wireless lysimeters we...

Streamlining the Discovery, Evaluation, and Integration of Data, Models, and Decision Support Systems: a Big Picture View

EPA Science Inventory

21st century environmental problems are wicked and require holistic systems thinking and solutions that integrate social and economic knowledge with knowledge of the environment. Computer-based technologies are fundamental to our ability to research and understand the relevant sy...

Applying Collective Impact to Wicked Problems in Aboriginal Health

ERIC Educational Resources Information Center

Gwynne, Kylie; Cairnduff, Annette

2017-01-01

Aboriginal people fare worse than other Australians in every measure of health, including in a ten-year gap in life expectancy, infant mortality, cardiovascular disease, dental disease, mental health, chronic disease and maternal health. Despite sustained government effort, progress to improve Aboriginal health has been very slow. The collective…

Teaching Strategy: Reflections on Professional Practice

ERIC Educational Resources Information Center

Ruth, Damian

2014-01-01

This paper explores how strategic management concepts, especially the notion of 'wicked problems', can be useful in analysing the professional practice of teachers in higher education. The keeping of a dialogical journal with a colleague helped illuminate that strategic management and education have much in common. Both are situated in…

Extension Agents and Conflict Narratives: A Case of Laikipia County, Kenya

ERIC Educational Resources Information Center

Bond, Jennifer

2016-01-01

Purpose: This work investigated the narratives of development extensionists in relation to natural resource conflict, in order to understand the competing discourses surrounding the wicked problems of natural resource management in Laikipia County, Kenya. Methodology: Q methodology was used to elicit the conflict narratives present among extension…

Military Leadership Preparedness to Meet Counterinsurgency Requirements

DTIC Science & Technology

2008-03-19

describes by Brian Holden Reid in a wicked spoof as a 6 “diminutive, blinking, bespectacled swot whose muscles compare with peas and who grows exhausted...Schoomaker “A Campaign Quality Army with Joint and Expeditionary Capabilities,” Parameters 34 (Summer 2004). 8 Lacquement, 212. 9 Steven M. Jones

Perspiration Thresholds and Secure Suspension for Lower Limb Amputees in Demanding Environments

DTIC Science & Technology

2015-10-01

VAPSHCS) site, fabricating custom, moisture-wicking textile sock with a proximal elastomeric seal, fabricating prosthetic sockets, fabricating electronic...Aims: This research has two specific aims: (1) determine if lower limb amputees are willing to use smart activity monitors as part of their daily life

Polycyclic Aromatic Hydrocarbons in Fine Particulate Matter Emitted from Burning Kerosene, Liquid Petroleum Gas, and Wood Fuels in Household Cookstoves

EPA Science Inventory

This study measured polycyclic aromatic hydrocarbon (PAH) composition in particulate matter emissions from residential cookstoves. A variety of fuel and cookstove combinations were examined, including: (i) liquid petroleum gas (LPG), (ii) kerosene in a wick stove, (iii) wood (10%...

ANALYSIS OF LEAD IN CANDLE PARTICULATE EMISSIONS BY XRF USING UNIQUANT 4

EPA Science Inventory

As part of an extensive program to study the small combustion sources of indoor fine particulate matter (PM), candles with lead-core wicks were burned in a 46-L glass flow- through chamber. The particulate emissions with aerodynamic diameters <10 micrometers (PM10) were captured ...

Initial performance of advanced designs for IPV nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Smithrick, John J.

1986-01-01

Advanced designs for individual pressure vessel nickel-hydrogen cells have been conceived which should improve the cycle life at deep depths-of-discharge and improve thermal management. Features of the designs which are new and not incorporated in either of the contemporary cells (Air Force/Hughes, Comsat) are: (1) use of alternate methods of oxygen recombination, (2) use of serrated edge separators to facilitate movement of gas within the cell while still maintaining required physical contact with the wall wick, and (3) use of an expandable stack to accommodate some of the nickel electrode expansion. The designs also consider electrolyte volume requirements over the life of the cells, and are fully compatible with the Air Force/Hughes design.

ION PUMP

DOEpatents

Milleron, N.

1961-01-01

An ion pump and pumping method are given for low vacuum pressures in which gases introduced into a pumping cavity are ionized and thereafter directed and accelerated into a quantity of liquid gettering metal where they are absorbed. In the preferred embodiment the metal is disposed as a liquid pool upon one electrode of a Phillips ion gauge type pump. Means are provided for continuously and remotely withdrawing and degassing the gettering metal. The liquid gettering metal may be heated if desired, although various combinations of gallium, indium, tin, bismuth, and lead, the preferred metals, have very low melting points. A background pressure of evaporated gettering metal may be provided by means of a resistance heated refractory metal wick protruding from the surface of the pcol of gettering metal.

Bipolar membranes with fluid distribution passages

NASA Technical Reports Server (NTRS)

Hitchens, G. Duncan (Inventor); Archer, Shivaun (Inventor); Tennakoon, Charles L. (Inventor); Gonzalez-Martin, Anuncia (Inventor); Cisar, Alan J. (Inventor)

1999-01-01

The present invention provides a bipolar membrane and methods for making and using the membrane. The bipolar membrane comprises a cation-selective region, an anion-selective region, an interfacial region between the anion-selective region and the cation-selective region, and means for delivering fluid directly into the interfacial region. The means for delivering fluid includes passages that may comprise a fluid-permeable material, a wicking material, an open passage disposed within the membrane or some combination thereof. The passages may be provided in many shapes, sizes and configurations, but preferably deliver fluid directly to the interfacial region so that the rate of electrodialysis is no longer limited by the diffusion of fluid through the cation- or anion-selective regions to the interfacial region.

Initial performance of advanced designs for IPV nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Smithrick, J. J.

1985-01-01

Advanced designs for individual pressure vessel nickel hydrogen cells were conceived which should improve the life cycle at deep depths of discharge and improve thermal management. Features of the designs which are new and not incorporated in either of the contemporary cells (Air Force/Hughes, Comsat) are: (1) the use of alternate methods of oxygen recombination, (2) use of serrated edge separators to facilitate movement of gas within the cell while still maintaining required physical contact with the wall wick, and (3) use of an expandable stack to accommodate some of the nickel electrode expansion. The designs also consider electrolyte volume requirements over the life of the cells, and are fully compatible with the Air Force/Hughes design.

Open-pore polyurethane product

DOEpatents

Jefferson, R.T.; Salyer, I.O.

1974-02-17

The method is described of producing an open-pore polyurethane foam having a porosity of at least 50% and a density of 0.1 to 0.5 g per cu cm, and which consists of coherent spherical particles of less than 10 mu diam separated by interconnected interstices. It is useful as a filter and oil absorbent. The product is admirably adapted to scavenging of crude oil from the surface of seawater by preferential wicking. The oil-soaked product may then be compressed to recover the oil or burned for disposal. The crosslinked polyurethane structures are remarkably solvent and heat-resistance as compared with known thermoplastic structures. Because of their relative inertness, they are useful filters for gasoline and other hydrocarbon compounds. (7 claims)

The wettability of selected organic soils in Poland

NASA Astrophysics Data System (ADS)

Całka, A.; Hajnos, M.

2009-04-01

The wettability was measured in the laboratory by means of two methods: Water Drop Penetration Time (WDPT) test and Thin Column Wicking (TCW) method. WDPT is fast and simple method and was used to investigate potential water repellency of analyzed samples. TCW is an indirect method and was used to determine contact angles and surface free energy components. The measurement was performed in horizontal teflon chambers for thin-layer chromatography, adapted for tubes 10 cm long. The experiment was carried out on muck soils (samples were taken from two levels of soil profile: 0-20 cm and 20-40 cm) and peat soils. There were two types of peats: low-moor peats and high moor peats. Samples of low-moor peats were taken from level 25-75 cm (alder peat) and 75-125cm (sedge peat) and 25-75 cm (peloid peat). Samples of high moor peats from level 25-175 cm (sphagnum peat) and 175-225 cm (sphagnum peat with Eriophorum). There was found no variability in persistence of potential water repellency but there were differences in values of contact angles of individual soil samples. Both muck and peat samples are extremely water repellent soils. Water droplets persisted on the surface of soils for more than 24 hours. Contact angles and surface free energy components for all samples were differentiated. Ranges of water contact angles for organic soils are from 27,54o to 96,50o. The highest values of contact angles were for sphagnum peats, and the lowest for muck soil from 20-40 cm level. It means, that there are differences in wettability between these samples. Muck soil is the best wettable and sphagnum peats is the worst wettable soil. If the content of organic compounds in the soil exceeds 40% (like in peats), the tested material displays only dispersion-type interactions. Therefore for peat soils, the technique of thin column wicking could only be used to determine the dispersive component γiLW. For muck soils it was also determined electron-acceptor (Lewis acid) γ+ and electron-donor (Lewis base) γ- surface free energy components. The authors gratefully acknowledge the Ministry of Science and Higher Education for financial support of this work (grant No. N N310 149335).

Use of H2Ri wicking fabric to prevent frost boils in the Dalton Highway Beaver Slide area, Alaska final report.

DOT National Transportation Integrated Search

2012-08-01

Many roads in Alaska, such as the Dalton Highway, experience degradation during spring thaw due to the downslope running of shallow groundwater. The water flow : down the slope and pools up in the road embankments, where it freezes, causing frost boi...

Evaluating Action Learning: A Critical Realist Complex Network Theory Approach

ERIC Educational Resources Information Center

Burgoyne, John G.

2010-01-01

This largely theoretical paper will argue the case for the usefulness of applying network and complex adaptive systems theory to an understanding of action learning and the challenge it is evaluating. This approach, it will be argued, is particularly helpful in the context of improving capability in dealing with wicked problems spread around…

Amino Acids in Nectar Enhance Longevity of Female Culex quinquefasciatus

DTIC Science & Technology

2010-01-01

via a piece of a saturated cotton dental wick (1 cm 4.5 cm) (Richmond Dental , Charlotte, NC). This assay was conducted separately from the...Ding, J., Wang, J.-L., Brakefield, P.M., Carey , J.R., Zwann, B.J., 2008. Amino acid sources in the adult diet do not affect lifespan and fecundity

The Guardians Initiative: A Student-Centered Approach to Bullying

ERIC Educational Resources Information Center

Toledo, Gregory

2008-01-01

Something wicked is being chased out of the classrooms and hallways at a high school in Massachusetts, something prevalent in schools across the globe: bullying. For generations, victims have carried invisible scars or nursed open wounds. Concerns related to bullying have been confirmed by extensive research over the past decade, including…

What Does "Wicked Good" Really Mean? Students Talk about Their ESL Problems.

ERIC Educational Resources Information Center

Celona, Jennie M.

1983-01-01

A survey of 25 international students studying in Massachusetts colleges gathered information on 4 specific aspects of their American college experience (recruitment, orientation, adaptation, and acculturation) as well as about their experiences with English. In interviews, nine students said they had had no problems with the English language;…

Prolonged Treadmill Load Carriage: Acute Injuries and Changes in Foot Anthropometry

DTIC Science & Technology

1990-06-01

keep the feet dry by wicking away foot moisture (15,16). Reynolds, et al (17) reported that antiperspirants may be a helpful measure in reducing the...Sports Medicine Digest. Vol. 11 No. 12:7, 1989. 17. Reynolds KL, Darrigrand A, Jackson R, Roberts D, Hamlet M. Effects of pedal antiperspirants on sweat

78 FR 62676 - Anthony E. Wicks, M.D. Decision and Order

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-22

... registration BW7987184, while listing his address as Pain Management of Winter Springs, 165 W. SR 434, Winter... practice address. Id. at 2, ] 5. \\2\\ Documentary evidence, which the Government acquired through... prescriptions for oxycodone,\\4\\ diazepam, and lorazepam.\\5\\ GX 15, at 2, ] 7; GX 13. \\3\\ The documentary...

46 CFR 160.151-15 - Design and performance of inflatable liferafts.

Code of Federal Regulations, 2013 CFR

2013-10-01

... deterioration from sunlight and salt spray, and resistant to absorption and wicking of water. (l) Inflation..., buckling, galvanic corrosion, or other incompatibilities. (e) Color (IMO LSA Code, as amended by Resolution... may not exceed 185 kg (407.8 lb), unless the liferaft is intended for launching into the water...

46 CFR 160.151-15 - Design and performance of inflatable liferafts.

Code of Federal Regulations, 2014 CFR

2014-10-01

... deterioration from sunlight and salt spray, and resistant to absorption and wicking of water. (l) Inflation..., buckling, galvanic corrosion, or other incompatibilities. (e) Color (IMO LSA Code, as amended by Resolution... may not exceed 185 kg (407.8 lb), unless the liferaft is intended for launching into the water...

46 CFR 160.151-15 - Design and performance of inflatable liferafts.

Code of Federal Regulations, 2012 CFR

2012-10-01

... deterioration from sunlight and salt spray, and resistant to absorption and wicking of water. (l) Inflation..., buckling, galvanic corrosion, or other incompatibilities. (e) Color (IMO LSA Code, as amended by Resolution... may not exceed 185 kg (407.8 lb), unless the liferaft is intended for launching into the water...

El Paso/Yslete schools Get-Away Special Space Shuttle student projects

NASA Technical Reports Server (NTRS)

Azar, S. S.

1984-01-01

Student projects for the Get Away Special (GAS) space shuttle program were summarized. Experimental topics included: seed germination, shrimp growth, liquid lasers, planaria regeneration, fluid dynamics (wicking), soil molds, antibiotics, crystallization, the symbiosis of yeast and fungi, and the performance of electronic chips. A brief experimental design is included for each project.

Optimists' Creed: Brave New Cyberlearning, Evolving Utopias (Circa 2041)

ERIC Educational Resources Information Center

Burleson, Winslow; Lewis, Armanda

2016-01-01

This essay imagines the role that artificial intelligence innovations play in the integrated living, learning and research environments of 2041. Here, in 2041, in the context of increasingly complex wicked challenges, whose solutions by their very nature continue to evade even the most capable experts, society and technology have co-evolved to…

Common Ground for Action Software and Professional Development to Support Online Deliberation in Classrooms

ERIC Educational Resources Information Center

Christelle, Andrea; Dillard, Kara N.; Lindaman, Kara

2018-01-01

The Common Ground for Action (CGA) online deliberation platform is a dynamic tool designed to encourage diverse group members to identify collective responses to deeply controversial or "wicked" public problems that have no simple solution. The program promotes authentic deliberation, while minimizing the tactics of horse-trading and…

The Wicked Problem of Information Sharing in Homeland Security - A Leadership Perspective

DTIC Science & Technology

2014-06-01

filled environment. One such coping strategy termed emotion work, describes how analysts manage their feelings to display a public face or bodily ...in many aspects of Western culture but 56 Jeff Conklin, Dialogue Mapping : Building Shared...effective, whether modifications should be 60 Conklin, Dialogue Mapping : Building Shared Understanding

NASA Lewis steady-state heat pipe code users manual

NASA Technical Reports Server (NTRS)

Tower, Leonard K.; Baker, Karl W.; Marks, Timothy S.

1992-01-01

The NASA Lewis heat pipe code was developed to predict the performance of heat pipes in the steady state. The code can be used as a design tool on a personal computer or with a suitable calling routine, as a subroutine for a mainframe radiator code. A variety of wick structures, including a user input option, can be used. Heat pipes with multiple evaporators, condensers, and adiabatic sections in series and with wick structures that differ among sections can be modeled. Several working fluids can be chosen, including potassium, sodium, and lithium, for which monomer-dimer equilibrium is considered. The code incorporates a vapor flow algorithm that treats compressibility and axially varying heat input. This code facilitates the determination of heat pipe operating temperatures and heat pipe limits that may be encountered at the specified heat input and environment temperature. Data are input to the computer through a user-interactive input subroutine. Output, such as liquid and vapor pressures and temperatures, is printed at equally spaced axial positions along the pipe as determined by the user.

NASA Lewis steady-state heat pipe code users manual

NASA Astrophysics Data System (ADS)

Tower, Leonard K.; Baker, Karl W.; Marks, Timothy S.

1992-06-01

The NASA Lewis heat pipe code was developed to predict the performance of heat pipes in the steady state. The code can be used as a design tool on a personal computer or with a suitable calling routine, as a subroutine for a mainframe radiator code. A variety of wick structures, including a user input option, can be used. Heat pipes with multiple evaporators, condensers, and adiabatic sections in series and with wick structures that differ among sections can be modeled. Several working fluids can be chosen, including potassium, sodium, and lithium, for which monomer-dimer equilibrium is considered. The code incorporates a vapor flow algorithm that treats compressibility and axially varying heat input. This code facilitates the determination of heat pipe operating temperatures and heat pipe limits that may be encountered at the specified heat input and environment temperature. Data are input to the computer through a user-interactive input subroutine. Output, such as liquid and vapor pressures and temperatures, is printed at equally spaced axial positions along the pipe as determined by the user.

Identification of Fungal Colonies on Ground Control and Flight Veggie Plant Pillows

NASA Technical Reports Server (NTRS)

Scotten, Jessica E.; Hummerick, Mary E.; Khodadad, Christina L.; Spencer, Lashelle E.; Massa, Gioia D.

2017-01-01

The Veggie system focuses on growing fresh produce that can be harvested and consumed by astronauts. The microbial colonies in each Veggie experiment are evaluated to determine the safety level of the produce and then differences between flight and ground samples. The identifications of the microbial species can detail risks or benefits to astronaut and plant health. Each Veggie ground or flight experiment includes six plants grown from seeds that are glued into wicks in Teflon pillows filled with clay arcillite and fertilizer. Fungal colonies were isolated from seed wicks, growth media, and lettuce (cv. 'Outredgeous') roots grown in VEG-01B pillows on ISS and in corresponding ground control pillows grown in controlled growth chambers. The colonies were sorted by morphology and identified using MicroSeq(TM) 500 16s rDNA Bacterial Identification System and BIOLOG GEN III MicroPlate(TM). Health risks for each fungal identification were then assessed using literature sources. The goal was to identify all the colonies isolated from flight and ground control VEG-01B plants, roots, and rooting medium and compare the resulting identifications.

Fluid balance within the canine anterolateral compartment and its relationship to compartment syndromes.

PubMed

Hargens, A R; Akeson, W H; Mubarak, S J; Owen, C A; Evans, K L; Garetto, L P; Gonsalves, M R; Schmidt, D A

1978-06-01

Fluid homeostasis within muscle compartments is maintained by four pressures: capillary blood pressure, capillary blood oncotic pressure, tissue-fluid pressure, and tissue fluid oncotic pressure. As determined in the canine anterolateral compartment, capillary blood pressure is 25 +/- 3 millimeters of mercury; capillary blood oncotic pressure, 26 +/- 3 millimeters of mercury, tissue-pbessure, -2 +/- 2 millimeters of mercury; and tissue-fluid oncotic pressure, 11 +/- 1 millimeters of mercury. The wick technique allows direct measurement of tissue-fluid pressure in skeletal muscle and, with minor modifications, is adapted to collect microsamples of interstitial fluid for determinations of tissue-fluid oncotic pressure. The wick technique detects very slight fluctuations in intracompartmental pressure such as light finger compression, injection of small volumes of fluid, and even pulsation due to adjacent arterial pressure. Adjacent muscle compartments may contain different tissue-fluid pressure due to impermeable osseofascial barriers. Our results obtained in canine muscle compartments pressurized by infusion of autologous plasma suggest that risks of muscle damage are significant at intracompartmental pressures greater than thirty millimeters of mercury.

Study of vapor flow into a capillary acquisition device. [for cryogenic rocket propellants

NASA Technical Reports Server (NTRS)

Dodge, F. T.; Bowles, E. B.

1982-01-01

An analytical model was developed that prescribes the conditions for vapor flow through the window screen of a start basket. Several original submodels were developed as part of this model. The submodels interrelate such phenomena as the effect of internal evaporation of the liquid, the bubble point change of a screen in the presence of wicking, the conditions for drying out of a screen through a combination of evaporation and pressure difference, the vapor inflow rate across a wet screen as a function of pressure difference, and the effect on wicking of a difference between the static pressure of the liquid reservoir and the surrounding vapor. Most of these interrelations were verified by a series of separate effects tests, which were also used to determine certain empirical constants in the models. The equations of the model were solved numerically for typical start basket designs, and a simplified start basket was constructed to verify the predictions, using both volatile and nonvolatile test liquids. The test results verified the trends predicted by the model.

Flexible Cryogenic Heat Pipe Development Program

NASA Technical Reports Server (NTRS)

1976-01-01

A heat pipe was designed for operation in the 100 - 200 K temperature range with maximum heat transport as a primary design goal; another designed for operation in the 15 - 100 K temperature range with maximum flexibility as a design goal. Optimum geometry and materials for the container and wicking systems were determined. The high power (100 - 200 K) heat pipe was tested with methane at 100 - 140 K, and test data indicated only partial priming with a performance limit of less than 50 percent of theoretical. A series of tests were conducted with ammonia at approximately 280 K to determine the performance under varying fluid charge and test conditions. The low temperature heat pipe was tested with oxygen at 85 - 95 K and with methanol at 295 - 315 K. Performance of the low temperature heat pipe was below theoretical predictions. Results of the completed testing are presented and possible performance limitation mechanisms are discussed. The lower-than-expected performance was felt to be due to small traces of non-condensible gases which prevented the composite wick from priming.

The effects of a moisture-wicking fabric shirt on the physiological and perceptual responses during acute exercise in the heat.

PubMed

De Sousa, Justin; Cheatham, Christopher; Wittbrodt, Matthew

2014-11-01

This study investigated the effects that a form fitted, moisture-wicking fabric shirt, promoted to have improved evaporative and ventilation properties, has on the physiological and perceptual responses during exercise in the heat. Ten healthy male participants completed two heat stress tests consisting of 45 min of exercise (50% VO2peak) in a hot environment (33 °C, 60% RH). One heat stress test was conducted with the participant wearing a 100% cotton short sleeved t-shirt and the other heat stress test was conducted with the participant wearing a short sleeved synthetic shirt (81% polyester and 19% elastane). Rectal temperature was significantly lower (P < 0.05) in the synthetic condition during the last 15 min of exercise. Furthermore, the synthetic polyester shirt retained less sweat (P < 0.05). As exercise duration increases, the ventilation and evaporation properties of the synthetic garment may prove beneficial in the preservation of body temperature during exercise in the heat. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Observations and model predictions of water skin temperatures at MTI core site lakes and reservoirs

NASA Astrophysics Data System (ADS)

Garrett, Alfred J.; Kurzeja, Robert J.; O'Steen, Byron L.; Parker, Matthew J.; Pendergast, Malcolm M.; Villa-Aleman, Eliel; Pagnutti, Mary A.

2001-08-01

The Savannah River Technology Center (SRTC) measured water skin temperatures at four of the Multi-spectral Thermal Imager (MTI) core sites. The depression of the skin temperature relative to the bulk water temperature ((Delta) T) a few centimeters below the surface is a complex function of the weather conditions, turbulent mixing in the water and the bulk water temperature. Observed skin temperature depressions range from near zero to more than 1.0 degree(s)C. Skin temperature depressions tend to be larger when the bulk water temperature is high, but large depressions were also observed in cool bodies of water in calm conditions at night. We compared (Delta) T predictions from three models (SRTC, Schlussel and Wick) against measured (Delta) T's from 15 data sets taken at the MTI core sites. The SRTC and Wick models performed somewhat better than the Schlussel model, with RMSE and average absolute errors of about 0.2 degree(s)C, relative to 0.4 degree(s)C for the Schlussel model. The average observed (Delta) T for all 15 databases was -0.7 degree(s)C.

Advanced radiator concepts utilizing honeycomb panel heat pipes

NASA Technical Reports Server (NTRS)

Fleischman, G. L.; Peck, S. J.; Tanzer, H. J.

1987-01-01

The feasibility of fabricating and processing moderate temperature range vapor chamber type heat pipes in a low mass honeycomb panel configuration for highly efficient radiator fins for potential use on the space station was investigated. A variety of honeycomb panel facesheet and core-ribbon wick concepts were evaluated within constraints dictated by existing manufacturing technology and equipment. Concepts evaluated include type of material, material and panel thickness, wick type and manufacturability, liquid and vapor communication among honeycomb cells, and liquid flow return from condenser to evaporator facesheet areas. A thin-wall all-welded stainless steel design with methanol as the working fluid was the initial prototype unit. It was found that an aluminum panel could not be fabricated in the same manner as a stainless steel panel due to diffusion bonding and resistance welding considerations. Therefore, a formed and welded design was developed. The prototype consists of ten panels welded together into a large panel 122 by 24 by 0.15 in., with a heat rejection capability of 1000 watts and a fin efficiency of essentially 1.0.

Rapid Generation of Superheated Steam Using a Water-containing Porous Material

NASA Astrophysics Data System (ADS)

Mori, Shoji; Okuyama, Kunito

Heat treatment by superheated steam has been utilized in several industrial fields including sterilization, desiccation, and cooking. In particular, cooking by superheated steam is receiving increased attention because it has advantages of reducing the salt and fat contents in foods as well as suppressing the oxidation of vitamin C and fat. In this application, quick startup and cut-off responses are required. Most electrically energized steam generators require a relatively long time to generate superheated steam due to the large heat capacities of the water in container and of the heater. Zhao and Liao (2002) introduced a novel process for rapid vaporization of subcooled liquid, in which a low-thermal-conductivity porous wick containing water is heated by a downward-facing grooved heating block in contact with the upper surface of the wick structure. They showed that saturated steam is generated within approximately 30 seconds from room-temperature water at a heat flux 41.2 kW⁄m2. In order to quickly generate superheated steam of approximately 300°C, which is required for cooking, the heat capacity of the heater should be as small as possible and the imposed heat flux should be so high enough that the porous wick is able to dry out in the vicinity of the contact with the heater and that the resulting heater temperature becomes much higher than the saturation temperature. The present paper proposes a simple structured generator to quickly produce superheated steam. Only a fine wire heater is contacted spirally on the inside wall in a hollow porous material. The start-up, cut-off responses and the rate of energy conversion for input power are investigated experimentally. Superheated steam of 300°C is produced in approximately 19 seconds from room-temperature water for an input power of 300 W. The maximum rate of energy conversion in the steady state is approximately 0.9.

Electroweak precision data and the Lee-Wick standard model

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

Underwood, Thomas E. J.; Zwicky, Roman

2009-02-01

We investigate the electroweak precision constraints on the recently proposed Lee-Wick standard model at tree level. We analyze low-energy, Z-pole (LEP1/SLC) and LEP2 data separately. We derive the exact tree-level low-energy and Z-pole effective Lagrangians from both the auxiliary field and higher derivative formulation of the theory. For the LEP2 data we use the fact that the Lee-Wick standard model belongs to the class of models that assumes a so-called 'universal' form which can be described by seven oblique parameters at leading order in m{sub W}{sup 2}/M{sub 1,2}{sup 2}. At tree level we find that Y=-m{sub W}{sup 2}/M{sub 1}{sup 2}more » and W=-m{sub W}{sup 2}/M{sub 2}{sup 2}, where the negative sign is due to the presence of the negative norm states. All other oblique parameters (S,X) and (T,U,V) are found to be zero. In the addendum we show how our results differ from previous investigations, where contact terms, which are found to be of leading order, have been neglected. The LEP1/SLC constraints are slightly stronger than LEP2 and much stronger than the low-energy ones. The LEP1/SLC results exclude gauge boson masses of M{sub 1}{approx_equal}M{sub 2}{approx}3 TeV at the 99% confidence level. Somewhat lower masses are possible when one of the masses assumes a large value. Loop corrections to the electroweak observables are suppressed by the standard {approx}1/(4{pi}){sup 2} factor and are therefore not expected to change the constraints on M1 and M{sub 2}. This assertion is most transparent from the higher derivative formulation of the theory.« less

Geoscience Laser Altimetry System (GLAS) Loop Heat Pipe Anomaly and On Orbit Testing

NASA Technical Reports Server (NTRS)

Baker, Charles; Butler, Dan; Grob, Eric; Jester, Peggy

2011-01-01

The Geoscience Laser Altimetry System (GLAS) is the sole instrument on the ICESat Satellite. On day 230 of 2003, the GLAS Component Loop Heat Pipe (CLHP) entered a slow circulation mode that resulted in the main electronics box reaching its hot safing temperature, after which the entire instrument was turned off. The CLHP had a propylene working fluid and was actively temperature controlled via a heater on the compensation chamber. The slow circulation mode happened right after a planned propulsive yaw maneuver with the spacecraft. It took several days to recover the CLHP and ensure that it was still operational. The recovery occurred after the entire instrument was cooled to survival temperatures and the CLHP compensation chamber cycled on a survival heater. There are several theories as to why this slow circulation mode exhibited itself, including: accumulation of Non-Condensible Gas (NCG), the secondary wick being under designed or improperly implemented, or an expanded (post-launch) leak across the primary wick. Each of these is discussed in turn, and the secondary wick performance is identified as the most likely source of the anomalous behavior. After the anomaly, the CLHP was controlled to colder temperatures to improve its performance (as the surface tension increases with lower temperature, as does the volume of liquid in the compensation chamber) and only precursor pulses occurred later in the mission. After GLAS s last laser failed, in late 2009, a decision was made to conduct engineering tests of both LHPs to try and duplicate this flight anomaly. The engineering tests consisted of control setpoint changes, sink changes, and one similar propulsive Yaw maneuver. The only test that showed any similar anomaly precursors on the CLHP was the propulsive maneuver followed by a setpoint increase. The ICESat Satellite was placed in a decaying orbit and ended its mission on August 30, 2010 in Barents Sea.

Normal order and extended Wick theorem for a multiconfiguration reference wave function

NASA Astrophysics Data System (ADS)

Kutzelnigg, Werner; Mukherjee, Debashis

1997-07-01

A generalization of normal ordering and of Wick's theorem with respect to an arbitrary reference function Φ as some generalized "physical vacuum" is formulated in a different (but essentially equivalent) way than that suggested previously by one of the present authors. Guiding principles are that normal order operators with respect to any reference state must be expressible as linear combinations of those with respect to the genuine vacuum, that the vacuum expectation value of a normal order operator must vanish (with respect to the vacuum to which it is in normal order), and that the well-known formalism for a single Slater determinant as physical vacuum must be contained as a special case. The derivation is largely based on the concepts of "Quantum Chemistry in Fock space," which means that particle-number-conserving operators (excitation operators) play a central role. Nevertheless, the contraction rules in the frame of a generalized Wick theorem are derived, that hold for non-particle-number-conserving operators as well. The contraction rules are formulated and illustrated in terms of diagrams. The contractions involve the "residual n-particle density matrices" λ, which are the irreducible (non-factorizable) parts of the conventional n-particle density matrices γ, in the sense of a cumulant expansion for the density. A spinfree formulation is presented as well. The expression of the Hamiltonian in normal order with respect to a multiconfiguration reference function leads to a natural definition of a generalized Fock operator. MC-SCF-theory is easily worked out in this context. The paper concludes with a discussion of the excited configurations and the first-order interacting space, that underlies a perturbative coupled cluster type correction to the MCSCF function for an arbitrary reference function, and with general implications of the new formalism, that is related to "internally contracted multireference configuration interaction." The present generalization of normal ordering is not only valid for arbitrary reference functions, but also if the reference state is an ensemble state.

Programmable diagnostic devices made from paper and tape.

PubMed

Martinez, Andres W; Phillips, Scott T; Nie, Zhihong; Cheng, Chao-Min; Carrilho, Emanuel; Wiley, Benjamin J; Whitesides, George M

2010-10-07

This paper describes three-dimensional microfluidic paper-based analytical devices (3-D microPADs) that can be programmed (postfabrication) by the user to generate multiple patterns of flow through them. These devices are programmed by pressing single-use 'on' buttons, using a stylus or a ballpoint pen. Pressing a button closes a small space (gap) between two vertically aligned microfluidic channels, and allows fluids to wick from one channel to the other. These devices are simple to fabricate, and are made entirely out of paper and double-sided adhesive tape. Programmable devices expand the capabilities of microPADs and provide a simple method for controlling the movement of fluids in paper-based channels. They are the conceptual equivalent of field-programmable gate arrays (FPGAs) widely used in electronics.

Interdisciplinarity in an Era of New Public Management: A Case Study of Graduate Business Schools

ERIC Educational Resources Information Center

Ryan, Suzanne; Neumann, Ruth

2013-01-01

In an era of rapid knowledge transmission and creation spurred on by advances in technology and globalisation, calls for interdisciplinarity to solve "wicked" problems are common. In the same era, universities are increasingly adopting new public management practices. The extent to which these practices affect knowledge production is an…

Reconsidering Social Science Theories in Natural Resource Management Continuing Professional Education

ERIC Educational Resources Information Center

Stummann, C. B.; Gamborg, C.

2014-01-01

Over 25 years ago, the "wicked problems" concept was introduced into forestry to describe the increasingly complex work situations faced by many natural resource management (NRM) professionals and at the same time the demand and frequency of public involvement in NRM issues also grew. Research on the impact of these changes for NRM…

Aboriginal Identity in Education Settings: Privileging Our Stories as a Way of Deconstructing the Past and Re-Imagining the Future

ERIC Educational Resources Information Center

Shay, Marnee; Wickes, Judi

2017-01-01

From Aboriginal Australian perspectives and experiences, Aunty Judi Wickes and Marnee Shay bring a cross-generational, critical race analysis of Aboriginal identities and how they are implicated in the schooling experiences of Aboriginal young people. Using autoethnography, Aunty Judi and Marnee discuss their educational experiences in the…

Mental Health Stigma and Communication and Their Intersections with Education. Wicked Problems Forum: Mental Health Stigma

ERIC Educational Resources Information Center

Smith, Rachel A.; Applegate, Amanda

2018-01-01

Roughly one in four Americans will experience a mental health issue during his or her lifetime (National Academy of Sciences, Engineering, and Medicine, 2016). The consequences of mental disorders can be profound: people with mental disorders experience higher rates of disability and mortality. People with depression and schizophrenia have a…

Automated Speech Intelligibility System for Head-Borne Personal Protective Equipment: Proof of Concept

DTIC Science & Technology

2008-04-01

selected as the listener headform for this effort. The HATS has binaural sound quality microphones inserted into the ear canals and rubber pinnae that...Blank 16 APPENDIX - WORD LISTS AND SUBJECT RESPONSES MRT Set 1 (spoken word is in bold type) kick, lick, sick, tick, wick, pick neat, beat , seat, meat

Action Learning for Organizational and Systemic Development: Towards a "Both-and" Understanding of "I" and "We"

ERIC Educational Resources Information Center

Rigg, Clare

2008-01-01

In public services delivery, action learning is increasingly employed in the hope of improving capacity to address complex, multi-casual and "wicked" social issues to improve the lives of citizens. Yet the understanding of how and why action learning might have potential for enhancing organizational or systemic capability rarely goes…

The Flipped Classroom, Disruptive Pedagogies, Enabling Technologies and Wicked Problems: Responding to "The Bomb in the Basement"

ERIC Educational Resources Information Center

Hutchings, Maggie; Quinney, Anne

2015-01-01

The adoption of enabling technologies by universities provides unprecedented opportunities for flipping the classroom to achieve student-centred learning. While higher education policies focus on placing students at the heart of the education process, the propensity for student identities to shift from partners in learning to consumers of…

Fostering Organizational Change through Deliberations: The Deliberative Jury in a University Setting

ERIC Educational Resources Information Center

Lindell, Juha

2014-01-01

Universities in Europe face a variety of reform initiatives, and university reform can be seen as a wicked problem that should be resolved through collaborative efforts. In Finland, there has been considerable resistance to proposed reforms, with university personnel complaining that they have not been heard. Students, on the other hand, seem…

Wicked Problems Forum: Immigration and Higher Education: From Me to We: Embracing Coperformative Witnessing and Critical Love in the Classroom

ERIC Educational Resources Information Center

Calafell, Bernadette Marie; Chuang, Andy Kai-chun

2018-01-01

Omar Swartz and Ware McGuffey's essay, "Migrating Pedagogy in American Universities: Cultivating Moral Imagination and Social Justice," available in this issue of "Communication Education," offers an overview of the current landscape in higher education and, in particular, the challenges immigrant students face, historically…

Foreign Television Programmes on New Zealand Television: Windows on the World or Wicked Imperialism?

ERIC Educational Resources Information Center

Lealand, Geoff

Focusing on the experience of New Zealand, this paper is a response to a 1978 essay which suggested that a study be done to compare the programming patterns of television in the developed countries of Australia and New Zealand. Significant differences between the two nations are presented, including conspicuous discrepancies in television…

Wicked Problems Forum: Immigration and Higher Education. Contours of a Storied Decolonial Pedagogy

ERIC Educational Resources Information Center

Chawla, Devika

2018-01-01

The author recounts her experiences as a South Asian-immigrant teaching public-speaking classes at an American higher education institution. In this paper, she illustrates how she puts to use her immigrant experience by accessing a storytelling mode of teaching and learning rooted in a postcolonial ethos. She humanizes, demystifies, and strives to…

"Mullin' the Yarndi" and Other Wicked Problems at a Multiracial Early Childhood Education Site in Regional Australia

ERIC Educational Resources Information Center

Kameniar, Barbara Maria; Imtoual, Alia; Bradley, Debra

2010-01-01

In this article, Grint's model of leadership is used to shape discussions of how "problems" are responded to in the context of a preschool in an Australian regional town. Authority styles are described as command, management, or leadership. These authority styles result in approaching problems as "crises," "tame…

On the Nature of Problems in Action Learning

ERIC Educational Resources Information Center

Edmonstone, John

2014-01-01

The article aims to explore the nature of problems in action learning. Beginning with Revans' distinction between problems and puzzles, it draws parallels with the notion of wicked and tame problems. It offers four means of considering problems in action learning--in terms of the locus of a set's work; from the viewpoint of an…

Development of a cryogenic rotating heat pipe joint

NASA Technical Reports Server (NTRS)

1978-01-01

The performance of two critical technology components required for a continuously rotatable heat pipe: (1) a low-leakage rotatable coupling for the heat pipe pressure vessel, and (2) a rotatable internal wick, is reported. Performance and leakage requirements were established based on 12 months operation of a cryogenic rotatable heat pipe on a satellite in earth orbit.

Demographic trends, the wildland-urban interface, and wildfire management

Treesearch

Roger B. Hammer; Susan I. Stewart; Volker C. Radeloff

2009-01-01

In this article, we provide an overview of the demographic trends that have impacted and will continue to impact the "wicked" wildfire management problem in the United States, with particular attention to the emergence of the wildland-urban interface (WUI). Although population growth has had an impact on the emergence of the WUI, the deconcentration of...

Design and fabrication of a four-man capacity urine wick evaporator system

NASA Technical Reports Server (NTRS)

1979-01-01

The integrated system was tested to determine the performance characteristics and limitations of the dual catalyst concept. The primary objective of the dual catalyst concept is to remove ammonia and other noxious substances in the gas phase and thereby eliminate the need for and current practice of chemically or electrochemically pretreating urine prior to distillation.

Promises Kept or Opportunities Lost: A Wicked Problem in Educational Leadership

ERIC Educational Resources Information Center

Beard, Karen Stansberry

2017-01-01

A novice principal's decision not to intervene on an ill-conceived policy prompts a parent to pursue a line of questioning administrators are not prepared for. In this case, a young man working through a high school transition while preparing for college is met with unexpected challenges in motivation. What the principal initially perceives as…

High efficiency vapor-fed AMTEC system for direct conversion. Appendices for final report

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

Anderson, W.G.; Bland, J.J.

1997-05-23

This report consists of four appendices for the final report. They are: Appendix A: 700 C Vapor-Fed AMTEC Cell Calculations; Appendix B: 700 C Vapor-Fed AMTEC Cell Parts Drawings; Appendix C: 800 C Vapor-Fed AMTEC Cell Calculations; and Appendix D: 800 C Wick-Pumped AMTEC Cell System Design.

Understanding the wicked nature of "unmanaged recreation" in Colorado's Front Range

Treesearch

Jeffrey J. Brooks; Patricia A. Champ

2006-01-01

Unmanaged recreation presents a challenge to both researchers and managers of outdoor recreation in the United States because it is shrouded in uncertainty resulting from disagreement over the definition of the problem, the strategies for resolving the problem, and the outcomes of management. Incomplete knowledge about recreation visitors’ values and relationships with...

Responding to Mental Health Issues in the College Classroom. Wicked Problems Forum: Mental Health Stigma

ERIC Educational Resources Information Center

Goldman, Zachary W.

2018-01-01

Concerns about the mental health of students have been documented at every level of formal education (cf., Castillo & Schwartz, 2013; Durlak & Wells, 1997; Soet & Sevig, 2006). Addressing the entirety of these concerns is beyond the scope of this forum, thus the author's comments are geared primarily toward higher education; however,…

Refining cotton-wick method for 15N plant labelling.

NASA Astrophysics Data System (ADS)

Fustec, Joëlle; Mahieu, Stéphanie

2010-05-01

The symbiosis Fabaceae/Rhizobiaceae plays a critical role in the nitrogen cycle. It gives the plant the ability to fix high amounts of atmospheric N. A part of this N can be transferred to the soil via rhizodeposition. The contribution of Fabaceae to the soil N pool is difficult to measure, since it is necessary for assessing N benefits for other crops, for soil biological activity, and for reducing water pollution in sustainable agriculture (Fustec, 2009). The aim of this study was to test and improve the reliability of the 15N cotton-wick method for measuring the soil N derived from plant rhizodeposition (Mahieu et al., 2007). The effects of the concentration of the 15N-urea labelling solution and of the feeding frequency (continuous or pulses) on the assessment of nitrogen rhizodeposition were studied in two greenhouse experiments using the field pea (Pisum sativum L.) and the non-nodulating isoline P2. The plant parts and the soil were prepared for 15N:14N measurements for assessing N rhizodeposition (Mahieu et al., 2009). The fraction of plants' belowground nitrogen allocated to rhizodeposition in both Frisson pea and P2 was 20 to more than 50% higher when plants were labelled continuously than when they were labelled using fortnightly pulses. Our results suggested that when 15N root enrichment was high, nitrogen rhizodeposition was underestimated only for plants that were 15N-fed by fortnightly pulses, and not in plants 15N-fed continuously. This phenomenon was especially observed for plants relying on symbiotic N fixation for N acquisition; it may be linked to the concentration of the labelling solution. In conclusion, N rhizodeposition assessment was strongly influenced by the 15N-feeding frequency and the concentration of the labelling solution. The estimation of N rhizodeposition was more reliable when plants were labelled continuously with a dilute solution of 15N urea. Fustec et al. 2009. Agron. Sustain. Dev., DOI 10.1051/agro/2009003, in press. Mahieu et al. 2007. Plant Soil 295, 193-205. Mahieu et al. 2009. Soil Biol. Biochem. 41, 2236-2243.

Method for braze-joining spirally wound tapes to inner walls of heat exchanger tubes

DOEpatents

Garrison, Melton E.

1984-01-01

The present invention is directed to a method of fabricating heat exchanger tubes in which twisted tapes are utilized for promoting turbulence and heat transfer. The method of the present invention provides for the brazing of the tapes to the inner walls of the tubes for enhancing heat transfer between the fluid within the conduit and a fluid medium outside of the conduit by conduction through the tape. The braze joint of the present invention is coextensive with the tape over the entire length thereof within the conduit. The practice of the present invention is achieved by placing a filler wire of brazing metal along the tape at a location removed from the side walls and then heating the conduit and tape sufficiently to effect the displacement of the filler metal by wicking to the contact point between the tape and the conduit wall to form a braze joint coextensive with the length of the tape within the conduit. This arrangement provides maximum heat transfer and assures that the tape is in contact with the conduit over the entire common length thereof.

Method for braze-joining spirally wound tapes to inner walls of heat exchanger tubes

DOEpatents

Garrison, M.E.

1982-09-03

The present invention is directed to a method of fabricating heat exchanger tubes in which twisted tapes are utilized for promoting turbulence and heat transfer. The method of the present invention provides for the brazing of the tapes to the inner walls of the tubes for enhancing heat transfer between the fluid within the conduit and a fluid medium outside of the conduit by conduction through the tape. The braze joint of the present invention is coextensive with the tape over the entire length thereof within the conduit. The practice of the present invention is achieved by placing a filler wire of brazing metal along the tape at a location removed from the side walls and then heating the conduit and tape sufficiently to effect the displacement of the filler metal by wicking to the contact point between the tape and the conduit wall to form a braze joint coextensive with the length of the tape within the conduit. This arrangement provides maximum heat transfer and assures that the tape is in contact with the conduit over the entire common length thereof.

Real Fantasies in Mathematics Education: Numeracy, Quantitative Reasoners, and Transdisciplinary Wicked Problems

ERIC Educational Resources Information Center

Craig, Jeffrey Carl

2017-01-01

This dissertation has seven chapters. In chapter one, I discuss through why I am doing this dissertation, my positionality, and how I learned from and with all of my committee members. Chapter two is where I situate my dissertation study through developing a social theory of quantitative literacy by translating a social theory of literacy (Barton…

Thermal Materials Drive Professional Apparel Line

NASA Technical Reports Server (NTRS)

2014-01-01

Johnson Space Center investigated phase change materials (PCMs) to use in spacesuit gloves to help maintain comfortable temperatures. Years later, Boston-based Ministry of Supply developed a dress shirt that incorporated the NASA-derived PCMs, could wick away moisture, and also control odors and bacterial growth. Deemed Apollo, the shirt performs like active wear and is available in white and oxford blue.

Deschool? Try Using Schools for Education First: The Educational Impasse in the Developing World. IDS Discussion Paper No. 6. Revised.

ERIC Educational Resources Information Center

Dore, Ronald

Schooling itself is not wicked, but schooling that seeks not to educate but merely to qualify is productive of many deplorable consequences (including "schooled" unemployment, irrelevance, ritualism, and cramping of the human spirit). The device of allocating occupational roles on the bases of certificates has only gradually replaced…

The Wicked Problem of Embedding Academic Literacies: Exploring Rhizomatic Ways of Working through an Adaptive Leadership Approach

ERIC Educational Resources Information Center

Benzie, Helen Joy; Pryce, Alison; Smith, Keith

2017-01-01

Embedding academic literacies in higher education courses has been a major focus of the work of learning advisers. A number of studies present the results of embedding in specific courses without discussing the processes of negotiation or the different people involved. This paper is about embedding academic literacies in the Business faculty as…

Analyzing genetic diversity in conifers...isozyme resolution by starch gel electrophoresis

Treesearch

M. Thompson Conkle

1972-01-01

Enzymes in forest tree materials can be resolved by starch gel electrophoresis. A gel slab is prepared in a mold assembled from glass and plastic. Wicks containing an aqueous extract of macerated plant material are inserted in the gel and processed. The gel is sliced, stained, examined, and photographed. Isozyme bands produced by differential migration of enzymes...

Euro-Philiacs, Euro-Sceptics and Europhobics: Higher Education Policy, Values and Institutional Research

ERIC Educational Resources Information Center

Neave, Guy

2005-01-01

The European higher education landscape is inhabited by three clans: the Euro-philiac, his wicked twin, the Euro-phobic and most interesting of all, the Euro-sceptic. This unholy trinity has long been with us. Though the recent Euro electoral fiasco has in all probability served to bolster the ranks of the second and third tribes.

Teachers, Students, and Ideological Bias in the College Classroom. Wicked Problems Forum: Freedom of Speech at Colleges and Universities

ERIC Educational Resources Information Center

Mazer, Joseph P.

2018-01-01

Discussions surrounding ideology and free speech on college and university campuses continually occur in the popular press. In this forum, Herbeck (see EJ1171161) chronicles several heated clashes over free speech that have recently erupted on campuses across the country, fueling news stories reported through traditional and social media. Issues…

Technological Innovation of Higher Education in New Zealand: A Wicked Problem?

ERIC Educational Resources Information Center

Marshall, Stephen

2016-01-01

New Zealand, like many countries, faces the challenge of building and sustaining an educated population. Particular challenges are posed by the need to educate an increasing proportion of the population to higher levels in order to support the growth of a modern skills and knowledge economy, as opposed to an economy built on low-cost labour and…

Analysis of amino acids in nectar from pitchers of Sarracenia purpurea (Sarraceniaceae).

PubMed

Dress, W; Newell, S; Nastase, A; Ford, J

1997-12-01

Sarracenia purpurea L. (northern pitcher plant) is an insectivorous plant with extrafloral nectar that attracts insects to a water-filled pitfall trap. We identified and quantified the amino acids in extrafloral nectar produced by pitchers of S. purpurea. Nectar samples were collected from 32 pitchers using a wick-sampling technique. Samples were analyzed for amino acids with reverse-phase high-performance liquid chromatography with phenylisothiocyanate derivatization. Detectable amounts of amino acids were found in each of the 32 nectar samples tested. Mean number of amino acids in a nectar sample was 9 (SD = 2.2). No amino acid was detected in all 32 samples. Mean amount of amino acids in a nectar sample (i.e., amount per wick) was 351.4 ng (SD = 113.2). Nine amino acids occurred in 20 of the 32 samples (aspartic acid, cysteine, glutamic acid, glycine, histidine, hydroxyproline, methionine, serine, valine) averaging 263.4 ng (SD = 94.9), and accounting for ~75% of the total amino acid content. Nectar production may constitute a significant cost of carnivory since the nectar contains amino acids. However, some insects prefer nectar with amino acids and presence of amino acids may increase visitation and capture of insect prey.

Biological control of invasive plant species: a reassessment for the Anthropocene.

PubMed

Seastedt, Timothy R

2015-01-01

The science of finding, testing and releasing herbivores and pathogens to control invasive plant species has achieved a level of maturity and success that argues for continued and expanded use of this program. The practice, however, remains unpopular with some conservationists, invasion biologists, and stakeholders. The ecological and economic benefits of controlling densities of problematic plant species using biological control agents can be quantified, but the risks and net benefits of biological control programs are often derived from social or cultural rather than scientific criteria. Management of invasive plants is a 'wicked problem', and local outcomes to wicked problems have both positive and negative consequences differentially affecting various groups of stakeholders. The program has inherent uncertainties; inserting species into communities that are experiencing directional or even transformational changes can produce multiple outcomes due to context-specific factors that are further confounded by environmental change drivers. Despite these uncertainties, biological control could play a larger role in mitigation and adaptation strategies used to maintain biological diversity as well as contribute to human well-being by protecting food and fiber resources. © 2014 The Author New Phytologist © 2014 New Phytologist Trust.

Oil-Impregnated Polyethylene Films

NASA Astrophysics Data System (ADS)

Mukherjee, Ranit; Habibi, Mohammad; Rashed, Ziad; Berbert, Otacilio; Shi, Shawn; Boreyko, Jonathan

2017-11-01

Slippery liquid-infused porous surfaces (SLIPS) minimize the contact angle hysteresis of a wide range of liquids and aqueous food products. Although hydrophobic polymers are often used as the porous substrate for SLIPS, the choice of polymer has been limited to silicone-based or fluorine-based materials. Hydrocarbon-based polymers, such as polyethylene, are cost effective and widely used in food packaging applications where SLIPS would be highly desirable. However, to date there have been no reports on using polyethylene as a SLIPS substrate, as it is considered highly impermeable. Here, we show that thin films of low-density polyethylene can be stably impregnated with carbon-based oils without requiring any surface modification. Wicking tests reveal that oils with sufficient chemical compatibility follow Washburn's equation. The nanometric effective pore size of the polyethylene does result in a very low wicking speed, but by using micro-thin films and a drawdown coater, impregnation can still be completed in under one second. The oil-impregnated polyethylene films promoted ultra-slippery behavior for water, ketchup, and yogurt while remaining durable even after being submerged in ketchup for over one month. This work was supported by Bemis North America (AT-23981).

Ultraviolet properties of the Higgs sector in the Lee-Wick standard model

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

Espinosa, Jose R.; Grinstein, Benjamin

2011-04-01

The Lee-Wick (LW) standard model (SM) offers a new solution to the hierarchy problem. We discuss, using effective potential techniques, its peculiar UV behavior. We show how quadratic divergences in the Higgs mass M{sub h} cancel as a result of the unusual dependence of LW fields on the Higgs background (in a manner reminiscent of little Higgses). We then extract from the effective potential the renormalization group evolution of the Higgs quartic coupling {lambda} above the LW scale. After clarifying an apparent discrepancy with previous results for the LW Abelian Higgs model, we focus on the LWSM. In contrast withmore » the SM case, for any M{sub h}, {lambda} grows monotonically and hits a Landau pole at a fixed trans-Planckian scale (never turning negative in the UV). Then, the perturbativity and stability bounds on M{sub h} disappear. We identify a cutoff {approx}10{sup 16} GeV for the LWSM due to the hypercharge gauge coupling hitting a Landau pole. Finally, we also discuss briefly the possible impact of the UV properties of the LW models on their behavior at finite temperature, in particular, regarding symmetry nonrestoration.« less

Generalized Lee-Wick formulation from higher derivative field theories

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

Cho, Inyong; Kwon, O-Kab; Department of Physics, BK21 Physics Research Division, Institute of Basic Science, Sungkyunkwan University, Suwon 440-746

2010-07-15

We study a higher derivative (HD) field theory with an arbitrary order of derivative for a real scalar field. The degree of freedom for the HD field can be converted to multiple fields with canonical kinetic terms up to the overall sign. The Lagrangian describing the dynamics of the multiple fields is known as the Lee-Wick (LW) form. The first step to obtain the LW form for a given HD Lagrangian is to find an auxiliary field (AF) Lagrangian which is equivalent to the original HD Lagrangian up to the quantum level. Until now, the AF Lagrangian has been studiedmore » only for N=2 and 3 cases, where N is the number of poles of the two-point function of the HD scalar field. We construct the AF Lagrangian for arbitrary N. By the linear combinations of AF fields, we also obtain the corresponding LW form. We find the explicit mapping matrices among the HD fields, the AF fields, and the LW fields. As an exercise of our construction, we calculate the relations among parameters and mapping matrices for N=2, 3, and 4 cases.« less

Design, fabrication and test of a hydrogen heat pipe. [extruding and grooving 6063-T6 aluminum tubes for cryogenic heat pipes

NASA Technical Reports Server (NTRS)

Alario, J.

1979-01-01

Re-entrant groove technology was extended to hydrogen heat pipes. Parametric analyses are presented which optimize the theoretical design while considering the limitations of state-of-the-art extrusion technology. The 6063-T6 aluminum extrusion is 14.6 mm OD with a wall thickness of 1.66 mm and contains 20 axial grooves which surround a central 9.3 mm diameter vapor core. Each axial groove is 0.775 mm diameter with a 0.33 mm opening. An excess vapor reservoir is provided at the evaporator to minimize the pressure containment hazard during ambient storage. Modifications to the basic re-entrant groove profile resulted in improved overall performance. While the maximum heat transport capacity decreased slightly to 103 w-m the static wicking height increased markedly to 4.5 cm. The heat pipe became operational between 20 and 30 K after a cooldown from 77 K without any difficulty. Steady state performance data taken over a 19 to 23 K temperature range indicated: (1) maximum heat transport capacity of 5.4 w-m; (2) static wicking height of 1.42 cm; and (3) overall heat pipe conductance of 1.7 watts/deg C.

The series product for gaussian quantum input processes

NASA Astrophysics Data System (ADS)

Gough, John E.; James, Matthew R.

2017-02-01

We present a theory for connecting quantum Markov components into a network with quantum input processes in a Gaussian state (including thermal and squeezed). One would expect on physical grounds that the connection rules should be independent of the state of the input to the network. To compute statistical properties, we use a version of Wicks' theorem involving fictitious vacuum fields (Fock space based representation of the fields) and while this aids computation, and gives a rigorous formulation, the various representations need not be unitarily equivalent. In particular, a naive application of the connection rules would lead to the wrong answer. We establish the correct interconnection rules, and show that while the quantum stochastic differential equations of motion display explicitly the covariances (thermal and squeezing parameters) of the Gaussian input fields we introduce the Wick-Stratonovich form which leads to a way of writing these equations that does not depend on these covariances and so corresponds to the universal equations written in terms of formal quantum input processes. We show that a wholly consistent theory of quantum open systems in series can be developed in this way, and as required physically, is universal and in particular representation-free.

Modeling of a heat sink and high heat flux vapor chamber

NASA Astrophysics Data System (ADS)

Vadnjal, Aleksander

An increasing demand for a higher heat flux removal capability within a smaller volume for high power electronics led us to focus on a novel cold plate design. A high heat flux evaporator and micro channel heat sink are the main components of a cold plate which is capable of removing couple of 100 W/cm2. In order to describe performance of such porous media device a proper modeling has to be addressed. A universal approach based on the volume average theory (VAT) to transport phenomena in porous media is shown. An approach on how to treat the closure for momentum and energy equations is addressed and a proper definition for friction factors and heat transfer coefficients are discussed. A numerical scheme using a solution to Navier-Stokes equations over a representative elementary volume (REV) and the use of VAT is developed to show how to compute friction factors and heat transfer coefficients. The calculation show good agreement with the experimental data. For the heat transfer coefficient closure, a proper average for both fluid and solid is investigated. Different types of heating are also investigated in order to determine how it influences the heat transfer coefficient. A higher heat fluxes in small area condensers led us to the micro channels in contrast to the classical heat fin design. A micro channel can have various shapes to enhance heat transfer, but the shape that will lead to a higher heat flux removal with a moderate pumping power needs to be determined. The standard micro-channel terminology is usually used for channels with a simple cross section, e.g. square, round, triangle, etc., but here the micro channel cross section is going to be expanded to describe more complicated and interconnected micro scale channel cross sections. The micro channel geometries explored are pin fins (in-line and staggered) and sintered porous micro channels. The problem solved here is a conjugate problem involving two heat transfer mechanisms; (1) porous media conductivity and (2) internal heat transfer coefficient. Volume averaging theory (VAT) is used to rigorously cast the point wise conservation of energy, momentum and mass equations into a form that represents the thermal and hydraulic properties of the micro channel (porous media) morphology. Using the resulting VAT based field equations, optimization of a micro channel heated from one side is used to determine the optimum micro channel morphology. A small square of 1 cm2 is chosen as an example and the thermal resistance, 0C/W, and pressure drop are shown as a function of Reynolds number. The high heat flux removal on small surfaces at moderately small temperatures is achieved by bi-porous evaporator The device was analyzed with the possibility of heat flux magnitudes exceeding 1kW/cm2 by using advantages of a dual pore structure of a bi-porous wick. The heat transfer model of a thin bi-porous wick is developed and it incorporates thermo-physical properties of a bi-porous media. It is shown that physics of heat removal is characterized in three stages; conduction, big pore drying out and small pore drying out. The operating conditions of the wick have to be in a safe margin away from the total dry out. A complete dry out of the wick inevitably leads to the burn out, therefore more concern has been added to modeling of big pore dry out, since this will be a desired operational. The construction of the boiling/evaporation curves was successfully constructed by the model showing that the physic of heat removal on two different length scales is governed by thermo-physical properties for the appropriate scale. The model shows good prediction for various combinations of big and small pores size in the bi-porous wicks tested.

Sodium heat pipe use in solar Stirling power conversion systems

NASA Astrophysics Data System (ADS)

Zimmerman, W. F.; Divakaruni, S. M.; Won, Y. S.

1980-08-01

Sodium heat pipes were selected for use as a thermal transport method in a focus-mounted, distributed concentrator solar Stirling power conversion system intended to produce 15-20 kWe per unit. Heat pipes were used both to receive thermal power in the solar receiver and to transmit it to a secondary heat pipe containing both latent heat salt (for up to 1.25 hours of thermal storage) and the heat exchanger of the Stirling engine. Experimental tests were performed on five solar receiver heat pipes with various internal wicking configurations. The performance of the heat pipes at various power levels and operating attitudes was investigated at temperatures near 1550 F; the unidirectional heat transfer in these heat pipes was demonstrated in normal operating attitudes and particularly in the inverted position required during overnight stowage of the concentrator.

Amplitudes for multiphoton quantum processes in linear optics

NASA Astrophysics Data System (ADS)

Urías, Jesús

2011-07-01

The prominent role that linear optical networks have acquired in the engineering of photon states calls for physically intuitive and automatic methods to compute the probability amplitudes for the multiphoton quantum processes occurring in linear optics. A version of Wick's theorem for the expectation value, on any vector state, of products of linear operators, in general, is proved. We use it to extract the combinatorics of any multiphoton quantum processes in linear optics. The result is presented as a concise rule to write down directly explicit formulae for the probability amplitude of any multiphoton process in linear optics. The rule achieves a considerable simplification and provides an intuitive physical insight about quantum multiphoton processes. The methodology is applied to the generation of high-photon-number entangled states by interferometrically mixing coherent light with spontaneously down-converted light.

Sodium heat pipe use in solar Stirling power conversion systems

NASA Technical Reports Server (NTRS)

Zimmerman, W. F.; Divakaruni, S. M.; Won, Y. S.

1980-01-01

Sodium heat pipes were selected for use as a thermal transport method in a focus-mounted, distributed concentrator solar Stirling power conversion system intended to produce 15-20 kWe per unit. Heat pipes were used both to receive thermal power in the solar receiver and to transmit it to a secondary heat pipe containing both latent heat salt (for up to 1.25 hours of thermal storage) and the heat exchanger of the Stirling engine. Experimental tests were performed on five solar receiver heat pipes with various internal wicking configurations. The performance of the heat pipes at various power levels and operating attitudes was investigated at temperatures near 1550 F; the unidirectional heat transfer in these heat pipes was demonstrated in normal operating attitudes and particularly in the inverted position required during overnight stowage of the concentrator.

Crack Growth Behavior of Alloy in-100 under Sustained Load at 732 C (1350 F).

DTIC Science & Technology

1981-04-01

were not taken into account in this investigation. pi 63 63 AFWAL-TR-80-4131 REFERENCES 1. D. E. Macha , "Fatigue Crack Growth Retardation Behavior of...IN-1O0 at Elevated Temperature," Eng. Fract. Mech, Vol. 12, pp. 1-11, 1979. 2. D. E. Macha , A. F. Grandt, and B. J. Wicks, "Effects of Gas Turbine

Explanation and the Theory of Expert Problem Solving

DTIC Science & Technology

1990-02-01

specified output, Our work has aimed to identify the individual generic tasks, to analyze them properly, and to clarify their relationships to more...coverage of hypotheses must be tractable. that there cannot be many incompatibility relationships or cancellation effects between individual hypotheses. and...no necessary relationship between this justificatory argument and the actual reasoning that produced the solution. In Wick’s system the explanation

"Should I Stay or Should I Go?": Unpacking Teacher Attrition/Retention as an Educational Issue

ERIC Educational Resources Information Center

Kelchtermans, Geert

2017-01-01

The paper starts from the observation that teacher attrition/retention seems to be a wicked issue: it seems to have strong face validity and a commonsense meaning, but the literature doesn't provide a clear and distinctive definition. In the first section, the author analyzes the different ways in which the issue of teacher attrition and retention…

Radio Frequency Tomography for Tunnel Detection

DTIC Science & Technology

2010-03-01

F. Soldovieri is with the Istituto per il Rilevamento Elettromagnetico dell’Ambiente, Italian National Research Council (CNR), 80124 Naples, Italy ...both directions. ACKNOWLEDGMENT The authors would like to thank J. Parker and Dr. M. Ferrara , Air Force Research Laboratory, Prof. R. Ansari...Monte, D. Erricolo, and M. C. Wicks, “Propagation model, optimal geometry and receiver design for RF geotomography,” in Proc. IEEE RadarCon, Rome, Italy

Systemic Review and Meta-analysis of Randomized Clinical Trials Comparing Primary vs Delayed Primary Skin Closure in Contaminated and Dirty Abdominal Incisions

DTIC Science & Technology

2013-06-26

Chatwiriyacharoen14 Betadine gauze Unclear 5 Unclear Until suitable for suture Purulent dis- charge or mate- rial or surround- ing cellulitis Unclear Reopened and...Opened McGreal et al20 Povidone-io- dine (1%)- soaked wick Subcuticu- lar suture 4 Unclear Steri-Strips on day 4 Cellulitis , cul- ture-positive

Heat Recovery at Army Materiel Command (AMC) Facilities

DTIC Science & Technology

1988-06-01

industrial complexes and somewhat smaller commercial/ HVAC ** systems, a portion of this waste heat can be recovered, improving energy efficiency. Heat...devices are used in sequence. Other shell-and-tube applications include heat transfer from process liquids, condensates, and cooling water. Two...pipe consists of a sealed element involving an annular capillary wick con- tained inside the full length of the tube, with an appropriate entrained

Design and Development of a Segmented Magnet Homopolar Torque Converter

DTIC Science & Technology

1975-07-01

configuration Hydrostatically-positioned seal ( sealed drain) Hydrostatically-positioned seal Power- leakage relationship for a single annular seal lip... Seal 1. conducting wick - stationary/rotating, fiber, foam 2. hydrodynamic/hydrostatic 3. flooded (alternately) labyrinth C. Low-Speed Flooding...between collectors may be used to introduce oil droplets to lubricate the seals and to drain any NaK leakage that might occur Alternatively, they

Confronting the implications of wicked problems: changes needed in Sierra Nevada National Forest planning and problem solving

Treesearch

Hal Salwasser

2004-01-01

Thirty years ago, the fate of migratory deer in the Sierra Nevada was thought to be the major forest wildlife issue. Ten years later, agencies were building the California Wildlife Habitat Relationships System to allow managers to integrate all terrestrial vertebrates with timber management in comprehensive National Forest planning. Another ten years after that, Tom...

High-Capacity Heat-Pipe Evaporator

NASA Technical Reports Server (NTRS)

Oren, J. A.; Duschatko, R. J.; Voss, F. E.; Sauer, L. W.

1989-01-01

Heat pipe with cylindrical heat-input surface has higher contact thermal conductance than one with usual flat surface. Cylindrical heat absorber promotes nearly uniform flow of heat into pipe at all places around periphery of pipe, helps eliminate hotspots on heat source. Lugs in aluminum pipe carry heat from outer surface to liquid oozing from capillaries of wick. Liquid absorbs heat, evaporates, and passes out of evaporator through interlug passages.

The Normalizing of Hate Speech and How Communication Educators Should Respond. Wicked Problems Forum: Freedom of Speech at Colleges and Universities

ERIC Educational Resources Information Center

Waltman, Michael S.

2018-01-01

Whereas hate is defined as extreme negative feelings for others because of some aspect of their identity (Perry, 2001; Waltman & Haas, 2011), hate speech is discourse devoted to the vilification of the other's identity (Waltman, 2015; Waltman & Mattheis, 2017). It is an attempt to vandalize the other's identity to such an extent that the…

Transsexualism and Flight Safety

DTIC Science & Technology

1987-05-08

Security Classification) Transsexualism and Flight Safety 12. PERSONAL AUTHOR(S) Clements, Thomas I. and Wicks, Roland E. 13a. TYPE OF REPORT 13b. TIME... transsexual pilot with questionable judgment affecting flight safety is reported. The definition, etiology, and presenting symptoms are discussed. Three...involve all the phases of therapy and can be significant. Though the transsexual tends to have more episodes of anxiety and depression than the norm

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.

Silicon Heat Pipe Array

NASA Technical Reports Server (NTRS)

Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.

2013-01-01

Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better suited for the cooling of semiconductor devices.

Transforming Conflict into Effective Action: A Case Study on the Effects of Anthropogenic Sound on Marine Mammals

NASA Astrophysics Data System (ADS)

Lewandowski, Jill K.

Like many wicked environmental problems of our time, marine sound and its potential effects on marine mammals is characterized by high levels of scientific uncertainty, diversified values across many stakeholder groups, political and regulatory complexities, and a continually evolving ecological and social environment. Further, the history of conflict and the relationships between major actors has rooted the issue firmly in identity conflict where prejudices lead to avoidance of working together. What results is continuing controversy, failed management decisions, litigation and an increasing frustration by all parties on why a better solution cannot be found. Ultimately, the intractability of the issue is not about the science, nor will the science ever tame the issue on its own. Rather, the issue is intractable because of the conflict between people about the most appropriate path forward. It is then imperative to understand, address, and transform this conflict in order to move off the decision carousel toward improved conservation outcomes and sustainable decisions for all. This research used an explanatory case study approach to quantitatively and qualitatively investigate the context and reasoning underlying conflict on this issue. Three methods were used in order to triangulate the data, and thus add rigor, including: (1) a document review of 230 publications: (2) exploratory interviews with 10 collaborative action experts and semi-structured interviews with 58 marine mammals and sound stakeholders; and (3) participant review of selected analyses. Data elucidate how different stakeholder groups define the problem and potential solutions, how they see their role and view the role of other stakeholders, specific experiences that increased or decrease conflict, and design preferences for a collaborative effort. These data are combined with conflict transformation principles to provide recommendations for a collaborative, transformative framework designed to help build capacity for groups to work together and ultimately tame this wicked issue.

Multi-scale silica structures for improved point of care detection

NASA Astrophysics Data System (ADS)

Lin, Sophia; Lin, Lancy; Cho, Eunbyul; Pezzani, Gaston A. O.; Khine, Michelle

2017-03-01

The need for sensitive, portable diagnostic tests at the point of care persists. We report on a simple method to obtain improved detection of biomolecules by a two-fold mechanism. Silica (SiO2) is coated on pre-stressed thermoplastic shrink-wrap film. When the film retracts, the resulting micro- and nanostructures yield far-field fluorescence signal enhancements over their planar or wrinkled counterparts. Because the film shrinks by 95% in surface area, there is also a 20x concentration effect. The SiO2 structured substrate is therefore used for improved detection of labeled proteins and DNA hybridization via both fluorescent and bright field. Through optical characterization studies, we attribute the fluorescence signal enhancements of 100x to increased surface density and light scattering from the rough SiO2 structures. Combining with our open channel self-wicking microfluidics, we can achieve extremely low cost yet sensitive point of care diagnostics.

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.

Effect of Pore Size and Pore Connectivity on Unidirectional Capillary Penetration Kinetics in 3-D Porous Media using Direct Numerical Simulation

NASA Astrophysics Data System (ADS)

Fu, An; Palakurthi, Nikhil; Konangi, Santosh; Comer, Ken; Jog, Milind

2017-11-01

The physics of capillary flow is used widely in multiple fields. Lucas-Washburn equation is developed by using a single pore-sized capillary tube with continuous pore connection. Although this equation has been extended to describe the penetration kinetics into porous medium, multiple studies have indicated L-W does not accurately predict flow patterns in real porous media. In this study, the penetration kinetics including the effect of pore size and pore connectivity will be closely examined since they are expected to be the key factors effecting the penetration process. The Liquid wicking process is studied from a converging and diverging capillary tube to the complex virtual 3-D porous structures with Direct Numerical Simulation (DNS) using the Volume-Of-Fluid (VOF) method within the OpenFOAM CFD Solver. Additionally Porous Medium properties such as Permeability (k) , Tortuosity (τ) will be also analyzed.

A Designer Fluid For Aluminum Phase Change Devices. Performance Enhancement in Copper Heat Pipes Performance Enhancement in Copper Heat Pipes. Volume 3

DTIC Science & Technology

2016-11-17

out dynamics of a designer fluid were investigated experimentally in a flat grooved heat pipe. Generated coatings were observed during heat pipe... experimental temperature distributions matched well. Uncertainties in the closure properties were the major source of error. 15. SUBJECT TERMS...72  Results and Discussion ( Experimental Results for IAS 2 in Grooved Wick #1

Freedom of Speech and the Communication Discipline: Defending the Value of Low-Value Speech. Wicked Problems Forum: Freedom of Speech at Colleges and Universities

ERIC Educational Resources Information Center

Herbeck, Dale A.

2018-01-01

Heated battles over free speech have erupted on college campuses across the United States in recent months. Some of the most prominent incidents involve efforts by students to prevent public appearances by speakers espousing controversial viewpoints. Efforts to silence offensive speakers on college campuses are not new; in these endeavors, one can…

Irregular Conflict and the Wicked Problem Dilemma: Strategies of Imperfection

DTIC Science & Technology

2011-06-01

behavioral concepts will enhance the pros- pects of achieving “good enough” resolutions. The elements of such an approach are set forth below. Goal...strategic communications.5 The manual assumes competency in, among other areas, the ability to collect useful intelligence, the ability to train host...including the difficulty of useful intelligence collection, the history of multiple ineffective training efforts, and the com- petition for what are

Comfortable with Chaos: Operational Design in the Naval Special Warfare Planning Process

DTIC Science & Technology

2011-05-08

President Alvaro Uribe Velez took office, Colombia was enduring a multi- faceted and interactively complex strategic situation. Three major insurgent groups...President Uribe took office and designed a comprehensive strategy to tackle the "wicked" problem. President Uribe designed an operational approach that...government -unattainable by previous presidents. From 2002 to 2006, the Uribe administration reframed 19 their understanding of the problem and

The Effects of Transverse Vibration on the Performance of an Axial Groove Wick Heat Pipe.

DTIC Science & Technology

1994-12-01

Kenneth A. Carpenter, Captain, USAIF 6ý AF1T/GA/ENY/94D -- ~~~~~ ----- - - -- - -- - - --- -- - --- Approved for public release; distribution...of Master of Science in Astronautical Engineering Kenneth A. Carpenter, B.S. Captain, USAF December, 1994 Approved for public release; distribution...discrepancies were determined by comparing DAS temperature readings to those achieved by connecting the same thermocouple to an Omega Omnical

Production cross sections for Lee-Wick massive electromagnetic bosons and for spin-zero and spin-one W bosons at high energies.

NASA Technical Reports Server (NTRS)

Linsker, R.

1972-01-01

Production cross sections for three types of hypothetical particles are calculated in the presented paper. Several (Z, Z') cases were studied corresponding to elastic scattering off protons and neutrons (either free or embedded within a Fermi sea), coherent scattering off a nucleus, and inelastic scattering off a proton (in which case Z' denotes a nucleon resonance or hadronic system in the continuum). Detailed structure-function data are used to improve the accuracy of the inelastic scattering calculation. Results of calculations are given for beam energies between 50 and 10,000 GeV, and masses between 5 and 40 GeV for the massive Lee-Wick spin-1 boson. Cross sections were computed for resonant and semiweak processes. The production cross section of spin-zero weak intermediate bosons was found to be at least one order of magnitude smaller than for spin-1 weak bosons in nearly all regions of interest. The production cross section of spin-zero weak intermediate bosons for inelastic scattering off protons compares with that for elastic scattering in the regions of interest. In the case of massive spin-1 bosons and spin-1 weak intermediates, the main contribution to total production cross section off protons is elastic.

Contrasting liquid imbibition into uncoated versus pigment coated paper enables a description of imbibition into new-generation surface-filled paper.

PubMed

Liu, Guodong; Fu, Sijia; Lu, Zhaoqing; Zhang, Meiyun; Ridgway, Cathy; Gane, Patrick

2017-12-18

The transport of print fluids into paper is directly dependent on the imbibition characteristic of the paper including both the z-, x- and y-directions. As the measurement of free liquid imbibition into the paper thickness (z-direction) is difficult experimentally, due to the thin nature of paper, in this paper we resort to imbibition along the y-direction of paper to analyse and explore the possibility of understanding the mechanistic differences between wicking into uncoated unfilled paper versus that of controllable pigment-filled paper and paper coating. Considering the classical imbibition dynamic, the measured imbibition was characterised firstly with respect to [Formula: see text] and secondly with respect to linear t. It is shown that the wicking behaviour of uncoated unfilled paper follows neither the classical viscous drag balance model of Lucas-Washburn ([Formula: see text]) nor the more comprehensive inertia-included imbibition described by Bosanquet. However, by increasing the filler load into the surface layer of the paper, the imbibition dynamic is seen to revert to the Bosanquet model. Thus, when using highly filled papers, the imbibition dynamic for printing liquid shows a fast imbibition at the initial stages dominated by inertial plug flow, and then transits to the Lucas-Washburn viscosity-dominated imbibition component over longer time.

Active water management at the cathode of a planar air-breathing polymer electrolyte membrane fuel cell using an electroosmotic pump

NASA Astrophysics Data System (ADS)

Fabian, T.; O'Hayre, R.; Litster, S.; Prinz, F. B.; Santiago, J. G.

In a typical air-breathing fuel cell design, ambient air is supplied to the cathode by natural convection and dry hydrogen is supplied to a dead-ended anode. While this design is simple and attractive for portable low-power applications, the difficulty in implementing effective and robust water management presents disadvantages. In particular, excessive flooding of the open-cathode during long-term operation can lead to a dramatic reduction of fuel cell power. To overcome this limitation, we report here on a novel air-breathing fuel cell water management design based on a hydrophilic and electrically conductive wick in conjunction with an electroosmotic (EO) pump that actively pumps water out of the wick. Transient experiments demonstrate the ability of the EO-pump to "resuscitate" the fuel cell from catastrophic flooding events, while longer term galvanostatic measurements suggest that the design can completely eliminate cathode flooding using less than 2% of fuel cell power, and lead to stable operation with higher net power performance than a control design without EO-pump. This demonstrates that active EO-pump water management, which has previously only been demonstrated in forced-convection fuel cell systems, can also be applied effectively to miniaturized (<5 W) air-breathing fuel cell systems.

Plant essential oils and potassium metabisulfite as repellents for Drosophila suzukii (Diptera: Drosophilidae)

PubMed Central

Renkema, Justin M.; Wright, Derek; Buitenhuis, Rose; Hallett, Rebecca H.

2016-01-01

Spotted wing drosophila, Drosophila suzukii, is a globally invasive pest of soft-skinned fruit. Females oviposit into ripening fruit and larvae cause direct destruction of tissues. As many plant essential oils are permitted food additives, they may provide a safe means of protecting fruit from D. suzukii infestation in both conventional and organic production systems. Twelve oils and potassium metabisulfite (KMS) were screened in the laboratory as repellents for D. suzukii flies. Most essential oils deterred D. suzukii flies from cotton wicks containing attractive raspberry juice. Peppermint oil was particularly effective, preventing almost all flies from contacting treated wicks and remaining 100% repellent for 6 d post-application. Thyme oil was unique because it caused high male mortality and reduced the number of responding flies compared to other oils. KMS was not found to be repellent to D. suzukii, but may have fumigant properties, particularly at high concentrations. Peppermint oil appears to be the best candidate for field testing to determine the effectiveness and feasibility of using essential oils as part of a push-pull management strategy against D. suzukii. This is the first time that essential oils have been evaluated and proven effective in preventing fruit-infesting flies from contacting attractive stimuli. PMID:26893197

Principles for fostering the transdisciplinary development of assistive technologies.

PubMed

Boger, Jennifer; Jackson, Piper; Mulvenna, Maurice; Sixsmith, Judith; Sixsmith, Andrew; Mihailidis, Alex; Kontos, Pia; Miller Polgar, Janice; Grigorovich, Alisa; Martin, Suzanne

2017-07-01

Developing useful and usable assistive technologies often presents complex (or "wicked") challenges that require input from multiple disciplines and sectors. Transdisciplinary collaboration can enable holistic understanding of challenges that may lead to innovative, impactful and transformative solutions. This paper presents generalised principles that are intended to foster transdisciplinary assistive technology development. The paper introduces the area of assistive technology design before discussing general aspects of transdisciplinary collaboration followed by an overview of relevant concepts, including approaches, methodologies and frameworks for conducting and evaluating transdisciplinary working and assistive technology design. The principles for transdisciplinary development of assistive technologies are presented and applied post hoc to the COACH project, an ambient-assisted living technology for guiding completion of activities of daily living by older adults with dementia as an illustrative example. Future work includes the refinement and validation of these principles through their application to real-world transdisciplinary assistive technology projects. Implications for rehabilitation Transdisciplinarity encourages a focus on real world 'wicked' problems. A transdisciplinary approach involves transcending disciplinary boundaries and collaborating with interprofessional and community partners (including the technology's intended users) on a shared problem. Transdisciplinarity fosters new ways of thinking about and doing research, development, and implementation, expanding the scope, applicability, and commercial viability of assistive technologies.

Thermal performance analysis of a flat heat pipe working with carbon nanotube-water nanofluid for cooling of a high heat flux heater

NASA Astrophysics Data System (ADS)

Arya, A.; Sarafraz, M. M.; Shahmiri, S.; Madani, S. A. H.; Nikkhah, V.; Nakhjavani, S. M.

2018-04-01

Experimental investigation on the thermal performance of a flat heat pipe working with carbon nanotube nanofluid is conducted. It is used for cooling a heater working at high heat flux conditions up to 190 kW/m2. The heat pipe is fabricated from aluminium and is equipped with rectangular fin for efficient cooling of condenser section. Inside the heat pipe, a screen mesh was inserted as a wick structure to facilitate the capillary action of working fluid. Influence of different operating parameters such as heat flux, mass concentration of carbon nanotubes and filling ratio of working fluid on thermal performance of heat pipe and its thermal resistance are investigated. Results showed that with an increase in heat flux, the heat transfer coefficient in evaporator section of the heat pipe increases. For filling ratio, however, there is an optimum value, which was 0.8 for the test heat pipe. In addition, CNT/water enhanced the heat transfer coefficient up to 40% over the deionized water. Carbon nanotubes intensified the thermal performance of wick structure by creating a fouling layer on screen mesh structure, which changes the contact angle of liquid with the surface, intensifying the capillary forces.

Effect of moisture transport on microclimate under T-shirts.

PubMed

Dai, Xiao-Qun; Imamura, Ritsuko; Liu, Guo-Lian; Zhou, Fu-Ping

2008-09-01

Water transport through garments has influence on the microclimate between the garments and the body beneath; thus the thermal comfort feeling for the wearer. Soybean protein fiber (SPF), a new type environmental fiber, which has been reported to be superior in water transfer, is often blended with cotton to improve the water transport property. In this paper, T-shirts made of this SPF/cotton blended fabric were focused in comparison with T-shirts made of cotton fabric. Wicking and immersion tests were carried out on the two types of fabrics to investigate the water transport and absorption properties, respectively; wear trials of T-shirts made of the fabrics were also conducted. Comparing with the cotton fabric which had better water absorptive property, it was found that the blended fabric with superior wicking ability could not only delay the increase of the vapor pressure under the T-shirt at the beginning of the exercise, but also help to keep it lower through the exercise significantly, and also kept the skin temperature under the T-shirt lower. It was made clear that it is the water transfer property rather than the water absorption property helps to take away sweat quickly and prevents the increase of the humidity and temperature at skin surface, thus maintaining a comfort microclimate under garments.

Life Test Approach for Refractory Metal/Sodium Heat Pipes

NASA Technical Reports Server (NTRS)

Martin, James J.; Reid, Robert S.

2006-01-01

Heat pipe life tests described in the literature have seldom been conducted on a systematic basis. Typically one or more heat pipes are built and tested for an extended period at a single temperature with simple condenser loading. This paper describes an approach to generate carefully controlled data that can conclusively establish heat pipe operating life with material-fluid combinations capable of extended operation. Approximately 10 years of operational life might be compressed into 3 years of laboratory testing through a combination of increased temperature and mass fluence. Two specific test series have been identified and include: investigation of long term corrosion rates based on the guidelines contained in ASTM G-68-80 (using 7 heat pipes); and investigation of corrosion trends in a cross correlation sequence at various temperatures and mass fluences based on a central composite test design (using 9 heat pipes). The heat pipes selected for demonstration purposes are fabricated from a Mo-44.5%Re alloy with a length of 0.3 meters and a diameter of 1.59 cm(to conserve material) with a condenser to evaporator length ratio of approximately 3. The wick is a crescent annular design formed from 400-mesh Mo-Re alloy material hot isostatically pressed to produce a final wick core of 20 microns or less.

Paper-based microfluidic devices by asymmetric calendaring

PubMed Central

Oyola-Reynoso, S.; Frankiewicz, C.; Chang, B.; Chen, J.; Bloch, J.-F.

2017-01-01

We report a simple, efficient, one-step, affordable method to produce open-channel paper-based microfluidic channels. One surface of a sheet of paper is selectively calendared, with concomitant hydrophobization, to create the microfluidic channel. Our method involves asymmetric mechanical modification of a paper surface using a rolling ball (ball-point pen) under a controlled amount of applied stress (σz) to ascertain that only one side is modified. A lubricating solvent (hexane) aids in the selective deformation. The lubricant also serves as a carrier for a perfluoroalkyl trichlorosilane allowing the channel to be made hydrophobic as it is formed. For brevity and clarity, we abbreviated this method as TACH (Targeted Asymmetric Calendaring and Hydrophobization). We demonstrate that TACH can be used to reliably produce channels of variable widths (size of the ball) and depths (number of passes), without affecting the nonworking surface of the paper. Using tomography, we demonstrate that these channels can vary from 10s to 100s of microns in diameter. The created hydrophobic barrier extends around the channel through wicking to ensure no leakages. We demonstrate, through modeling and fabrication, that flow properties of the resulting channels are analogous to conventional devices and are tunable based on associated dimensionless numbers. PMID:28798839

Experimental Investigations, Modeling, and Analyses of High-Temperature Devices for Space Applications. Part 2

DTIC Science & Technology

1999-01-01

AMTEC cell during operation is essential to maximize the thermal -to- electric conversion efficiency of the device. The cell efficiency , rQ, is defined...the cell current is relatively high (usually above 2 A), and we found that the former thermal model of the conical evaporator wick underpredicted... high temperature, sodium vapor environment in a typical multi-tube AMTEC cell , where thermal radiation exchange is significant, an

Topology Optimization for Reducing Additive Manufacturing Processing Distortions

DTIC Science & Technology

2017-12-01

features that curl or warp under thermal load and are subsequently struck by the recoater blade /roller. Support structures act to wick heat away and...was run for 150 iterations. The material properties for all examples were Young’s modulus E = 1 GPa, Poisson’s ratio ν = 0.25, and thermal expansion...the element-birth model is significantly more computationally expensive for a full op- timization run . Consider, the computational complexity of a

The Lord’s Resistance Army Wicked Problem

DTIC Science & Technology

2012-03-14

alarming proportions after the failure of the Juba Peace Talks and “Operation Lightning Thunder” ( OLT ). Consequently between September 2008 and December...phase, followed with an assault by ground forces.60 The planners of OLT had assumed that the air strikes would have a decisive effect on the morale...different capabilities. 18 During OLT , dozens of LRA officers were killed or captured or simply surrendered and LRA’s core fighters were reduced to

Enhancing Interoperability Among Enlisted Medical Personnel. A Case Study of Military Surgical Technologists

DTIC Science & Technology

2009-01-01

Thomas Manacapilli, Daniel Gershwin, Andrew Baxter, Roland J. Yardley Prepared for the Office of the Secretary of Defense Approved for public release...particularly thank Pete Altman, LTC Kathleen McArthur, CAPT Leigh Wickes, HMCS Douglas Glascoe, HMCM James Menke, Jerral Behnke, LTC Katrina Glavan-Heise, and...TIO Transformation Integration Office TNCC Thomas Nelson Community College TRADOC Training and Doctrine Command TS-C Tech in Surgery—Certified USD

Multi-Scale Fusion of Information for Uncertainty Quantification and Management in Large-Scale Simulations

DTIC Science & Technology

2015-12-02

simplification of the equations but at the expense of introducing modeling errors. We have shown that the Wick solutions have accuracy comparable to...the system of equations for the coefficients of formal power series solutions . Moreover, the structure of this propagator is seemingly universal, i.e...the problem of computing the numerical solution to kinetic partial differential equa- tions involving many phase variables. These types of equations

Heat pipe dynamic behavior

NASA Technical Reports Server (NTRS)

Issacci, F.; Roche, G. L.; Klein, D. B.; Catton, I.

1988-01-01

The vapor flow in a heat pipe was mathematically modeled and the equations governing the transient behavior of the core were solved numerically. The modeled vapor flow is transient, axisymmetric (or two-dimensional) compressible viscous flow in a closed chamber. The two methods of solution are described. The more promising method failed (a mixed Galerkin finite difference method) whereas a more common finite difference method was successful. Preliminary results are presented showing that multi-dimensional flows need to be treated. A model of the liquid phase of a high temperature heat pipe was developed. The model is intended to be coupled to a vapor phase model for the complete solution of the heat pipe problem. The mathematical equations are formulated consistent with physical processes while allowing a computationally efficient solution. The model simulates time dependent characteristics of concern to the liquid phase including input phase change, output heat fluxes, liquid temperatures, container temperatures, liquid velocities, and liquid pressure. Preliminary results were obtained for two heat pipe startup cases. The heat pipe studied used lithium as the working fluid and an annular wick configuration. Recommendations for implementation based on the results obtained are presented. Experimental studies were initiated using a rectangular heat pipe. Both twin beam laser holography and laser Doppler anemometry were investigated. Preliminary experiments were completed and results are reported.

How does the VPD response of isohydric and anisohydric plants depend on leaf surface particles?

PubMed

Burkhardt, J; Pariyar, S

2016-01-01

Atmospheric vapour pressure deficit (VPD) is the driving force for plant transpiration. Plants have different strategies to respond to this 'atmospheric drought'. Deposited aerosols on leaf surfaces can interact with plant water relations and may influence VPD response. We studied transpiration and water use efficiency of pine, beech and sunflower by measuring sap flow, gas exchange and carbon isotopes, thereby addressing different time scales of plant/atmosphere interaction. Plants were grown (i) outdoors under rainfall exclusion (OD) and in ventilated greenhouses with (ii) ambient air (AA) or (iii) filtered air (FA), the latter containing <1% ambient aerosol concentrations. In addition, some AA plants were sprayed once with 25 mM salt solution of (NH4 )2 SO4 or NaNO3 . Carbon isotope values (δ(13) C) became more negative in the presence of more particles; more negative for AA compared to FA sunflower and more negative for OD Scots pine compared to other growth environments. FA beech had less negative δ(13) C than AA, OD and NaNO3 -treated beech. Anisohydric beech showed linearly increasing sap flow with increasing VPD. The slopes doubled for (NH4 )2 SO4 - and tripled for NaNO3 -sprayed beech compared to control seedlings, indicating decreased ability to resist atmospheric demand. In contrast, isohydric pine showed constant transpiration rates with increasing VPD, independent of growth environment and spray, likely caused by decreasing gs with increasing VPD. Generally, NaNO3 spray had stronger effects on water relations than (NH4 )2 SO4 spray. The results strongly support the role of leaf surface particles as an environmental factor affecting plant water use. Hygroscopic and chaotropic properties of leaf surface particles determine their ability to form wicks across stomata. Such wicks enhance unproductive water loss of anisohydric plant species and decrease CO2 uptake of isohydric plants. They become more relevant with increasing number of fine particles and increasing VPD and are thus related to air pollution and climate change. Wicks cause a deviation from the analogy between CO2 and water pathways through stomata, bringing some principal assumptions of gas exchange theory into question. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

The Search for Peace in Mindanao: Resolving a Wicked Problem

DTIC Science & Technology

2012-03-22

negotiating panel, still led by Mohagher Iqbal, but with new members such as Professor Abhoud Syed Linga and Datu Antonio Kinoc of B‘laan tribe...that the MILF received funds from charitable institutions operated by Mohammed Jamal Khalifa, Osama Bin Laden‘s brother-in-law.53 The MILF has...Crucible: A Reader (Quezon City: CenPeg Publications), 2008, p. 136. 19 7 Hermoso, p. 61. 8 Dato‘ Md Ismael bin Ahmad Khan, ―The International

Solving Homeland Security’s Wicked Problems: A Design Thinking Approach

DTIC Science & Technology

2015-09-01

spur solutions. This thesis provides a framework for how S&T can incorporate design- thinking principles that are working well in other domains to...to spur solutions. This thesis provides a framework for how S&T can incorporate design-thinking principles that are working well in other domains to...Galbraith’s Star Model was used to analyze how DHS S&T, MindLab, and DARPA apply design-thinking principles to inform the framework to apply and

Microgravity

NASA Image and Video Library

2001-01-24

The Protein Crystallization for Microgravity (DCAM) was developed at NASA's Marshall Space Flight Center. A droplet of solution with protein molecules dissolved in it is isolated in the center of a small well. In orbit, an elastomer seal is lifted so the solution can evaporate and be absorbed by a wick material. This raises the concentration of the solution, thus prompting protein molecules in the solution to form crystals. The principal investigator is Dr. Dan Carter of New Century Pharmaceuticals in Huntsville, AL.

Heroes for a Wicked World: Enders Game as a Case for Fiction in PME

DTIC Science & Technology

2015-06-10

Sengers, “Narrative Intelligence,” 3. 84. Blair, D. and Meyer, T. “Tools for an Interactive Virtual Cinema .” Creating Personalities for Synthetic Actors...Conflict . . . in Space. Historian Max Hastings writes, “It was the Japanese people’s ill-fortune that it became feasible to bomb them just when American...2012). Blair, D. and Meyer, T. “Tools for an Interactive Virtual Cinema .” Creating Personalities for Synthetic Actors: Towards Autonomous Personality

An Experimental Study of Pressure Oscillation in a Capillary Pumped Loop with Multiple Evaporators and Condensers

NASA Technical Reports Server (NTRS)

Ku, Jen-Tung; Hoang, Triem T.

1998-01-01

The heat transport capability of a capillary pumped loop (CPL) is limited by the pressure drop that its evaporator wick can sustain. The pressure drop in a CPL is not constant even under seemingly steady operation, but rather exhibits an oscillatory behavior. A hydrodynamic theory based on a mass-spring-dashpot model was previously developed to predict the pressure oscillation in a CPL with a single evaporator and a single condenser. The theory states that the pressure oscillation is a function of physical dimensions of the CPL components and operating conditions. Experimental data agreed very well with theoretical predictions. The hydrodynamic stability theory has recently been extended to predict the pressure oscillations in CPLs with multiple evaporators and multiple condensers. Concurrently, an experimental study was conducted to verify the theory and to investigate the effects of various parameters on the pressure oscillation. Four evaporators with different wick properties were tested using a test loop containing two condenser plates. The test loop allowed the four evaporators to be tested in a single-pump, two-pump or four-pump configuration, and the two condenser plates to be plumbed either in parallel or in series. Test conditions included varying the power input, the reservoir set point temperature, the condenser sink temperature, and the flow resistance between the reservoir and the loop. Experimental results agreed well with theoretical predictions.

Durable Suit Bladder with Improved Water Permeability for Pressure and Environment Suits

NASA Technical Reports Server (NTRS)

Bue, Grant C.; Kuznetz, Larry; Orndoff, Evelyne; Tang, Henry; Aitchison, Lindsay; Ross, Amy

2009-01-01

Water vapor permeability is shown to be useful in rejecting heat and managing moisture accumulation in launch-and-entry pressure suits. Currently this is accomplished through a porous Gortex layer in the Advanced Crew and Escape Suit (ACES) and in the baseline design of the Constellation Suit System Element (CSSE) Suit 1. Non-porous dense monolithic membranes (DMM) that are available offer potential improvements for water vapor permeability with reduced gas leak. Accordingly, three different pressure bladder materials were investigated for water vapor permeability and oxygen leak: ElasthaneTM 80A (thermoplastic polyether urethane) provided from stock polymer material and two custom thermoplastic polyether urethanes. Water vapor, carbon dioxide and oxygen permeability of the DMM's was measured in a 0.13 mm thick stand-alone layer, a 0.08 mm and 0.05 mm thick layer each bonded to two different nylon and polyester woven reinforcing materials. Additional water vapor permeability and mechanical compression measurements were made with the reinforced 0.05 mm thick layers, further bonded with a polyester wicking and overlaid with moistened polyester fleece thermal underwear .This simulated the pressure from a supine crew person. The 0.05 mm thick nylon reinforced sample with polyester wicking layer was further mechanically tested for wear and abrasion. Concepts for incorporating these materials in launch/entry and Extravehicular Activity pressure suits are presented.

Wicking of light hydrophobic liquid phase from water by pulverized rubber: Theoretical and experimental analyses.

PubMed

Boglaienko, Daria; Tansel, Berrin

2017-03-05

Pulverized rubber (PR) can be utilized for capturing floating oils to prevent spreading and volatilization of hydrocarbons. Experiments were conducted using PR with four different particle sizes (ranging from 0.075 to 0.600mm) and South Louisiana crude oil. The oil capture performance of the PR particles was compared with that of powdered activated carbon (AC). Oil-particle interactions were analyzed using capillary theories for lateral aggregation and wicking processes, as well as sorption capacity in relation to particle size. The sorption capacity (as oil to sorbent ratio) for PR with particle size 0.115mm (4.41g/g) was comparable to that of AC with particle size 0.187mm (5.00g/g). Sorption efficiency (oil:powder ratio, g/g) of the PR increased with decreasing particle size. Sorption of oil by PR occurred rapidly (in less than 10min) which indicated strong capillary action. No additional sorption occurred after 30min. For the PR sample with larger particle size (0.600-0.400mm), lateral aggregation was clearly noticeable. The PR-oil aggregates could be easily removed from the water surface without breaking. The cost, availability and recycling potential of PR make it a feasible alternative material for oil spill response and industrial applications which require removal of floating oils. Copyright © 2016 Elsevier B.V. All rights reserved.

Possible treatment of the ghost states in the Lee-Wick standard model

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

Shalaby, Abouzeid M.; Physics Department, Faculty of Science, Qassim University

2009-07-15

In this work, we employ the techniques used to cure the indefinite norm problem in pseudo-Hermitian Hamiltonians to show that the ghost states in a higher derivative scalar field theory are not real ghosts. For the model under investigation, an imaginary auxiliary field is introduced to have an equivalent non-Hermitian two-field scalar theory. We were able to calculate exactly the positive definite metric operator {eta} for the quantum mechanical as well as the quantum field versions of the theory. While the equivalent Hamiltonian is non-Hermitian in a Hilbert space characterized by the Dirac sense inner product, it is, however, amore » Hermitian in a Hilbert space endowed with the inner product . The main feature of the latter Hilbert space is that the propagator has the correct sign (no Lee-Wick fields). Moreover, the calculated metric operator diagonalizes the Hamiltonian in the two fields (no mixing). We found that the Hermiticity of the calculated metric operator to lead to the constrain M>2m for the two Higgs masses, in agreement with other calculations in the literature. Besides, our mass formulas coincide with those obtained in other works (obtained by a very different regime but with the existence of ghost states), which means that our positive normed Hamiltonian form preserves the mass spectra.« less

Dish/stirling hybrid-receiver

DOEpatents

Mehos, Mark S.; Anselmo, Kenneth M.; Moreno, James B.; Andraka, Charles E.; Rawlinson, K. Scott; Corey, John; Bohn, Mark S.

2002-01-01

A hybrid high-temperature solar receiver is provided which comprises a solar heat-pipe-receiver including a front dome having a solar absorber surface for receiving concentrated solar energy, a heat pipe wick, a rear dome, a sidewall joining the front and the rear dome, and a vapor and a return liquid tube connecting to an engine, and a fossil fuel fired combustion system in radial integration with the sidewall for simultaneous operation with the solar heat pipe receiver, the combustion system comprising an air and fuel pre-mixer, an outer cooling jacket for tangentially introducing and cooling the mixture, a recuperator for preheating the mixture, a burner plenum having an inner and an outer wall, a porous cylindrical metal matrix burner firing radially inward facing a sodium vapor sink, the mixture ignited downstream of the matrix forming combustion products, an exhaust plenum, a fossil-fuel heat-input surface having an outer surface covered with a pin-fin array, the combustion products flowing through the array to give up additional heat to the receiver, and an inner surface covered with an extension of the heat-pipe wick, a pin-fin shroud sealed to the burner and exhaust plenums, an end seal, a flue-gas diversion tube and a flue-gas valve for use at off-design conditions to limit the temperature of the pre-heated air and fuel mixture, preventing pre-ignition.

Prenuptial perfume: Alloanointing in the social rituals of the crested auklet ( Aethia cristatella) and the transfer of arthropod deterrents

NASA Astrophysics Data System (ADS)

Douglas, Hector D.

2008-01-01

Alloanointing, the transfer of chemicals between conspecifics, is known among mammals, but hitherto, the behavior has not been documented for birds. The crested auklet ( Aethia cristatella), a colonial seabird of Alaskan and Siberian waters, alloanoints during courtship with fragrant aldehydes that are released from specialized wick-like feathers located in the interscapular region. Crested auklets solicit anointment at the colony, and prospective mates rub bill, breast, head, and neck over wick feathers of their partners. This distributes aldehydes over the head, neck, and face where the birds cannot self-preen. The resulting chemical concentrations are sufficient to deter ectoparasites. Auklets that emit more odorant can transfer more defensive chemicals to mates and are thus more sexually attractive. Behavioral studies showed that crested auklets are attracted to their scent. Wild birds searched for dispensers that emitted their scent and rubbed their bills on the dispensers and engaged in vigorous anointment behaviors. In captive experiments, naïve crested auklets responded more strongly to synthetic auklet scent than controls, and the greatest behavioral response occurred during early courtship. This study extends scientific knowledge regarding functions of alloanointing. Alloanointing had previously been attributed to scent marking and individual recognition in vertebrates. Alloanointing is described here in the context of an adaptive social cue — the transfer of arthropod deterrents between prospective mates.

Comparisons of Gas-phase Temperature Measurements in a Flame Using Thin-Filament Pyrometry and Thermocouples

NASA Technical Reports Server (NTRS)

Struk, Peter; Dietrich, Daniel; Valentine, Russell; Feier, Ioan

2003-01-01

Less-intrusive, fast-responding, and full-field temperature measurements have long been a desired tool for the research community. Recently, the emission of a silicon-carbide (SiC) fiber placed in a flowing hot (or reacting) gas has been used to measure the temperature profile along the length of the fiber. The relationship between the gas and fiber temperature comes from an energy balance on the fiber. In the present work, we compared single point flame temperature measurements using thin-filament pyrometry (TFP) and thermocouples. The data was from vertically traversing a thermocouple and a SiC fiber through a methanol/air diffusion flame of a porous-metal wick burner. The results showed that the gas temperature using the TFP technique agreed with the thermocouple measurements (25.4 m diameter wire) within 3.5% for temperatures above 1200 K. Additionally, we imaged the entire SiC fiber (with a spatial resolution of 0.14 mm) while it was in the flame using a high resolution CCD camera. The intensity level along the fiber length is a function of the temperature. This results in a one-dimensional temperature profiles at various heights above the burner wick. This temperature measurement technique, while having a precision of less than 1 K, showed data scatter as high as 38 K. Finally, we discuss the major sources of uncertainty in gas temperature measurement using TFP.

Can Joined-Up Data Lead to Joined-Up Thinking? The Western Australian Developmental Pathways Project

PubMed Central

Stanley, Fiona; Glauert, Rebecca; McKenzie, Anne; O'Donnell, Melissa

2011-01-01

Modern societies are challenged by “wicked problems” – by definition, those that are difficult to define, multi-causal and hard to treat. Problems such as low birth weight, obesity, mental ill health, teenage pregnancy, educational difficulties and juvenile crime fit this category. Given the complex nature of these problems, they require the best data in order to measure them, guide policy frameworks and evaluate whether the steps taken to address them are actually making a difference. What such problems really require are joined-up approaches to enable effective solutions. In this paper, we describe a unique initiative to encourage a more preventive, whole-of-government approach to these problems – the Developmental Pathways Project, which has enabled the linkage of a large number of de-identified administrative databases in order to explore the pathways into and out of the negative outcomes affecting our children and youth. This project has not only enabled the linkage of agency data, but also of agency personnel, in order to improve and promote cross-agency research, policy and preventive solutions. Through the use of these linkages we are attempting to shift the paradigm to encourage agencies to appreciate that these “wicked problems” demand a preventive approach, as well as the provision of effective services for those already affected. PMID:24933374

The wicked question answered: positive deviance delivers patient-centered care.

PubMed

Gary, Jodie C

2014-01-01

How nurses respond when faced with the dilemma of providing patient-centered care in the absence of patient-centered practice guidelines remains relatively unreported. Standards may not be available to guide nurses or may not be realistic for implementation at the point of care. Nurses may be forced to react creatively to meet the needs of their patients. The purpose was to understand nursing care when standard practice guidelines did not meet patient-specific care needs and to develop various viewpoints related to the use of positive deviance in providing patient-centered care. Complexity theory and the framework of a wicked question were used to guide a 3-round online national Delphi study from November 2011 to February 2012. The panel was accessed through the American Association of Critical Care Nurses to expose the care provided when standard practice guidelines were lacking. Findings support the presence of positive deviance and expose care provided by nurses when standard practice guidelines lacked the ability to provide patient-centered care. Dominant themes of positive deviance are recommended as priorities for future research. Better guidelines are needed that work for nurses, instead of against them, that would not force a nurse into actions that are not patient centered. Guidelines should guide practice and assist in allowing nurses to provide care that is centered on the best needs of the patient in the specific care situation.

Sampling gaseous compounds from essential oils evaporation by solid phase microextraction devices

NASA Astrophysics Data System (ADS)

Cheng, Wen-Hsi; Lai, Chin-Hsing

2014-12-01

Needle trap samplers (NTS) are packed with 80-100 mesh divinylbenzene (DVB) particles to extract indoor volatile organic compounds (VOCs). This study compared extraction efficiency between an NTS and a commercially available 100 μm polydimethylsiloxane-solid phase microextration (PDMS-SPME) fiber sampler used to sample gaseous products in heated tea tree essential oil in different evaporation modes, which were evaporated respectively by free convection inside a glass evaporation dish at 27 °C, by evaporation diffuser at 60 °C, and by thermal ceramic wicks at 100 °C. The experimental results indicated that the NTS performed better than the SPME fiber samplers and that the NTS primarily adsorbed 5.7 ng ethylbenzene, 5.8 ng m/p-xylenes, 11.1 ng 1,2,3-trimethylbenzene, 12.4 ng 1,2,4-trimethylbenzene and 9.99 ng 1,4-diethylbenzene when thermal ceramic wicks were used to evaporate the tea tree essential oil during a 1-hr evaporation period. The experiment also indicated that the temperature used to heat the essential oils should be as low as possible to minimize irritant VOC by-products. If the evaporation temperature does not exceed 100 °C, the concentrations of main by-products trimethylbenzene and diethylbenzene are much lower than the threshold limit values recommended by the National Institute for Occupational Safety and Health (NIOSH).

Lateral flow strip assay

DOEpatents

Miles, Robin R [Danville, CA; Benett, William J [Livermore, CA; Coleman, Matthew A [Oakland, CA; Pearson, Francesca S [Livermore, CA; Nasarabadi, Shanavaz L [Livermore, CA

2011-03-08

A lateral flow strip assay apparatus comprising a housing; a lateral flow strip in the housing, the lateral flow strip having a receiving portion; a sample collection unit; and a reagent reservoir. Saliva and/or buccal cells are collected from an individual using the sample collection unit. The sample collection unit is immersed in the reagent reservoir. The tip of the lateral flow strip is immersed in the reservoir and the reagent/sample mixture wicks up into the lateral flow strip to perform the assay.

EM Transition Sum Rules Within the Framework of sdg Proton-Neutron Interacting Boson Model, Nuclear Pair Shell Model and Fermion Dynamical Symmetry Model

NASA Astrophysics Data System (ADS)

Zhao, Yumin

1997-07-01

By the techniques of the Wick theorem for coupled clusters, the no-energy-weighted electromagnetic sum-rule calculations are presented in the sdg neutron-proton interacting boson model, the nuclear pair shell model and the fermion-dynamical symmetry model. The project supported by Development Project Foundation of China, National Natural Science Foundation of China, Doctoral Education Fund of National Education Committee, Fundamental Research Fund of Southeast University

Physics and Applications of Unipolar Barriers in Infrared (IR) Detectors

DTIC Science & Technology

2016-08-23

SE 11. SPONSOR/MONITOR’S REPORT Kirtland AFB, NM 87117-5776 NUMBER(S) AFRL -RV-PS-TR-2016-0120 12. DISTRIBUTION / AVAILABILITY STATEMENT Approved for...DISTRIBUTION LIST DTIC/OCP 8725 John J. Kingman Rd, Suite 0944 Ft Belvoir, VA 22060-6218 1 cy AFRL /RVIL Kirtland AFB, NM 87117-5776 2 cys Official... AFRL -RV-PS- TR-2016-0120 AFRL -RV-PS- TR-2016-0120 PHYSICS AND APPLICATIONS OF UNIPOLAR BARRIERS IN INFRARED (IR) DETECTORS Gary Wicks University

Public health and media advocacy.

PubMed

Dorfman, Lori; Krasnow, Ingrid Daffner

2014-01-01

Media advocacy blends communications, science, politics, and advocacy to advance public health goals. In this article, we explain how media advocacy supports the social justice grounding of public health while addressing public health's "wicked problems" in the context of American politics. We outline media advocacy's theoretical foundations in agenda setting and framing and describe its practical application, from the layers of strategy to storytelling, which can illuminate public health solutions for journalists, policy makers, and the general public. Finally, we describe the challenges in evaluating media advocacy campaigns.

Thermal Analysis of Heat Pipe Radiators with A Rectangular Groove Wick Structure

DTIC Science & Technology

1990-06-01

heat pipe inside radius r, .... heat pipe vapor core radius R ..... radiosity R, . Reynolds number of vapor flow Rf .... reduction factor t ..... one...The radiosity of the fin element, R(x), consists of the emission from the surface of the fin element plus the reflected irradiation from both...the radiosity received from both heat pipe condensers, i.e., heat pipe condenser 1 and condenser 2. It can 2-12 be expressed as I(x)wedx = l R(O2)Fi

Reduced size fuel cell for portable applications

NASA Technical Reports Server (NTRS)

Narayanan, Sekharipuram R. (Inventor); Valdez, Thomas I. (Inventor); Clara, Filiberto (Inventor); Frank, Harvey A. (Inventor)

2004-01-01

A flat pack type fuel cell includes a plurality of membrane electrode assemblies. Each membrane electrode assembly is formed of an anode, an electrolyte, and an cathode with appropriate catalysts thereon. The anode is directly into contact with fuel via a wicking element. The fuel reservoir may extend along the same axis as the membrane electrode assemblies, so that fuel can be applied to each of the anodes. Each of the fuel cell elements is interconnected together to provide the voltage outputs in series.

Wicked Problems in Large Organizations: Why Pilot Retention Continues to Challenge the Air Force

DTIC Science & Technology

2017-05-25

ABSTRACT This monograph in military studies investigates the makeup of and approach to complex problems, with a case study on the Air Force’s...priorities, as well as a short, recent history of the pilot retention problem. Following that is a case study on the work done by the Air Staff in...Lonsberry, USAF, 38 pages. This monograph in military studies investigates the makeup of and approach to complex problems, with a case study on the

Mathematical modeling of high and low temperature heat pipes

NASA Technical Reports Server (NTRS)

Chi, S. W.

1971-01-01

Mathematical models are developed for calculating heat-transfer limitations of high-temperature heat pipes and heat-transfer limitations and temperature gradient of low temperature heat pipes. Calculated results are compared with the available experimental data from various sources to increase confidence in the present math models. Complete listings of two computer programs for high- and low-temperature heat pipes respectively are appended. These programs enable the performance of heat pipes with wrapped-screen, rectangular-groove or screen-covered rectangular-groove wick to be predicted.

Heat Pipe with Axial Wick

NASA Technical Reports Server (NTRS)

Ambrose, Jay H. (Inventor); Holmes, Rolland (Inventor)

2016-01-01

A heat pipe has an evaporator portion, a condenser portion, and at least one flexible portion that is sealingly coupled between the evaporator portion and the condenser portion. The flexible portion has a flexible tube and a flexible separator plate held in place within the flexible tube so as to divide the flexible tube into a gas-phase passage and a liquid-phase artery. The separator plate and flexible tube are configured such that the flexible portion is flexible in a plane that is perpendicular to the separator plate.

Unique features of a new nickel-hydrogen 2-cell CPV

NASA Technical Reports Server (NTRS)

Wheeler, James R.

1995-01-01

Two-cell nickel-hydrogen common pressure vessel (CPV) units with some unusual design features have been successfully built and tested. The features of interest are half-normal platinum loading for the negative electrodes, the use of rabbit-ear terminals for a CPV unit, and the incorporation of a wall wick. The units have a nominal capacity of 20 Ah and are 3.5 inches in diameter. Electric performance data are provided. The data support the growing viability of the two-cell CPV design concept.

Black swans, wicked problems, and science during crises

USGS Publications Warehouse

Machlis, G.E.; McNutt, M.K.

2011-01-01

Oceanic resources face challenges that are significant and widespread, including (but not limited to) overharvesting, climate change, selected stock collapse, coral reef decline, species extinction, pollution, and more. These challenges are the focus of much ocean science, which is helping to inform policy and guide management actions. The steady growth of research results and the emergence of new research needs have been systematically reviewed through periodic assessments, such as those of the Intergovernmental Oceanographic Commission (Valdés et al., 2010).

Suspended-slurry reactor

DOEpatents

None

2016-03-22

An apparatus for generating a large volume of gas from a liquid stream is disclosed. The apparatus includes a first channel through which the liquid stream passes. The apparatus also includes a layer of catalyst particles suspended in a solid slurry for generating gas from the liquid stream. The apparatus further includes a second channel through which a mixture of converted liquid and generated gas passes. A heat exchange channel heats the liquid stream. A wicking structure located in the second channel separates the gas generated from the converted liquid.

Therapeutic drug monitoring of flucytosine in serum using a SERS-active membrane system

NASA Astrophysics Data System (ADS)

Berger, Adam G.; White, Ian M.

2017-02-01

A need exists for near real-time therapeutic drug monitoring (TDM), in particular for antibiotics and antifungals in patient samples at the point-of-care. To truly fit the point-of-care need, techniques must be rapid and easy to use. Here we report a membrane system utilizing inkjet-fabricated surface enhanced Raman spectroscopy (SERS) sensors that allows sensitive and specific analysis despite the elimination of sophisticated chromatography equipment, expensive analytical instruments, and other systems relegated to the central lab. We utilize inkjet-fabricated paper SERS sensors as substrates for 5FC detection; the use of paper-based SERS substrates leverages the natural wicking ability and filtering properties of microporous membranes. We investigate the use of microporous membranes in the vertical flow assay to allow separation of the flucytosine from whole blood. The passive vertical flow assay serves as a valuable method for physical separation of target analytes from complex biological matrices. This work further establishes a platform for easy, sensitive, and specific TDM of 5FC from whole blood.

Functional Integration

NASA Astrophysics Data System (ADS)

Cartier, Pierre; DeWitt-Morette, Cecile

2006-11-01

Acknowledgements; List symbols, conventions, and formulary; Part I. The Physical and Mathematical Environment: 1. The physical and mathematical environment; Part II. Quantum Mechanics: 2. First lesson: gaussian integrals; 3. Selected examples; 4. Semiclassical expansion: WKB; 5. Semiclassical expansion: beyond WKB; 6. Quantum dynamics: path integrals and operator formalism; Part III. Methods from Differential Geometry: 7. Symmetries; 8. Homotopy; 9. Grassmann analysis: basics; 10. Grassmann analysis: applications; 11. Volume elements, divergences, gradients; Part IV. Non-Gaussian Applications: 12. Poisson processes in physics; 13. A mathematical theory of Poisson processes; 14. First exit time: energy problems; Part V. Problems in Quantum Field Theory: 15. Renormalization 1: an introduction; 16. Renormalization 2: scaling; 17. Renormalization 3: combinatorics; 18. Volume elements in quantum field theory Bryce DeWitt; Part VI. Projects: 19. Projects; Appendix A. Forward and backward integrals: spaces of pointed paths; Appendix B. Product integrals; Appendix C. A compendium of gaussian integrals; Appendix D. Wick calculus Alexander Wurm; Appendix E. The Jacobi operator; Appendix F. Change of variables of integration; Appendix G. Analytic properties of covariances; Appendix H. Feynman's checkerboard; Bibliography; Index.

Functional Integration

NASA Astrophysics Data System (ADS)

Cartier, Pierre; DeWitt-Morette, Cecile

2010-06-01

Acknowledgements; List symbols, conventions, and formulary; Part I. The Physical and Mathematical Environment: 1. The physical and mathematical environment; Part II. Quantum Mechanics: 2. First lesson: gaussian integrals; 3. Selected examples; 4. Semiclassical expansion: WKB; 5. Semiclassical expansion: beyond WKB; 6. Quantum dynamics: path integrals and operator formalism; Part III. Methods from Differential Geometry: 7. Symmetries; 8. Homotopy; 9. Grassmann analysis: basics; 10. Grassmann analysis: applications; 11. Volume elements, divergences, gradients; Part IV. Non-Gaussian Applications: 12. Poisson processes in physics; 13. A mathematical theory of Poisson processes; 14. First exit time: energy problems; Part V. Problems in Quantum Field Theory: 15. Renormalization 1: an introduction; 16. Renormalization 2: scaling; 17. Renormalization 3: combinatorics; 18. Volume elements in quantum field theory Bryce DeWitt; Part VI. Projects: 19. Projects; Appendix A. Forward and backward integrals: spaces of pointed paths; Appendix B. Product integrals; Appendix C. A compendium of gaussian integrals; Appendix D. Wick calculus Alexander Wurm; Appendix E. The Jacobi operator; Appendix F. Change of variables of integration; Appendix G. Analytic properties of covariances; Appendix H. Feynman's checkerboard; Bibliography; Index.

Apparatus and method for maintaining an article at a temperature that is less than the temperature of the ambient air

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

Klett, James; Klett, Lynn

An apparatus for maintaining the temperature of an article at a temperature that is below the ambient air temperature includes an enclosure having an outer wall that defines an interior chamber for holding a volume of sealed air. An insert is disposed inside of the chamber and has a body that is made of a porous graphite foam material. A vacuum pump penetrates the outer wall and fluidly connects the sealed air in the interior chamber with the ambient air outside of the enclosure. The temperatures of the insert and article is maintained at temperatures that are below the ambientmore » air temperature when a volume of a liquid is wicked into the pores of the porous insert and the vacuum pump is activated to reduce the pressure of a volume of sealed air within the interior chamber to a pressure that is below the vapor pressure of the liquid.« less

Smartphone-based point-of-care testing of salivary α-amylase for personal psychological measurement.

PubMed

Zhang, Lin; Yang, Wentao; Yang, Yuankui; Liu, Hong; Gu, Zhongze

2015-11-07

Here we report a smartphone-based potentiometric biosensor for point-of-care testing of salivary α-amylase (sAA), which is one of the most sensitive indices of autonomic nervous system activity, and therefore a promising non-invasive biomarker for mental health. The biosensing system includes a smartphone having a sAA-detection App, a potentiometric reader and a sensing chip with preloaded reagents. The saliva sample wicks into the reaction zone on the sensing chip so that the sAA reacts with the preloaded reagents, resulting in conversion of an electron mediator Fe(CN)6(3-) to Fe(CN)6(4-). The sensing chip is then pressed by fingers to push the reaction mixture into the detection zone for the potentiometric measurement. The potential measured by the smartphone-powered potentiometric reader is sent to the smartphone App via the USB port, and converted into sAA concentration based on a calibration curve. Using our method, sAA in real human sample is quantitatively analyzed within 5 min. The results are in good agreement with that obtained using a reference method, and correlated to psychological states of the subjects.

Spontaneous human combustion in the light of the 21st century.

PubMed

Koljonen, Virve; Kluger, Nicolas

2012-01-01

The term "spontaneous human combustion" refers to a situation when a human body is found with significant portions of the middle parts of the body reduced to ashes, much less damage to the head and extremities, and minimal damage to the direct surroundings of the body. Typically, no observable source of ignition is found in the vicinity of the victim and a bad smelling oily substance is noted. In the past, such a situation was erroneously attributed to supernatural powers, as such phenomenon occurs in the absence of any witness. The purpose of this review article was to analyze articles published from January 1, 2000, on this unique type of burn injury. Further aims were to gather and present data on the causes and events leading to this situation. The literature was reviewed with PubMed interface using the key words spontaneous human combustion and preternatural combustion. Specific inclusion criteria resulted in 12 patients. A unique sequence of events takes place for the human body to incinerate to ashes. The flame burn victim has to die for the body fat to start melting. A tear in the skin has to occur for the melted fat to impregnate the charred clothes, igniting a wick effect that produces localized heat for extended period. A phenomenon called spontaneous human combustion is reality. The term "spontaneous human combustion" has nuances which are not applicable to this situation or to these modern times, therefore we suggest a new term "fat wick burns."

Bump Bonding Using Metal-Coated Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Lamb, James L.; Dickie, Matthew R.; Kowalczyk, Robert S.; Liao, Anna; Bronikowski, Michael J.

2012-01-01

Bump bonding hybridization techniques use arrays of indium bumps to electrically and mechanically join two chips together. Surface-tension issues limit bump sizes to roughly as wide as they are high. Pitches are limited to 50 microns with bumps only 8-14 microns high on each wafer. A new process uses oriented carbon nanotubes (CNTs) with a metal (indium) in a wicking process using capillary actions to increase the aspect ratio and pitch density of the connections for bump bonding hybridizations. It merges the properties of the CNTs and the metal bumps, providing enhanced material performance parameters. By merging the bumps with narrow and long CNTs oriented in the vertical direction, higher aspect ratios can be obtained if the metal can be made to wick. Possible aspect ratios increase from 1:1 to 20:1 for most applications, and to 100:1 for some applications. Possible pitch density increases of a factor of 10 are possible. Standard capillary theory would not normally allow indium or most other metals to be drawn into the oriented CNTs, because they are non-wetting. However, capillary action can be induced through the ability to fabricate oriented CNT bundles to desired spacings, and the use of deposition techniques and temperature to control the size and mobility of the liquid metal streams and associated reservoirs. This hybridization of two technologies (indium bumps and CNTs) may also provide for some additional benefits such as improved thermal management and possible current density increases.

Custodial isospin violation in the Lee-Wick standard model

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

Chivukula, R. Sekhar; Farzinnia, Arsham; Foadi, Roshan

2010-05-01

We analyze the tension between naturalness and isospin violation in the Lee-Wick standard model (LW SM) by computing tree-level and fermionic one-loop contributions to the post-LEP electroweak parameters (S-circumflex, T-circumflex, W, and Y) and the Zb{sub L}b-bar{sub L} coupling. The model is most natural when the LW partners of the gauge bosons and fermions are light, but small partner masses can lead to large isospin violation. The post-LEP parameters yield a simple picture in the LW SM: the gauge sector contributes to Y and W only, with leading contributions arising at tree level, while the fermion sector contributes to S-circumflexmore » and T-circumflex only, with leading corrections arising at one loop. Hence, W and Y constrain the masses of the LW gauge bosons to satisfy M{sub 1}, M{sub 2} > or approx. 2.4 TeV at 95% C.L. Likewise, experimental limits on T-circumflex reveal that the masses of the LW fermions must satisfy M{sub q}, M{sub t} > or approx. 1.6 TeV at 95% C.L. if the Higgs mass is light and tend to exclude the LW SM for any LW fermion masses if the Higgs mass is heavy. Contributions from the top-quark sector to the Zb{sub L}b{sub L} coupling can be even more stringent, placing a lower bound of 4 TeV on the LW fermion masses at 95% C.L.« less

Methodology for Life Testing of Refractory Metal/Sodium Heat Pipes

NASA Technical Reports Server (NTRS)

Martin, James J.; Reid, Robert S.

2006-01-01

The focus of this work was to establish an approach to generate carefully controlled data that can conclusively establish heat pipe operating life with material-fluid combinations capable of extended operation. To accomplish this goal acceleration is required to compress 10 years of operational life into 3 years of laboratory testing through a combination of increased temperature and mass fluence. Specific test series have been identi3ed, based on American Society for Testing and Materials (ASTM) specifications, to investigate long term corrosion rates. The refractory metal selected for demonstration purposes is a Molybdenum-44.5%Rhenium alloy formed by powder metallurgy. The heat pipe makes use of an annular crescent wick design formed by hot isostatic pressing of Molybdenum-Rhenium wire mesh. The heat pipes are filled using vacuum distillation and purity sampling is considered. Testing of these units is round-the-clock with 6-month destructive and non-destructive inspection intervals to identify the onset and level of corrosion. Non-contact techniques are employed for providing power to the evaporator (radio frequency induction heating at I to 5 kW per unit) and calorimetry at the condenser (static gas gap coupled water cooled calorimeter). The planned operating temperature range would extend from 1123 to 1323 K. Accomplishments prior to project cancellation included successful demonstration of the heat pipe wick fabrication technique, establishment of all engineering designs, baselined operational test requirements and procurement/assembly of supporting test hardware systems.

Integrating research and practice for optimal clinical outcomes: an interview with Tim Porter-O'Grady. Interview by Gail S Wick.

PubMed

Porter-O'Grady, T

1996-06-01

Dr. Porter-O'Grady has written over 125 articles and book chapters and has published eight books and is completing a ninth. He has consulted with over 500 institutions and has spoken in 1300 settings in the U.S., Canada, Europe, and Asia and logs about 350,000 miles a year. Dr. Porter-O'Grady is listed in six different categories of Who's Who in America, serves on 7 editorial boards, and is a member of the New York Academy of Sciences and a Fellow in the American Academy of Nursing. He has served on a number of community boards and has been an elected officer in a variety of health related agencies and organizations. He is currently a health systems expert for the National Health Policy Council and is a member of the Georgia Health Care Reform Project. In this interview, which took place in Atlanta by ANNA Past President Gail Wick, Dr. Porter-O'Grady shares his wealth of knowledge and experience by challenging us to move beyond the old thinking of caring for a specific patient population to managing lives on a continuum of care in an interdependent relationship with other providers, to refine the term "patient care," letting go of the medical sickness model and returning to our life-centered, health-oriented nursing roots and to broaden our educational preparation to a systems perspective and a continuum of caring.

Avoid, Control, Succumb, or Balance: Engineering Students' Approaches to a Wicked Sustainability Problem

NASA Astrophysics Data System (ADS)

Lönngren, Johanna; Ingerman, Åke; Svanström, Magdalena

2017-08-01

Wicked sustainability problems (WSPs) are an important and particularly challenging type of problem. Science and engineering education can play an important role in preparing students to deal with such problems, but current educational practice may not adequately prepare students to do so. We address this gap by providing insights related to students' abilities to address WSPs. Specifically, we aim to (I) describe key constituents of engineering students' approaches to a WSP, (II) evaluate these approaches in relation to the normative context of education for sustainable development (ESD), and (III) identify relevant aspects of learning related to WSPs. Aim I is addressed through a phenomenographic study, while aims II and III are addressed by relating the results to research literature about human problem solving, sustainable development, and ESD. We describe four qualitatively different ways of approaching a specific WSP, as the outcome of the phenomenographic study: A. Simplify and avoid, B. Divide and control, C. Isolate and succumb, and D. Integrate and balance. We identify approach D as the most appropriate approach in the context of ESD, while A and C are not. On this basis, we identify three learning objectives related to students' abilities to address WSPs: learn to use a fully integrative approach, distinguish WSPs from tame and well-structured problems, and understand and consider the normative context of SD. Finally, we provide recommendations for how these learning objectives can be used to guide the design of science and engineering educational activities.

A Novel Silicon Micromachined Integrated MCM Thermal Management System

NASA Technical Reports Server (NTRS)

Kazmierczak, M. J.; Henderson, H. T.; Gerner, F. M.

1997-01-01

"Micromachining" is a chemical means of etching three-dimensional structures, typically in single- crystalline silicon. These techniques are leading toward what is coming to be referred to as MEMS (Micro Electro Mechanical Systems), where in addition to the ordinary two-dimensional (planar) microelectronics, it is possible to build three-dimensional n-ticromotors, electrically- actuated raicrovalves, hydraulic systems and much more on the same microchip. These techniques become possible because of differential etching rates of various crystallographic planes and materials used for semiconductor n-ticrofabfication. The University of Cincinnati group in collaboration with Karl Baker at NASA Lewis were the first to form micro heat pipes in silicon by the above techniques. Current work now in progress using MEMS technology is now directed towards the development of the next generation in MCM (Multi Chip Module) packaging. Here we propose to develop a complete electronic thermal management system which will allow densifica6on in chip stacking by perhaps two orders of magnitude. Furthermore the proposed technique will allow ordinary conu-nercial integrated chips to be utilized. Basically, the new technique involves etching square holes into a silicon substrate and then inserting and bonding commercially available integrated chips into these holes. For example, over a 100 1/4 in. by 1 /4 in. integrated chips can be placed on a 4 in. by 4 in. silicon substrate to form a Multi-Chip Module (MCM). Placing these MCM's in-line within an integrated rack then allows for three-diniensional stacking. Increased miniaturization of microelectronic circuits will lead to very high local heat fluxes. A high performance thermal management system will be specifically designed to remove the generated energy. More specifically, a compact heat exchanger with milli / microchannels will be developed and tested to remove the heat through the back side of this MCM assembly for moderate and high heat flux applications, respectively. The high heat load application of particular interest in mind is the motor controller developed by Martin Marietta for Nasa to control the thruster's directional actuators on space vechicles. Work is also proposed to develop highly advanced and improved porous wick structures for use in advanced heat loops. The porous wick will be micromachined from silicon using MEMS technology, thus permitting far superior control of pore size and pore distribution (over wicks made from sintered n-ietals), which in turn is expected to led to significantly improved heat loop performance.

Synthesis and characterization of polymer layers for control of fluid transport

NASA Astrophysics Data System (ADS)

Vatansever, Fehime

The level of wetting of fiber surface with liquids is an important characteristic of fibrous materials. It is related to fiber surface energy and the structure of the material. Surface energy can be changed by surface modification via the grafting methodologies that have been reported for introducing new and stable functionality to fibrous substrates without changing bulk properties. Present work is dedicated to synthesis and characterization of macromolecular layers grafted to fiber surface in order to achieve directional liquid transport for the modified fabric. Modification technique used here is based on formation of stable polymer layer on fabric surface using "grafting to" technique. Specifically, modification of fabric with wettability gradient for facilitated one way-liquid transport, and pointed modification of yarn-based channels on textile microfluidic device for directional liquid transport are reported here. First, fabric was activated with alkali (NaOH) solution. Second, poly (glycidyl methacrylate) (PGMA) was deposited on fabric as an anchoring layer. Finally, polymers of interest were grafted to surface through the epoxy functionality of PGMA. Effect of polymer grafting on the wicking property of the fabric has been evaluated by vertical wicking technique at the each step of surface modification. The results shows that wicking performance of fabric can be altered by grafting of a thin nanoscale polymeric film. For the facilitated liquid transport, the gradient polymer coating was created using "grafting to" technique and its dependence on the grafting temperature. Wettability gradient from hydrophilic to hydrophobic (change in water contact angle from 0 to 140 degrees on fabric) was achieved by grafting of polystyrene (PS) and polyacrylic acid (PAA) sequentially with concentration gradient. This study proposes that fabric with wettability gradient property can be used to transfer sweat from skin and support moisture management when it is used in a laminated garment structure. For cooling performance evaluation, modified fabrics were tested with surface differential scanning calorimeter, and improved cooling effect was found with the fabric that has wettability gradient. Directional liquid transport can be achieved on amphiphilic fabric. To this end, fabric consisting of PET and PP yarn is fabricated. Activation and PGMA deposition yields an array of highly reactive PET channels that are constrained by hydrophobic PP boundaries. Aqueous solutions are transported in the channels by capillary forces where the direction of the liquid transport is defined by pH-response of the grafted polymers. The system of pH-selective channels in the developed textile based microfluidic chip could find analytical applications and can be used for smart cloth.

Apollo-Soyuz pamphlet no. 8: Zero-g technology. [experimental designispace processing and aerospace engineering

NASA Technical Reports Server (NTRS)

Page, L. W.; From, T. P.

1977-01-01

The behavior of liquids in zero gravity environments is discussed with emphasis on foams, wetting, and wicks. A multipurpose electric furnace (MA-010) for the high temperature processing of metals and salts in zero-g is described. Experiments discussed include: monolectic and synthetic alloys (MA-041); multiple material melting point (MA-150); zero-g processing of metals (MA-070); surface tension induced convection (MA-041); halide eutectic growth; interface markings in crystals (MA-060); crystal growth from the vapor phase (MA-085); and photography of crystal growth (MA-028).

A Wicked Problem? Whistleblowing in Healthcare Organisations

PubMed Central

Hyde, Paula

2016-01-01

Mannion and Davies’ article recognises whistleblowing as an important means of identifying quality and safety issues in healthcare organisations. While ‘voice’ is a useful lens through which to examine whistleblowing, it also obscures a shifting pattern of uncertain ‘truths.’ By contextualising cultures which support or impede whislteblowing at an organisational level, two issues are overlooked; the power of wider institutional interests to silence those who might raise the alarm and changing ideas about what constitutes adequate care. A broader contextualisation of whistleblowing might illuminate further facets of this multi-dimensional problem. PMID:27239870

Results of air samples at American Asbestos Textile Corporation, Meredith, New Hampshire. Industrywide study

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

Lynch, J.R.

1966-06-01

Worker exposures to asbestos were surveyed at the American Asbestos Textile Corporation in Meredith, New Hampshire, June 21, 1966. Asbestos-fiber concentrations in the fiber preparation, carding, spinning, twisting, winding, weaving, finishing, and rope, wick, braid and cord areas were 6.0 to 17.1, 14.8 to 118.6, 7.4 to 26.2, 5.6 to 15.1, 4.3 to 27.0, 5.8 to 35.9, 7.5, and 6.3 to 7.4 fibers greater than 5 microns per cubic centimeter, respectively.

Investigation of micro-gravity effects on heat pipe thermal performance and working fluid behavior, phase B

NASA Technical Reports Server (NTRS)

Gier, K. D.; Smith, M. O.

1990-01-01

The purpose of this experiment is to develop an in-depth understanding of the behavior of heat pipes in space. Both fixed conductance heat pipes (FCHPs) with axial grooves and variable conductance heat pipes (VCHPs) with porous wicks will be investigated. This understanding will be applied to the development of improved performance heat pipes subjected to various accelerations in space, including those encountered on a lunar base or Mars mission. More efficient, reliable, and lighter weight spacecraft thermal control systems should result from these investigations.

Simple, field portable colorimetric detection device for organic peroxides and hydrogen peroxide

DOEpatents

Pagoria, Philip F.; Mitchell, Alexander R.; Whipple, Richard E.; Carman, M. Leslie; Reynolds, John G.; Nunes, Peter; Shields, Sharon J.

2010-11-09

A simple and effective system for the colorimetric determination of organic peroxides and hydrogen peroxide. A peroxide pen utilizing a swipe material attached to a polyethylene tube contains two crushable vials. The two crushable vials contain a colorimetric reagent separated into dry ingredients and liquid ingredients. After swiping a suspected substance or surface the vials are broken, the reagent is mixed thoroughly and the reagent is allowed to wick into the swipe material. The presence of organic peroxides or hydrogen peroxide is confirmed by a deep blue color.

Development of a Phosphorus-Eutrophication Management Strategy for Vermont: Evaluations Available Phosphorus Loads.

DTIC Science & Technology

1985-11-01

1980). " J . V. DePinto, T . C. Young, J . S. Bonner, and P. W. Rodgers, "Microbial Recycling of Phytoplankton Phosphorus," Canadian Journal of...algal growth, 97 9 3 S. C. Chapra, H. D. Wicke, T . M. Heidtke, "Effectiveness of Treatment to Meet Phosphorus Objectives in the Great Lakes," J . Water...Conference on Management Strategies for Phosphorus in the Environment (Selper Ltd., London, 1985.) 1 0 4 G. F. Lee, et al. (1980). 105 T . C. Young and J . V

Fast light-evoked potential from leaves.

PubMed

Ebrey, T G

1967-03-24

When a leaf is illuminated with an intense flash of light, an elec trical response with a time course in milliseconds can be recorded. This re sponse was obtained between two wick electrodes placed at different positions on top of the leaf, with the entire leaf uniformly illuminated by the flash. During the first millisecond or so, the electrode nearer the apex of the leaf always became negative with respect to an electrode at the base, which indi cates that the voltage-generating source is fixed longitudinally in the leaf.

Chemistry and Defects in Semiconductor Heterostructures. Materials Research Society Symposium Proceedings. Volume 148

DTIC Science & Technology

1990-05-01

Pennington:The Electrochemical Society), p. 54 1. 12. A. Hiraki , in Proceedings of the Symosium on Thin Film Interfaces and Reactions, J.EE. Baglin...Biefeld, l.J. Fritz and T.E. Zipperian, Nucl. Inst. Meth. B7/8 (1985)453. 2. M. Sekoguchi, T. Taguchi and A. Hiraki , Nucl. Instr. and Meth. B37/38...1989)728 3. Y. Kawakami, T. Taguchi and A. Hiraki , J. Cryst. Growth 89 (1988)331. 4. D.F. Welch. G.W. Wicks and L. F. Eastman, Appl. Phys. Lett. 46

Water-assisted femtosecond laser machining of electrospray nozzles on glass microfluidic devices.

PubMed

An, Ran; Hoffman, Michelle D; Donoghue, Margaret A; Hunt, Alan J; Jacobson, Stephen C

2008-09-15

Using water-assisted femtosecond laser machining, we fabricated electrospray nozzles on glass coverslips and on assembled microfluidic devices. Machining the nozzles after device assembly facilitated alignment of the nozzles over the microchannels. The basic nozzle design is a through-hole in the coverslip to pass liquids and a trough machined around the through-hole to confine the electrospray and prevent liquid from wicking across the glass surface. Electrospray from the nozzles was stable with and without pressure-driven flow applied and was evaluated using mass spectra of the peptide bradykinin.

Numerically pricing American options under the generalized mixed fractional Brownian motion model

NASA Astrophysics Data System (ADS)

Chen, Wenting; Yan, Bowen; Lian, Guanghua; Zhang, Ying

2016-06-01

In this paper, we introduce a robust numerical method, based on the upwind scheme, for the pricing of American puts under the generalized mixed fractional Brownian motion (GMFBM) model. By using portfolio analysis and applying the Wick-Itô formula, a partial differential equation (PDE) governing the prices of vanilla options under the GMFBM is successfully derived for the first time. Based on this, we formulate the pricing of American puts under the current model as a linear complementarity problem (LCP). Unlike the classical Black-Scholes (B-S) model or the generalized B-S model discussed in Cen and Le (2011), the newly obtained LCP under the GMFBM model is difficult to be solved accurately because of the numerical instability which results from the degeneration of the governing PDE as time approaches zero. To overcome this difficulty, a numerical approach based on the upwind scheme is adopted. It is shown that the coefficient matrix of the current method is an M-matrix, which ensures its stability in the maximum-norm sense. Remarkably, we have managed to provide a sharp theoretic error estimate for the current method, which is further verified numerically. The results of various numerical experiments also suggest that this new approach is quite accurate, and can be easily extended to price other types of financial derivatives with an American-style exercise feature under the GMFBM model.

Multiphysics modeling of two-phase film boiling within porous corrosion deposits

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

Jin, Miaomiao, E-mail: mmjin@mit.edu; Short, Michael, E-mail: hereiam@mit.edu

2016-07-01

Porous corrosion deposits on nuclear fuel cladding, known as CRUD, can cause multiple operational problems in light water reactors (LWRs). CRUD can cause accelerated corrosion of the fuel cladding, increase radiation fields and hence greater exposure risk to plant workers once activated, and induce a downward axial power shift causing an imbalance in core power distribution. In order to facilitate a better understanding of CRUD's effects, such as localized high cladding surface temperatures related to accelerated corrosion rates, we describe an improved, fully-coupled, multiphysics model to simulate heat transfer, chemical reactions and transport, and two-phase fluid flow within these deposits.more » Our new model features a reformed assumption of 2D, two-phase film boiling within the CRUD, correcting earlier models' assumptions of single-phase coolant flow with wick boiling under high heat fluxes. This model helps to better explain observed experimental values of the effective CRUD thermal conductivity. Finally, we propose a more complete set of boiling regimes, or a more detailed mechanism, to explain recent CRUD deposition experiments by suggesting the new concept of double dryout specifically in thick porous media with boiling chimneys. - Highlights: • A two-phase model of CRUD's effects on fuel cladding is developed and improved. • This model eliminates the formerly erroneous assumption of wick boiling. • Higher fuel cladding temperatures are predicted when accounting for two-phase flow. • Double-peaks in thermal conductivity vs. heat flux in experiments are explained. • A “double dryout” mechanism in CRUD is proposed based on the model and experiments.« less

Burning a Candle in a Vessel, a Simple Experiment with a Long History

NASA Astrophysics Data System (ADS)

Vera, Francisco; Rivera, Rodrigo; Núñez, César

2011-09-01

The experiment in which a candle is burned inside an inverted vessel partially immersed in water has a history of more than 2,200 years, but even nowadays it is common that students and teachers relate the change in volume of the enclosed air to its oxygen content. Contrary to what many people think, Lavoisier concluded that any change in volume in this experiment is negligible; moreover, the explanation relating oxygen consumption in the air with its change in volume is known to be wrong. In this work we briefly review the history behind the candle experiment and its relationship with some typical erroneous explanations. One of the key factors behind Lavoisier's success was the use of experiments carefully designed to test different hypotheses. Following these steps, we performed several closed volume experiments where the candle wick was replaced by a capillary stainless steel cylinder supported and heated by a nichrome filament connected to an external power supply. Our recorded experiments are displayed as web pages, designed with the purpose that the reader can easily visualize and analyze modern versions of Lavoisier's experiments. These experiments clearly show an initial phase of complete combustion, followed by a phase of incomplete combustion with elemental carbon or soot rising to the top of the vessel, and a final phase where the hot artificial wick only evaporates a white steam of wax that cannot ignite because no oxygen is left in the closed atmosphere. After either a complete or incomplete combustion of the oxygen, our experiments show that the final gas volume is nearly equal to the initial air volume.

Validation test of advanced technology for IPV nickel-hydrogen flight cells - Update

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1992-01-01

Individual pressure vessel (IPV) nickel-hydrogen technology was advanced at NASA Lewis and under Lewis contracts with the intention of improving cycle life and performance. One advancement was to use 26 percent potassium hydroxide (KOH) electrolyte to improve cycle life. Another advancement was to modify the state-of-the-art cell design to eliminate identified failure modes. The modified design is referred to as the advanced design. A breakthrough in the LEO cycle life of IPV nickel-hydrogen cells has been previously reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3,500 cycles for cells containing 31 percent KOH. The boiler plate test results are in the process of being validated using flight hardware and real time LEO testing. The primary function of the advanced cell is to store and deliver energy for long-term, LEO spacecraft missions. The new features of this design are: (1) use of 26 percent rather than 31 percent KOH electrolyte; (2) use of a patented catalyzed wall wick; (3) use of serrated-edge separators to facilitate gaseous oxygen and hydrogen flow within the cell, while still maintaining physical contact with the wall wick for electrolyte management; and (4) use of a floating rather than a fixed stack (state-of-the-art) to accommodate nickel electrode expansion due to charge/discharge cycling. The significant improvements resulting from these innovations are: extended cycle life; enhanced thermal, electrolyte, and oxygen management; and accommodation of nickel electrode expansion.

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.

Tackling racism as a "wicked" public health problem: Enabling allies in anti-racism praxis.

PubMed

Came, Heather; Griffith, Derek

2018-02-01

Racism is a "wicked" public health problem that fuels systemic health inequities between population groups in New Zealand, the United States and elsewhere. While literature has examined racism and its effects on health, the work describing how to intervene to address racism in public health is less developed. While the notion of raising awareness of racism through socio-political education is not new, given the way racism has morphed into new narratives in health institutional settings, it has become critical to support allies to make informing efforts to address racism as a fundamental cause of health inequities. In this paper, we make the case for anti-racism praxis as a tool to address inequities in public health, and focus on describing an anti-racism praxis framework to inform the training and support of allies. The limited work on anti-racism rarely articulates the unique challenges or needs of allies or targets of racism, but we seek to help fill that gap. Our anti-racism praxis for allies includes five core elements: reflexive relational praxis, structural power analysis, socio-political education, monitoring and evaluation and systems change approaches. We recognize that racism is a modifiable determinant of health and racial inequities can be eliminated with the necessary political will and a planned system change approach. Anti-racism praxis provides the tools to examine the interconnection and interdependence of cultural and institutional factors as a foundation for examining where and how to intervene to address racism. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

A low-cost, manufacturable method for fabricating capillary and optical fiber interconnects for microfluidic devices.

PubMed

Hartmann, Daniel M; Nevill, J Tanner; Pettigrew, Kenneth I; Votaw, Gregory; Kung, Pang-Jen; Crenshaw, Hugh C

2008-04-01

Microfluidic chips require connections to larger macroscopic components, such as light sources, light detectors, and reagent reservoirs. In this article, we present novel methods for integrating capillaries, optical fibers, and wires with the channels of microfluidic chips. The method consists of forming planar interconnect channels in microfluidic chips and inserting capillaries, optical fibers, or wires into these channels. UV light is manually directed onto the ends of the interconnects using a microscope. UV-curable glue is then allowed to wick to the end of the capillaries, fibers, or wires, where it is cured to form rigid, liquid-tight connections. In a variant of this technique, used with light-guiding capillaries and optical fibers, the UV light is directed into the capillaries or fibers, and the UV-glue is cured by the cone of light emerging from the end of each capillary or fiber. This technique is fully self-aligned, greatly improves both the quality and the manufacturability of the interconnects, and has the potential to enable the fabrication of interconnects in a fully automated fashion. Using these methods, including a semi-automated implementation of the second technique, over 10,000 interconnects have been formed in almost 2000 microfluidic chips made of a variety of rigid materials. The resulting interconnects withstand pressures up to at least 800psi, have unswept volumes estimated to be less than 10 femtoliters, and have dead volumes defined only by the length of the capillary.

Research on the output bit error rate of 2DPSK signal based on stochastic resonance theory

NASA Astrophysics Data System (ADS)

Yan, Daqin; Wang, Fuzhong; Wang, Shuo

2017-12-01

Binary differential phase-shift keying (2DPSK) signal is mainly used for high speed data transmission. However, the bit error rate of digital signal receiver is high in the case of wicked channel environment. In view of this situation, a novel method based on stochastic resonance (SR) is proposed, which is aimed to reduce the bit error rate of 2DPSK signal by coherent demodulation receiving. According to the theory of SR, a nonlinear receiver model is established, which is used to receive 2DPSK signal under small signal-to-noise ratio (SNR) circumstances (between -15 dB and 5 dB), and compared with the conventional demodulation method. The experimental results demonstrate that when the input SNR is in the range of -15 dB to 5 dB, the output bit error rate of nonlinear system model based on SR has a significant decline compared to the conventional model. It could reduce 86.15% when the input SNR equals -7 dB. Meanwhile, the peak value of the output signal spectrum is 4.25 times as that of the conventional model. Consequently, the output signal of the system is more likely to be detected and the accuracy can be greatly improved.

Lefschetz thimbles in fermionic effective models with repulsive vector-field

NASA Astrophysics Data System (ADS)

Mori, Yuto; Kashiwa, Kouji; Ohnishi, Akira

2018-06-01

We discuss two problems in complexified auxiliary fields in fermionic effective models, the auxiliary sign problem associated with the repulsive vector-field and the choice of the cut for the scalar field appearing from the logarithmic function. In the fermionic effective models with attractive scalar and repulsive vector-type interaction, the auxiliary scalar and vector fields appear in the path integral after the bosonization of fermion bilinears. When we make the path integral well-defined by the Wick rotation of the vector field, the oscillating Boltzmann weight appears in the partition function. This "auxiliary" sign problem can be solved by using the Lefschetz-thimble path-integral method, where the integration path is constructed in the complex plane. Another serious obstacle in the numerical construction of Lefschetz thimbles is caused by singular points and cuts induced by multivalued functions of the complexified scalar field in the momentum integration. We propose a new prescription which fixes gradient flow trajectories on the same Riemann sheet in the flow evolution by performing the momentum integration in the complex domain.

Quantitative evaluation of analyte transport on microfluidic paper-based analytical devices (μPADs).

PubMed

Ota, Riki; Yamada, Kentaro; Suzuki, Koji; Citterio, Daniel

2018-02-07

The transport efficiency during capillary flow-driven sample transport on microfluidic paper-based analytical devices (μPADs) made from filter paper has been investigated for a selection of model analytes (Ni 2+ , Zn 2+ , Cu 2+ , PO 4 3- , bovine serum albumin, sulforhodamine B, amaranth) representing metal cations, complex anions, proteins and anionic molecules. For the first time, the transport of the analytical target compounds rather than the sample liquid, has been quantitatively evaluated by means of colorimetry and absorption spectrometry-based methods. The experiments have revealed that small paperfluidic channel dimensions, additional user operation steps (e.g. control of sample volume, sample dilution, washing step) as well as the introduction of sample liquid wicking areas allow to increase analyte transport efficiency. It is also shown that the interaction of analytes with the negatively charged cellulosic paper substrate surface is strongly influenced by the physico-chemical properties of the model analyte and can in some cases (Cu 2+ ) result in nearly complete analyte depletion during sample transport. The quantitative information gained through these experiments is expected to contribute to the development of more sensitive μPADs.

In vitro flow-through assay for rapid detection of endotoxin in human sera: A proof-of-concept.

PubMed

Kalita, Prasanta; Chaturvedula, Lakshmi M; Sritharan, Venkataraman; Gupta, Shalini

2017-05-01

An increase in endotoxin concentration in the bloodstream can trigger activation of innate immune response leading to septic shock. There is currently no method available for rapid endotoxin detection at a patient's bedside. We demonstrate a simple, portable and cost-effective strategy to measure endotoxin levels in human serum within 5min using a flow-through assay. A drop of serum containing LPS was spotted on an endotoxin-affinity membrane placed over high-wicking absorbent pads. Subsequent addition of polymyxin B sulfate drug-conjugated gold nanoparticles allowed concentration-dependent visualization of spots by the naked eye in the clinically-relevant range of 10pg/mL to 10ng/mL. The results were quantified using a concentration-calibrated color chart and the assay performance was tested with archival plasma samples of 18 known septicemia patients. The results showed a reasonably good correlation with the patients' hematological data. This proof-of-concept study puts forth an interesting alternative for early septicemia diagnosis in future. Copyright © 2017 Elsevier Inc. All rights reserved.

Domestic violence against women, public policies and community health workers in Brazilian Primary Health Care.

PubMed

Signorelli, Marcos Claudio; Taft, Angela; Pereira, Pedro Paulo Gomes

2018-01-01

Domestic violence creates multiple harms for women's health and is a 'wicked problem' for health professionals and public health systems. Brazil recently approved public policies to manage and care for women victims of domestic violence. Facing these policies, this study aimed to explore how domestic violence against women is usually managed in Brazilian primary health care, by investigating a basic health unit and its family health strategy. We adopted qualitative ethnographic research methods with thematic analysis of emergent categories, interrogating data with gender theory and emergent Brazilian collective health theory. Field research was conducted in a local basic health unit and the territory for which it is responsible, in Southern Brazil. The study revealed: 1) a yawning gap between public health policies for domestic violence against women at the federal level and its practical application at local/decentralized levels, which can leave both professionals and women unsafe; 2) the key role of local community health workers, paraprofessional health promotion agents, who aim to promote dialogue between women experiencing violence, health care professionals and the health care system.

Lost in space: design of experiments and scientific exploration in a Hogarth Universe.

PubMed

Lendrem, Dennis W; Lendrem, B Clare; Woods, David; Rowland-Jones, Ruth; Burke, Matthew; Chatfield, Marion; Isaacs, John D; Owen, Martin R

2015-11-01

A Hogarth, or 'wicked', universe is an irregular environment generating data to support erroneous beliefs. Here, we argue that development scientists often work in such a universe. We demonstrate that exploring these multidimensional spaces using small experiments guided by scientific intuition alone, gives rise to an illusion of validity and a misplaced confidence in that scientific intuition. By contrast, design of experiments (DOE) permits the efficient mapping of such complex, multidimensional spaces. We describe simulation tools that enable research scientists to explore these spaces in relative safety. Copyright © 2015 Elsevier Ltd. All rights reserved.

Parallel-plate heat pipe apparatus having a shaped wick structure

DOEpatents

Rightley, Michael J.; Adkins, Douglas R.; Mulhall, James J.; Robino, Charles V.; Reece, Mark; Smith, Paul M.; Tigges, Chris P.

2004-12-07

A parallel-plate heat pipe is disclosed that utilizes a plurality of evaporator regions at locations where heat sources (e.g. semiconductor chips) are to be provided. A plurality of curvilinear capillary grooves are formed on one or both major inner surfaces of the heat pipe to provide an independent flow of a liquid working fluid to the evaporator regions to optimize heat removal from different-size heat sources and to mitigate the possibility of heat-source shadowing. The parallel-plate heat pipe has applications for heat removal from high-density microelectronics and laptop computers.

Perturbative computation in a generalized quantum field theory

NASA Astrophysics Data System (ADS)

Bezerra, V. B.; Curado, E. M.; Rego-Monteiro, M. A.

2002-10-01

We consider a quantum field theory that creates at any point of the space-time particles described by a q-deformed Heisenberg algebra which is interpreted as a phenomenological quantum theory describing the scattering of spin-0 composed particles. We discuss the generalization of Wick's expansion for this case and we compute perturbatively the scattering 1+2-->1'+2' to second order in the coupling constant. The result we find shows that the structure of a composed particle, described here phenomenologically by the deformed algebraic structure, can modify in a simple but nontrivial way the perturbation expansion for the process under consideration.

Heat pipes for spacecraft temperature control: Their usefulness and limitations

NASA Technical Reports Server (NTRS)

Ollendorf, S.; Stipandic, E.

1972-01-01

Heat pipes are used in spacecraft to equalize the temperature of structures and maintain temperature control of electronic components. Information is provided for a designer on: (1) a typical mounting technique, (2) choices available in wick geometries and fluids, (3) tests involved in flight-qualifying the design, and (4) heat pipe limitations. An evaluation of several heat pipe designs showed that the behavior of heat pipes at room temperature does not necessarily correlate with the classic equations used to predict their performance. They are sensitive to such parameters as temperature, fluid inventory, orientation, and noncondensable gases.

Thermal energy transformer

NASA Technical Reports Server (NTRS)

Berdahl, C. M.; Thiele, C. L. (Inventor)

1979-01-01

For use in combination with a heat engine, a thermal energy transformer is presented. It is comprised of a flux receiver having a first wall defining therein a radiation absorption cavity for converting solar flux to thermal energy, and a second wall defining an energy transfer wall for the heat engine. There is a heat pipe chamber interposed between the first and second walls having a working fluid disposed within the chamber and a wick lining the chamber for conducting the working fluid from the second wall to the first wall. Thermal energy is transferred from the radiation absorption cavity to the heat engine.

Feynman propagators on static spacetimes

NASA Astrophysics Data System (ADS)

Dereziński, Jan; Siemssen, Daniel

We consider the Klein-Gordon equation on a static spacetime and minimally coupled to a static electromagnetic potential. We show that it is essentially self-adjoint on Cc∞. We discuss various distinguished inverses and bisolutions of the Klein-Gordon operator, focusing on the so-called Feynman propagator. We show that the Feynman propagator can be considered the boundary value of the resolvent of the Klein-Gordon operator, in the spirit of the limiting absorption principle known from the theory of Schrödinger operators. We also show that the Feynman propagator is the limit of the inverse of the Wick rotated Klein-Gordon operator.

Mathematical modeling of high and low temperature heat pipes

NASA Technical Reports Server (NTRS)

Chi, S. W.

1971-01-01

Following a review of heat and mass transfer theory relevant to heat pipe performance, math models are developed for calculating heat-transfer limitations of high-temperature heat pipes and heat-transfer limitations and temperature gradient of low temperature heat pipes. Calculated results are compared with the available experimental data from various sources to increase confidence in the present math models. Complete listings of two computer programs for high- and low-temperature heat pipes respectively are included. These programs enable the performance to be predicted of heat pipes with wrapped-screen, rectangular-groove, or screen-covered rectangular-groove wick.

Berezin-Toeplitz quantization and naturally defined star products for Kähler manifolds

NASA Astrophysics Data System (ADS)

Schlichenmaier, Martin

2018-04-01

For compact quantizable Kähler manifolds the Berezin-Toeplitz quantization schemes, both operator and deformation quantization (star product) are reviewed. The treatment includes Berezin's covariant symbols and the Berezin transform. The general compact quantizable case was done by Bordemann-Meinrenken-Schlichenmaier, Schlichenmaier, and Karabegov-Schlichenmaier. For star products on Kähler manifolds, separation of variables, or equivalently star product of (anti-) Wick type, is a crucial property. As canonically defined star products the Berezin-Toeplitz, Berezin, and the geometric quantization are treated. It turns out that all three are equivalent, but different.

Heat pipe life and processing study

NASA Technical Reports Server (NTRS)

Antoniuk, D.; Luedke, E. E.

1979-01-01

The merit of adding water to the reflux charge in chemically and solvent cleaned aluminum/slab wick/ammonia heat pipes was evaluated. The effect of gas in the performance of three heat pipe thermal control systems was found significant in simple heat pipes, less significant in a modified simple heat pipe model with a short wickless pipe section. Use of gas data for the worst and best heat pipes of the matrix in a variable conductance heat pipe model showed a 3 C increase in the source temperature at full on condition after 20 and 246 years, respectively.

Large-scale forcing of the European Slope Current and associated inflows to the North Sea

NASA Astrophysics Data System (ADS)

Marsh, Robert; Haigh, Ivan D.; Cunningham, Stuart A.; Inall, Mark E.; Porter, Marie; Moat, Ben I.

2017-04-01

The European Slope Current provides a shelf-edge conduit for Atlantic Water, a substantial fraction of which is destined for the northern North Sea, with implications for regional hydrography and ecosystems. Drifters drogued at 50 m in the European Slope Current at the Hebridean shelf break follow a wide range of pathways, indicating highly variable Atlantic inflow to the North Sea. Slope Current pathways, timescales and transports over 1988-2007 are further quantified in an eddy-resolving ocean model hindcast. Particle trajectories calculated with model currents indicate that Slope Current water is largely recruited from the eastern subpolar North Atlantic. Observations of absolute dynamic topography and climatological density support theoretical expectations that Slope Current transport is to first order associated with meridional density gradients in the eastern subpolar gyre, which support a geostrophic inflow towards the slope. In the model hindcast, Slope Current transport variability is dominated by abrupt 25-50 % reductions of these density gradients over 1996-1998. Concurrent changes in wind forcing, expressed in terms of density gradients, act in the same sense to reduce Slope Current transport. This indicates that coordinated regional changes of buoyancy and wind forcing acted together to reduce Slope Current transport during the 1990s. Particle trajectories further show that 10-40 % of Slope Current water is destined for the northern North Sea within 6 months of passing to the west of Scotland, with a general decline in this percentage over 1988-2007. Salinities in the Slope Current correspondingly decreased, evidenced in ocean analysis data. Further to the north, in the Atlantic Water conveyed by the Slope Current through the Faroe-Shetland Channel (FSC), salinity is observed to increase over this period while declining in the hindcast. The observed trend may have broadly compensated for a decline in the Atlantic inflow, limiting salinity changes in the northern North Sea during this period. Proxies for both Slope Current transport and Atlantic inflow to the North Sea are sought in sea level height differences across the FSC and between Shetland and the Scottish mainland (Wick). Variability of Slope Current transport on a wide range of timescales, from seasonal to multi-decadal, is implicit in sea level differences between Lerwick (Shetland) and Tórshavn (Faroes), in both tide gauge records from 1957 and a longer model hindcast spanning 1958-2012. Wick-Lerwick sea level differences in tide gauge records from 1965 indicate considerable decadal variability in the Fair Isle Current transport that dominates Atlantic inflow to the northwest North Sea, while sea level differences in the hindcast are dominated by strong seasonal variability. Uncertainties in the Wick tide gauge record limit confidence in this proxy.

Systematic investigation of drip stains on apparel fabrics: The effects of prior-laundering, fibre content and fabric structure on final stain appearance.

PubMed

de Castro, Therese C; Taylor, Michael C; Kieser, Jules A; Carr, Debra J; Duncan, W

2015-05-01

Bloodstain pattern analysis is the investigation of blood deposited at crime scenes and the interpretation of that pattern. The surface that the blood gets deposited onto could distort the appearance of the bloodstain. The interaction of blood and apparel fabrics is in its infancy, but the interaction of liquids and apparel fabrics has been well documented and investigated in the field of textile science (e.g. the processes of wetting and wicking of fluids on fibres, yarns and fabrics). A systematic study on the final appearance of drip stains on torso apparel fabrics (100% cotton plain woven, 100% polyester plain woven, blend of polyester and cotton plain woven and 100% cotton single jersey knit) that had been laundered for six, 26 and 52 cycles prior to testing was investigated in the paper. The relationship between drop velocity (1.66±0.50m/s, 4.07±0.03m/s, 5.34±0.18m/s) and the stain characteristics (parent stain area, axes 1 and 2 and number of satellite stains) for each fabric was examined using analysis of variance. The experimental design and effect of storing blood were investigated on a reference sample, which indicated that the day (up to five days) at which the drops were generated did not affect the bloodstain. The effect of prior-laundering (six, 26 and 52 laundering cycles), fibre content (cotton vs. polyester vs. blend) and fabric structure (plain woven vs. single jersey knit) on the final appearance of the bloodstain were investigated. Distortion in the bloodstains produced on non-laundered fabrics indicated the importance of laundering fabrics to remove finishing treatments before conducting bloodstain experiments. For laundered fabrics, both the cotton fabrics and the blend had a circular to oval stain appearance, while the polyester fabric had a circular appearance with evidence of spread along the warp and weft yarns, which resulted in square-like stains at the lowest drop velocity. A significant (p<0.001) increase in the stain size on laundered blend fabric was identified. Bloodstain characteristics varied due to fibre content (p<0.001) and fabric structure (p<0.001). Blood on polyester fabric, after impact, primarily moved due to capillary force and wicking of the blood along the fibres/yarns, while for the cotton fabrics wicking was accompanied by movement of blood into the fibres/yarns. This study highlights the importance for forensic analysts of apparel evidence to consider the age, the fibre type and the fabric structure before interpreting bloodstain patterns. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Comparison of pollutant emission rates from unvented kerosene and gas space heaters

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

Apte, M.G.; Traynor, G.W.

1986-05-01

In this paper the pollutant emission rates of all five types of unvented space heaters are compared. Pollutant emission rates for carbon dioxide, carbon monoxide (CO), nitric oxide, nitrogen dioxide (NO/sub 2/), formaldehyde, and submicron suspended particles were measured. Special emphasis is placed on CO and NO/sub 2/ emissions. Pollutant measurements were made in a 27-m/sup 3/ environmental chamber and emission rates were calculated using a mass-balance model. Emission rates for propane and natural gas space heaters were similar. Emissions from the various types of heaters fall into three distinct groups. The groups are better characterized by burner design thanmore » by the type of fuel used. Radiant kerosene heaters and infrared UVGSHs constitute one group; convective kerosene heaters and convective UVGSHs the second, and two-stage kerosene heaters the third group. When groups are compared, emission rates vary by an order of magnitude for carbon monoxide and for nitrogen dioxide. The two-stage kerosene heaters emitted the least CO and also the least NO/sub 2/ per unit of fuel energy consumed. The radiant/infrared heaters emitted the most CO, and the convective heaters emitted the most NO/sub 2/. The effects of various operation parameters such as the wick height for kerosene heaters and the air shutter adjustment for gas heaters are discussed. Convective UVGSHs operating at half input were found to have lower emission rates on average than when operating at full input. Some maltuned convective UVGSHs were capable of emitting very high amounts of CO. Kerosene heaters were found to emit more CO and NO/sub 2/ on average when they were operated with lowered wicks.« less

Design for On-Sun Evaluation of Evaporator Receivers

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.; Colozza, Anthony; Sechkar, Edward A.

2011-01-01

A heat pipe designed for operation as a solar power receiver should be optimized to accept the solar energy flux and transfer this heat into a reactor. Optical properties of the surface, thermal conductance of the receiver wall, contact resistance of the heat pipe wick, and other heat pipe wick properties ultimately define the maximum amount of power that can be extracted from the concentrated sunlight impinging on the evaporator surface. Modeling of solar power receivers utilizing optical and physical properties provides guidance to their design. On-sun testing is another important means of gathering information on performance. A test rig is being designed and built to conduct on-sun testing. The test rig is incorporating a composite strip mirror concentrator developed as part of a Small Business Innovative Research effort and delivered to NASA Glenn Research Center. In the strip concentrator numerous, lightweight composite parabolic strips of simple curvature were combined to form an array 1.5 m x 1.5 m in size. The line focus of each strip is superimposed in a central area simulating a point of focus. A test stand is currently being developed to hold the parabolic strip concentrator, track the sun, and turn the beam downward towards the ground. The hardware is intended to be sufficiently versatile to accommodate on-sun testing of several receiver concepts, including those incorporating heat pipe evaporators. Characterization devices are also being developed to evaluate the effectiveness of the solar concentrator, including a receiver designed to conduct calorimetry. This paper describes the design and the characterization devices of the on-sun test rig, and the prospect of coupling the concentrated sunlight to a heat pipe solar power receiver developed as part of another Small Business Innovative Research effort.