Conceptualizing Programme Evaluation

ERIC Educational Resources Information Center

Hassan, Salochana

2013-01-01

The main thrust of this paper deals with the conceptualization of theory-driven evaluation pertaining to a tutor training programme. Conceptualization of evaluation, in this case, is an integration between a conceptualization model as well as a theoretical framework in the form of activity theory. Existing examples of frameworks of programme…

Wide-view transflective liquid crystal display for mobile applications

NASA Astrophysics Data System (ADS)

Kim, Hyang Yul; Ge, Zhibing; Wu, Shin-Tson; Lee, Seung Hee

2007-12-01

A high optical efficiency and wide-view transflective liquid crystal display based on fringe-field switching structure is proposed. The transmissive part has a homogenous liquid crystal (LC) alignment and is driven by a fringe electric field, which exhibits excellent electro-optic characteristics. The reflective part has a hybrid LC alignment with quarter-wave phase retardation and is also driven by a fringe electric field. Consequently, the transmissive and reflective parts have similar gamma curves.

Solid–Liquid Phase Change Driven by Internal Heat Generation

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

John Crepeau; Ali s. Siahpush

2012-07-01

This article presents results of solid-liquid phase change, the Stefan Problem, where melting is driven internal heat generation, in a cylindrical geometry. The comparison between a quasi-static analytical solution for Stefan numbers less than one and numerical solutions shows good agreement. The computational results of phase change with internal heat generation show how convection cells form in the liquid region. A scale analysis of the same problem shows four distinct regions of the melting process.

Back-end of the fuel cycle - Indian scenario

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

Wattal, P.K.

Nuclear power has a key role in meeting the energy demands of India. This can be sustained by ensuring robust technology for the back end of the fuel cycle. Considering the modest indigenous resources of U and a huge Th reserve, India has adopted a three stage Nuclear Power Programme (NPP) based on 'closed fuel cycle' approach. This option on 'Recovery and Recycle' serves twin objectives of ensuring adequate supply of nuclear fuel and also reducing the long term radio-toxicity of the wastes. Reprocessing of the spent fuel by Purex process is currently employed. High Level Liquid Waste (HLW) generatedmore » during reprocessing is vitrified and undergoes interim storage. Back-end technologies are constantly modified to address waste volume minimization and radio-toxicity reduction. Long-term management of HLW in Indian context would involve partitioning of long lived minor actinides and recovery of valuable fission products specifically cesium. Recovery of minor actinides from HLW and its recycle is highly desirable for the sustained growth of India's NPPs. In this context, programme for developing and deploying partitioning technologies on industrial scale is pursued. The partitioned elements could be either transmuted in Fast Reactors (FRs)/Accelerated Driven Systems (ADS) as an integral part of sustainable Indian NPP. (authors)« less

Liquid Marble Coalescence and Triggered Microreaction Driven by Acoustic Levitation.

PubMed

Chen, Zhen; Zang, Duyang; Zhao, Liang; Qu, Mengfei; Li, Xu; Li, Xiaoguang; Li, Lixin; Geng, Xingguo

2017-06-27

Liquid marbles show promising potential for application in the microreactor field. Control of the coalescence between two or among multiple liquid marbles is critical; however, the successful merging of two isolated marbles is difficult because of their mechanically robust particle shells. In this work, the coalescence of multiple liquid marbles was achieved via acoustic levitation. The dynamic behaviors of the liquid marbles were monitored by a high-speed camera. Driven by the sound field, the liquid marbles moved toward each other, collided, and eventually coalesced into a larger single marble. The underlying mechanisms of this process were probed via sound field simulation and acoustic radiation pressure calculation. The results indicated that the pressure gradient on the liquid marble surface favors the formation of a liquid bridge between the liquid marbles, resulting in their coalescence. A preliminary indicator reaction was induced by the coalescence of dual liquid marbles, which suggests that expected chemical reactions can be successfully triggered with multiple reagents contained in isolated liquid marbles via acoustic levitation.

Hydration of dimethyldodecylamine-N-oxide: enthalpy and entropy driven processes.

PubMed

Kocherbitov, Vitaly; Söderman, Olle

2006-07-13

Dimethyldodecylamine-N-oxide (DDAO) has only one polar atom that is able to interact with water. Still, this surfactant shows very hydrophilic properties: in mixtures with water, it forms normal liquid crystalline phases and micelles. Moreover, there is data in the literature indicating that the hydration of this surfactant is driven by enthalpy while other studies show that hydration of surfactants and lipids typically is driven by entropy. Sorption calorimetry allows resolving enthalpic and entropic contributions to the free energy of hydration at constant temperature and thus directly determines the driving forces of hydration. The results of the present sorption calorimetric study show that the hydration of liquid crystalline phases of DDAO is driven by entropy, except for the hydration of the liquid crystalline lamellar phase which is co-driven by enthalpy. The exothermic heat effect of the hydration of the lamellar phase arises from formation of strong hydrogen bonds between DDAO and water. Another issue is the driving forces of the phase transitions caused by the hydration. The sorption calorimetric results show that the transitions from the lamellar to cubic and from the cubic to the hexagonal phase are driven by enthalpy. Transitions from solid phases to the liquid crystalline lamellar phase are entropically driven, while the formation of the monohydrate from the dry surfactant is driven by enthalpy. The driving forces of the transition from the hexagonal phase to the isotropic solution are close to zero. These sorption calorimetric results are in good agreement with the analysis of the binary phase diagram based on the van der Waals differential equation. The phase diagram of the DDAO-water system determined using DSC and sorption calorimetry is presented.

Dimensions of Professional Growth in Work- Related Teacher Education

ERIC Educational Resources Information Center

Aarto-Pesonen, Leena; Tynjälä, Päivi

2017-01-01

This article conceptualises adult learners' professional growth in a tailored, work-related, teacher-qualification programme in physical education. The study data consisted of the reflectivelearning diaries of 20 adult learners during a 2-year tertiary and work-related teacher-qualification programme. The data were analysed using data-driven open…

Flexible Programmes in Higher Professional Education: Expert Validation of a Flexible Educational Model

ERIC Educational Resources Information Center

Schellekens, Ad; Paas, Fred; Verbraeck, Alexander; van Merrienboer, Jeroen J. G.

2010-01-01

In a preceding case study, a process-focused demand-driven approach for organising flexible educational programmes in higher professional education (HPE) was developed. Operations management and instructional design contributed to designing a flexible educational model by means of discrete-event simulation. Educational experts validated the model…

Safe or Unsafe? The Paradox of Action Learning

ERIC Educational Resources Information Center

Robertson, Jane; Bell, Diane

2017-01-01

Business Driven Action Learning (BDAL), as a learning philosophy that attempts to create real value for business is often used by executive education providers in their management development programmes. As the action learning facilitator, I found that the learning that took place during such a management development programme resulted in…

What are the most effective strategies for improving quality and safety of health care?

PubMed

Scott, I

2009-06-01

There is now a plethora of different quality improvement strategies (QIS) for optimizing health care, some clinician/patient driven, others manager/policy-maker driven. Which of these are most effective remains unclear despite expressed concerns about potential for QIS-related patient harm and wasting of resources. The objective of this study was to review published literature assessing the relative effectiveness of different QIS. Data sources comprising PubMed Clinical Queries, Cochrane Library and its Effective Practice and Organization of Care database, and HealthStar were searched for studies of QIS between January 1985 and February 2008 using search terms based on an a priori QIS classification suggested by experts. Systematic reviews of controlled trials were selected in determining effect sizes for specific QIS, which were compared as a narrative meta-review. Clinician/patient driven QIS were associated with stronger evidence of efficacy and larger effect sizes than manager/policy-maker driven QIS. The most effective strategies (>10% absolute increase in appropriate care or equivalent measure) included clinician-directed audit and feedback cycles, clinical decision support systems, specialty outreach programmes, chronic disease management programmes, continuing professional education based on interactive small-group case discussions, and patient-mediated clinician reminders. Pay-for-performance schemes directed to clinician groups and organizational process redesign were modestly effective. Other manager/policy-maker driven QIS including continuous quality improvement programmes, risk and safety management systems, public scorecards and performance reports, external accreditation, and clinical governance arrangements have not been adequately evaluated with regard to effectiveness. QIS are heterogeneous and methodological flaws in much of the evaluative literature limit validity and generalizability of results. Based on current best available evidence, clinician/patient driven QIS appear to be more effective than manager/policy-maker driven QIS although the latter have, in many instances, attracted insufficient robust evaluations to accurately determine their comparative effectiveness.

High-speed multi-frame dynamic transmission electron microscope image acquisition system with arbitrary timing

DOEpatents

Reed, Bryan W.; DeHope, William J.; Huete, Glenn; LaGrange, Thomas B.; Shuttlesworth, Richard M.

2016-02-23

An electron microscope is disclosed which has a laser-driven photocathode and an arbitrary waveform generator (AWG) laser system ("laser"). The laser produces a train of temporally-shaped laser pulses each being of a programmable pulse duration, and directs the laser pulses to the laser-driven photocathode to produce a train of electron pulses. An image sensor is used along with a deflector subsystem. The deflector subsystem is arranged downstream of the target but upstream of the image sensor, and has a plurality of plates. A control system having a digital sequencer controls the laser and a plurality of switching components, synchronized with the laser, to independently control excitation of each one of the deflector plates. This allows each electron pulse to be directed to a different portion of the image sensor, as well as to enable programmable pulse durations and programmable inter-pulse spacings.

The "Uptake" of a Sport-for-Development Programme in South Africa

ERIC Educational Resources Information Center

Burnett, Cora

2015-01-01

This article reports on the "uptake" dynamics and resultant manifestations of a school-based, incentive-driven, sport-for-development programme in the South African context of poverty. The ecological systems theory of Brofenbrenner, the theory of complexity and a neo-liberal framework underpin the social constructions of local meanings…

A phenomenological continuum model for force-driven nano-channel liquid flows

NASA Astrophysics Data System (ADS)

Ghorbanian, Jafar; Celebi, Alper T.; Beskok, Ali

2016-11-01

A phenomenological continuum model is developed using systematic molecular dynamics (MD) simulations of force-driven liquid argon flows confined in gold nano-channels at a fixed thermodynamic state. Well known density layering near the walls leads to the definition of an effective channel height and a density deficit parameter. While the former defines the slip-plane, the latter parameter relates channel averaged density with the desired thermodynamic state value. Definitions of these new parameters require a single MD simulation performed for a specific liquid-solid pair at the desired thermodynamic state and used for calibration of model parameters. Combined with our observations of constant slip-length and kinematic viscosity, the model accurately predicts the velocity distribution and volumetric and mass flow rates for force-driven liquid flows in different height nano-channels. Model is verified for liquid argon flow at distinct thermodynamic states and using various argon-gold interaction strengths. Further verification is performed for water flow in silica and gold nano-channels, exhibiting slip lengths of 1.2 nm and 15.5 nm, respectively. Excellent agreements between the model and the MD simulations are reported for channel heights as small as 3 nm for various liquid-solid pairs.

Perspectives on continuum flow models for force-driven nano-channel liquid flows

NASA Astrophysics Data System (ADS)

Beskok, Ali; Ghorbanian, Jafar; Celebi, Alper

2017-11-01

A phenomenological continuum model is developed using systematic molecular dynamics (MD) simulations of force-driven liquid argon flows confined in gold nano-channels at a fixed thermodynamic state. Well known density layering near the walls leads to the definition of an effective channel height and a density deficit parameter. While the former defines the slip-plane, the latter parameter relates channel averaged density with the desired thermodynamic state value. Definitions of these new parameters require a single MD simulation performed for a specific liquid-solid pair at the desired thermodynamic state and used for calibration of model parameters. Combined with our observations of constant slip-length and kinematic viscosity, the model accurately predicts the velocity distribution and volumetric and mass flow rates for force-driven liquid flows in different height nano-channels. Model is verified for liquid argon flow at distinct thermodynamic states and using various argon-gold interaction strengths. Further verification is performed for water flow in silica and gold nano-channels, exhibiting slip lengths of 1.2 nm and 15.5 nm, respectively. Excellent agreements between the model and the MD simulations are reported for channel heights as small as 3 nm for various liquid-solid pairs.

IPLIB (Image processing library) user's manual

NASA Technical Reports Server (NTRS)

Faulcon, N. D.; Monteith, J. H.; Miller, K.

1985-01-01

IPLIB is a collection of HP FORTRAN 77 subroutines and functions that facilitate the use of a COMTAL image processing system driven by an HP-1000 computer. It is intended for programmers who want to use the HP 1000 to drive the COMTAL Vision One/20 system. It is assumed that the programmer knows HP 1000 FORTRAN 77 or at least one FORTRAN dialect. It is also assumed that the programmer has some familiarity with the COMTAL Vision One/20 system.

Advances in Electrically Driven Thermal Management

NASA Technical Reports Server (NTRS)

Didion, Jeffrey R.

2017-01-01

Electrically Driven Thermal Management is a vibrant technology development initiative incorporating ISS based technology demonstrations, development of innovative fluid management techniques and fundamental research efforts. The program emphasizes high temperature high heat flux thermal management required for future generations of RF electronics and power electronic devices. This presentation reviews i.) preliminary results from the Electrohydrodynamic (EHD) Long Term Flight Demonstration launched on STP-H5 payload in February 2017 ii.) advances in liquid phase flow distribution control iii.) development of the Electrically Driven Liquid Film Boiling Experiment under the NASA Microgravity Fluid Physics Program.

Nanotechnology and chip level systems for pressure driven liquid chromatography and emerging analytical separation techniques: a review.

PubMed

Lavrik, N V; Taylor, L T; Sepaniak, M J

2011-05-23

Pressure driven liquid chromatography (LC) is a powerful and versatile separation technique particularly suitable for differentiating species present in extremely small quantities. This paper briefly reviews main historical trends and focuses on more recently developed technological approaches in miniaturization and on-chip integration of LC columns. The review emphasizes enabling technologies as well as main technological challenges specific to pressure driven separations and highlights emerging concepts that could ultimately overcome fundamental limitations of conventional LC columns. Copyright © 2011 Elsevier B.V. All rights reserved.

Development of liquid crystal based adaptive optical elements for space applications

NASA Astrophysics Data System (ADS)

Geday, M. A.; Quintana, X.; Otón, E.; Cerrolaza, B.; Lopez, D.; Garcia de Quiro, F.; Manolis, I.; Short, A.

2017-11-01

In this paper we present the results obtained within the context of the ESA-funded project Programmable Optoelectronic Adaptive Element (AO/1-5476/07/NL/EM). The objective of this project is the development of adaptive (reconfigurable) optical elements for use in space applications and the execution of preliminary qualification tests in the relevant environment. The different designs and materials that have been considered and manufactured for a 2D beam steerer based on passive matrix liquid crystal programmable blaze grating will described and discussed.

Programmable liquid crystal waveplate polarization gratings as elements for polarimetric and interference applications

NASA Astrophysics Data System (ADS)

Moreno, I.; Davis, J. A.

2010-06-01

We review the use of a parallel aligned nematic liquid crystal spatial light modulator as a very useful and flexible device for polarimetric and interferometric applications. The device acts as a programmable pixelated waveplate, and the encoding of a linear grating permits its use as a polarization beam splitter. When a grating with a reduced period is encoded, the diffracted beams are spatially separated and the device can be used for polarimetric analysis. On the contrary when a large period grating is displayed, the beams are not spatially separated, and they are useful to realize a common path interferometric system with polarization sensitivity. The flexibility offered by the programmability of the display allows non-conventional uses, including the analysis of light beams with structured spatial polarizations.

The CE-Way of Thinking: "All Is Relative!".

PubMed

Schmitt-Kopplin, Philippe; Fekete, Agnes

2016-01-01

Over the last two decades the development of capillary electrophoresis instruments lead to systems with programmable sampler, separation column, separation buffer, and detection devices comparable visually in many aspects to the setup of classical chromatography.Two processes make capillary electrophoresis essentially different from chromatography and are the basis of the CE-way of thinking, namely, the injection type and the liquid flow within the capillary. (1) When the injection is made hydrodynamically (such as in most of the found applications in the literature), the injected volumes are directly dependent on the type and size of the separation capillary. (2) The buffer velocity is not pressure driven as in liquid chromatography but electrokinetically governed by the quality of the capillary surface (separation buffer dependant surface charge) inducing an electroosmotic flow (EOF). The EOF undergoes small variations and is not necessarily identical from one separation or day to the other. The direct consequence is an apparent nonreproducible migration time of the analytes, even though the own velocity of the ions is the same.The effective mobility (field strength normalized velocity) of the ions is a possible parameterization from acquired timescale to effective mobility-scale electropherograms leading to a reproducible visualization and better quantification with a direct relation to structural characters of the analytes (i.e., charge and size-see chapter on semiempirical modelization).

Programmable diffractive lens for ophthalmic application

NASA Astrophysics Data System (ADS)

Millán, María S.; Pérez-Cabré, Elisabet; Romero, Lenny A.; Ramírez, Natalia

2014-06-01

Pixelated liquid crystal displays have been widely used as spatial light modulators to implement programmable diffractive optical elements, particularly diffractive lenses. Many different applications of such components have been developed in information optics and optical processors that take advantage of their properties of great flexibility, easy and fast refreshment, and multiplexing capability in comparison with equivalent conventional refractive lenses. We explore the application of programmable diffractive lenses displayed on the pixelated screen of a liquid crystal on silicon spatial light modulator to ophthalmic optics. In particular, we consider the use of programmable diffractive lenses for the visual compensation of refractive errors (myopia, hypermetropia, astigmatism) and presbyopia. The principles of compensation are described and sketched using geometrical optics and paraxial ray tracing. For the proof of concept, a series of experiments with artificial eye in optical bench are conducted. We analyze the compensation precision in terms of optical power and compare the results with those obtained by means of conventional ophthalmic lenses. Practical considerations oriented to feasible applications are provided.

Ophthalmic compensation of visual ametropia based on a programmable diffractive lens

NASA Astrophysics Data System (ADS)

Millán, Maria S.; Pérez-Cabré, Elisabet; Romero, Lenny A.; Ramírez, Natalia

2013-11-01

Pixelated liquid crystal displays have been widely used as spatial light modulators to implement programmable diffractive optical elements (DOEs), particularly diffractive lenses. Many different applications of such components have been developed in information optics and optical processors that take advantage of their properties of great flexibility, easy and fast refreshment, and multiplexing capability in comparison with equivalent conventional refractive lenses. In this paper, we explore the application of programmable diffractive lenses displayed on the pixelated screen of a liquid crystal on silicon spatial light modulator (LCoS-SLM) to ophthalmic optics. In particular, we consider the use of programmable diffractive lenses for the visual compensation of some refractive errors (myopia, hyperopia). The theoretical principles of compensation are described and sketched using geometrical optics and paraxial ray tracing. A series of experiments with artificial eye in optical bench are conducted to analyze the compensation accuracy in terms of optical power and to compare the results with those obtained by means of conventional ophthalmic lenses. Practical considerations oriented to feasible applications are provided.

Fluid-driven reciprocating apparatus and valving for controlling same

DOEpatents

Whitehead, John C.; Toews, Hans G.

1993-01-01

A control valve assembly for alternately actuating a pair of fluid-driven free-piston devices by using fluid pressure communication therebetween. Each control valve is switched by a pressure signal depending on the state of its counterpart's piston. The communication logic is arranged to provide overlap of the forward strokes of the pistons, so that at least one of the pair will always be pressurized. Thus, uninterrupted pumping of liquid is made possible from a pair of free-piston pumps. In addition, the speed and frequency of piston stroking is entirely dependent on the mechanical power load applied. In the case of a pair of pumps, this enables liquid delivery at a substantially constant pressure over the full range of flow rates, from zero to maximum flow. One embodiment of the invention utilized two pairs of fluid-driven free-piston devices whereby a bipropellant liquid propulsion system may be operated, so as to provide continuous flow of both fuel and oxidizer liquids when used in rocket applications, for example.

A framework for a process-driven common foundation programme for graduates.

PubMed

Jasper, M; Rolfe, G

1993-10-01

This paper discusses some of the problems encountered in writing a shortened Common Foundation Programme in nursing for graduates, and outlines a course which takes as its starting point the particular educational needs and requirements of the student group. Thus, the first question to be addressed by the curriculum writers when designing the course was "How can we teach these students?", rather than "What can we teach them?". The resulting process-driven course is heavily influenced by the student-centred philosophy of Carl Rogers, and utilizes a variety of large- and small-group methods to facilitate the students in gradually taking responsibility for, and making decisions about, their learning needs. The paper continues with some strategies for ensuring a smooth transition from a tutor-led, syllabus-driven start to the course, to a student-led, process-driven finish for both the theoretical and clinical components, and for the assessment schedule. Finally, a student-centred approach to evaluation is briefly outlined, and the paper concludes by suggesting that the principles employed in designing and implementing this course could be successfully transferred to a wide variety of other educational settings.

Rigorous buoyancy driven bubble mixing for centrifugal microfluidics.

PubMed

Burger, S; Schulz, M; von Stetten, F; Zengerle, R; Paust, N

2016-01-21

We present batch-mode mixing for centrifugal microfluidics operated at fixed rotational frequency. Gas is generated by the disk integrated decomposition of hydrogen peroxide (H2O2) to liquid water (H2O) and gaseous oxygen (O2) and inserted into a mixing chamber. There, bubbles are formed that ascent through the liquid in the artificial gravity field and lead to drag flow. Additionaly, strong buoyancy causes deformation and rupture of the gas bubbles and induces strong mixing flows in the liquids. Buoyancy driven bubble mixing is quantitatively compared to shake mode mixing, mixing by reciprocation and vortex mixing. To determine mixing efficiencies in a meaningful way, the different mixers are employed for mixing of a lysis reagent and human whole blood. Subsequently, DNA is extracted from the lysate and the amount of DNA recovered is taken as a measure for mixing efficiency. Relative to standard vortex mixing, DNA extraction based on buoyancy driven bubble mixing resulted in yields of 92 ± 8% (100 s mixing time) and 100 ± 8% (600 s) at 130g centrifugal acceleration. Shake mode mixing yields 96 ± 11% and is thus equal to buoyancy driven bubble mixing. An advantage of buoyancy driven bubble mixing is that it can be operated at fixed rotational frequency, however. The additional costs of implementing buoyancy driven bubble mixing are low since both the activation liquid and the catalyst are very low cost and no external means are required in the processing device. Furthermore, buoyancy driven bubble mixing can easily be integrated in a monolithic manner and is compatible to scalable manufacturing technologies such as injection moulding or thermoforming. We consider buoyancy driven bubble mixing an excellent alternative to shake mode mixing, in particular if the processing device is not capable of providing fast changes of rotational frequency or if the low average rotational frequency is challenging for the other integrated fluidic operations.

Dotette: Programmable, high-precision, plug-and-play droplet pipetting.

PubMed

Fan, Jinzhen; Men, Yongfan; Hao Tseng, Kuo; Ding, Yi; Ding, Yunfeng; Villarreal, Fernando; Tan, Cheemeng; Li, Baoqing; Pan, Tingrui

2018-05-01

Manual micropipettes are the most heavily used liquid handling devices in biological and chemical laboratories; however, they suffer from low precision for volumes under 1  μ l and inevitable human errors. For a manual device, the human errors introduced pose potential risks of failed experiments, inaccurate results, and financial costs. Meanwhile, low precision under 1  μ l can cause severe quantification errors and high heterogeneity of outcomes, becoming a bottleneck of reaction miniaturization for quantitative research in biochemical labs. Here, we report Dotette, a programmable, plug-and-play microfluidic pipetting device based on nanoliter liquid printing. With automated control, protocols designed on computers can be directly downloaded into Dotette, enabling programmable operation processes. Utilizing continuous nanoliter droplet dispensing, the precision of the volume control has been successfully improved from traditional 20%-50% to less than 5% in the range of 100 nl to 1000 nl. Such a highly automated, plug-and-play add-on to existing pipetting devices not only improves precise quantification in low-volume liquid handling and reduces chemical consumptions but also facilitates and automates a variety of biochemical and biological operations.

Patient level cost of diabetes self-management education programmes: an international evaluation

PubMed Central

Doyle, Gerardine; O'Donnell, Shane; Quigley, Etáin; Cullen, Kate; Gibney, Sarah; Levin-Zamir, Diane; Ganahl, Kristin; Müller, Gabriele; Muller, Ingrid; Maindal, Helle Terkildsen; Chang, Wushou Peter; Van Den Broucke, Stephan

2017-01-01

Objectives The objective of this study was to examine the value of time-driven activity-based costing (TDABC) in understanding the process and costs of delivering diabetes self-management education (DSME) programmes in a multicountry comparative study. Setting Outpatient settings in five European countries (Austria, Denmark, Germany, Ireland, UK) and two countries outside Europe, Taiwan and Israel. Participants Providers of DSME programmes across participating countries (N=16) including healthcare professionals, administrators and patients taking part in DSME programmes. Primary and secondary measures Primary measure: time spent by providers in the delivery of DSME and resources consumed in order to compute programme costs. Secondary measures: self-report measures of behavioural self-management and diabetes disease/health-related outcomes. Results We found significant variation in costs and the processes of how DSME programmes are provided across and within countries. Variations in costs were driven by a combination of price variances, mix of personnel skill and efficiency variances. Higher cost programmes were not found to have achieved better relative outcomes. The findings highlight the value of TDABC in calculating a patient level cost and potential of the methodology to identify process improvements in guiding the optimal allocation of scarce resources in diabetes care, in particular for DSME that is often underfunded. Conclusions This study is the first to measure programme costs using estimates of the actual resources used to educate patients about managing their medical condition and is the first study to map such costs to self-reported behavioural and disease outcomes. The results of this study will inform clinicians, managers and policy makers seeking to enhance the delivery of DSME programmes. The findings highlight the benefits of adopting a TDABC approach to understanding the drivers of the cost of DSME programmes in a multicountry study to reveal opportunities to bend the cost curve for DSME. PMID:28583913

Patient level cost of diabetes self-management education programmes: an international evaluation.

PubMed

Doyle, Gerardine; O'Donnell, Shane; Quigley, Etáin; Cullen, Kate; Gibney, Sarah; Levin-Zamir, Diane; Ganahl, Kristin; Müller, Gabriele; Muller, Ingrid; Maindal, Helle Terkildsen; Chang, Wushou Peter; Van Den Broucke, Stephan

2017-06-04

The objective of this study was to examine the value of time-driven activity-based costing (TDABC) in understanding the process and costs of delivering diabetes self-management education (DSME) programmes in a multicountry comparative study. Outpatient settings in five European countries (Austria, Denmark, Germany, Ireland, UK) and two countries outside Europe, Taiwan and Israel. Providers of DSME programmes across participating countries (N=16) including healthcare professionals, administrators and patients taking part in DSME programmes. Primary measure: time spent by providers in the delivery of DSME and resources consumed in order to compute programme costs. Secondary measures: self-report measures of behavioural self-management and diabetes disease/health-related outcomes. We found significant variation in costs and the processes of how DSME programmes are provided across and within countries. Variations in costs were driven by a combination of price variances, mix of personnel skill and efficiency variances. Higher cost programmes were not found to have achieved better relative outcomes. The findings highlight the value of TDABC in calculating a patient level cost and potential of the methodology to identify process improvements in guiding the optimal allocation of scarce resources in diabetes care, in particular for DSME that is often underfunded. This study is the first to measure programme costs using estimates of the actual resources used to educate patients about managing their medical condition and is the first study to map such costs to self-reported behavioural and disease outcomes. The results of this study will inform clinicians, managers and policy makers seeking to enhance the delivery of DSME programmes. The findings highlight the benefits of adopting a TDABC approach to understanding the drivers of the cost of DSME programmes in a multicountry study to reveal opportunities to bend the cost curve for DSME. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

An adaptive liquid microlens driven by a ferrofluidic transducer

NASA Astrophysics Data System (ADS)

Xiao, Wenjia; Hardt, Steffen

2010-05-01

Ferrofluids behave superparamagnetically and can be manipulated by external magnetic fields, providing numerous applications in microfluidic systems. In this paper, an adaptive liquid microlens driven by a ferrofluidic actuator is presented. The microlens consists of a cylindrical well filled with a lens liquid connected to a microchannel containing a ferrofluid plug. When the ferrofluid plug is moved back and forth by an external magnetic field, the lens liquid is displaced, forming a liquid lens with an adaptive focus in the cylindrical well. The focal length of the lens can be changed from infinity to the scale of the radius of the cylindrical well, leading to a high optical power compared to conventional liquid lenses utilizing liquid crystals or electrowetting. The lens curvature is reversibly tunable without hysteresis when the ferrofluid plug moves with a speed below a specific threshold value. The lens can be acted on by a magnetic field of about 100 mT which can be generated by microcoils requiring much lower voltages than the electrowetting principle.

Conditions for Employee Learning and Innovation--Interweaving Competence Development Activities Provided by a Workplace Development Programme with Everyday Work Activities in SMEs

ERIC Educational Resources Information Center

Halvarsson Lundkvist, Agneta; Gustavsson, Maria

2018-01-01

The aim of this article is to investigate how the formal competence development activities provided by the Production Leap, a workplace development programme (WPDP), were interwoven with everyday work activities and to identify the conditions that enabled learning and employee-driven innovation that contributed to production improvement, in small…

A Review of Research on Content-Based Foreign/Second Language Education in US K-12 Contexts

ERIC Educational Resources Information Center

Tedick, Diane J.; Wesely, Pamela M.

2015-01-01

This review of the extant research literature focuses on research about content-based language instruction (CBI) programmes in K-12 foreign/second language education in the USA. The review emphasises studies on one-way language immersion (OWI) and two-way language immersion (TWI) programmes, which are school-based and subject matter-driven. OWI…

The Programmers' Collective: Fostering Participatory Culture by Making Music Videos in a High School Scratch Coding Workshop

ERIC Educational Resources Information Center

Fields, Deborah; Vasudevan, Veena; Kafai, Yasmin B.

2015-01-01

We highlight ways to support interest-driven creation of digital media in Scratch, a visual-based programming language and community, within a high school programming workshop. We describe a collaborative approach, the programmers' collective, that builds on social models found in do-it-yourself and open source communities, but with scaffolding…

Eco-Driven Chemical Research in the Boundary between Academia and Industry

ERIC Educational Resources Information Center

Sjöström, Jesper

2013-01-01

This paper examines and discusses the views on science and society held among PhD students working in two different industrially and environmentally driven research programmes in the broad area of green chemistry. It is based on thirteen in-depth interviews. The analysis shows three main ways of handling the situation as "post-academic"…

Welcome to 2012: Australian Academic Developers and Student-Driven University Funding

ERIC Educational Resources Information Center

Ling, Peter; Fraser, Kym; Gosling, David

2013-01-01

Are there consequences for academic development arising from the move to student-driven funding in the Australian higher education sector from 2012? In a move that has similarities to the UK, Australian government-supported student university funding will, from 2012, attach to students who can select a programme at the university of their choice…

Cash efficiency for bank branches.

PubMed

Cabello, Julia García

2013-01-01

Bank liquidity management has become a major issue during the financial crisis as liquidity shortages have intensified and have put pressure on banks to diversity and improve their liquidity sources. While a significant strand of the literature concentrates on wholesale liquidity generation and on the alternative to deposit funding, the management of an inventory of cash holdings within the banks' branches is also a relevant issue as any significant improvement in cash management at the bank distribution channels may have a positive effect in reducing liquidity tensions. In this paper, we propose a simple programme of cash efficiency for the banks' branches, very easy to implement, which conform to a set of instructions to be imposed from the bank to their branches. This model proves to significantly reduce cash holdings at branches thereby providing efficiency improvements in liquidity management. The methodology we propose is based on the definition of some stochastic processes combined with renewal processes, which capture the random elements of the cash flow, before applying suitable optimization programmes to all the costs involved in cash movements. The classical issue of the Transaction Demand for the Cash and some aspects of Inventory Theory are also present. Mathematics Subject Classification (2000) C02, C60, E50.

Electrohydrodynamically driven large-area liquid ion sources

DOEpatents

Pregenzer, Arian L.

1988-01-01

A large-area liquid ion source comprises means for generating, over a large area of the surface of a liquid, an electric field of a strength sufficient to induce emission of ions from a large area of said liquid. Large areas in this context are those distinct from emitting areas in unidimensional emitters.

A Liquid-Liquid Transition in an Undercooled Ti-Zr-Ni Liquid

NASA Technical Reports Server (NTRS)

Lee, G. W.; Gangopadhyay, A. K.; Kelton, K. F.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.

2003-01-01

If crystallization can be avoided, liquids enter a metastable (undercooled) state below their equilibrium liquidus temperatures, TI, finally freezing into a glass below a characteristic temperature called the glass transition temperature, T,. In rare cases, the undercooled liquid may undergo a liquid-liquid phase transition (liquid polymorphism) before entering the glassy state. This has been suggested from experimental studies of HzO and Si4. Such phase transitions have been predicted in some stable liquids, i.e. above TI at atmospheric pressure, for Si02 and BeF;, but these have not been verified experimentally. They have been observed in liquids of P7, Sis and C9, but only under high pressure. All of these transitions are driven by an anomalous density change, i.e. change in local structure, with temperature or pressure. In this letter we present the first experimental evidence for a phase transition in a low viscosity liquid that is not driven by an anomalous density change, but by an approach to a constant configuration state. A maximum in the specific heat at constant pressure, similar to what is normally observed near T,, is reported here for undercooled low viscosity liquids of quasicrystal- forming Ti-Zr-Ni alloys. that includes cooperativity, by incorporating a temperature dependent excitation energy fits the data well, signaling a phase transition.

A synchronized particle image velocimetry and infrared thermography technique applied to convective mass transfer in champagne glasses

NASA Astrophysics Data System (ADS)

Beaumont, Fabien; Liger-Belair, Gérard; Bailly, Yannick; Polidori, Guillaume

2016-05-01

In champagne glasses, it was recently suggested that ascending bubble-driven flow patterns should be involved in the release of gaseous carbon dioxide (CO2) and volatile organic compounds. A key assumption was that the higher the velocity of the upward bubble-driven flow patterns in the liquid phase, the higher the volume fluxes of gaseous CO2 desorbing from the supersaturated liquid phase. In the present work, simultaneous monitoring of bubble-driven flow patterns within champagne glasses and gaseous CO2 escaping above the champagne surface was performed, through particle image velocimetry and infrared thermography techniques. Two quite emblematic types of champagne drinking vessels were investigated, namely a long-stemmed flute and a wide coupe. The synchronized use of both techniques proved that the cloud of gaseous CO2 escaping above champagne glasses strongly depends on the mixing flow patterns found in the liquid phase below.

Challenges and complexities of multifrequency atomic force microscopy in liquid environments.

PubMed

Solares, Santiago D

2014-01-01

This paper illustrates through numerical simulation the complexities encountered in high-damping AFM imaging, as in liquid enviroments, within the specific context of multifrequency atomic force microscopy (AFM). The focus is primarily on (i) the amplitude and phase relaxation of driven higher eigenmodes between successive tip-sample impacts, (ii) the momentary excitation of non-driven higher eigenmodes and (iii) base excitation artifacts. The results and discussion are mostly applicable to the cases where higher eigenmodes are driven in open loop and frequency modulation within bimodal schemes, but some concepts are also applicable to other types of multifrequency operations and to single-eigenmode amplitude and frequency modulation methods.

Exploring the components of physician volunteer engagement: a qualitative investigation of a national Canadian simulation-based training programme

PubMed Central

Sarti, Aimee J; Sutherland, Stephanie; Landriault, Angele; DesRosier, Kirk; Brien, Susan; Cardinal, Pierre

2017-01-01

Objectives Conceptual clarity on physician volunteer engagement is lacking in the medical literature. The aim of this study was to present a conceptual framework to describe the elements which influence physician volunteer engagement and to explore volunteer engagement within a national educational programme. Setting The context for this study was the Acute Critical Events Simulation (ACES) programme in Canada, which has successfully evolved into a national educational programme, driven by physician volunteers. From 2010 to 2014, the programme recruited 73 volunteer healthcare professionals who contributed to the creation of educational materials and/or served as instructors. Method A conceptual framework was constructed based on an extensive literature review and expert consultation. Secondary qualitative analysis was undertaken on 15 semistructured interviews conducted from 2012 to 2013 with programme directors and healthcare professionals across Canada. An additional 15 interviews were conducted in 2015 with physician volunteers to achieve thematic saturation. Data were analysed iteratively and inductive coding techniques applied. Results From the physician volunteer data, 11 themes emerged. The most prominent themes included volunteer recruitment, retention, exchange, recognition, educator network and quasi-volunteerism. Captured within these interrelated themes were the framework elements, including the synergistic effects of emotional, cognitive and reciprocal engagement. Behavioural engagement was driven by these factors along with a cue to action, which led to contributions to the ACES programme. Conclusion This investigation provides a preliminary framework and supportive evidence towards understanding the complex construct of physician volunteer engagement. The need for this research is particularly important in present day, where growing fiscal constraints create challenges for medical education to do more with less. PMID:28645956

Exploring the components of physician volunteer engagement: a qualitative investigation of a national Canadian simulation-based training programme.

PubMed

Sarti, Aimee J; Sutherland, Stephanie; Landriault, Angele; DesRosier, Kirk; Brien, Susan; Cardinal, Pierre

2017-06-23

Conceptual clarity on physician volunteer engagement is lacking in the medical literature. The aim of this study was to present a conceptual framework to describe the elements which influence physician volunteer engagement and to explore volunteer engagement within a national educational programme. The context for this study was the Acute Critical Events Simulation (ACES) programme in Canada, which has successfully evolved into a national educational programme, driven by physician volunteers. From 2010 to 2014, the programme recruited 73 volunteer healthcare professionals who contributed to the creation of educational materials and/or served as instructors. A conceptual framework was constructed based on an extensive literature review and expert consultation. Secondary qualitative analysis was undertaken on 15 semistructured interviews conducted from 2012 to 2013 with programme directors and healthcare professionals across Canada. An additional 15 interviews were conducted in 2015 with physician volunteers to achieve thematic saturation. Data were analysed iteratively and inductive coding techniques applied. From the physician volunteer data, 11 themes emerged. The most prominent themes included volunteer recruitment, retention, exchange, recognition, educator network and quasi-volunteerism. Captured within these interrelated themes were the framework elements, including the synergistic effects of emotional, cognitive and reciprocal engagement. Behavioural engagement was driven by these factors along with a cue to action, which led to contributions to the ACES programme. This investigation provides a preliminary framework and supportive evidence towards understanding the complex construct of physician volunteer engagement. The need for this research is particularly important in present day, where growing fiscal constraints create challenges for medical education to do more with less. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Development and evaluation of a structured programme for promoting physical activity among seniors with intellectual disabilities: a study protocol for a cluster randomized trial

PubMed Central

2013-01-01

Background Older people with intellectual disabilities have very low physical activity levels. Well designed, theory-driven and evidence-based health promotion programmes for the target population are lacking. This paper describes the design of a cluster-randomised trial for a systematically developed health promotion programme aimed at improving physical activity and increasing fitness among seniors with intellectual disabilities. Methods and design The Intervention Mapping protocol was used for programme development. After defining the programme’s objectives, the following behavioural techniques were selected to achieve them: Tailoring, Education, Modelling, Mirroring, Feedback, Reinforcement and Grading. With professionals and managers of provider services for people with intellectual disabilities, we translated these strategies into a structured day-activity programme, that consisted of a physical activity and an education programme. The programme will be executed in five day-activity centres in groups of eight to ten seniors during eight months, whereas seniors in five other centres receive care as usual. The physical activity level, as measured in number of steps a day, will be used as primary outcome measurement. Secondary outcome measurements include motor fitness, cardio respiratory fitness, morphological and metabolic fitness, ADL, functional deterioration and depressive symptoms. Differences in the primary and secondary outcome measures between participants and controls will be analysed using generalized estimation equations, correcting for day-activity center as cluster. Discussion This paper provides insight into the development and content of a theory-driven intervention aimed at behavioural change in a population with a low intellectual level. Its evaluation design is described. The programme’s applicability to other populations is discussed. Trial registration Trial number: ISRCTN82341588 PMID:23938154

Learning Our Way into Communication: The Making of the Communication and Information Strategy "with" the National Agricultural Advisory Services Programme in Uganda

ERIC Educational Resources Information Center

Ramirez, Ricardo

2005-01-01

This paper reports on the making of the Communication and Information Strategy with the National Agricultural Advisory Services Programme (NAADS) in Uganda. The NAADS is a new organization in government responsible for the implementation of a demand-driven agricultural extension approach. The new extension approach calls for fundamental changes in…

Microcontroller-driven fluid-injection system for atomic force microscopy.

PubMed

Kasas, S; Alonso, L; Jacquet, P; Adamcik, J; Haeberli, C; Dietler, G

2010-01-01

We present a programmable microcontroller-driven injection system for the exchange of imaging medium during atomic force microscopy. Using this low-noise system, high-resolution imaging can be performed during this process of injection without disturbance. This latter circumstance was exemplified by the online imaging of conformational changes in DNA molecules during the injection of anticancer drug into the fluid chamber.

43. Upper level, left to rightground missile guidance system liquid ...

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

43. Upper level, left to right--ground missile guidance system liquid cooling equipment, guidance and control coupler rack, programmer group - Ellsworth Air Force Base, Delta Flight, Launch Facility, On County Road T512, south of Exit 116 off I-90, Interior, Jackson County, SD

Evaluation of regional climate simulations for air quality modelling purposes

NASA Astrophysics Data System (ADS)

Menut, Laurent; Tripathi, Om P.; Colette, Augustin; Vautard, Robert; Flaounas, Emmanouil; Bessagnet, Bertrand

2013-05-01

In order to evaluate the future potential benefits of emission regulation on regional air quality, while taking into account the effects of climate change, off-line air quality projection simulations are driven using weather forcing taken from regional climate models. These regional models are themselves driven by simulations carried out using global climate models (GCM) and economical scenarios. Uncertainties and biases in climate models introduce an additional "climate modeling" source of uncertainty that is to be added to all other types of uncertainties in air quality modeling for policy evaluation. In this article we evaluate the changes in air quality-related weather variables induced by replacing reanalyses-forced by GCM-forced regional climate simulations. As an example we use GCM simulations carried out in the framework of the ERA-interim programme and of the CMIP5 project using the Institut Pierre-Simon Laplace climate model (IPSLcm), driving regional simulations performed in the framework of the EURO-CORDEX programme. In summer, we found compensating deficiencies acting on photochemistry: an overestimation by GCM-driven weather due to a positive bias in short-wave radiation, a negative bias in wind speed, too many stagnant episodes, and a negative temperature bias. In winter, air quality is mostly driven by dispersion, and we could not identify significant differences in either wind or planetary boundary layer height statistics between GCM-driven and reanalyses-driven regional simulations. However, precipitation appears largely overestimated in GCM-driven simulations, which could significantly affect the simulation of aerosol concentrations. The identification of these biases will help interpreting results of future air quality simulations using these data. Despite these, we conclude that the identified differences should not lead to major difficulties in using GCM-driven regional climate simulations for air quality projections.

Solutal Marangoni flows of miscible liquids drive transport without surface contamination

NASA Astrophysics Data System (ADS)

Kim, Hyoungsoo; Muller, Koen; Shardt, Orest; Afkhami, Shahriar; Stone, Howard A.

2017-11-01

Mixing and spreading of different liquids are omnipresent in nature, life and technology, such as oil pollution on the sea, estuaries, food processing, cosmetic and beverage industries, lab-on-a-chip devices, and polymer processing. However, the mixing and spreading mechanisms for miscible liquids remain poorly characterized. Here, we show that a fully soluble liquid drop deposited on a liquid surface remains as a static lens without immediately spreading and mixing, and simultaneously a Marangoni-driven convective flow is generated, which are counterintuitive results when two liquids have different surface tensions. To understand the dynamics, we develop a theoretical model to predict the finite spreading time and length scales, the Marangoni-driven convection flow speed, and the finite timescale to establish the quasi-steady state for the Marangoni flow. The fundamental understanding of this solutal Marangoni flow may enable driving bulk flows and constructing an effective drug delivery and surface cleaning approach without causing surface contamination by immiscible chemical species.

Human factors for capacity building: lessons learned from the OpenMRS implementers network.

PubMed

Seebregts, C J; Mamlin, B W; Biondich, P G; Fraser, H S F; Wolfe, B A; Jazayeri, D; Miranda, J; Blaya, J; Sinha, C; Bailey, C T; Kanter, A S

2010-01-01

The overall objective of this project was to investigate ways to strengthen the OpenMRS community by (i) developing capacity and implementing a network focusing specifically on the needs of OpenMRS implementers, (ii) strengthening community-driven aspects of OpenMRS and providing a dedicated forum for implementation-specific issues, and; (iii) providing regional support for OpenMRS implementations as well as mentorship and training. The methods used included (i) face-to-face networking using meetings and workshops; (ii) online collaboration tools, peer support and mentorship programmes; (iii) capacity and community development programmes, and; (iv) community outreach programmes. The community-driven approach, combined with a few simple interventions, has been a key factor in the growth and success of the OpenMRS Implementers Network. It has contributed to implementations in at least twenty-three different countries using basic online tools; and provided mentorship and peer support through an annual meeting, workshops and an internship program. The OpenMRS Implementers Network has formed collaborations with several other open source networks and is evolving regional OpenMRS Centres of Excellence to provide localized support for OpenMRS development and implementation. These initiatives are increasing the range of functionality and sustainability of open source software in the health domain, resulting in improved adoption and enterprise-readiness. Social organization and capacity development activities are important in growing a successful community-driven open source software model.

Active suppression of vortex-driven combustion instability using controlled liquid-fuel injection

NASA Astrophysics Data System (ADS)

Pang, Bin

Combustion instabilities remain one of the most challenging problems encountered in developing propulsion and power systems. Large amplitude pressure oscillations, driven by unsteady heat release, can produce numerous detrimental effects. Most previous active control studies utilized gaseous fuels to suppress combustion instabilities. However, using liquid fuel to suppress combustion instabilities is more realistic for propulsion applications. Active instability suppression in vortex-driven combustors using a direct liquid fuel injection strategy was theoretically established and experimentally demonstrated in this dissertation work. Droplet size measurements revealed that with pulsed fuel injection management, fuel droplet size could be modulated periodically. Consequently, desired heat release fluctuation could be created. If this oscillatory heat release is coupled with the natural pressure oscillation in an out of phase manner, combustion instabilities can be suppressed. To identify proper locations of supplying additional liquid fuel for the purpose of achieving control, the natural heat release pattern in a vortex-driven combustor was characterized in this study. It was found that at high Damkohler number oscillatory heat release pattern closely followed the evolving vortex front. However, when Damkohler number became close to unity, heat release fluctuation wave no longer coincided with the coherent structures. A heat release deficit area was found near the dump plane when combustor was operated in lean premixed conditions. Active combustion instability suppression experiments were performed in a dump combustor using a controlled liquid fuel injection strategy. High-speed Schlieren results illustrated that vortex shedding plays an important role in maintaining self-sustained combustion instabilities. Complete combustion instability control requires total suppression of these large-scale coherent structures. The sound pressure level at the excited dominant frequency was reduced by more than 20 dB with controlled liquid fuel injection method. Scaling issues were also investigated in this dump combustor to test the effectiveness of using pulsed liquid fuel injection strategies to suppress instabilities at higher power output conditions. With the liquid fuel injection control method, it was possible to suppress strong instabilities with initial amplitude of +/-5 psi down to the background noise level. The stable combustor operating range was also expanded from equivalence ratio of 0.75 to beyond 0.9.

The CE way of thinking: "all is relative!".

PubMed

Schmitt-Kopplin, Philippe; Fekete, Agnes

2008-01-01

Over the last two decades, the development of capillary electrophoresis (CE) instruments has lead to systems with programmable samplers, separation columns, separation buffers, and detection devices comparable visually in many aspects to the setup of classical chromatography. Two characteristics make CE essentially different from chromatography and are the basis of the CE way of thinking: first is the injection type and the liquid flow within the capillary. When the injection is made hydrodynamically (such as in most of the applications found in the literature), the injected volumes are directly dependent on the type and size of the separation capillary. The second characteristic is that in CE, buffer velocity is not pressure-driven, as in liquid chromatography, but is electrokinetically governed by the quality of the capillary surface (separation buffer dependent surface charge) inducing an electroosmotic flow (EOF). The EOF undergoes small variations and is not necessarily identical from one separation or day to the other. The direct consequence is that the migration time of the analytes apparently nonreproducible, although the velocity of the ions is the same. The effective mobility (field strength normalized velocity) of the ions is a possible parameterization from acquired time-scale to effective mobility-scale electropherograms leading to a reproducible visualization and better quantification with a direct relation to structural characters of the analytes (i.e., charge and size; see Chapter 23).

Challenges and complexities of multifrequency atomic force microscopy in liquid environments

PubMed Central

2014-01-01

Summary This paper illustrates through numerical simulation the complexities encountered in high-damping AFM imaging, as in liquid enviroments, within the specific context of multifrequency atomic force microscopy (AFM). The focus is primarily on (i) the amplitude and phase relaxation of driven higher eigenmodes between successive tip–sample impacts, (ii) the momentary excitation of non-driven higher eigenmodes and (iii) base excitation artifacts. The results and discussion are mostly applicable to the cases where higher eigenmodes are driven in open loop and frequency modulation within bimodal schemes, but some concepts are also applicable to other types of multifrequency operations and to single-eigenmode amplitude and frequency modulation methods. PMID:24778952

Embedding operational research into national disease control programme: lessons from 10 years of experience in Indonesia

PubMed Central

Mahendradhata, Yodi; Probandari, Ari; Widjanarko, Bagoes; Riono, Pandu; Mustikawati, Dyah; Tiemersma, Edine W.; Alisjahbana, Bachti

2014-01-01

There is growing recognition that operational research (OR) should be embedded into national disease control programmes. However, much of the current OR capacity building schemes are still predominantly driven by international agencies with limited integration into national disease control programmes. We demonstrated that it is possible to achieve a more sustainable capacity building effort across the country by establishing an OR group within the national tuberculosis (TB) control programme in Indonesia. Key challenges identified include long-term financial support, limited number of scientific publications, and difficulties in documenting impact on programmatic performance. External evaluation has expressed concerns in regard to utilisation of OR in policy making. Efforts to address this concern have been introduced recently and led to indications of increased utilisation of research evidence in policy making by the national TB control programme. Embedding OR in national disease control programmes is key in establishing an evidence-based disease control programme. PMID:25361728

Universe Awareness: Inspiring young children around the world

NASA Astrophysics Data System (ADS)

Ödman, Carolina J.

2011-06-01

Universe Awareness (UNAWE) has over three years of experience enthusing young children with the scale and beauty of the Universe. UNAWE is an outreach programme with a strong social vision aiming at broadening children's minds, awakening their curiosity in science and stimulating global citizenship. UNAWE uses the inspirational aspects of astronomy to instil a culture of peace and tolerance. We present the main principles of the programme, describe how it functions as a community-driven organisation and share some of the UNAWE experience. We describe projects and opportunities for IYA2009 and the future of the global programme.

Field-Controlled Electrical Switch with Liquid Metal.

PubMed

Wissman, James; Dickey, Michael D; Majidi, Carmel

2017-12-01

When immersed in an electrolyte, droplets of Ga-based liquid metal (LM) alloy can be manipulated in ways not possible with conventional electrocapillarity or electrowetting. This study demonstrates how LM electrochemistry can be exploited to coalesce and separate droplets under moderate voltages of ~1-10 V. This novel approach to droplet interaction can be explained with a theory that accounts for oxidation and reduction as well as fluidic instabilities. Based on simulations and experimental analysis, this study finds that droplet separation is governed by a unique limit-point instability that arises from gradients in bipolar electrochemical reactions that lead to gradients in interfacial tension. The LM coalescence and separation are used to create a field-programmable electrical switch. As with conventional relays or flip-flop latch circuits, the system can transition between bistable (separated or coalesced) states, making it useful for memory storage, logic, and shape-programmable circuitry using entirely liquids instead of solid-state materials.

From the genetic to the computer program: the historicity of 'data' and 'computation' in the investigations on the nematode worm C. elegans (1963-1998).

PubMed

García-Sancho, Miguel

2012-03-01

This paper argues that the history of the computer, of the practice of computation and of the notions of 'data' and 'programme' are essential for a critical account of the emergence and implications of data-driven research. In order to show this, I focus on the transition that the investigations on the worm C. elegans experienced in the Laboratory of Molecular Biology of Cambridge (UK). Throughout the 1980s, this research programme evolved from a study of the genetic basis of the worm's development and behaviour to a DNA mapping and sequencing initiative. By examining the changing computing technologies which were used at the Laboratory, I demonstrate that by the time of this transition researchers shifted from modelling the worm's genetic programme on a mainframe apparatus to writing minicomputer programs aimed at providing map and sequence data which was then circulated to other groups working on the genetics of C. elegans. The shift in the worm research should thus not be simply explained in the application of computers which transformed the project from hypothesis-driven to a data-intensive endeavour. The key factor was rather a historically specific technology-in-house and easy programmable minicomputers-which redefined the way of achieving the project's long-standing goal, leading the genetic programme to co-evolve with the practices of data production and distribution. Copyright © 2011 Elsevier Ltd. All rights reserved.

Electrically Driven Liquid Film Boiling Experiment

NASA Technical Reports Server (NTRS)

Didion, Jeffrey R.

2016-01-01

This presentation presents the science background and ground based results that form the basis of the Electrically Driven Liquid Film Boiling Experiment. This is an ISS experiment that is manifested for 2021. Objective: Characterize the effects of gravity on the interaction of electric and flow fields in the presence of phase change specifically pertaining to: a) The effects of microgravity on the electrically generated two-phase flow. b) The effects of microgravity on electrically driven liquid film boiling (includes extreme heat fluxes). Electro-wetting of the boiling section will repel the bubbles away from the heated surface in microgravity environment. Relevance/Impact: Provides phenomenological foundation for the development of electric field based two-phase thermal management systems leveraging EHD, permitting optimization of heat transfer surface area to volume ratios as well as achievement of high heat transfer coefficients thus resulting in system mass and volume savings. EHD replaces buoyancy or flow driven bubble removal from heated surface. Development Approach: Conduct preliminary experiments in low gravity and ground-based facilities to refine technique and obtain preliminary data for model development. ISS environment required to characterize electro-wetting effect on nucleate boiling and CHF in the absence of gravity. Will operate in the FIR - designed for autonomous operation.

Programmable snapping composites with bio-inspired architecture.

PubMed

Schmied, Jascha U; Le Ferrand, Hortense; Ermanni, Paolo; Studart, André R; Arrieta, Andres F

2017-03-13

The development of programmable self-shaping materials enables the onset of new and innovative functionalities in many application fields. Commonly, shape adaptation is achieved by exploiting diffusion-driven swelling or nano-scale phase transition, limiting the change of shape to slow motion predominantly determined by the environmental conditions and/or the materials specificity. To address these shortcomings, we report shape adaptable programmable shells that undergo morphing via a snap-through mechanism inspired by the Dionaea muscipula leaf, known as the Venus fly trap. The presented shells are composite materials made of epoxy reinforced by stiff anisotropic alumina micro-platelets oriented in specific directions. By tailoring the microstructure via magnetically-driven alignment of the platelets, we locally tune the pre-strain and stiffness anisotropy of the composite. This novel approach enables the fabrication of complex shapes showing non-orthotropic curvatures and stiffness gradients, radically extending the design space when compared to conventional long-fibre reinforced multi-stable composites. The rare combination of large stresses, short actuation times and complex shapes, results in hinge-free artificial shape adaptable systems with large design freedom for a variety of morphing applications.

Liquid metal actuator driven by electrochemical manipulation of surface tension

NASA Astrophysics Data System (ADS)

Russell, Loren; Wissman, James; Majidi, Carmel

2017-12-01

We examine the electrocapillary properties of a fluidic actuator composed of a liquid metal droplet that is submerged in electrolytic solution and attached to an elastic beam. The beam deflection is controlled by electrochemically driven changes in the surface energy of the droplet. The metal is a eutectic gallium-indium alloy that is liquid at room temperature and forms an nm-thin Ga2O3 skin when oxidized. The effective surface tension of the droplet changes dramatically with oxidation and reduction, which are reversibly controlled by applying low voltage to the electrolytic bath. Wetting the droplet to two copper pads allows for a controllable tensile force to be developed between the opposing surfaces. We demonstrate the ability to reliably control force by changing the applied oxidizing voltage. Actuator forces and droplet geometries are also examined by performing a computational fluid mechanics simulation using Surface Evolver. The theoretical predictions are in qualitative agreement with the experimental measurements and provide additional confirmation that actuation is driven by surface tension.

Controller and data acquisition system for SIDECAR ASIC driven HAWAII detectors

NASA Astrophysics Data System (ADS)

Ramaprakash, Anamparambu; Burse, Mahesh; Chordia, Pravin; Chillal, Kalpesh; Kohok, Abhay; Mestry, Vilas; Punnadi, Sujit; Sinha, Sakya

2010-07-01

SIDECAR is an Application Specific Integrated Circuit (ASIC), which can be used for control and data acquisition from near-IR HAWAII detectors offered by Teledyne Imaging Sensors (TIS), USA. The standard interfaces provided by Teledyne are COM API and socket servers running under MS Windows platform. These interfaces communicate to the ASIC (and the detector) through an intermediate card called JWST ASIC Drive Electronics (JADE2). As part of an ongoing programme of several years, for developing astronomical focal plane array (CCDs, CMOS and Hybrid) controllers and data acquisition systems (CDAQs), IUCAA is currently developing the next generation controllers employing Virtex-5 family FPGA devices. We present here the capabilities which are built into these new CDAQs for handling HAWAII detectors. In our system, the computer which hosts the application programme, user interface and device drivers runs on a Linux platform. It communicates through a hot-pluggable USB interface (with an optional optical fibre extender) to the FPGA-based card which replaces the JADE2. The FPGA board in turn, controls the SIDECAR ASIC and through it a HAWAII-2RG detector, both of which are located in a cryogenic test Dewar set up which is liquid nitrogen cooled. The system can acquire data over 1, 4, or 32 readout channels, with or without binning, at different speeds, can define sub-regions for readout, offers various readout schemes like Fowler sampling, up-theramp etc. In this paper, we present the performance results obtained from a prototype system.

Application of a theoretical model to evaluate COPD disease management.

PubMed

Lemmens, Karin M M; Nieboer, Anna P; Rutten-Van Mölken, Maureen P M H; van Schayck, Constant P; Asin, Javier D; Dirven, Jos A M; Huijsman, Robbert

2010-03-26

Disease management programmes are heterogeneous in nature and often lack a theoretical basis. An evaluation model has been developed in which theoretically driven inquiries link disease management interventions to outcomes. The aim of this study is to methodically evaluate the impact of a disease management programme for patients with chronic obstructive pulmonary disease (COPD) on process, intermediate and final outcomes of care in a general practice setting. A quasi-experimental research was performed with 12-months follow-up of 189 COPD patients in primary care in the Netherlands. The programme included patient education, protocolised assessment and treatment of COPD, structural follow-up and coordination by practice nurses at 3, 6 and 12 months. Data on intermediate outcomes (knowledge, psychosocial mediators, self-efficacy and behaviour) and final outcomes (dyspnoea, quality of life, measured by the CRQ and CCQ, and patient experiences) were obtained from questionnaires and electronic registries. Implementation of the programme was associated with significant improvements in dyspnoea (p < 0.001) and patient experiences (p < 0.001). No significant improvement was found in mean quality of life scores. Improvements were found in several intermediate outcomes, including investment beliefs (p < 0.05), disease-specific knowledge (p < 0.01; p < 0.001) and medication compliance (p < 0.01). Overall, process improvement was established. The model showed associations between significantly improved intermediate outcomes and improvements in quality of life and dyspnoea. The application of a theory-driven model enhances the design and evaluation of disease management programmes aimed at improving health outcomes. This study supports the notion that a theoretical approach strengthens the evaluation designs of complex interventions. Moreover, it provides prudent evidence that the implementation of COPD disease management programmes can positively influence outcomes of care.

Application of a theoretical model to evaluate COPD disease management

PubMed Central

2010-01-01

Background Disease management programmes are heterogeneous in nature and often lack a theoretical basis. An evaluation model has been developed in which theoretically driven inquiries link disease management interventions to outcomes. The aim of this study is to methodically evaluate the impact of a disease management programme for patients with chronic obstructive pulmonary disease (COPD) on process, intermediate and final outcomes of care in a general practice setting. Methods A quasi-experimental research was performed with 12-months follow-up of 189 COPD patients in primary care in the Netherlands. The programme included patient education, protocolised assessment and treatment of COPD, structural follow-up and coordination by practice nurses at 3, 6 and 12 months. Data on intermediate outcomes (knowledge, psychosocial mediators, self-efficacy and behaviour) and final outcomes (dyspnoea, quality of life, measured by the CRQ and CCQ, and patient experiences) were obtained from questionnaires and electronic registries. Results Implementation of the programme was associated with significant improvements in dyspnoea (p < 0.001) and patient experiences (p < 0.001). No significant improvement was found in mean quality of life scores. Improvements were found in several intermediate outcomes, including investment beliefs (p < 0.05), disease-specific knowledge (p < 0.01; p < 0.001) and medication compliance (p < 0.01). Overall, process improvement was established. The model showed associations between significantly improved intermediate outcomes and improvements in quality of life and dyspnoea. Conclusions The application of a theory-driven model enhances the design and evaluation of disease management programmes aimed at improving health outcomes. This study supports the notion that a theoretical approach strengthens the evaluation designs of complex interventions. Moreover, it provides prudent evidence that the implementation of COPD disease management programmes can positively influence outcomes of care. PMID:20346135

On the universality of Marangoni-driven spreading

NASA Astrophysics Data System (ADS)

Visser, Claas; van Capelleveen, Bram; Koldeweij, Robin; Lohse, Detlef

2017-11-01

When two liquids of different surface tensions come into contact, the liquid with lower surface tension spreads over the other. Here we measure the dynamics of this Marangoni-driven spreading in the drop-drop geometry, revealing universal behavior with respect to the control parameters as well as other geometries (such as spreading over a flat interface). The distance L over which the low-surface-tension liquid has covered the high-surface-tension droplet is measured as a function of time t, surface tension difference between the liquids Δσ , and viscosity η, revealing power-law behavior L(t) tα . The exponent α is discussed for the early and late spreading regimes. Spreading inhibition is observed at high viscosity, for which the threshold is discussed. Finally, we show that our results collapse onto a single curve of dimensionless L(t) as a function of dimensionless time, which also captures previous results for different geometries, surface tension modifiers, and miscibility. As this curve spans 7 orders of magnitude, Marangoni-induced spreading can be considered a universal phenomenon for many practically encountered liquid-liquid systems.

Recent Developments in Non-Fermi Liquid Theory

NASA Astrophysics Data System (ADS)

Lee, Sung-Sik

2018-03-01

Non-Fermi liquids are unconventional metals whose physical properties deviate qualitatively from those of noninteracting fermions due to strong quantum fluctuations near Fermi surfaces. They arise when metals are subject to singular interactions mediated by soft collective modes. In the absence of well-defined quasiparticles, universal physics of non-Fermi liquids is captured by interacting field theories which replace Landau Fermi liquid theory. However, it has been difficult to understand their universal low-energy physics due to a lack of theoretical methods that take into account strong quantum fluctuations in the presence of abundant low-energy degrees of freedom. In this review, we discuss two approaches that have been recently developed for non-Fermi liquid theory with emphasis on two space dimensions. The first is a perturbative scheme based on a dimensional regularization, which achieves a controlled access to the low-energy physics by tuning the codimension of Fermi surface. The second is a nonperturbative approach which treats the interaction ahead of the kinetic term through a non-Gaussian scaling called interaction-driven scaling. Examples of strongly coupled non-Fermi liquids amenable to exact treatments through the interaction-driven scaling are discussed.

Thermo- and photo-driven soft actuators based on crosslinked liquid crystalline polymers

NASA Astrophysics Data System (ADS)

Gu, Wei; Wei, Jia; Yu, Yanlei

2016-09-01

Crosslinked liquid crystalline polymers (CLCPs) are a type of promising material that possess both the order of liquid crystals and the properties of polymer networks. The anisotropic deformation of the CLCPs takes place when the mesogens experience order to disorder change in response to external stimuli; therefore, they can be utilized to fabricate smart actuators, which have potential applications in artificial muscles, micro-optomechanical systems, optics, and energy-harvesting fields. In this review the recent development of thermo- and photo-driven soft actuators based on the CLCPs are summarized. Project supported by the National Natural Science Foundation of China (Grant Nos. 21134003, 21273048, 51225304, and 51203023) and Shanghai Outstanding Academic Leader Program, China (Grant No. 15XD1500600).

Community-based preparedness programmes and the 2009 Australian bushfires: policy implications derived from applying theory.

PubMed

MacDougall, Colin; Gibbs, Lisa; Clark, Rachel

2014-04-01

The Victorian Country Fire Authority in Australia runs the Community Fireguard (CFG) programme to assist individuals and communities in preparing for fire. The objective of this qualitative research was to understand the impact of CFG groups on their members' fire preparedness and response during the 2009 Australian bushfires. Social connectedness emerged as a strong theme, leading to an analysis of data using social capital theory. The main strength of the CFG programme was that it was driven by innovative community members; however, concerns arose regarding the extent to which the programme covered all vulnerable areas, which led the research team to explore the theory of diffusion of innovation. The article concludes by stepping back from the evaluation and using both applied theories to reflect on broad options for community fire preparedness programmes in general. The exercise produced two contrasting options for principles underlying community fire preparedness programmes. © 2014 The Author(s). Disasters © Overseas Development Institute, 2014.

Support for All in the UK Work Programme? Differential Payments, Same Old Problem

PubMed Central

Rees, James; Whitworth, Adam; Carter, Elle

2014-01-01

The UK has been a high profile policy innovator in welfare-to-work provision which has led in the Coalition government's Work Programme to a fully outsourced, ‘black box’ model with payments based overwhelmingly on job outcome results. A perennial fear in such programmes is providers' incentives to ‘cream’ and ‘park’ claimants, and the Department for Work and Pensions has sought to mitigate such provider behaviours through Work Programme design, particularly via the use of claimant groups and differential pricing. In this article, we draw on a qualitative study of providers in the programme alongside quantitative analysis of published performance data to explore evidence around creaming and parking. The combination of the quantitative and qualitative evidence suggest that creaming and parking are widespread, seem systematically embedded within the Work Programme, and are driven by a combination of intense cost-pressures and extremely ambitious performance targets alongside overly diverse claimant groups and inadequately calibrated differentiated payment levels. PMID:25411516

Support for All in the UK Work Programme? Differential Payments, Same Old Problem.

PubMed

Rees, James; Whitworth, Adam; Carter, Elle

2014-04-01

The UK has been a high profile policy innovator in welfare-to-work provision which has led in the Coalition government's Work Programme to a fully outsourced, 'black box' model with payments based overwhelmingly on job outcome results. A perennial fear in such programmes is providers' incentives to 'cream' and 'park' claimants, and the Department for Work and Pensions has sought to mitigate such provider behaviours through Work Programme design, particularly via the use of claimant groups and differential pricing. In this article, we draw on a qualitative study of providers in the programme alongside quantitative analysis of published performance data to explore evidence around creaming and parking. The combination of the quantitative and qualitative evidence suggest that creaming and parking are widespread, seem systematically embedded within the Work Programme, and are driven by a combination of intense cost-pressures and extremely ambitious performance targets alongside overly diverse claimant groups and inadequately calibrated differentiated payment levels.

Solar-Driven Liquid-Metal MHD Generator

NASA Technical Reports Server (NTRS)

Hohl, F.; Lee, J. H.

1982-01-01

Liquid-metal magnetohydrodynamic (MHD) power generator with solar oven as its heat source has potential to produce electric power in space and on Earth at high efficiency. Generator focuses radiation from Sun to heat driving gas that pushes liquid metal past magnetic coil. Power is extracted directly from electric currents set up in conducting liquid. Using solar energy as fuel can save considerable costs and payload weight, compared to previous systems.

Drop impact on flowing liquid films: asymmetric splashing

NASA Astrophysics Data System (ADS)

Ismail, Renad; Che, Zhizhao; Rotkovitz, Lauren; Adebayo, Idris; Matar, Omar

2015-11-01

The splashing of droplets on flowing liquid films is studied experimentally using high-speed photography. The flowing liquid films are generated on an inclined substrate. The flow rate of the liquid film, the inclination angle, and the droplet speed are controlled and their effects on the splashing process studied. Due to the flow in the liquid film and the oblique impact direction, the splashing process is asymmetric. The propagation of the asymmetric crown and the generation of secondary droplets on the rim of the crown are analysed through image processing. The results show that the flow in the liquid films significantly affects the propagation of the liquid crown and the generation of secondary droplets. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

Propagation of a viscous thin film over an elastic membran

NASA Astrophysics Data System (ADS)

Zheng, Zhong; Griffiths, Ian; Stone, Howard

2016-11-01

We study the buoyancy-driven spreading of a thin viscous film over a thin elastic membrane. Neglecting the effects of membrane bending and the membrane weight, we study the case of constant fluid injection and obtain a system of coupled partial differential equations to describe the shape of the air-liquid interface, and the deformation and the radial tension of the stretched membrane. We obtain self-similar solutions to describe the dynamics. In particular, in the early time period, the dynamics is dominated by buoyancy-driven spreading of the liquid film, and membrane stretching is a response to the buoyancy-controlled distribution of liquid weight; the location of the liquid front obeys the power-law form rf (t) t 1 / 2 . However, in the late time period, the system is quasi-steady, the air-liquid interface is flat, and membrane stretching, due to the liquid weight, causes the spreading of the liquid front; the location of the front obeys a different power-law form rf (t) t 1 / 4 before the edge effects of the membrane become significant. In addition, we report laboratory experiments for constant fluid injection using different viscous liquids and thin elastic membranes. Very good agreement is obtained between the theory and experiments.

A thermo-electric-driven flowing liquid lithium limiter/divertor for magnetic confined fusion

NASA Astrophysics Data System (ADS)

Ruzic, D. N.; Xu, Wenyu; Curreli, Davide; Andruczyk, Daniel; Mui, Travis

2012-10-01

The concept of using a liquid metal, especially liquid lithium, as the plasma facing surface may provide the best path forward toward reactor designs. A liquid PFC can effectively eliminate the erosion and thermal stress problems compared to the solid PFC while transferring heat and prolong the lifetime limit of the PFCs. A liquid lithium surface can also suppress the hydrogen isotopes recycling and getter the impurities in fusion reactor. The Lithium/metal infused trench (LiMIT) concept successfully proved that the thermoelectric effect can induce electric currents inside liquid lithium and an external magnetic field can drive liquid lithium to flow within metallic open trenches. IR camera and thermocouple measurements prove the strong heat transfer ability of this concept. A new flowing lithium system with active control of the temperature gradient inside the lithium trenches and back flow channels has been designed. TEMHD driven liquid lithium run steady state and pulsed for a few seconds of high heat flux (˜15MW/m^2) has been used to investigate the transient reaction of the flowing lithium. A similar tray is scheduled to be tested in HT-7, Hefei, China as a limiter in Sept. 2012. Related movies and analysis will be shown.

The Back 2 Activity Trial: education and advice versus education and advice plus a structured walking programme for chronic low back pain

PubMed Central

2010-01-01

Background Current evidence supports the use of exercise-based treatment for chronic low back pain that encourages the patient to assume an active role in their recovery. Walking has been shown it to be an acceptable type of exercise with a low risk of injury. However, it is not known whether structured physical activity programmes are any more effective than giving advice to remain active. Methods/Design The proposed study will test the feasibility of using a pedometer-driven walking programme, as an adjunct to a standard education and advice session in participants with chronic low back pain. Fifty adult participants will be recruited via a number of different sources. Baseline outcome measures including self reported function; objective physical activity levels; fear-avoidance beliefs and health-related quality of life will be recorded. Eligible participants will be randomly allocated under strict, double blind conditions to one of two treatments groups. Participants in group A will receive a single education and advice session with a physiotherapist based on the content of the 'Back Book'. Participants in group B will receive the same education and advice session. In addition, they will also receive a graded pedometer-driven walking programme prescribed by the physiotherapist. Follow up outcomes will be recorded by the same researcher, who will remain blinded to group allocation, at eight weeks and six months post randomisation. A qualitative exploration of participants' perception of walking will also be examined by use of focus groups at the end of the intervention. As a feasibility study, treatment effects will be represented by point estimates and confidence intervals. The assessment of participant satisfaction will be tabulated, as will adherence levels and any recorded difficulties or adverse events experienced by the participants or therapists. This information will be used to modify the planned interventions to be used in a larger randomised controlled trial. Discussion This paper describes the rationale and design of a study which will test the feasibility of using a structured, pedometer-driven walking programme in participants with chronic low back pain. Trial Registration [ISRCTN67030896] PMID:20633256

The Impact of a Cryogenics-Based Enrichment Programme on Attitude Towards Science and the Learning of Science Concepts. Research Report

ERIC Educational Resources Information Center

Caleon, Imelda; Subramaniam, R.

2005-01-01

This study explores the impact of a cryogenics-based enrichment programme, which involves demonstrations that use liquid nitrogen, on attitudes towards science and the learning of science concepts. The findings presented in this paper are based on a sample of 214 fifth-grade students from two schools in Singapore who had their enrichment lesson in…

Transmittance tuning by particle chain polarization in electrowetting-driven droplets

PubMed Central

Fan, Shih-Kang; Chiu, Cheng-Pu; Huang, Po-Wen

2010-01-01

A tiny droplet containing nano∕microparticles commonly handled in digital microfluidic lab-on-a-chip is regarded as a micro-optical component with tunable transmittance at programmable positions for the application of micro-opto-fluidic-systems. Cross-scale electric manipulations of droplets on a millimeter scale as well as suspended particles on a micrometer scale are demonstrated by electrowetting-on-dielectric (EWOD) and particle chain polarization, respectively. By applying electric fields at proper frequency ranges, EWOD and polarization can be selectively achieved in designed and fabricated parallel plate devices. At low frequencies, the applied signal generates EWOD to pump suspension droplets. The evenly dispersed particles reflect and∕or absorb the incident light to exhibit a reflective or dark droplet. When sufficiently high frequencies are used on to the nonsegmented parallel electrodes, a uniform electric field is established across the liquid to polarize the dispersed neutral particles. The induced dipole moments attract the particles each other to form particle chains and increase the transmittance of the suspension, demonstrating a transmissive or bright droplet. In addition, the reflectance of the droplet is measured at various frequencies with different amplitudes. PMID:21267088

Tuned, driven, and active soft matter

NASA Astrophysics Data System (ADS)

Menzel, Andreas M.

2015-02-01

One characteristic feature of soft matter systems is their strong response to external stimuli. As a consequence they are comparatively easily driven out of their ground state and out of equilibrium, which leads to many of their fascinating properties. Here, we review illustrative examples. This review is structured by an increasing distance from the equilibrium ground state. On each level, examples of increasing degree of complexity are considered. In detail, we first consider systems that are quasi-statically tuned or switched to a new state by applying external fields. These are common liquid crystals, liquid crystalline elastomers, or ferrogels and magnetic elastomers. Next, we concentrate on systems steadily driven from outside e.g. by an imposed flow field. In our case, we review the reaction of nematic liquid crystals, of bulk-filling periodically modulated structures such as block copolymers, and of localized vesicular objects to an imposed shear flow. Finally, we focus on systems that are "active" and "self-driven". Here our range spans from idealized self-propelled point particles, via sterically interacting particles like granular hoppers, via microswimmers such as self-phoretically driven artificial Janus particles or biological microorganisms, via deformable self-propelled particles like droplets, up to the collective behavior of insects, fish, and birds. As we emphasize, similarities emerge in the features and behavior of systems that at first glance may not necessarily appear related. We thus hope that our overview will further stimulate the search for basic unifying principles underlying the physics of these soft materials out of their equilibrium ground state.

Programmable and electrically controllable light scattering from surface-polymer stabilized liquid crystals.

PubMed

Bédard-Arcand, Jean-Philippe; Galstian, Tigran

2012-08-01

We report the creation and study of a polarization independent light scattering material system based on surface-polymer stabilized liquid crystals. Originally isotropic cell substrates with thin nonpolymerized reactive mesogen layers are used for the alignment of pure nonreactive nematic liquid crystals. The partial interdiffusion of the two materials followed by the application of orienting external electric and magnetic fields and the photo polymerization of the reactive mesogen allow us the control of electro-optic scattering properties of obtained cells.

Of taps and toilets: quasi-experimental protocol for evaluating community-demand-driven projects.

PubMed

Pattanayak, Subhrendu K; Poulos, Christine; Yang, Jui-Chen; Patil, Sumeet R; Wendland, Kelly J

2009-09-01

Sustainable and equitable access to safe water and adequate sanitation are widely acknowledged as vital, yet neglected, development goals. Water supply and sanitation (WSS) policies are justified because of the usual efficiency criteria, but also major equity concerns. Yet, to date there are few scientific impact evaluations showing that WSS policies are effective in delivering social welfare outcomes. This lack of an evaluation culture is partly because WSS policies are characterized by diverse mechanisms, broad goals and the increasing importance of decentralized delivery, and partly because programme administrators are unaware of appropriate methods. We describe a protocol for a quasi-experimental evaluation of a community-demand-driven programme for water and sanitation in rural India, which addresses several evaluation challenges. After briefly reviewing policy and implementation issues in the sector, we describe key features of our protocol, including control group identification, pre-post measurement, programme theory, sample sufficiency and robust indicators. At its core, our protocol proposes to combine propensity score matching and difference-in-difference estimation. We conclude by briefly summarizing how quasi-experimental impact evaluations can address key issues in WSS policy design and when such evaluations are needed.

Magnetically driven oscillator and resonance: a teaching tool

NASA Astrophysics Data System (ADS)

Erol, M.; Çolak, İ. Ö.

2018-05-01

This paper reports a simple magnetically driven oscillator, designed and resolved in order to achieve a better student understanding and to overcome certain instructional difficulties. The apparatus is mainly comprised of an ordinary spring pendulum with a neodymium magnet attached to the bottom, a coil placed in the same vertical direction, an ordinary function generator, an oscilloscope and a smartphone. Driven oscillation and resonance is basically managed by applying a sinusoidal voltage to the coil and tuning the driving frequency to the natural frequency of the pendulum. The resultant oscillation is recorded by a smartphone video application and analyzed via a video analysis programme. The designed apparatus can easily be employed in basic physics laboratories to achieve an enhanced and deeper understanding of driven oscillation and resonance.

Tissue banking in Asia Pacific region: past, present and future.

PubMed

Nather, Aziz; Mandy, Foong Shi Yun; Ning, Tan; Kaiying, Wang

2018-04-25

Tissue banking in the Asia Pacific regions is driven by two main forces-firstly the International Atomic Energy Agency (IAEA) via Regional Co-operative Agreement projects and secondly by the Asia Pacific Association of Surgical Tissue Banking (APASTB). This overview is written in three sections: (1) History of tissue banking in individual country in the region. (2) History of APASTB. (3) History of IAEA programme in Asia Pacific region. The current status and future of the tissue banking programme in the region will be discussed.

Electricity in foams: from one soapy interface to the macroscopic material

NASA Astrophysics Data System (ADS)

Biance, Anne-Laure

2017-11-01

Liquid foams (a dispersion of gas bubbles in a soapy solution) destabilize with time due to coarsening, coalescence and gravity driven drainage. We propose here to inhibit (or trigger) the foam destabilization by applying an electric field to the material. This effect is investigated at the different scales of the system: one soapy interface, one liquid film, the macroscopic foam. The generation of an electroosmotic flow near a soapy liquid/gas interface raises many issues. How does the flow affect surfactant repartition? Is there a Marangoni stress at the interface? At the scale of one soap film, how the electric field affects the film stability and deformation? In a macroscopic foam, one can wonder whether the electric field can indeed reverse gravity driven drainage and increase foam lifetime? These different issues are considered by developing new experimental techniques allowing us to probe surfactant repartition at liquid interfaces, soap film thicknesses and liquid foam properties when an electric field is applied. The results will be presented together with a comprehensive picture of the mechanisms arising at each scale of the material, to conclude with the potential use of electricity in liquid foams to control destabilization. Collaborators: Baptiste Blanc, Oriane Bonhomme, Laurent Joly, Christophe Ybert.

Exploring the structure of high temperature, iron-bearing liquids

DOE PAGES

Wilding, Martin; Benmore, Chris; Weber, Rick; ...

2015-06-25

This paper describes the direct measurements of the structure of iron-bearing liquids using a combination of containerless techniques and in–situ high energy x-ray diffraction. These capabilities provide data that is important to help model and optimize processes such as smelting, steel making, and controlling slag chemistry. A successful programme of liquid studies has been undertaken and the Advanced Photon Source using these combined techniques which include the provision of gas mixing and the control of pO₂ and the changing influence of mixed valance elements. It is possible to combine rapid image acquisition with quenching of liquids to obtain the fullmore » diffraction patterns of deeply supercooled liquids and the metastable supercooled liquid regime, where the liquid structures and viscosity change most dramatically, can also be explored.« less

Heat-driven thermoacoustic cryocooler operating at liquid hydrogen temperature with a unique coupler

NASA Astrophysics Data System (ADS)

Hu, J. Y.; Luo, E. C.; Li, S. F.; Yu, B.; Dai, W.

2008-05-01

A heat-driven thermoacoustic cryocooler is constructed. A unique coupler composed of a tube, reservoir, and elastic diaphragm is introduced to couple a traveling-wave thermoacoustic engine (TE) and two-stage pulse tube refrigerator (PTR). The amplitude of the pressure wave generated in the engine is first amplified in the coupler and the wave then passes into the refrigerator to pump heat. The TE uses nitrogen as its working gas and the PTR still uses helium as its working gas. With this coupler, the efficiency of the system is doubled. The engine and coupler match at a much lower operating frequency, which is of great benefit for the PTR to obtain a lower cooling temperature. The coupling place between the coupler and engine is also optimized. The onset problem is effectively solved. With these improvements, the heat-driven thermoacoustic cryocooler reaches a lowest temperature of 18.1K, which is the demonstration of heat-driven thermoacoustic refrigeration technology used for cooling at liquid hydrogen temperatures.

Photochemically and Thermally Driven Full-Color Reflection in a Self-Organized Helical Superstructure Enabled by a Halogen-Bonded Chiral Molecular Switch.

PubMed

Wang, Hao; Bisoyi, Hari Krishna; Wang, Ling; Urbas, Augustine M; Bunning, Timothy J; Li, Quan

2018-02-05

Supramolecular approaches toward the fabrication of functional materials and systems have been an enabling endeavor. Recently, halogen bonding has been harnessed as a promising supramolecular tool. Herein we report the synthesis and characterization of a novel halogen-bonded light-driven axially chiral molecular switch. The photoactive halogen-bonded chiral switch is able to induce a self-organized, tunable helical superstructure, that is, cholesteric liquid crystal (CLC), when doped into an achiral liquid crystal (LC) host. The halogen-bonded switch as a chiral dopant has a high helical twisting power (HTP) and shows a large change of its HTP upon photoisomerization. This light-driven dynamic modulation enables reversible selective reflection color tuning across the entire visible spectrum. The chiral switch also displays a temperature-dependent HTP change that enables thermally driven red, green, and blue (RGB) reflection colors in the self-organized helical superstructure. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface Tension Driven Instability in the Regime of Stokes Flow

NASA Astrophysics Data System (ADS)

Yao, Zhenwei; Bowick, Mark; Xing, Xiangjun

2010-03-01

A cylinder of liquid inside another liquid is unstable towards droplet formation. This instability is driven by minimization of surface tension energy and was analyzed first by [1,2] and then by [3]. We revisit this problem in the limit of small Laplace number, where the inertial of liquids can be completely ignored. The stream function is found to obey biharmonic equation, and its analytic solutions are found. We rederive Tomotika's main results, and also obtain many new analytic results about the velocity fields. We also apply our formalism to study the recent experiment on toroidal liquid droplet[4]. Our framework shall have many applications in micro-fluidics. [1] L.Rayleigh, On The Instability of A Cylinder of Viscous Liquid Under Capillary Force, Scientific Papers, Cambridge, Vol.III, 1902. [2] L.Rayleigh, On The Instability of Cylindrical Fluid Surfaces, Scientific Papers, Cambridge, Vol.III, 1902. [3] S.Tomotika, On the Instability of a Cylindrical Thread of a Viscous Liquid surround by Another Viscous Fluid, Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Volume 150, Issue 870, pp. 322-337. [4] E.Pairam and A.Fern'andez-Nieves, Generation and Stability of Toroidal Droplets in a Viscous Liquid, Physical Review Letters 102, 234501 (2009).

On-axis programmable microscope using liquid crystal spatial light modulator

NASA Astrophysics Data System (ADS)

García-Martínez, Pascuala; Martínez, José Luís.; Moreno, Ignacio

2017-06-01

Spatial light modulators (SLM) are currently used in many applications in optical microscopy and imaging. One of the most promising methods is the use of liquid crystal displays (LCD) as programmable phase diffractive optical elements (DOE) placed in the Fourier plane giving access to the spatial frequencies which can be phased shifted individually, allowing to emulate a wealth of contrast enhancing methods for both amplitude and phase samples. We use phase and polarization modulation of LCD to implement an on-axis microscope optical system. The LCD used are Hamamatsu liquid crystal on silicon (LCOS) SLM free of flicker, thus showing a full profit of the SLM space bandwidth, as opposed to optical systems in the literature forced to work off-axis due to the strong zero-order component. Taking benefits of the phase modulation of the LCOS we have implemented different microscopic imaging operations, such as high-pass and low-pass filtering in parallel using programmable blazed gratings. Moreover, we are able to control polarization modulation to display two orthogonal linear state of polarization images than can be subtracted or added by changing the period of the blazed grating. In that sense, Differential Interference Contrast (DIC) microscopy can be easily done by generating two images exploiting the polarization splitting properties when a blazed grating is displayed in the SLM. Biological microscopy samples are also used.

The liquid drop nature of nucleoli.

PubMed

Marko, John F

2012-03-01

Nucleoli are prominent subnuclear organelles, and are known to be hubs of ribosome synthesis. A recent study of Brangwynne et al. reports that the nucleoli of Xenopus oocytes display "liquid drop" behavior, suggesting that nucleolar structure may be driven by rather simple physical principles.

Elastic stress transmission and transformation (ESTT) by confined liquid: A new mechanics for fracture in elastic lithosphere of the earth

USGS Publications Warehouse

Xu, Xing-Wang; Peters, Stephen; Liang, Guang-He; Zhang, Bao-Lin

2016-01-01

Tectonic stress alters local stress fields in the surrounding country rocks and therefore synchronously varies the local effective tensile tangential stress and the nature and geometry of the liquid-driven fractures.

A swing driven by liquid crystals

NASA Astrophysics Data System (ADS)

Cheng, Cheng

Angular momentum in liquid crystals exists as flow, director reorientation, etc. However, it is hard to observe and measure angular momentum in liquid crystals by a direct mechanical approach. Torsion pendulum is a general tool to measure angular momentum by torque balance. Our torsion pendulum can harvest the angular momentum in liquid crystals to make it observable. The oscillation of the pendulum keeps increasing by constructively adding a small angular momentum of liquid crystals each period at the resonant frequency of the pendulum. Its similar to a swing driven by a force at its resonant frequency. For the torsion pendulum, a cage made of two aluminum discs, in which a liquid crystal cell is placed, is suspended between two thin tungsten wires. A gold mirror, which is a part of the optical lever system, is attached on one tungsten wire. As first demonstration, we fabricate a circular hybrid liquid crystal cell, which can induce concentric backflows to generate angular momentum. The alignment on the planar substrate is concentric and tangential. Due to the coupling between director rotation and flow, the induced backflow goes around the cell when we add electrical pulses between top and bottom substrates. The oscillation is observed by a position sensitive detector and analyzed on the basis of Eriksen-Leslie theory. With vacuum condition and synchronous driving system, the oscillation signal is improved. We demonstrate that this torsion pendulum can sensitively detect the angular momentum in liquid crystals.

Actuating materials. Voxelated liquid crystal elastomers.

PubMed

Ware, Taylor H; McConney, Michael E; Wie, Jeong Jae; Tondiglia, Vincent P; White, Timothy J

2015-02-27

Dynamic control of shape can bring multifunctionality to devices. Soft materials capable of programmable shape change require localized control of the magnitude and directionality of a mechanical response. We report the preparation of soft, ordered materials referred to as liquid crystal elastomers. The direction of molecular order, known as the director, is written within local volume elements (voxels) as small as 0.0005 cubic millimeters. Locally, the director controls the inherent mechanical response (55% strain) within the material. In monoliths with spatially patterned director, thermal or chemical stimuli transform flat sheets into three-dimensional objects through controlled bending and stretching. The programmable mechanical response of these materials could yield monolithic multifunctional devices or serve as reconfigurable substrates for flexible devices in aerospace, medicine, or consumer goods. Copyright © 2015, American Association for the Advancement of Science.

Foam-Mixing-And-Dispensing Machine

NASA Technical Reports Server (NTRS)

Chong, Keith Y.; Toombs, Gordon R.; Jackson, Richard J.

1996-01-01

Time-and-money-saving machine produces consistent, homogeneously mixed foam, enhancing production efficiency. Automatically mixes and dispenses polyurethane foam in quantities specified by weight. Consists of cart-mounted, air-driven proportioning unit; air-activated mechanical mixing gun; programmable timer/counter, and controller.

Lessons learned from stakeholder-driven sustainability analysis of six national HIV programmes.

PubMed

Katz, Itamar; Glandon, Douglas; Wong, Wendy; Kargbo, Brima; Ombam, Regina; Singh, Shanti; Ramsammy, Leslie; Tal-Dia, Anta; Seck, Ibrahima; Osika, John S

2014-05-01

In light of the decline in donor HIV funding, HIV programmes increasingly need to assess their available and potential resources and maximize their utilization. This article presents lessons learned related to how countries have addressed the sustainability of HIV programmes in a stakeholder-driven sustainability analysis. During HIV/AIDS Programme Sustainability Analysis Tool (HAPSAT) applications in six countries (Benin, Guyana, Kenya, Lesotho, Sierra Leone and South Sudan), stakeholders identified key sustainability challenges for their HIV responses. Possible policy approaches were prepared, and those related to prioritization and resource mobilization are analysed in this article. The need to prioritize evidence-based interventions and apply efficiency measures is being accepted by countries. Five of the six countries in this study requested that the HAPSAT team prepare 'prioritization' strategies. Countries recognize the need to prepare for an alternative to 'universal access by 2015', acknowledging that their capacity might be insufficient to reach such high-coverage levels by then. There is further acceptance of the importance of reaching the most-at-risk, marginalized populations, as seen, for example, in South Sudan and Sierra Leone. However, the pace at which resources are shifting towards these populations is slow. Finally, only two of the six countries, Kenya and Benin, chose to examine options for generating additional financial resources beyond donor funding. In Kenya, three non-donor sources were recommended, yet even if all were to be implemented, it would cover only 25% of the funding needed. Countries are increasingly willing to address the challenges of HIV programme sustainability, yet in different ways and with varying urgency. To secure achievements made to date and maximize future impact, countries would benefit from strengthening their strategic plans, operational plans and funding proposals with concrete timelines and responsibilities for addressing sustainability issues.

Versatile all-digital time interval measuring system

NASA Astrophysics Data System (ADS)

Vyhlidal, David; Cech, Miroslav

2011-06-01

This paper describes a design and performance of a versatile all-digital time interval measuring system. The measurement method is based on an interpolation principle. In this principle the time interval is first roughly digitized by a coarse counter driven by a high stability reference clock and the fractions between the clock periods are measured by two Time-to-Digital Converter chips TDC-GPX manufactured by Acam messelectronic. Control circuits allow programmable customization of the system to satisfy many applications such as laser range finding, event counting, or time-of-flight measurements in various physics experiments. The system has two reference clocks inputs and two independent channels for measuring start and stop events. Only one 40 MHz reference is required for the measurement. The second reference can be, for example, 1 PPS (Pulse per Second) signal from a GPS (Global Positioning System) to time tag events. Time intervals are measured using the highest resolution mode of the TDC-GPX chips. The resolution of each chip is software programmable and is PLL (Phase Locked Loop) stabilized against temperature and voltage variations. The system can achieve a timing resolution better than 15 ps rms with up to 90 kHz repetition rate. The time interval measurement range is from 0 ps up to 1 second. The power consumption of the whole system is 18 W including an embedded computer board and an LCD (Liquid Crystal Display) screen. The embedded computer controls the whole system, collects and evaluates measurement data and with the display provides a user interface. The system is implemented using commercially available components.

An electric stimulation system for electrokinetic particle manipulation in microfluidic devices.

PubMed

Lopez-de la Fuente, M S; Moncada-Hernandez, H; Perez-Gonzalez, V H; Lapizco-Encinas, B H; Martinez-Chapa, S O

2013-03-01

Microfluidic devices have grown significantly in the number of applications. Microfabrication techniques have evolved considerably; however, electric stimulation systems for microdevices have not advanced at the same pace. Electric stimulation of micro-fluidic devices is an important element in particle manipulation research. A flexible stimulation instrument is desired to perform configurable, repeatable, automated, and reliable experiments by allowing users to select the stimulation parameters. The instrument presented here is a configurable and programmable stimulation system for electrokinetic-driven microfluidic devices; it consists of a processor, a memory system, and a user interface to deliver several types of waveforms and stimulation patterns. It has been designed to be a flexible, highly configurable, low power instrument capable of delivering sine, triangle, and sawtooth waveforms with one single frequency or two superimposed frequencies ranging from 0.01 Hz to 40 kHz, and an output voltage of up to 30 Vpp. A specific stimulation pattern can be delivered over a single time period or as a sequence of different signals for different time periods. This stimulation system can be applied as a research tool where manipulation of particles suspended in liquid media is involved, such as biology, medicine, environment, embryology, and genetics. This system has the potential to lead to new schemes for laboratory procedures by allowing application specific and user defined electric stimulation. The development of this device is a step towards portable and programmable instrumentation for electric stimulation on electrokinetic-based microfluidic devices, which are meant to be integrated with lab-on-a-chip devices.

An electric stimulation system for electrokinetic particle manipulation in microfluidic devices

NASA Astrophysics Data System (ADS)

Lopez-de la Fuente, M. S.; Moncada-Hernandez, H.; Perez-Gonzalez, V. H.; Lapizco-Encinas, B. H.; Martinez-Chapa, S. O.

2013-03-01

Microfluidic devices have grown significantly in the number of applications. Microfabrication techniques have evolved considerably; however, electric stimulation systems for microdevices have not advanced at the same pace. Electric stimulation of micro-fluidic devices is an important element in particle manipulation research. A flexible stimulation instrument is desired to perform configurable, repeatable, automated, and reliable experiments by allowing users to select the stimulation parameters. The instrument presented here is a configurable and programmable stimulation system for electrokinetic-driven microfluidic devices; it consists of a processor, a memory system, and a user interface to deliver several types of waveforms and stimulation patterns. It has been designed to be a flexible, highly configurable, low power instrument capable of delivering sine, triangle, and sawtooth waveforms with one single frequency or two superimposed frequencies ranging from 0.01 Hz to 40 kHz, and an output voltage of up to 30 Vpp. A specific stimulation pattern can be delivered over a single time period or as a sequence of different signals for different time periods. This stimulation system can be applied as a research tool where manipulation of particles suspended in liquid media is involved, such as biology, medicine, environment, embryology, and genetics. This system has the potential to lead to new schemes for laboratory procedures by allowing application specific and user defined electric stimulation. The development of this device is a step towards portable and programmable instrumentation for electric stimulation on electrokinetic-based microfluidic devices, which are meant to be integrated with lab-on-a-chip devices.

Analysis Grid for Environments Linked to Obesity (ANGELO) framework to develop community-driven health programmes in an Indigenous community in Canada.

PubMed

Willows, Noreen; Dyck Fehderau, David; Raine, Kim D

2016-09-01

Indigenous First Nations people in Canada have high chronic disease morbidity resulting in part from enduring social inequities and colonialism. Obesity prevention strategies developed by and for First Nations people are crucial to improving the health status of this group. The research objective was to develop community-relevant strategies to address childhood obesity in a First Nations community. Strategies were derived from an action-based workshop based on the Analysis Grid for Environments Linked to Obesity (ANGELO) framework. Thirteen community members with wide-ranging community representation took part in the workshop. They combined personal knowledge and experience with community-specific and national research to dissect the broad array of environmental factors that influenced childhood obesity in their community. They then developed community-specific action plans focusing on healthy eating and physical activity for children and their families. Actions included increasing awareness of children's health issues among the local population and community leadership, promoting nutrition and physical activity at school, and improving recreation opportunities. Strengthening children's connection to their culture was considered paramount to improving their well-being; thus, workshop participants developed programmes that included elders as teachers and reinforced families' acquaintance with First Nations foods and activities. The research demonstrated that the ANGELO framework is a participatory way to develop community-driven health programmes. It also demonstrated that First Nations people involved in the creation of solutions to health issues in their communities may focus on decolonising approaches such as strengthening their connection to indigenous culture and traditions. External funds were not available to implement programmes and there was no formal follow-up to determine if community members implemented programmes. Future research needs to examine the extent to which community members can implement programmes on their own and whether community action plans, when implemented, lead to short- and long-term benefits in health outcomes. © 2015 John Wiley & Sons Ltd.

An Interactive Computer Program for Simulating the Effects of Olivine Fractionation from Basaltic and Ultrabasic Liquids.

ERIC Educational Resources Information Center

Pearce, Thomas H.

1983-01-01

Describes interactive computer program (listing available from author) which simulates olivine fractionation from basaltic/ultrabasic liquid. The menu-driven nature of the program (for Apple II microcomputer) allows students to select ideal Rayleigh fractionation or equilibrium crystallization. (JN)

Liquid interfacial water and brines in the upper surface of Mars

NASA Astrophysics Data System (ADS)

Moehlmann, Diedrich

2013-04-01

Liquid interfacial water and brines in the upper surface of Mars Diedrich T.F. Möhlmann DLR Institut für Planetenforschung, Rutherfordstr. 2, D - 12489 Berlin, Germany dirk.moehlmann@dlr.de Interfacial water films and numerous brines are known to remain liquid at temperatures far below 0° C. The physical processes behind are described in some detail. Deliquescence, i.e. the liquefaction of hygroscopic salts at the threshold of a specific "Deliquescence Relative Humidity", is shown to be that process, which on present Mars supports the formation of stable interfacial water and bulk liquids in form of temporary brines on and in a salty upper surface of present Mars in a diurnally temporary and repetitive process. Temperature and relative humidity are the governing conditions for deliquescence (and the counterpart "efflorescence") to evolve. The current thermo-dynamical conditions on Mars support these processes to evolve on present Mars. The deliquescence-driven presence of liquid brines in the soil of the upper surface of Mars can expected to be followed by physical and chemical processes like "surface cementation", down-slope flows, and physical and chemical weathering processes. A remarkable and possibly also biologically relevant evolution towards internally interfacial water bearing structures of dendritic capillaries is related to their freezing - thawing driven formation. The internal walls of these network-pores or -tubes can be covered by films of interfacial water, providing that way possibly habitable crack-systems in soil and rock. These evolutionary processes of networks, driven by their tip-growth, can expected to be ongoing also at present.

Solar driven liquid metal MHD power generator

NASA Technical Reports Server (NTRS)

Lee, J. H.; Hohl, F. (Inventor)

1983-01-01

A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical power. The mixture is then separated and recycled.

Heat and Mass Transfer of Ammonia Gas Absorption into Falling Liquid Film on a Horizontal Tube

NASA Astrophysics Data System (ADS)

Inoue, Norihiro; Yabuuchi, Hironori; Goto, Masao; Koyama, Shigeru

Heat and mass transfer coefficients during ammonia gas absorption into a falling liquid film formed by distilled water on a horizontal tube were obtained experimentally. The test absorber consists of 200 mm i.d., 600 mm long stainless steel shell, a 1 7.3 mm o.d., 14.9 mm i.d. stainless steel test tube with 600 mm working length mounted along the axis of shell, and a 12.7 mm o.d. pipe manifold of supplying the absorbent. In this paper, it was clear that heat and mass transfer coefficient could be enhanced by increasing the flow rate of absorbent and temperature difference between inlet absorbent and ammonia gas, also heat driven by the temperature difference have an effect on heat transfer of the fa1ling liquid film and mass transfer of vapor side. And the new correlation of heat transfer in dimensionless form was proposed by the temperature difference which was considered heat driven of vapor and liquid film side using a interface temperature of vapor and liquid phase. The new correlations of mass transfer on a interface of vapor and liquid phase in dimensionless form were proposed by using effect factors could be suppose from absorption phenomena.

75 FR 62122 - Energy Conservation Program for Certain Industrial Equipment: Publication of the Petition for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-07

... rating the Altherma products in Europe. The test procedures are EN 14511 ``Air conditioners, liquid chilling packages and heat pumps with electrically driven compressors for space heating and cooling'' and... rated according to European Standard EN 14511, ``Air conditioners, liquid chilling packages and heat...

Fabrication and Testing of Microfluidic Optomechanical Oscillators

PubMed Central

Han, Kewen; Kim, Kyu Hyun; Kim, Junhwan; Lee, Wonsuk; Liu, Jing; Fan, Xudong; Carmon, Tal; Bahl, Gaurav

2014-01-01

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including microresonators. However, because of the increased acoustic radiative losses during direct liquid immersion of optomechanical devices, almost all published optomechanical experiments have been performed in solid phase. This paper discusses a recently introduced hollow microfluidic optomechanical resonator. Detailed methodology is provided to fabricate these ultra-high-Q microfluidic resonators, perform optomechanical testing, and measure radiation pressure-driven breathing mode and SBS-driven whispering gallery mode parametric vibrations. By confining liquids inside the capillary resonator, high mechanical- and optical- quality factors are simultaneously maintained. PMID:24962013

Liquid Tunable Microlenses based on MEMS techniques

PubMed Central

Zeng, Xuefeng; Jiang, Hongrui

2013-01-01

The recent rapid development in microlens technology has provided many opportunities for miniaturized optical systems, and has found a wide range of applications. Of these microlenses, tunable-focus microlenses are of special interest as their focal lengths can be tuned using micro-scale actuators integrated with the lens structure. Realization of such tunable microlens generally relies on the microelectromechanical system (MEMS) technologies. Here, we review the recent progress in tunable liquid microlenses. The underlying physics relevant to these microlenses are first discussed, followed by description of three main categories of tunable microlenses involving MEMS techniques, mechanically driven, electrically driven, and those integrated within microfluidic systems. PMID:24163480

Auto-Origami and Soft Programmable Transformers: Simulation Studies of Liquid Crystal Elastomers and Swelling Polymer Gels

NASA Astrophysics Data System (ADS)

Konya, Andrew; Santangelo, Christian; Selinger, Robin

2014-03-01

When the underlying microstructure of an actuatable material varies in space, simple sheets can transform into complex shapes. Using nonlinear finite element elastodynamic simulations, we explore the design space of two such materials: liquid crystal elastomers and swelling polymer gels. Liquid crystal elastomers (LCE) undergo shape transformations induced by stimuli such as heating/cooling or illumination; complex deformations may be programmed by ``blueprinting'' a non-uniform director field in the sample when the polymer is cross-linked. Similarly, swellable gels can undergo shape change when they are swollen anisotropically as programmed by recently developed halftone gel lithography techniques. For each of these materials we design and test programmable motifs which give rise to complex deformation trajectories including folded structures, soft swimmers, apertures that open and close, bas relief patterns, and other shape transformations inspired by art and nature. In order to accommodate the large computational needs required to model these materials, our 3-d nonlinear finite element elastodynamics simulation algorithm is implemented in CUDA, running on a single GPU-enabled workstation.

Fabrication of miniature elastomer lenses with programmable liquid mold for smartphone microscopy: curing polydimethylsiloxane with in situ curvature control

NASA Astrophysics Data System (ADS)

Karunakaran, Bhuvaneshwari; Tharion, Joseph; Dhawangale, Arvind Ramrao; Paul, Debjani; Mukherji, Soumyo

2018-02-01

Miniature lenses can transform commercial imaging systems, e.g., smartphones and webcams, into powerful, low-cost, handheld microscopes. To date, the reproducible fabrication of polymer lenses is still a challenge as they require controlled dispensing of viscous liquid. This paper reports a reproducible lens fabrication technique using liquid mold with programmable curvature and off-the-shelf materials. The lens curvature is controlled during fabrication by tuning the curvature of an interface of two immiscible liquids [polydimethylsiloxane (PDMS) and glycerol]. The curvature control is implemented using a visual feedback system, which includes a software-based guiding system to produce lenses of desired curvature. The technique allows PDMS lens fabrication of a wide range of sizes and focal lengths, within 20 min. The fabrication of two lens diameters: 1 and 5 mm with focal lengths ranging between 1.2 and 11 mm are demonstrated. The lens surface and bulk quality check performed using X-ray microtomography and atomic force microscopy reveal that the lenses are suitable for optical imaging. Furthermore, a smartphone microscope with ˜1.4-μm resolution is developed using a self-assembly of a single high power fabricated lens and microaperture. The lenses have various potential applications, e.g., optofluidics, diagnostics, forensics, and surveillance.

On-demand generation and mixing of liquid-in-gas slugs with digitally-programmable composition and size

PubMed Central

Chen, Yi-Chun; Liu, Kan; Shen, Clifton Kwang-Fu; van Dam, R. Michael

2017-01-01

Microscopic droplets or slugs of mixed reagents provide a convenient platform for performing large numbers of isolated biochemical or chemical reactions for many screening and optimization applications. Myriad microfluidic approaches have emerged for creating droplets or slugs with controllable size and composition, generally using an immiscible carrier fluid to assist with the formation or merging processes. We report a novel device for generation of liquid slugs in air when the use of a carrier liquid is not compatible with the application. The slug generator contains two adjacent chambers, each of which has a volume that can be digitally adjusted by closing selected microvalves. Reagents are filled into the two chambers, merged together into a contiguous liquid slug, ejected at the desired time from the device using gas pressure, and mixed by flowing in a downstream channel. Programmable size and composition of slugs is achieved by dynamically adjusting the volume of each chamber prior to filling. Slug formation in this fashion is independent of fluid properties and can easily be scaled to mix larger numbers of reagents. This device has already been used to screen monomer ratios in supramolecular nanoparticle assembly and radiolabeling conditions of engineered antibodies, and here we provide a detailed description of the underlying device. PMID:29167603

Vacuum compatible, high-speed, 2-D mirror tilt stage

DOEpatents

Denham; Paul E.

2007-09-25

A compact and vacuum compatible magnetic-coil driven tiltable stage that is equipped with a high efficiency reflective coating can be employed as a scanner in EUV applications. The drive electronics for the scanner is fully in situ programmable and rapidly switchable.

Large-area Overhead Manipulator for Access of Fields

USDA-ARS?s Scientific Manuscript database

Multi-axis, cable-driven manipulators have evolved over many years providing large area suspended platform access, programmability, relatively rigid and flexibly-positioned platform control and full six degree of freedom (DOF) manipulation of sensors and tools. We describe innovations for a new six...

XPI: The Xanadu Parameter Interface

NASA Technical Reports Server (NTRS)

White, N.; Barrett, P.; Oneel, B.; Jacobs, P.

1992-01-01

XPI is a table driven parameter interface which greatly simplifies both command driven programs such as BROWSE and XIMAGE as well as stand alone single-task programs. It moves all of the syntax and semantic parsing of commands and parameters out of the users code into common code and externally defined tables. This allows the programmer to concentrate on writing the code unique to the application rather than reinventing the user interface and for external graphical interfaces to interface with no changes to the command driven program. XPI also includes a compatibility library which allows programs written using the IRAF host interface (Mandel and Roll) to use XPI in place of the IRAF host interface.

The impact of an international initiative on exposures to liquid laundry detergent capsules reported to the United Kingdom National Poisons Information Service between 2008 and 2015.

PubMed

Day, Rachael; Eddleston, Michael; Thomas, Simon H L; Thompson, John P; Vale, J Allister

2017-03-01

Although the majority of those exposed to liquid laundry detergent capsules remain asymptomatic or suffer only minor clinical features after exposure, a small proportion develop central nervous system depression, stridor, pulmonary aspiration and/or airway burns following ingestion or conjunctivitis and corneal ulceration following eye exposure. As a consequence, the International Association for Soaps, Detergents and Maintenance Products (AISE) established a Product Stewardship Programme in Europe, requiring that safety measures be implemented to reduce the visibility of, and restrict access to, these detergent capsules by small children. Implementation occurred in the United Kingdom over several months during the first half of 2013. This study investigated whether the AISE Programme had an impact on the number and severity of exposures reported to the United Kingdom National Poisons Information Service. Telephone enquiries to the National Poisons Information Service relating to liquid laundry detergent capsules were analysed for the period January 2008 to December 2015. While there was a significant difference (p = 0.0002) between the mean number of annual exposures (469.4) reported between 2008 and 2012 and the mean number reported between 2014 and 2015 (403.5), the number of exposures was decreasing steadily prior to implementation of the Programme in 2013, which did not impact this fall from 2013 onwards. In addition, the number of exposures per million units sold was not impacted by the Programme. There was no significant difference (p = 0.68) between the mean number of exposures (11.8) with PSS ≥2 reported between 2008 and 2012 and the mean number (13.0) reported between 2014 and 2015. Although there was a 28.7% decrease between 2010-2012 and 2014-2015 in the number of exposures with PSS ≥2 per million units sold, this decrease was not statistically significant (p = 0.18). There is no evidence that the Product Stewardship Programme had a beneficial impact on the number of exposures reported to the National Poisons Information Service or their severity.

Enhanced recovery clinical education programme improves quality of post-operative care.

PubMed

McDonald, Ruth

2015-01-01

Quality is the driving principle of Enhanced Recovery (ER). It improves the patient experience by getting patients better sooner and changes clinical practice to make care safer and more efficient. As a consequence of ER patients spend less time in hospital. A successful ER programme began to fail after organisational restructuring and staff changes. Patients did not meet their ER goals and length of stay (LOS) increased. An ER nurse was appointed to get the programme back on track. This involved a multidisciplinary approach to an ER clinical education programme. The programme aimed to develop knowledge of the physiology of post-operative recovery and the evidence underpinning the interventions required. This was considered crucial to secure longer term staff engagement while avoiding unthinking protocol driven compliance. Success of the education programme was measured by improved outcomes in patient LOS and readmission statistics. During the four months of the clinical education programme there were no significant changes in monthly LOS. At six months post implementation of the programme there was a reduction in LOS of 0.6 days compared to the previous six months. At 12 months there was a reduction in 1.1 days compared with previous 12 months. There was a mean reduction of 28 day readmissions for all elective gynaecology surgery of 1.1 patients per month in the 12 months post programme implementation compared to the 12 months before. Delivering a multidisciplinary participatory education programme improved overall understanding of ER, and achieved sustained improvement in ER for patient benefit.

Transition of vertically aligned liquid crystal driven by fan-shaped electric field

NASA Astrophysics Data System (ADS)

Tsung, J. W.; Ting, T. L.; Chen, C. Y.; Liang, W. L.; Lai, C. W.; Lin, T. H.; Hsu, W. H.

2017-09-01

Interdigital electrodes are implemented in many commercial and novel liquid crystal devices to align molecules. Although many empirical principles and patents apply to electrode design, only a few numerical simulations of alignment have been conducted. Why and how the molecules align in an ordered manner has never been adequately explained. Hence, this investigation addresses the Fréedericksz transition of vertically aligned liquid crystal that is driven by fishbone electrodes, and thereafter identifies the mechanism of liquid crystal alignment. Theoretical calculations suggest that the periodic deformation that is caused by the fan-shaped fringe field minimizes the free energy in the liquid crystal cell, and the optimal alignment can be obtained when the cell parameters satisfy the relation p /2 d =√{k11/k33 } , where p is the spatial period of the strips of the electrode; d denotes the cell gap; and k11 and k33 are the splay and bend elastic constants of the liquid crystal, respectively. Polymer-stabilized vertical alignment test cells with various p values and spacings between the electrodes were fabricated, and the process of liquid crystal alignment was observed under an optical microscope. The degree of alignment was evaluated by measuring the transmittance of the test cell. The experimental results were consistent with the theoretical predictions. The principle of design, p /2 d =√{k11/k33 } , greatly improves the uniformity and stability of the aligned liquid crystal. The methods that are presented here can be further applied to cholesteric liquid crystal and other self-assembled soft materials.

Long-Wavelength Rupturing Instability in Surface-Tension-Driven Benard Convection

NASA Technical Reports Server (NTRS)

Swift, J. B.; Hook, Stephen J. Van; Becerril, Ricardo; McCormick, W. D.; Swinney, H. L.; Schatz, Michael F.

1999-01-01

A liquid layer with a free upper surface and heated from below is subject to thermocapillary-induced convective instabilities. We use very thin liquid layers (0.01 cm) to significantly reduce buoyancy effects and simulate Marangoni convection in microgravity. We observe thermocapillary-driven convection in two qualitatively different modes, short-wavelength Benard hexagonal convection cells and a long-wavelength interfacial rupturing mode. We focus on the long-wavelength mode and present experimental observations and theoretical analyses of the long-wavelength instability. Depending on the depths and thermal conductivities of the liquid and the gas above it, the interface can rupture downwards and form a dry spot or rupture upwards and form a high spot. Linear stability theory gives good agreement to the experimental measurements of onset as long as sidewall effects are taken into account. Nonlinear theory correctly predicts the subcritical nature of the bifurcation and the selection between the dry spot and high spots.

Temperature-difference-driven mass transfer through the vapor from a cold to a warm liquid.

PubMed

Struchtrup, Henning; Kjelstrup, Signe; Bedeaux, Dick

2012-06-01

Irreversible thermodynamics provides interface conditions that yield temperature and chemical potential jumps at phase boundaries. The interfacial jumps allow unexpected transport phenomena, such as the inverted temperature profile [Pao, Phys. Fluids 14, 306 (1971)] and mass transfer from a cold to a warm liquid driven by a temperature difference across the vapor phase [Mills and Phillips, Chem. Phys. Lett. 372, 615 (2002)]. Careful evaluation of the thermodynamic laws has shown [Bedeaux et al., Physica A 169, 263 (1990)] that the inverted temperature profile is observed for processes with a high heat of vaporization. In this paper, we show that cold to warm mass transfer through the vapor from a cold to a warm liquid is only possible when the heat of evaporation is sufficiently small. A necessary criterium for the size of the mass transfer coefficient is given.

Low-thrust chemical propulsion system pump technology

NASA Technical Reports Server (NTRS)

Meadville, J. W.

1980-01-01

A study was conducted within the thrust range 450 to 9000 N (100 to 2000 pounds). Performance analyses were made on centrifugal, pitot, Barske, drag, Tesla, gear, piston, lobe, and vane pumps with liquid hydrogen, liquid methane, and liquid oxygen as propellants. Gaseous methane and hydrogen driven axial impulse turbines, vane expanders, piston expanders, and electric motors were studied as drivers. Data are presented on performance, sizes, weights, and estimated service lives and costs.

Experimental Investigation of Shear Driven Liquid Films for Film Cooling Applications in Liquid Rocket Engines

DTIC Science & Technology

2012-12-01

6 1.1.1 Differences Between Hot-Fire at Subcritical Conditions and Cold Flow ........10 1.1.2 Differences at Supercritical Conditions...cooling. 1.1.2 Differences at Supercritical Conditions Liquid film cooling is expected to behave even more differently at supercritical conditions...phase will behave more like the mixing of two gases of dissimilar densities. Once enough heat is imparted into the supercritical fuel film, it

Onset of space charge effects in liquid argon ionization chambers

NASA Astrophysics Data System (ADS)

Toggerson, B.; Newcomer, A.; Rutherfoord, J.; Walker, R. B.

2009-09-01

Using a thin-gap liquid argon ionization chamber and Strontium-90 beta sources we have measured ionization currents over a wide range of gap potentials. These precision "HV plateau curves" advance the understanding of liquid argon sampling calorimeter signals, particularly at high ionization rates. The order of magnitude differences in the activities of the beta sources allow us to estimate where the ionization chamber is driven into the space-charge dominated regime.

Light-driven liquid microlenses

NASA Astrophysics Data System (ADS)

Angelini, A.; Pirani, F.; Frascella, F.; Ricciardi, S.; Descrovi, E.

2017-02-01

We propose a liquid polymeric compound based on photo-responsive azo-polymers to be used as light-activated optical element with tunable and reversible functionalities. The interaction of a laser beam locally modifies the liquid density thus producing a refractive index gradient. The laser induced refractive index profiles are observed along the optical axis of the microscope to evaluate the total phase shift induced and along the orthogonal direction to provide the axial distribution of the refractive index variation. The focusing and imaging properties of the liquid lenses as functions of the light intensity are illustrated.

Numerical parametric studies of spray combustion instability

NASA Technical Reports Server (NTRS)

Pindera, M. Z.

1993-01-01

A coupled numerical algorithm has been developed for studies of combustion instabilities in spray-driven liquid rocket engines. The model couples gas and liquid phase physics using the method of fractional steps. Also introduced is a novel, efficient methodology for accounting for spray formation through direct solution of liquid phase equations. Preliminary parametric studies show marked sensitivity of spray penetration and geometry to droplet diameter, considerations of liquid core, and acoustic interactions. Less sensitivity was shown to the combustion model type although more rigorous (multi-step) formulations may be needed for the differences to become apparent.

Reconfigurable virtual electrowetting channels.

PubMed

Banerjee, Ananda; Kreit, Eric; Liu, Yuguang; Heikenfeld, Jason; Papautsky, Ian

2012-02-21

Lab-on-a-chip systems rely on several microfluidic paradigms. The first uses a fixed layout of continuous microfluidic channels. Such lab-on-a-chip systems are almost always application specific and far from a true "laboratory." The second involves electrowetting droplet movement (digital microfluidics), and allows two-dimensional computer control of fluidic transport and mixing. The merging of the two paradigms in the form of programmable electrowetting channels takes advantage of both the "continuous" functionality of rigid channels based on which a large number of applications have been developed to date and the "programmable" functionality of digital microfluidics that permits electrical control of on-chip functions. In this work, we demonstrate for the first time programmable formation of virtual microfluidic channels and their continuous operation with pressure driven flows using an electrowetting platform. Experimental, theoretical, and numerical analyses of virtual channel formation with biologically relevant electrolyte solutions and electrically-programmable reconfiguration are presented. We demonstrate that the "wall-less" virtual channels can be formed reliably and rapidly, with propagation rates of 3.5-3.8 mm s(-1). Pressure driven transport in these virtual channels at flow rates up to 100 μL min(-1) is achievable without distortion of the channel shape. We further demonstrate that these virtual channels can be switched on-demand between multiple inputs and outputs. Ultimately, we envision a platform that would provide rapid prototyping of microfluidic concepts and would be capable of a vast library of functions and benefitting applications from clinical diagnostics in resource-limited environments to rapid system prototyping to high throughput pharmaceutical applications.

Barriers and facilitators to initial and continued attendance at community‐based lifestyle programmes among families of overweight and obese children: a systematic review

PubMed Central

Davoren, M. P.; Harrington, J. M.; Shiely, F.; Perry, I. J.; McHugh, S. M.

2016-01-01

Summary The success of childhood weight management programmes relies on family engagement. While attendance offers many benefits including the support to make positive lifestyle changes, the majority of families referred to treatment decline. Moreover, for those who do attend, benefits are often compromised by high programme attrition. This systematic review investigated factors influencing attendance at community‐based lifestyle programmes among families of overweight or obese children. A narrative synthesis approach was used to allow for the inclusion of quantitative, qualitative and mixed‐method study designs. Thirteen studies met the inclusion criteria. Results suggest that parents provided the impetus for programme initiation, and this was driven largely by a concern for their child's psychological health and wellbeing. More often than not, children went along without any real reason or interest in attending. Over the course of the programme, however, children's positive social experiences such as having fun and making friends fostered the desire to continue. The stigma surrounding excess weight and the denial of the issue amongst some parents presented barriers to enrolment and warrant further study. This study provides practical recommendations to guide future policy makers, programme delivery teams and researchers in developing strategies to boost recruitment and minimise attrition. PMID:27862851

Unexpected Preferential Dehydration of Artemisinin in Ionic Liquids

NASA Astrophysics Data System (ADS)

Sanders, Marc W.; Wright, Lawrence; Tate, Lauren; Fairless, Gayle; Crowhurst, Lorna; Bruce, Neil C.; Walker, Adam J.; Hembury, Guy A.; Shimizu, Seishi

2009-09-01

Thermodynamic measurements (at 298 K) reveal that a crucial step in the extraction process of the key antimalarial drug artemisinin by ionic liquids (ILs), namely, precipitation through the addition of water, is driven by artemisinin dehydration due to the differences in the water's interaction with the bulk ILs, rather than with the artemisinin itself.

Solar-driven liquid metal magnetohydrodynamic generator

NASA Technical Reports Server (NTRS)

Lee, J. H.; Hohl, F.

1981-01-01

A solar oven heated by concentrated solar radiation as the heat source of a liquid metal magnetohydrodynamic (LMMHD) power generation system is proposed. The design allows the production of electric power in space, as well as on Earth, at high rates of efficiency. Two types of the solar oven suitable for the system are discussed.

Wetting in a Colloidal Liquid-Gas System

NASA Astrophysics Data System (ADS)

Wijting, W. K.; Besseling, N. A.; Stuart, M. A.

2003-05-01

We present first observations of wetting phenomena in depletion interaction driven, phase separated colloidal dispersions (coated silica cyclohexane-polydimethylsiloxane). The contact angle of the colloidal liquid-gas interface at a solid substrate (coated glass) was determined for a series of compositions. Upon approach to the critical point, a transition occurs from partial to complete wetting.

Wetting in a colloidal liquid-gas system.

PubMed

Wijting, W K; Besseling, N A M; Stuart, M A Cohen

2003-05-16

We present first observations of wetting phenomena in depletion interaction driven, phase separated colloidal dispersions (coated silica-cyclohexane-polydimethylsiloxane). The contact angle of the colloidal liquid-gas interface at a solid substrate (coated glass) was determined for a series of compositions. Upon approach to the critical point, a transition occurs from partial to complete wetting.

The effect of dry spots on heat transfer in a locally heated liquid film moving under the action of gas flow in a channel

NASA Astrophysics Data System (ADS)

Zaitsev, D. V.; Tkachenko, E. M.; Bykovskaya, E. F.

2017-11-01

Intensive evaporation of a thin liquid film, moving in a flat micro-/minichannel under the action of gas flow is very promising for the use in cooling systems of modern semiconductor devices with localized heat sources of high intensity. In this work, using the high-speed visualization, the effect of the formation of dry spots on heat transfer in a locally heated liquid film shear-driven in a channel was investigated. It was found that the maximum intensity of heat removal from the heater is achieved in the mode, when the film flow continuity is broken. During the experiment the total area of dry spots increases with increasing heat flux and heater temperature, but when the heater reaches a certain temperature (≈100°C), the total area begins to decrease. However, the length of contact line increases with increasing heat flux and reaches a maximum in the pre-crisis regime. Intensive evaporation in the region of the contact line may explain the achievement of high heat fluxes in the shear-driven liquid film.

Shuttle cryogenics supply system optimization study. Volume 5, B-3, part 2: Appendix to programmers manual for math model

NASA Technical Reports Server (NTRS)

1973-01-01

A computer programmer's manual for a digital computer which will permit rapid and accurate parametric analysis of current and advanced attitude control propulsion systems is presented. The concept is for a cold helium pressurized, subcritical cryogen fluid supplied, bipropellant gas-fed attitude control propulsion system. The cryogen fluids are stored as liquids under low pressure and temperature conditions. The mathematical model provides a generalized form for the procedural technique employed in setting up the analysis program.

Optical reversible programmable Boolean logic unit.

PubMed

Chattopadhyay, Tanay

2012-07-20

Computing with reversibility is the only way to avoid dissipation of energy associated with bit erase. So, a reversible microprocessor is required for future computing. In this paper, a design of a simple all-optical reversible programmable processor is proposed using a polarizing beam splitter, liquid crystal-phase spatial light modulators, a half-wave plate, and plane mirrors. This circuit can perform 16 logical operations according to three programming inputs. Also, inputs can be easily recovered from the outputs. It is named the "reversible programmable Boolean logic unit (RPBLU)." The logic unit is the basic building block of many complex computational operations. Hence the design is important in sense. Two orthogonally polarized lights are defined here as two logical states, respectively.

Programmable Liquid Crystal Elastomers Prepared by Thiol-Ene Photopolymerization (Postprint)

DTIC Science & Technology

2015-08-17

defect forms a 2D wrinkling pattern that leads to an areal contraction (Figure 4c,d). Both of these films return to a largely flat state on cooling...photopolymerization. ■ MATERIALS AND METHODS RM82 (1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylben- zene) was purchased from Synthon Chemicals. 1,2...noted. Liquid crystal cells were prepared using methods described elsewhere.10 Briefly for cells patterned using rubbed surfaces, Elvamide was

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction.

PubMed

Saed, Mohand O; Torbati, Amir H; Nair, Devatha P; Yakacki, Christopher M

2016-01-19

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline elastomers (LCEs) with facile control over network structure and programming of an aligned monodomain. Tailored LCE networks were synthesized using routine mixing of commercially available starting materials and pouring monomer solutions into molds to cure. An initial polydomain LCE network is formed via a self-limiting thiol-acrylate Michael-addition reaction. Strain-to-failure and glass transition behavior were investigated as a function of crosslinking monomer, pentaerythritol tetrakis(3-mercaptopropionate) (PETMP). An example non-stoichiometric system of 15 mol% PETMP thiol groups and an excess of 15 mol% acrylate groups was used to demonstrate the robust nature of the material. The LCE formed an aligned and transparent monodomain when stretched, with a maximum failure strain over 600%. Stretched LCE samples were able to demonstrate both stress-driven thermal actuation when held under a constant bias stress or the shape-memory effect when stretched and unloaded. A permanently programmed monodomain was achieved via a second-stage photopolymerization reaction of the excess acrylate groups when the sample was in the stretched state. LCE samples were photo-cured and programmed at 100%, 200%, 300%, and 400% strain, with all samples demonstrating over 90% shape fixity when unloaded. The magnitude of total stress-free actuation increased from 35% to 115% with increased programming strain. Overall, the two-stage TAMAP methodology is presented as a powerful tool to prepare main-chain LCE systems and explore structure-property-performance relationships in these fascinating stimuli-sensitive materials.

Fractionalized Fermi liquids and exotic superconductivity in the Kitaev-Kondo lattice

NASA Astrophysics Data System (ADS)

Seifert, Urban F. P.; Meng, Tobias; Vojta, Matthias

2018-02-01

Fractionalized Fermi liquids (FL*) have been introduced as non-Fermi-liquid metallic phases, characterized by coexisting electron-like charge carriers and local moments which form a fractionalized spin liquid. Here we investigate a Kondo lattice model on the honeycomb lattice with Kitaev interactions among the local moments, a concrete model hosting FL* phases based on Kitaev's Z2 spin liquid. We characterize the FL* phases via perturbation theory, and we employ a Majorana-fermion mean-field theory to map out the full phase diagram. Most remarkably we find nematic triplet superconducting phases which mask the quantum phase transition between fractionalized and conventional Fermi liquid phases. Their pairing structure is inherited from the Kitaev spin liquid; i.e., superconductivity is driven by Majorana glue.

Liquid on Paper: Rapid Prototyping of Soft Functional Components for Paper Electronics.

PubMed

Han, Yu Long; Liu, Hao; Ouyang, Cheng; Lu, Tian Jian; Xu, Feng

2015-07-01

This paper describes a novel approach to fabricate paper-based electric circuits consisting of a paper matrix embedded with three-dimensional (3D) microchannels and liquid metal. Leveraging the high electric conductivity and good flowability of liquid metal, and metallophobic property of paper, it is possible to keep electric and mechanical functionality of the electric circuit even after a thousand cycles of deformation. Embedding liquid metal into paper matrix is a promising method to rapidly fabricate low-cost, disposable, and soft electric circuits for electronics. As a demonstration, we designed a programmable displacement transducer and applied it as variable resistors and pressure sensors. The unique metallophobic property, combined with softness, low cost and light weight, makes paper an attractive alternative to other materials in which liquid metal are currently embedded.

Capacity building for hydrological change - using a blended learning approach

NASA Astrophysics Data System (ADS)

Nacken, H.

2015-04-01

Extreme hydrological events have always been a challenge to societies. There is growing evidence that hydrological extremes have already become more severe in some regions. The Middle East and North Africa (MENA) region is characterized as one of the world's most water-scarce and driest regions, with a high dependency on climate-sensitive agriculture. There is an urgent need for capacity building programmes that prepare water professionals and communities to deal with the expected hydrological changes and extremes. The most successful capacity building programmes are the country driven ones which involve a wide range of national stakeholders, have a high degree of in-country ownership and have an applicability character. The method of choice to set up such capacity building programmes will be through blended learning.

The Utility of Handheld Programmable Calculators in Aircraft Life Cycle Cost Estimation.

DTIC Science & Technology

1982-09-01

are available for extended mem - ory, hardcopy printout, video interface, and special application software. Any calculator of comparable memory could...condi- tioning system. OG Total number of engine, air turbine motor (ATM) and auxiliary power unit (APU) driven generator/alternators. OHP Total number

Physics Notes.

ERIC Educational Resources Information Center

School Science Review, 1981

1981-01-01

Outlines several laboratory procedures and demonstrations including electric fields using sawdust, experiments with capacitors, particle spacing in a vapor and a liquid, metrology, momentum, Moire patterns and interference fringes, equipping for practical electronics, and using programmable calculators for rapid plotting of graphs. (DS)

SENARIET, A Programme To Solve Transient Flows Of Liquids In Complex Circuits

NASA Astrophysics Data System (ADS)

Vargas-Munoz, M.; Rodriguez-Fernandez, M.; Perena-Tapiador, A.

2011-05-01

SENARIET is a programme to study fluid transients in pipeline systems in order to obtain pressure and velocity distributions along a circuit. When a transient process occurs in periods of the same order of the pressure waves’ travelling time along a circuit (the order of the circuit length divided by the effective propagation speed), the compressibility effects in liquids have to be considered. Taking this effect into account, the appropriate equations of continuity and momentum are solved by the method of characteristics, to obtain pressure and velocity along pipes as a function of time. The simulated results have been compared to theoretical and experimental ones to validate and evaluate the precision of the software. The results help to perform efficient and accurate predictions in order to define the propulsion sub-system. This type of analysis is very important in order to evaluate the water hammer effects in propulsion systems used on spacecrafts and launchers.

Electrogates for stop-and-go control of liquid flow in microfluidics

NASA Astrophysics Data System (ADS)

Arango, Y.; Temiz, Y.; Gökçe, O.; Delamarche, E.

2018-04-01

Diagnostics based on microfluidic devices necessitate specific reagents, flow conditions, and kinetics for optimal performance. Such an optimization is often achieved using assay-specific microfluidic chip designs or systems with external liquid pumps. Here, we present "electrogates" for stop-and-go control of flow of liquids in capillary-driven microfluidic chips by combining liquid pinning and electrowetting. Electrogates are simple to fabricate and efficient: a sample pipetted to a microfluidic chip flows autonomously in 15-μm-deep hydrophilic channels until the liquid meniscus is pinned at the edge of a 1.5-μm-deep trench patterned at the bottom of a rectangular microchannel. The flow can then be resumed by applying a DC voltage between the liquid and the trench via integrated electrodes. Using a trench geometry with a semicircular shape, we show that retention times longer than 30 min are achieved for various aqueous solutions such as biological buffers, artificial urine, and human serum. We studied the activation voltage and activation delay of electrogates using a chip architecture having 6 independent flow paths and experimentally showed that the flow can be resumed in less than 1 s for voltages smaller than 10 V, making this technique compatible with low-power and portable microfluidic systems. Electrogates therefore can make capillary-driven microfluidic chips very versatile by adding flow control in microfluidic channels in a flexible manner.

Heat-driven liquid metal cooling device for the thermal management of a computer chip

NASA Astrophysics Data System (ADS)

Ma, Kun-Quan; Liu, Jing

2007-08-01

The tremendous heat generated in a computer chip or very large scale integrated circuit raises many challenging issues to be solved. Recently, liquid metal with a low melting point was established as the most conductive coolant for efficiently cooling the computer chip. Here, by making full use of the double merits of the liquid metal, i.e. superior heat transfer performance and electromagnetically drivable ability, we demonstrate for the first time the liquid-cooling concept for the thermal management of a computer chip using waste heat to power the thermoelectric generator (TEG) and thus the flow of the liquid metal. Such a device consumes no external net energy, which warrants it a self-supporting and completely silent liquid-cooling module. Experiments on devices driven by one or two stage TEGs indicate that a dramatic temperature drop on the simulating chip has been realized without the aid of any fans. The higher the heat load, the larger will be the temperature decrease caused by the cooling device. Further, the two TEGs will generate a larger current if a copper plate is sandwiched between them to enhance heat dissipation there. This new method is expected to be significant in future thermal management of a desk or notebook computer, where both efficient cooling and extremely low energy consumption are of major concern.

In-drop capillary spooling of spider capture thread inspires hybrid fibers with mixed solid–liquid mechanical properties

PubMed Central

Elettro, Hervé; Neukirch, Sébastien; Vollrath, Fritz; Antkowiak, Arnaud

2016-01-01

An essential element in the web-trap architecture, the capture silk spun by ecribellate orb spiders consists of glue droplets sitting astride a silk filament. Mechanically this thread presents a mixed solid–liquid behavior unknown to date. Under extension, capture silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behavior in compression to now become liquid-like: It shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behavior of this ”liquid wire” and demonstrate that its mechanical response originates in the shape-switching of the silk filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured programmable liquid wires that present previously unidentified pathways for the design of new hybrid solid–liquid materials. PMID:27185930

A Microwave Thermostatic Reactor for Processing Liquid Materials Based on a Heat-Exchanger.

PubMed

Zhou, Yongqiang; Zhang, Chun; Xie, Tian; Hong, Tao; Zhu, Huacheng; Yang, Yang; Liu, Changjun; Huang, Kama

2017-10-08

Microwaves have been widely used in the treatment of different materials. However, the existing adjustable power thermostatic reactors cannot be used to analyze materials characteristics under microwave effects. In this paper, a microwave thermostatic chemical reactor for processing liquid materials is proposed, by controlling the velocity of coolant based on PLC (programmable logic controller) in different liquid under different constant electric field intensity. A nonpolar coolant (Polydimethylsiloxane), which is completely microwave transparent, is employed to cool the liquid materials. Experiments are performed to measure the liquid temperature using optical fibers, the results show that the precision of temperature control is at the range of ±0.5 °C. Compared with the adjustable power thermostatic control system, the effect of electric field changes on material properties are avoided and it also can be used to detect the properties of liquid materials and special microwave effects.

A Microwave Thermostatic Reactor for Processing Liquid Materials Based on a Heat-Exchanger

PubMed Central

Zhou, Yongqiang; Zhang, Chun; Xie, Tian; Hong, Tao; Yang, Yang; Liu, Changjun; Huang, Kama

2017-01-01

Microwaves have been widely used in the treatment of different materials. However, the existing adjustable power thermostatic reactors cannot be used to analyze materials characteristics under microwave effects. In this paper, a microwave thermostatic chemical reactor for processing liquid materials is proposed, by controlling the velocity of coolant based on PLC (programmable logic controller) in different liquid under different constant electric field intensity. A nonpolar coolant (Polydimethylsiloxane), which is completely microwave transparent, is employed to cool the liquid materials. Experiments are performed to measure the liquid temperature using optical fibers, the results show that the precision of temperature control is at the range of ±0.5 °C. Compared with the adjustable power thermostatic control system, the effect of electric field changes on material properties are avoided and it also can be used to detect the properties of liquid materials and special microwave effects. PMID:28991195

In-drop capillary spooling of spider capture thread inspires hybrid fibers with mixed solid-liquid mechanical properties.

PubMed

Elettro, Hervé; Neukirch, Sébastien; Vollrath, Fritz; Antkowiak, Arnaud

2016-05-31

An essential element in the web-trap architecture, the capture silk spun by ecribellate orb spiders consists of glue droplets sitting astride a silk filament. Mechanically this thread presents a mixed solid-liquid behavior unknown to date. Under extension, capture silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behavior in compression to now become liquid-like: It shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behavior of this "liquid wire" and demonstrate that its mechanical response originates in the shape-switching of the silk filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured programmable liquid wires that present previously unidentified pathways for the design of new hybrid solid-liquid materials.

In-drop capillary spooling of spider capture thread inspires hybrid fibers with mixed solid-liquid mechanical properties

NASA Astrophysics Data System (ADS)

Elettro, Hervé; Neukirch, Sébastien; Vollrath, Fritz; Antkowiak, Arnaud

2016-05-01

An essential element in the web-trap architecture, the capture silk spun by ecribellate orb spiders consists of glue droplets sitting astride a silk filament. Mechanically this thread presents a mixed solid-liquid behavior unknown to date. Under extension, capture silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behavior in compression to now become liquid-like: It shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behavior of this ”liquid wire” and demonstrate that its mechanical response originates in the shape-switching of the silk filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured programmable liquid wires that present previously unidentified pathways for the design of new hybrid solid-liquid materials.

Systems and methods for analyzing liquids under vacuum

DOEpatents

Yu, Xiao-Ying; Yang, Li; Cowin, James P.; Iedema, Martin J.; Zhu, Zihua

2013-10-15

Systems and methods for supporting a liquid against a vacuum pressure in a chamber can enable analysis of the liquid surface using vacuum-based chemical analysis instruments. No electrical or fluid connections are required to pass through the chamber walls. The systems can include a reservoir, a pump, and a liquid flow path. The reservoir contains a liquid-phase sample. The pump drives flow of the sample from the reservoir, through the liquid flow path, and back to the reservoir. The flow of the sample is not substantially driven by a differential between pressures inside and outside of the liquid flow path. An aperture in the liquid flow path exposes a stable portion of the liquid-phase sample to the vacuum pressure within the chamber. The radius, or size, of the aperture is less than or equal to a critical value required to support a meniscus of the liquid-phase sample by surface tension.

Enhanced recovery clinical education programme improves quality of post-operative care

PubMed Central

McDonald, Ruth

2015-01-01

Quality is the driving principle of Enhanced Recovery (ER). It improves the patient experience by getting patients better sooner and changes clinical practice to make care safer and more efficient. As a consequence of ER patients spend less time in hospital. A successful ER programme began to fail after organisational restructuring and staff changes. Patients did not meet their ER goals and length of stay (LOS) increased. An ER nurse was appointed to get the programme back on track. This involved a multidisciplinary approach to an ER clinical education programme. The programme aimed to develop knowledge of the physiology of post-operative recovery and the evidence underpinning the interventions required. This was considered crucial to secure longer term staff engagement while avoiding unthinking protocol driven compliance. Success of the education programme was measured by improved outcomes in patient LOS and readmission statistics. During the four months of the clinical education programme there were no significant changes in monthly LOS. At six months post implementation of the programme there was a reduction in LOS of 0.6 days compared to the previous six months. At 12 months there was a reduction in 1.1 days compared with previous 12 months. There was a mean reduction of 28 day readmissions for all elective gynaecology surgery of 1.1 patients per month in the 12 months post programme implementation compared to the 12 months before. Delivering a multidisciplinary participatory education programme improved overall understanding of ER, and achieved sustained improvement in ER for patient benefit. PMID:26734343

Mexico's conditional cash transfer programme increases cesarean section rates among the rural poor.

PubMed

Barber, Sarah L

2010-08-01

Caesarean section rates are increasing in Mexico and Latin America. This study evaluates the impact of a large-scale, conditional cash transfer programme in Mexico on caesarean section rates. The programme provides cash transfers to participating low income, rural households in Mexico conditional on accepting health care and nutrition supplements. The primary analyses uses retrospective reports from 979 women in poor rural communities participating in an effectiveness study and randomly assigned to incorporation into the programme in 1998 or 1999 across seven Mexican states. Using multivariate and instrumental variable analyses, we estimate the impact of the programme on caesarean sections and predict the adjusted mean rates by clinical setting. Programme participation is measured by beneficiary status, programme months and cash transfers. More than two-thirds of poor rural women delivered in a health facility. Beneficiary status is associated with a 5.1 percentage point increase in caesarean rates; this impact increases to 7.5 percentage points for beneficiaries enrolled in the programme for >or=6 months before delivery. Beneficiaries had significantly higher caesarean delivery rates in social security facilities (24.0 compared with 5.6% among non-beneficiaries) and in other government facilities (19.3 compared with 9.5%). The Oportunidades conditional cash transfer programme is associated with higher caesarean section rates in social security and government health facilities. This effect appears to be driven by the increases in disposable income from the cash transfer. These findings are relevant to other countries implementing conditional cash transfer programmes and health care requirements.

Elasticity-driven partial demixing in cholesteric liquid crystal films.

PubMed

Schmidtke, Jürgen; Coles, Harry J

2009-07-01

We discuss the partial demixing of a chiral nematic mixture of a chiral and an achiral compound, induced by inhomogeneous confinement between substrates. While the effect is tiny in low molar mass mixtures, it is predicted to be noticeable in polymeric systems. The potential of the effect for improving performance of liquid crystal based photonic devices is discussed.

75 FR 42740 - Ryckman Creek Resources, LLC; Notice of Intent To Prepare an Environmental Assessment for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-22

.... Create a central gas/liquids separation facility (Ryckman Plant) where all of the gas pipelines meet. It would contain a small electric-driven compressor to compress casing head gas, liquids separation... Convenience and Necessity under section 7 of the Natural Gas Act. The Bureau of Land Management (BLM) is...

Anomalous contact angle hysteresis of a captive bubble: advancing contact line pinning.

PubMed

Hong, Siang-Jie; Chang, Feng-Ming; Chou, Tung-He; Chan, Seong Heng; Sheng, Yu-Jane; Tsao, Heng-Kwong

2011-06-07

Contact angle hysteresis of a sessile drop on a substrate consists of continuous invasion of liquid phase with the advancing angle (θ(a)) and contact line pinning of liquid phase retreat until the receding angle (θ(r)) is reached. Receding pinning is generally attributed to localized defects that are more wettable than the rest of the surface. However, the defect model cannot explain advancing pinning of liquid phase invasion driven by a deflating bubble and continuous retreat of liquid phase driven by the inflating bubble. A simple thermodynamic model based on adhesion hysteresis is proposed to explain anomalous contact angle hysteresis of a captive bubble quantitatively. The adhesion model involves two solid–liquid interfacial tensions (γ(sl) > γ(sl)′). Young’s equation with γ(sl) gives the advancing angle θ(a) while that with γ(sl)′ due to surface rearrangement yields the receding angle θ(r). Our analytical analysis indicates that contact line pinning represents frustration in surface free energy, and the equilibrium shape corresponds to a nondifferential minimum instead of a local minimum. On the basis of our thermodynamic model, Surface Evolver simulations are performed to reproduce both advancing and receding behavior associated with a captive bubble on the acrylic glass.

Fabrication of miniature elastomer lenses with programmable liquid mold for smartphone microscopy: curing polydimethylsiloxane with in situ curvature control.

PubMed

Karunakaran, Bhuvaneshwari; Tharion, Joseph; Dhawangale, Arvind Ramrao; Paul, Debjani; Mukherji, Soumyo

2018-02-01

Miniature lenses can transform commercial imaging systems, e.g., smartphones and webcams, into powerful, low-cost, handheld microscopes. To date, the reproducible fabrication of polymer lenses is still a challenge as they require controlled dispensing of viscous liquid. This paper reports a reproducible lens fabrication technique using liquid mold with programmable curvature and off-the-shelf materials. The lens curvature is controlled during fabrication by tuning the curvature of an interface of two immiscible liquids [polydimethylsiloxane (PDMS) and glycerol]. The curvature control is implemented using a visual feedback system, which includes a software-based guiding system to produce lenses of desired curvature. The technique allows PDMS lens fabrication of a wide range of sizes and focal lengths, within 20 min. The fabrication of two lens diameters: 1 and 5 mm with focal lengths ranging between 1.2 and 11 mm are demonstrated. The lens surface and bulk quality check performed using X-ray microtomography and atomic force microscopy reveal that the lenses are suitable for optical imaging. Furthermore, a smartphone microscope with ∼1.4-μm resolution is developed using a self-assembly of a single high power fabricated lens and microaperture. The lenses have various potential applications, e.g., optofluidics, diagnostics, forensics, and surveillance. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Faculty Perspectives on Programme Curricular Assessment: Individual and Institutional Characteristics That Influence Participation Engagement

ERIC Educational Resources Information Center

Emil, Serap; Cress, Christine

2014-01-01

Driven by issues of accountability, the assessment movement in higher education has gained significant momentum in recent years. However, successful implementation of assessment processes varies radically across institutions. A key issue is faculty engagement. This qualitative inquiry explored factors that impact faculty participation in a…

Modeling Student Software Testing Processes: Attitudes, Behaviors, Interventions, and Their Effects

ERIC Educational Resources Information Center

Buffardi, Kevin John

2014-01-01

Effective software testing identifies potential bugs and helps correct them, producing more reliable and maintainable software. As software development processes have evolved, incremental testing techniques have grown in popularity, particularly with introduction of test-driven development (TDD). However, many programmers struggle to adopt TDD's…

Cost and impact of a quality improvement programme in mental health services.

PubMed

Beecham, Jennifer; Ramsay, Angus; Gordon, Kate; Maltby, Sophie; Walshe, Kieran; Shaw, Ian; Worrall, Adrian; King, Sarah

2010-04-01

To estimate the cost and impact of a centrally-driven quality improvement initiative in four UK mental health communities. Total costs in year 1 were identified using documentation, a staff survey, semi-structured interviews and discussion groups. Few outcome data were collected within the programme so thematic analysis was used to identify the programme's impact within its five broad underlying principles. The survey had a 40% response. Total costs ranged between pound164,000 and pound458,000 per site, plus staff time spent on workstreams. There was a very hazy view of the resources absorbed and poor recording of expenditure and activity. The initiative generated little demonstrable improvements in service quality but some participants reported changes in attitudes. Given the difficult contexts, short time-scales and capacity constraints, the programme's lack of impact is not surprising. It may, however, represent a worthwhile investment in cultural change which might facilitate improvements in how services are delivered.

Multichannel optical sensing device

DOEpatents

Selkowitz, S.E.

1985-08-16

A multichannel optical sensing device is disclosed, for measuring the outdoor sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optical elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

Multichannel optical sensing device

DOEpatents

Selkowitz, Stephen E.

1990-01-01

A multichannel optical sensing device is disclosed, for measuring the outr sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optic elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

Hole growth dynamics in a two dimensional Leidenfrost droplet

NASA Astrophysics Data System (ADS)

Raufaste, Christophe; Celestini, Franck; Barzyk, Alexandre; Frisch, Thomas

2015-03-01

We studied the behaviors of Leidenfrost droplets confined in a Hele-Shaw cell. These droplets are unstable above a critical size and a hole grows at their center. We experimentally investigate two different systems for which the hole growth dynamics exhibits peculiar features that are driven by capillarity and inertia. We report a first regime characterized by the liquid reorganization from a liquid sheet to a liquid torus with similarities to the burst of micron-thick soap films. In the second regime, the liquid torus expands and thins before fragmentation. Finally, we propose models to account for the experimental results.

A novel productivity-driven logic element for field-programmable devices

NASA Astrophysics Data System (ADS)

Marconi, Thomas; Bertels, Koen; Gaydadjiev, Georgi

2014-06-01

Although various techniques have been proposed for power reduction in field-programmable devices (FPDs), they are still all based on conventional logic elements (LEs). In the conventional LE, the output of the combinational logic (e.g. the look-up table (LUT) in many field-programmable gate arrays (FPGAs)) is connected to the input of the storage element; while the D flip-flop (DFF) is always clocked even when not necessary. Such unnecessary transitions waste power. To address this problem, we propose a novel productivity-driven LE with reduced number of transitions. The differences between our LE and the conventional LE are in the FFs-type used and the internal LE organisation. In our LEs, DFFs have been replaced by T flip-flops with the T input permanently connected to logic value 1. Instead of connecting the output of the combinational logic to the FF input, we use it as the FF clock. The proposed LE has been validated via Simulation Program with Integrated Circuit Emphasis (SPICE) simulations for a 45-nm Complementary Metal-Oxide-Semiconductor (CMOS) technology as well as via a real Computer-Aided Design (CAD) tools on a real FPGA using the standard Microelectronic Center of North Carolina (MCNC) benchmark circuits. The experimental results show that FPDs using our proposal not only have 48% lower total power but also run 17% faster than conventional FPDs on average.

Teaching an engine-driven preparation technique to undergraduates: initial observations.

PubMed

Hänni, S; Schönenberger, K; Peters, O A; Barbakow, F

2003-07-01

This paper describes the initial experiences following the introduction of a rotary engine-driven preparation technique into the undergraduate endodontic programme at the Zurich University Dental Centre. Forty third-year students practised the ProFile.04 (PF.04) technique between January and July 2001 in a preclinical course. Between November 2001 and February 2002, 20 of these students (Group A) root-treated 51 teeth in their clinical course using either PF.04, the balanced force technique (BFT) or a combination of both. The second group of 20 students (Group B) similarly treated another 36 randomly selected teeth between April and July 2002. Types of teeth treated by the students and the canal preparation techniques were recorded. The students also completed a short questionnaire, evaluating their opinions of the new course. Of the 87 teeth endodontically treated during the clinical course, 34, 14 and 39 were shaped using PF.04 alone, a combination of PF.04 and BFT and BFT alone, respectively. No rotary instruments were fractured during the 1-year clinical course, although some instruments were fractured during the preclinical laboratory course. Overall, the students rated the rotary technique as positive. A rotary technique was successfully introduced into an undergraduate endodontic programme (this will be continued in the foreseeable future). However, the continuity between the preclinical and the clinical courses was poor as a result of the constraints of the general teaching programme.

Supercritical-assistant liquid crystal template approach to synthesize mesoporous titania/multiwalled carbon nanotube composites with high visible-light driven photocatalytic performance

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

Liu, Chen; Li, Youji, E-mail: bcclyj@163.com; Xu, Peng

2014-12-15

Graphical abstract: We investigate the influence of mesoporous titania content upon the visible-light driven photocatalytic performance of MPT/MWCNTs in phenol degradation. - Highlights: • MPT/MWCNTs were fabricated by liquid-crystal template in supercritical CO{sub 2}. • MPT/MWCNTs show high visible-light driven photoactivity for phenol degradation. • MPT/MWCNTs also show high reusable photoactivity under visible irradiation. • MPT content can control visible-light driven photoactivity of MPT/MWCNTs. • MPT is not easily broken away from from MPT/MWCNT composites. - Abstract: Mesoporous titania (MPT) was deposited onto multiwalled carbon nanotubes (MWCNTs) by deposition of titanium sol containing liquid-crystal template with assistant of supercritical CO{submore » 2}. The products were characterized with various analytical techniques to determine their structural, morphological, optical absorption and photocatalytic properties. The results indicate that in photocatalytic degradation of phenol under visible light, the mixtures or composites of MPT and MWCNT show the high efficiency because of synergies between absorbing visible light, releasing electrons and facilitating transfer of charge carriers of MWCNTs and providing activated centers of MPT. Because of the mutual constraint between MPT and MWCNTs on the photocatalytic efficiency, the optimal loading of MPT in MPT/MWCNT-3 for phenol degradation is 48%. Because the intimate contact between MWCNTs and MPT is more beneficial to electron transformation, photoactivity of mixture is lower than that of composites with high reusable performance. The optimum conditions of phenol degradation were obtained.« less

Liquid on Paper: Rapid Prototyping of Soft Functional Components for Paper Electronics

PubMed Central

Long Han, Yu; Liu, Hao; Ouyang, Cheng; Jian Lu, Tian; Xu, Feng

2015-01-01

This paper describes a novel approach to fabricate paper-based electric circuits consisting of a paper matrix embedded with three-dimensional (3D) microchannels and liquid metal. Leveraging the high electric conductivity and good flowability of liquid metal, and metallophobic property of paper, it is possible to keep electric and mechanical functionality of the electric circuit even after a thousand cycles of deformation. Embedding liquid metal into paper matrix is a promising method to rapidly fabricate low-cost, disposable, and soft electric circuits for electronics. As a demonstration, we designed a programmable displacement transducer and applied it as variable resistors and pressure sensors. The unique metallophobic property, combined with softness, low cost and light weight, makes paper an attractive alternative to other materials in which liquid metal are currently embedded. PMID:26129723

Highly efficient and ultra-small volume separation by pressure-driven liquid chromatography in extended nanochannels.

PubMed

Ishibashi, Ryo; Mawatari, Kazuma; Kitamori, Takehiko

2012-04-23

The rapidly developing interest in nanofluidic analysis, which is used to examine liquids ranging in amounts from the attoliter to the femtoliter scale, correlates with the recent interest in decreased sample amounts, such as in the field of single-cell analysis. For general nanofluidic analysis, the fact that a pressure-driven flow does not limit the choice of solvents (aqueous or organic) is important. This study shows the first pressure-driven liquid chromatography technique that enables separation of atto- to femtoliter sample volumes, with a high separation efficiency within a few seconds. The apparent diffusion coefficient measurement of the unretentive sample suggests that there is no increase in the viscosity of toluene in the extended nanospace, unlike in aqueous solvents. Evaluation of the normal phase separation, therefore, should involve only the examination of the effect of the small size of the extended nanospace. Compared to a conventionally packed high-performance liquid chromatography column, the separation here results in a faster separation (4 s) by 2 orders of magnitude, a smaller injection volume (10(0) fL) by 9 orders, and a higher separation efficiency (440,000 plates/m) by 1 order. Moreover, the separation behavior agrees with the theory showing that this high efficiency was due to the small and controlled size of the separation channel, where the diffusion through the channel depth direction is fast enough to be neglected. Our chip-based platform should allow direct and real-time analysis or screening of ultralow volume of sample. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advanced SLMs for microscopy

NASA Astrophysics Data System (ADS)

Linnenberger, A.

2018-02-01

Wavefront shaping devices such as deformable mirrors, liquid crystal spatial light modulators (SLMs), and active lenses are of considerable interest in microscopy for aberration correction, volumetric imaging, and programmable excitation. Liquid crystal SLMs are high resolution phase modulators capable of creating complex phase profiles to reshape, or redirect light within a three-dimensional (3D) volume. Recent advances in Meadowlark Optics (MLO) SLMs reduce losses by increasing fill factor from 83.4% to 96%, and improving resolution from 512 x 512 pixels to 1920 x 1152 pixels while maintaining a liquid crystal response time of 300 Hz at 1064 nm. This paper summarizes new SLM capabilities, and benefits for microscopy.

Barriers and facilitators to initial and continued attendance at community-based lifestyle programmes among families of overweight and obese children: a systematic review.

PubMed

Kelleher, E; Davoren, M P; Harrington, J M; Shiely, F; Perry, I J; McHugh, S M

2017-02-01

The success of childhood weight management programmes relies on family engagement. While attendance offers many benefits including the support to make positive lifestyle changes, the majority of families referred to treatment decline. Moreover, for those who do attend, benefits are often compromised by high programme attrition. This systematic review investigated factors influencing attendance at community-based lifestyle programmes among families of overweight or obese children. A narrative synthesis approach was used to allow for the inclusion of quantitative, qualitative and mixed-method study designs. Thirteen studies met the inclusion criteria. Results suggest that parents provided the impetus for programme initiation, and this was driven largely by a concern for their child's psychological health and wellbeing. More often than not, children went along without any real reason or interest in attending. Over the course of the programme, however, children's positive social experiences such as having fun and making friends fostered the desire to continue. The stigma surrounding excess weight and the denial of the issue amongst some parents presented barriers to enrolment and warrant further study. This study provides practical recommendations to guide future policy makers, programme delivery teams and researchers in developing strategies to boost recruitment and minimise attrition. © 2016 The Authors. Obesity Reviews published by John Wiley & Sons Ltd on behalf of World Obesity Federation.

Good on paper: the gap between programme theory and real-world context in Pakistan's Community Midwife programme.

PubMed

Mumtaz, Z; Levay, A; Bhatti, A; Salway, S

2015-01-01

To understand why skilled birth attendance-an acknowledged strategy for reducing maternal deaths-has been effective in some settings but is failing in Pakistan and to demonstrate the value of a theory-driven approach to evaluating implementation of maternal healthcare interventions. Implementation research was conducted using an institutional ethnographic approach. National programme and local community levels in Pakistan. Observations, focus group discussions, and in-depth interviews were conducted with 38 Community Midwives (CMWs), 20 policymakers, 45 healthcare providers and 136 community members. A critical policy document review was conducted. National and local level data were brought together. Alignment of programme theory with real-world practice. Data revealed gaps between programme theory, assumptions and reality on the ground. The design of the programme failed to take into account: (1) the incongruity between the role of a midwife and dominant class and gendered norms that devalue such a role; (2) market and consumer behaviour that prevented CMWs from establishing private practices; (3) the complexity of public-private sector cooperation. Uniform deployment policies failed to consider existing provider density and geography. Greater attention to programme theory and the 'real-world' setting during design of maternal health strategies is needed to achieve consistent results in different contexts. © 2014 The Authors. BJOG An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists.

Good on paper: the gap between programme theory and real-world context in Pakistan's Community Midwife programme

PubMed Central

Mumtaz, Z; Levay, A; Bhatti, A; Salway, S

2015-01-01

Objective To understand why skilled birth attendance—an acknowledged strategy for reducing maternal deaths—has been effective in some settings but is failing in Pakistan and to demonstrate the value of a theory-driven approach to evaluating implementation of maternal healthcare interventions. Design Implementation research was conducted using an institutional ethnographic approach. Setting and population National programme and local community levels in Pakistan. Methods Observations, focus group discussions, and in-depth interviews were conducted with 38 Community Midwives (CMWs), 20 policymakers, 45 healthcare providers and 136 community members. A critical policy document review was conducted. National and local level data were brought together. Main outcomes Alignment of programme theory with real-world practice. Results Data revealed gaps between programme theory, assumptions and reality on the ground. The design of the programme failed to take into account: (1) the incongruity between the role of a midwife and dominant class and gendered norms that devalue such a role; (2) market and consumer behaviour that prevented CMWs from establishing private practices; (3) the complexity of public–private sector cooperation. Uniform deployment policies failed to consider existing provider density and geography. Conclusions Greater attention to programme theory and the ‘real-world’ setting during design of maternal health strategies is needed to achieve consistent results in different contexts. PMID:25315837

A Liquid Optical Phase Shifter with an Embedded Electrowetting Actuator

PubMed Central

Ashtiani, Alireza Ousati; Jiang, Hongrui

2017-01-01

We demonstrate an electrowetting-based liquid optical phase shifter. The phase shifter consists of two immiscible liquid layers with different refractive indices. Sandwiched between the two liquids is a rigid membrane that moves freely along the optical axis and supported by a compliant surround. When applied with a pressure, the thicknesses of both liquid layers change, which induces a difference in optical path, resulting in a phase shift. A miniaturized electrowetting-based actuator is used to produce hydraulic pressure. A multi-layered SU8 bonded structure was fabricated. A phase shift of 171° was observed when the device was incorporated in a Mach-Zehnder interferometer and driven with 100 V. PMID:29038640

Dynamic simulations of under-rib convection-driven flow-field configurations and comparison with experiment in polymer electrolyte membrane fuel cells

NASA Astrophysics Data System (ADS)

Duy, Vinh Nguyen; Lee, Jungkoo; Kim, Kyungcheol; Ahn, Jiwoong; Park, Seongho; Kim, Taeeun; Kim, Hyung-Man

2015-10-01

The under-rib convection-driven flow-field design for the uniform distribution of reacting gas and the generation of produced water generates broad scientific interest, especially among those who study the performance of polymer electrolyte membrane fuel cells (PEMFCs). In this study, we simulate the effects of an under-rib convection-driven serpentine flow-field with sub-channel and by-pass (SFFSB) and a conventional advanced serpentine flow-field (CASFF) on single cell performance, and we compare the simulation results with experimental measurements. In the under-rib convection-driven flow-field configuration with SFFSB, the pressure drop is decreased because of the greater cross-sectional area for gas flow, and the decreased pressure drop results in the reduction of the parasitic loss. The anode liquid water mass fraction increases with increasing channel height because of increased back diffusion, while the cathode liquid water mass fraction does not depend upon the sub-channels but is ascribed mainly to the electro-osmotic drag. Simulation results verify that the maximum current and the power densities of the SFFSB are increased by 18.85% and 23.74%, respectively, due to the promotion of under-rib convection. The findings in this work may enable the optimization of the design of under-rib convection-driven flow-fields for efficient PEMFCs.

Input variable selection for data-driven models of Coriolis flowmeters for two-phase flow measurement

NASA Astrophysics Data System (ADS)

Wang, Lijuan; Yan, Yong; Wang, Xue; Wang, Tao

2017-03-01

Input variable selection is an essential step in the development of data-driven models for environmental, biological and industrial applications. Through input variable selection to eliminate the irrelevant or redundant variables, a suitable subset of variables is identified as the input of a model. Meanwhile, through input variable selection the complexity of the model structure is simplified and the computational efficiency is improved. This paper describes the procedures of the input variable selection for the data-driven models for the measurement of liquid mass flowrate and gas volume fraction under two-phase flow conditions using Coriolis flowmeters. Three advanced input variable selection methods, including partial mutual information (PMI), genetic algorithm-artificial neural network (GA-ANN) and tree-based iterative input selection (IIS) are applied in this study. Typical data-driven models incorporating support vector machine (SVM) are established individually based on the input candidates resulting from the selection methods. The validity of the selection outcomes is assessed through an output performance comparison of the SVM based data-driven models and sensitivity analysis. The validation and analysis results suggest that the input variables selected from the PMI algorithm provide more effective information for the models to measure liquid mass flowrate while the IIS algorithm provides a fewer but more effective variables for the models to predict gas volume fraction.

Structural and evaporative evolutions in desiccating sessile drops of blood

NASA Astrophysics Data System (ADS)

Sobac, B.; Brutin, D.

2011-07-01

We report an experimental investigation of the drying of a deposited drop of whole blood. Flow motion, adhesion, gelation, and fracturation all occur during the evaporation of this complex matter, leading to a final typical pattern. Two distinct regimes of evaporation are highlighted: the first is driven by convection, diffusion, and gelation in a liquid phase, whereas the second, with a much slower rate of evaporation, is characterized by the mass transport of the liquid left over in the gellified biocomponent matter. A diffusion model of the drying process allows a prediction of the transition between these two regimes of evaporation. Moreover, the formation of cracks and other events occurring during the drying are examined and shown to be driven by critical solid mass concentrations.

Rigorous analysis of an electric-field-driven liquid crystal lens for 3D displays

NASA Astrophysics Data System (ADS)

Kim, Bong-Sik; Lee, Seung-Chul; Park, Woo-Sang

2014-08-01

We numerically analyzed the optical performance of an electric field driven liquid crystal (ELC) lens adopted for 3-dimensional liquid crystal displays (3D-LCDs) through rigorous ray tracing. For the calculation, we first obtain the director distribution profile of the liquid crystals by using the Erickson-Leslie motional equation; then, we calculate the transmission of light through the ELC lens by using the extended Jones matrix method. The simulation was carried out for a 9view 3D-LCD with a diagonal of 17.1 inches, where the ELC lens was slanted to achieve natural stereoscopic images. The results show that each view exists separately according to the viewing position at an optimum viewing distance of 80 cm. In addition, our simulation results provide a quantitative explanation for the ghost or blurred images between views observed from a 3D-LCD with an ELC lens. The numerical simulations are also shown to be in good agreement with the experimental results. The present simulation method is expected to provide optimum design conditions for obtaining natural 3D images by rigorously analyzing the optical functionalities of an ELC lens.

Multi-Mission Power Analysis Tool (MMPAT) Version 3

NASA Technical Reports Server (NTRS)

Wood, Eric G.; Chang, George W.; Chen, Fannie C.

2012-01-01

The Multi-Mission Power Analysis Tool (MMPAT) simulates a spacecraft power subsystem including the power source (solar array and/or radioisotope thermoelectric generator), bus-voltage control, secondary battery (lithium-ion or nickel-hydrogen), thermostatic heaters, and power-consuming equipment. It handles multiple mission types including heliocentric orbiters, planetary orbiters, and surface operations. Being parametrically driven along with its user-programmable features can reduce or even eliminate any need for software modifications when configuring it for a particular spacecraft. It provides multiple levels of fidelity, thereby fulfilling the vast majority of a project s power simulation needs throughout the lifecycle. It can operate in a stand-alone mode with a graphical user interface, in batch mode, or as a library linked with other tools. This software can simulate all major aspects of a spacecraft power subsystem. It is parametrically driven to reduce or eliminate the need for a programmer. Added flexibility is provided through user-designed state models and table-driven parameters. MMPAT is designed to be used by a variety of users, such as power subsystem engineers for sizing power subsystem components; mission planners for adjusting mission scenarios using power profiles generated by the model; system engineers for performing system- level trade studies using the results of the model during the early design phases of a spacecraft; and operations personnel for high-fidelity modeling of the essential power aspect of the planning picture.

Light-driven OR and XOR programmable chemical logic gates.

PubMed

Szaciłowski, Konrad; Macyk, Wojciech; Stochel, Grazyna

2006-04-12

Photoelectrodes made of nanocrystalline titanium dioxide modified with various pentacyanoferrates exhibit unique photoelectrochemical properties; photocurrent direction can be switched from anodic to cathodic and vice versa upon changes in photoelectrode potential and incident light wavelength (PhotoElectrochemical Photocurrent Switching, PEPS effect). At certain potentials, anodic photocurrent generated upon UV irradiation has the same intensity as the cathodic photocurrent generated upon visible irradiation. Under these conditions, simultaneous irradiation with UV and visible light results in compensation of anodic and cathodic photocurrents, and zero net photocurrent is observed. This process can be used for construction of unique light-driven chemical logic gates.

Electronic and structural transitions in dense liquid sodium.

PubMed

Raty, Jean-Yves; Schwegler, Eric; Bonev, Stanimir A

2007-09-27

At ambient conditions, the light alkali metals are free-electron-like crystals with a highly symmetric structure. However, they were found recently to exhibit unexpected complexity under pressure. It was predicted from theory--and later confirmed by experiment--that lithium and sodium undergo a sequence of symmetry-breaking transitions, driven by a Peierls mechanism, at high pressures. Measurements of the sodium melting curve have subsequently revealed an unprecedented (and still unexplained) pressure-induced drop in melting temperature from 1,000 K at 30 GPa down to room temperature at 120 GPa. Here we report results from ab initio calculations that explain the unusual melting behaviour in dense sodium. We show that molten sodium undergoes a series of pressure-induced structural and electronic transitions, analogous to those observed in solid sodium but commencing at much lower pressure in the presence of liquid disorder. As pressure is increased, liquid sodium initially evolves by assuming a more compact local structure. However, a transition to a lower-coordinated liquid takes place at a pressure of around 65 GPa, accompanied by a threefold drop in electrical conductivity. This transition is driven by the opening of a pseudogap, at the Fermi level, in the electronic density of states--an effect that has not hitherto been observed in a liquid metal. The lower-coordinated liquid emerges at high temperatures and above the stability region of a close-packed free-electron-like metal. We predict that similar exotic behaviour is possible in other materials as well.

Silicone rod extraction followed by liquid desorption-large volume injection-programmable temperature vaporiser-gas chromatography-mass spectrometry for trace analysis of priority organic pollutants in environmental water samples.

PubMed

Delgado, Alejandra; Posada-Ureta, Oscar; Olivares, Maitane; Vallejo, Asier; Etxebarria, Nestor

2013-12-15

In this study a priority organic pollutants usually found in environmental water samples were considered to accomplish two extraction and analysis approaches. Among those compounds organochlorine compounds, pesticides, phthalates, phenols and residues of pharmaceutical and personal care products were included. The extraction and analysis steps were based on silicone rod extraction (SR) followed by liquid desorption in combination with large volume injection-programmable temperature vaporiser (LVI-PTV) and gas chromatography-mass spectrometry (GC-MS). Variables affecting the analytical response as a function of the programmable temperature vaporiser (PTV) parameters were firstly optimised following an experimental design approach. The SR extraction and desorption conditions were assessed afterwards, including matrix modification, time extraction, and stripping solvent composition. Subsequently, the possibility of performing membrane enclosed sorptive coating extraction (MESCO) as a modified extraction approach was also evaluated. The optimised method showed low method detection limits (3-35 ng L(-1)), acceptable accuracy (78-114%) and precision values (<13%) for most of the studied analytes regardless of the aqueous matrix. Finally, the developed approach was successfully applied to the determination of target analytes in aqueous environmental matrices including estuarine and wastewater samples. © 2013 Elsevier B.V. All rights reserved.

International variation in programmes for assessment of children's neurodevelopment in the community: Understanding disparate approaches to evaluation of motor, social, emotional, behavioural and cognitive function.

PubMed

Wilson, Philip; Wood, Rachael; Lykke, Kirsten; Hauskov Graungaard, Anette; Ertmann, Ruth Kirk; Andersen, Merethe Kirstine; Haavet, Ole Rikard; Lagerløv, Per; Abildsnes, Eirik; Dahli, Mina P; Mäkelä, Marjukka; Varinen, Aleksi; Hietanen, Merja

2018-05-01

Few areas of medicine demonstrate such international divergence as child development screening and surveillance. Many countries have nationally mandated surveillance policies, but the content of programmes and mechanisms for delivery vary enormously. The cost of programmes is substantial but no economic evaluations have been carried out. We have critically examined the history, underlying philosophy, content and delivery of programmes for child development assessment in five countries with comprehensive publicly funded health services (Denmark, Finland, Norway, Scotland and Sweden). The specific focus of this article is on motor, social, emotional, behavioural and global cognitive functioning including language. Variations in developmental surveillance programmes are substantially explained by historical factors and gradual evolution although Scotland has undergone radical changes in approach. No elements of universal developmental assessment programmes meet World Health Organization screening criteria, although some assessments are configured as screening activities. The roles of doctors and nurses vary greatly by country as do the timing, content and likely costs of programmes. Inter-professional communication presents challenges to all the studied health services. No programme has evidence for improved health outcomes or cost effectiveness. Developmental surveillance programmes vary greatly and their structure appears to be driven by historical factors as much as by evidence. Consensus should be reached about which surveillance activities constitute screening, and the predictive validity of these components needs to be established and judged against World Health Organization screening criteria. Costs and consequences of specific programmes should be assessed, and the issue of inter-professional communication about children at remediable developmental risk should be prioritised.

Recognising and developing students as teachers: Introduction of a novel Undergraduate Certificate in Veterinary Medical Education.

PubMed

Hudson, Neil; Stansbie, Nigel; Rhind, Susan; Brown, Gillian; Handel, Ian; Mellanby, Richard; Bell, Catriona

2016-01-01

A key responsibility of healthcare professionals is the education of clients/patients, colleagues and students undertaking placements. Peer-assisted learning (PAL) has been incorporated in our veterinary medicine programme for a number of years. The aim of this project was to develop a mechanism to formally recognise the important role that students play in the School's teaching and learning processes and foster students as partners in education through the development of a novel Undergraduate Certificate in Veterinary Medical Education (UCVME). Students and veterinarians were surveyed in order to inform the design of the programme. The programme is modular and aligned with the UK Professional Standards Framework (UKPSF). Students enrol in their third year, undertaking core and elective components, with completion over the final three years of the degree. The UCVME has been positively received, with 30 of 160 third year students enrolling in the programme's first year. Activities receiving credit and designed in partnership between staff and students have included: PAL sessions, widening participation school educational workshops and client education events. This initiative has created numerous student-driven educational opportunities. It is hoped that this programme will facilitate the educational training of students and enhance employability and career satisfaction.

Changing the Nature of Lectures Using a Personal Response System

ERIC Educational Resources Information Center

Masikunis, George; Panayiotidis, Andreas; Burke, Linda

2009-01-01

This article describes the use of an Electronic Voting System (EVS) in large group lectures within a business and management undergraduate degree programme, in an attempt to make them more interactive. The intention was to ensure that the introduction of the EVS-style lecture was educationally driven, linked to interactive learning activities in…

Target-Driven Reforms: Education for All and the Translations of Equity and Inclusion in India

ERIC Educational Resources Information Center

Mukhopadhyay, Rahul; Sriprakash, Arathi

2013-01-01

This paper critically examines the ways in which inclusion and equity are constituted through education development policies in India. Programmes implemented under global and national Education for All (EFA) policies have largely involved the quantification of "equity" whereby schooling processes are measured against broad targets for…

Programmable Quantum Photonic Processor Using Silicon Photonics

DTIC Science & Technology

2017-04-01

quantum information processing and quantum sensing, ranging from linear optics quantum computing and quantum simulation to quantum ...transformers have driven experimental and theoretical advances in quantum simulation, cluster-state quantum computing , all-optical quantum repeaters...neuromorphic computing , and other applications. In addition, we developed new schemes for ballistic quantum computation , new methods for

High altitude subsonic parachute field programmable gate array

NASA Technical Reports Server (NTRS)

Kowalski, James E.; Gromov, Konstantin; Konefat, Edward H.

2005-01-01

This paper describes a rapid, top down requirements-driven design of an FPGA used in an Earth qualification test program for a new Mars subsonic parachute. The FPGA is used to process and control storage of telemetry data from multiple sensors throughout; launch, ascent, deployment and descent phases of the subsonic parachute test.

The Effects of Beacons, Comments, and Tasks on Program Comprehension Process in Software Maintenance

ERIC Educational Resources Information Center

Fan, Quyin

2010-01-01

Program comprehension is the most important and frequent process in software maintenance. Extensive research has found that individual characteristics of programmers, differences of computer programs, and differences of task-driven motivations are the major factors that affect the program comprehension results. There is no study specifically…

Practitioner Review: When Parent Training Doesn't Work--Theory-Driven Clinical Strategies

ERIC Educational Resources Information Center

Scott, Stephen; Dadds, Mark R.

2009-01-01

Improving the parent-child relationship by using strategies based on social learning theory has become the cornerstone for the treatment of conduct problems in children. Over the past 40 years, interventions have expanded greatly from small, experimental procedures to substantial, systematic programmes that provide clear guidelines in detailed…

Researching Academies in England

ERIC Educational Resources Information Center

Gunter, Helen; Woods, Philip; Woods, Glenys

2008-01-01

In 2002 the New Labour government launched the Academies programme (known initially as City Academies) with the target of 400, of which 200 are to opened by 2010. The espoused aim has been to tackle underachievement and encourage diversity of provision. However, it continues to be a controversial policy that is being driven by the Specialist…

Governments, off-patent vaccines, smallpox and universal childhood vaccination.

PubMed

Music, Stanley

2010-01-22

WHO is now celebrating more than 30 years of freedom from smallpox. What was originally seen as a victory over an ancient scourge can now be viewed as an epidemiologically driven programme to overcome governmental inertia and under-achievement in delivering an off-patent vaccine. Though efforts are accelerating global vaccine use, a plea is made to push the world's governments to commit to universal childhood vaccination via a proposed new programme. The latter should begin by exploiting a long list of ever more affordable off-patent vaccines, vaccines that can virtually eliminate the bulk of the world's current vaccine-preventable disease burden.

Emerging technologies and perspectives for nutrition research in European Union 7th Framework Programme.

PubMed

de Froidmont-Görtz, Isabelle B M

2009-12-01

Nutrition trends in Europe are driven by taste, health and convenience. The possibilities of research using new technologies and tools such as nutrigenomics, imaging techniques, nanotechnology, bioinformatics, cognitive sciences, innovative processes are very promising to support these nutrition trends and in particular their health aspects. This is supported by European Union research. The opportunities offered in the 7th Framework Programme (FP7), among other innovations, will contribute to the general aim of improving nutrition policy as well as improving products from the food industry in accordance with the Lisbon strategy to create employment and improve the quality of life of the European citizens.

SBEToolbox: A Matlab Toolbox for Biological Network Analysis

PubMed Central

Konganti, Kranti; Wang, Gang; Yang, Ence; Cai, James J.

2013-01-01

We present SBEToolbox (Systems Biology and Evolution Toolbox), an open-source Matlab toolbox for biological network analysis. It takes a network file as input, calculates a variety of centralities and topological metrics, clusters nodes into modules, and displays the network using different graph layout algorithms. Straightforward implementation and the inclusion of high-level functions allow the functionality to be easily extended or tailored through developing custom plugins. SBEGUI, a menu-driven graphical user interface (GUI) of SBEToolbox, enables easy access to various network and graph algorithms for programmers and non-programmers alike. All source code and sample data are freely available at https://github.com/biocoder/SBEToolbox/releases. PMID:24027418

SBEToolbox: A Matlab Toolbox for Biological Network Analysis.

PubMed

Konganti, Kranti; Wang, Gang; Yang, Ence; Cai, James J

2013-01-01

We present SBEToolbox (Systems Biology and Evolution Toolbox), an open-source Matlab toolbox for biological network analysis. It takes a network file as input, calculates a variety of centralities and topological metrics, clusters nodes into modules, and displays the network using different graph layout algorithms. Straightforward implementation and the inclusion of high-level functions allow the functionality to be easily extended or tailored through developing custom plugins. SBEGUI, a menu-driven graphical user interface (GUI) of SBEToolbox, enables easy access to various network and graph algorithms for programmers and non-programmers alike. All source code and sample data are freely available at https://github.com/biocoder/SBEToolbox/releases.

On-Chip Pressure Generation for Driving Liquid Phase Separations in Nanochannels.

PubMed

Xia, Ling; Choi, Chiwoong; Kothekar, Shrinivas C; Dutta, Debashis

2016-01-05

In this Article, we describe the generation of pressure gradients on-chip for driving liquid phase separations in submicrometer deep channels. The reported pressure-generation capability was realized by applying an electrical voltage across the interface of two glass channel segments with different depths. A mismatch in the electroosmotic flow rate at this junction led to the generation of pressure-driven flow in our device, a fraction of which was then directed to an analysis channel to carry out the desired separation. Experiments showed the reported strategy to be particularly conducive for miniaturization of pressure-driven separations yielding flow velocities in the separation channel that were nearly unaffected upon scaling down the depth of the entire fluidic network. Moreover, the small dead volume in our system allowed for high dynamic control over this pressure gradient, which otherwise was challenging to accomplish during the sample injection process using external pumps. Pressure-driven velocities up to 3.1 mm/s were realized in separation ducts as shallow as 300 nm using our current design for a maximum applied voltage of 3 kV. The functionality of this integrated device was demonstrated by implementing a pressure-driven ion chromatographic analysis that relied on analyte interaction with the nanochannel surface charges to yield a nonuniform solute concentration across the channel depth. Upon coupling such analyte distribution to the parabolic pressure-driven flow profile in the separation duct, a mixture of amino acids could be resolved. The reported assay yielded a higher separation resolution compared to its electrically driven counterpart in which sample migration was realized using electroosmosis/electrophoresis.

Capillary-Driven Flow in Liquid Filaments Connecting Orthogonal Channels

NASA Technical Reports Server (NTRS)

Allen, Jeffrey S.

2005-01-01

Capillary phenomena plays an important role in the management of product water in PEM fuel cells because of the length scales associated with the porous layers and the gas flow channels. The distribution of liquid water within the network of gas flow channels can be dramatically altered by capillary flow. We experimentally demonstrate the rapid movement of significant volumes of liquid via capillarity through thin liquid films which connect orthogonal channels. The microfluidic experiments discussed provide a good benchmark against which the proper modeling of capillarity by computational models may be tested. The effect of surface wettability, as expressed through the contact angle, on capillary flow will also be discussed.

Electric-field-driven Phenomena for Manipulating Particles in Micro-Devices

NASA Technical Reports Server (NTRS)

Khusid, Boris; Acrivos, Andreas

2004-01-01

Compared to other available methods, ac dielectrophoresis is particularly well-suited for the manipulation of minute particles in micro- and nano-fluidics. The essential advantage of this technique is that an ac field at a sufficiently high frequency suppresses unwanted electric effects in a liquid. To date very little has been achieved towards understanding the micro-scale field-and shear driven behavior of a suspension in that, the concepts currently favored for the design and operation of dielectrophoretic micro-devices adopt the approach used for macro-scale electric filters. This strategy considers the trend of the field-induced particle motions by computing the spatial distribution of the field strength over a channel as if it were filled only with a liquid and then evaluating the direction of the dielectrophoretic force, exerted on a single particle placed in the liquid. However, the exposure of suspended particles to a field generates not only the dielectrophoretic force acting on each of these particles, but also the dipolar interactions of the particles due to their polarization. Furthermore, the field-driven motion of the particles is accompanied by their hydrodynamic interactions. We present the results of our experimental and theoretical studies which indicate that, under certain conditions, these long-range electrical and hydrodynamic interparticle interactions drastically affect the suspension behavior in a micro-channel due to its small dimensions.

Fast Electrically Driven Capillary Rise Using Overdrive Voltage.

PubMed

Hong, Sung Jin; Hong, Jiwoo; Seo, Hee Won; Lee, Sang Joon; Chung, Sang Kug

2015-12-29

Enhancement of response speed (or reduction of response time) is crucial for the commercialization of devices based on electrowetting (EW), such as liquid lenses and reflective displays, and presents one of the main challenges in EW research studies. We demonstrate here that an overdrive EW actuation gives rise to a faster rise of a liquid column between parallel electrodes, compared to a DC EW actuation. Here, DC actuation is actually a simple applied step function, and overdrive is an applied step followed by reduction to a lower voltage. Transient behaviors and response time (i.e., the time required to reach the equilibrium height) of the rising liquid column are explored under different DC and overdrive EW actuations. When the liquid column rises up to a target height by means of an overdrive EW, the response time is reduced to as low as 1/6 of the response time using DC EW. We develop a theoretical model to simulate the EW-driven capillary rise by combining the kinetic equation of capillary flow (i.e., Lucas-Washburn equation) and the dynamic contact angle model considering contact line friction, contact angle hysteresis, contact angle saturation, and the EW effect. This theoretical model accurately predicts the outcome to within a ± 5% error in regard to the rising behaviors of the liquid column with a low viscosity, under both DC EW and overdrive actuation conditions, except for the early stage (

Computational And Experimental Studies Of Three-Dimensional Flame Spread Over Liquid Fuel Pools

NASA Technical Reports Server (NTRS)

Ross, Howard D. (Technical Monitor); Cai, Jinsheng; Liu, Feng; Sirignano, William A.; Miller, Fletcher J.

2003-01-01

Schiller, Ross, and Sirignano (1996) studied ignition and flame spread above liquid fuels initially below the flashpoint temperature by using a two-dimensional computational fluid dynamics code that solves the coupled equations of both the gas and the liquid phases. Pulsating flame spread was attributed to the establishment of a gas-phase recirculation cell that forms just ahead of the flame leading edge because of the opposing effect of buoyancy-driven flow in the gas phase and the thermocapillary-driven flow in the liquid phase. Schiller and Sirignano (1996) extended the same study to include flame spread with forced opposed flow in the gas phase. A transitional flow velocity was found above which an originally uniform spreading flame pulsates. The same type of gas-phase recirculation cell caused by the combination of forced opposed flow, buoyancy-driven flow, and thermocapillary-driven concurrent flow was responsible for the pulsating flame spread. Ross and Miller (1998) and Miller and Ross (1998) performed experimental work that corroborates the computational findings of Schiller, Ross, and Sirignano (1996) and Schiller and Sirignano (1996). Cai, Liu, and Sirignano (2002) developed a more comprehensive three-dimensional model and computer code for the flame spread problem. Many improvements in modeling and numerical algorithms were incorporated in the three-dimensional model. Pools of finite width and length were studied in air channels of prescribed height and width. Significant three-dimensional effects around and along the pool edge were observed. The same three-dimensional code is used to study the detailed effects of pool depth, pool width, opposed air flow velocity, and different levels of air oxygen concentration (Cai, Liu, and Sirignano, 2003). Significant three-dimensional effects showing an unsteady wavy flame front for cases of wide pool width are found for the first time in computation, after being noted previously by experimental observers (Ross and Miller, 1999). Regions of uniform and pulsating flame spread are mapped for the flow conditions of pool depth, opposed flow velocity, initial pool temperature, and air oxygen concentration under both normal and microgravity conditions. Details can be found in Cai et al. (2002, 2003). Experimental results recently performed at NASA Glenn of flame spread across a wide, shallow pool as a function of liquid temperature are also presented here.

Time and flow-direction responses of shear-styress-sensitive liquid crystal coatings

NASA Technical Reports Server (NTRS)

Reda, Daniel C.; Muraqtore, J. J.; Heinick, James T.

1994-01-01

Time and flow-direction responses of shear-stress liquid crystal coatings were exploresd experimentally. For the time-response experiments, coatings were exposed to transient, compressible flows created during the startup and off-design operation of an injector-driven supersonic wind tunnel. Flow transients were visualized with a focusing schlieren system and recorded with a 100 frame/s color video camera.

Combustion Studies of Acoustically Suspended Liquid Droplets.

DTIC Science & Technology

1988-03-01

34, 2 1 02 J Acoustic Levitation .’ ABSTRACT (Continue on reverse if necessary and identify by block number) piezoelectrically driven ultrasonic resonator...was developed and tested in this study. The device was used to levitate liquid fuel droplets for evaporation measurements and ignition :tudies. The... levitation technique may hold some promise for onducting non-combustion related droplet measurements, for example evaporation tests, but wIthout further

Experiments on pumping of liquids using arrays of microelectrodes subjected to travelling wave potentials

NASA Astrophysics Data System (ADS)

García-Sánchez, P.; Ramos, A.; Green, Nicolas G.; Morgan, H.

2008-12-01

Net fluid flow of electrolytes driven on an array of microelectrodes subjected to a travelling-wave potential is presented. Two sizes of platinum microelectrodes have been studied. In both arrays, at low voltages the liquid flows according to the prediction given by ac electroosmotic theory. At voltages above a threshold the fluid flow is reversed. Measurements of the electrical current when the microelectrode array is pumping the liquid are also reported. Transient behaviours in both electrical current and fluid velocity have been observed.

Electric-field driven jetting from dielectric liquids

NASA Astrophysics Data System (ADS)

Jayasinghe, S. N.; Edirisinghe, M. J.

2004-11-01

Three dielectric (electrical conductivity ˜10-13Sm-1) Newtonian liquids with viscosity in the range 1-100 mPa s were passed through a needle at a controlled flow rate under the influence of an electric field. At an electric field strength of 1.5kV/mm, the liquid exiting the needle instantaneously transformed from dripping droplets to an elliptically pendent droplet from the apex of which a fine jet evolved. Thus, a jet can be obtained on demand, and in this letter we define this phenomenon and explain a basis for it.

LLE Review 118 (January-March 2009)

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

Bittle, W., editor

2009-08-03

This issue has the following articles: (1) Applied Plasma Spectroscopy: Laser-Fusion Experiments; (2) Relativistic Electron-Beam Transport Studies Using High-Resolution, Coherent Transition Radiation Imaging; (3) Pressure-Driven, Resistive Magnetohydrodynamic Interchange Instabilities in Laser-Produced, High-Energy-Density Plasmas; (4) Extended Model for Polymer Cholesteric Liquid Crystal Flake Reorientation and Relaxation; (5) Modeling the Effects of Microencapsulation on the Electro-Optic Behavior of Polymer Cholesteric Liquid Crystal Flakes; (6) Capillarity and Dielectrophoresis of Liquid Deuterium; and (7) A Stable Mid-IR, GaSb-Based Diode Laser Source for Cryogenic Target Layering at the OMEGA Laser Facility.

Holographic zoom system based on spatial light modulator and liquid device

NASA Astrophysics Data System (ADS)

Wang, Di; Li, Lei; Liu, Su-Juan; Wang, Qiong-Hua

2018-02-01

In this paper, two holographic zoom systems are proposed based on the programmability of spatial light modulator (SLM) and zoom characteristics of liquid lens. An active optical zoom system is proposed in which the zoom module is composed of a liquid lens and an SLM. By controlling the focal lengths of the liquid lens and the encoded digital lens on the SLM, we can change the magnification of an image without mechanical moving parts and keep the output plane stationary. Then a color holographic zoom system based on a liquid lens is proposed. The system processes the color separation of the original object for red, green, and blue components and generated three holograms respectively. A new hologram with specific reconstructed distance can be generated by combing the hologram of the digital lens with the hologram of the image. By controlling the focal lengths of the liquid lens and the encoded digital lens on the SLM, we can change the magnification of the reconstructed image.

Chromatin programming by developmentally regulated transcription factors: lessons from the study of haematopoietic stem cell specification and differentiation.

PubMed

Obier, Nadine; Bonifer, Constanze

2016-11-01

Although the body plan of individuals is encoded in their genomes, each cell type expresses a different gene expression programme and therefore has access to only a subset of this information. Alterations to gene expression programmes are the underlying basis for the differentiation of multiple cell types and are driven by tissue-specific transcription factors (TFs) that interact with the epigenetic regulatory machinery to programme the chromatin landscape into transcriptionally active and inactive states. The haematopoietic system has long served as a paradigm for studying the molecular principles that regulate gene expression in development. In this review article, we summarize the current knowledge on the mechanism of action of TFs regulating haematopoietic stem cell specification and differentiation, and place this information into the context of general principles governing development. © 2016 Federation of European Biochemical Societies.

Innovation in learning and development in multilingual and multicultural contexts: Principles learned from a higher educational study programme in Luxembourg

NASA Astrophysics Data System (ADS)

Ziegler, Gudrun

2011-12-01

Multilingualism in education is a conceptual as well as a pedagogical challenge of the 21st century. Luxembourg, with its three statutory official languages (Luxembourgish, French and German), is an especially complex setting. The gap between traditional principles of language education on the one hand and the challenging impacts of today's multilingualisms on the other led the University of Luxembourg (founded in 2003) to set up a developmentally-driven Master's programme in 2007, entitled "Learning and Development in Multilingual and Multicultural Contexts". After a presentation of the general multilingual settings in Luxembourg, this paper discusses the constellation of the multilingual University's staff and students and provides an analysis of the concept of the course by outlining its innovative approach, its principles and lessons learned with regard to running a trilingual higher education programme.

ESA achievements: more than thirty years of pioneering space activity

NASA Astrophysics Data System (ADS)

Wilson, Andrew

2005-06-01

Contents: ESA and science. ESA and Earth observation (Explorer Core missions, Explorer opportunity missions, Earth Watch). ESA and telecommunications. ESA and navigation. ESA and launchers. ESA and manned spaceflight. The ESA Science Programme is one of the Agency's mandatory activities, in which all Member States participate. The origins of the Science Programme, the oldest in the Agency, hark back to the days of ESRO. ESRO's seven successful scientific satellites paved the way for ESA's remarkable series of pioneering missions that have placed Europe at the vanguard of disciplines such as X-ray, gamma-ray and infrared astronomy; astrometry; solar system sciences (especially cometary), solar and heliospheric physics, as well as space plasma physics. Driven by the limited available means, ESA's Science Programme has consistently focused on missions with strong innovative contents. All of the missions launched or approved so far are covered in separate entries in this volume.

HVEPS Scramjet-Driven MHD Power Demonstration Test Results (Preprint)

DTIC Science & Technology

2007-06-01

an outer annulus which provides the flow passage for the liquid NaK. Final fabrication and assembly of the seeding system was completed at UTRC as...ABSTRACT The Air Force sponsored Hypersonic Vehicle Electric Power System (HVEPS) program was a research program to develop scramjet driven...magnetohydrodynamic (MHD) power for an advanced high power, airborne electric power system . This program has been active for the past five years with various

Liquid lens driven by elastomer actuator

NASA Astrophysics Data System (ADS)

Jin, Boya; Lee, Ji-Hyeon; Zhou, Zuowei; Lee, Gi-Bbeum; Ren, Hongwen; Nah, Changwoon

2015-09-01

By filling a liquid droplet in the hole of a dielectric elastomer (DE) film directly, we prepared two small liquid lenses. The aperture of one lens is macro size and the other is micro size. The liquid droplet in each hole of the DE film exhibits a lens character due to its biconvex shape. In relaxed state, the focal length of each liquid droplet is the longest. When a sufficiently high DC voltage is applied, the diameter of each DE hole is decreased by the generated Maxwell stress, causing the curvature of its droplet to increase. As a result, the focal length of each lens is reduced. Here the DE film functions as an actuator. In contrast to previous approaches, our miniature liquid lenses possess the advantages of simple fabrication, fast response time (~ 540 ms), and high optical performance (~ 114 lp/mm). Moreover, the micro-sized liquid lens presents good mechanical stability.

Vapor-Enabled Propulsion for Plasmonic Photothermal Motor at the Liquid/Air Interface.

PubMed

Meng, Fanchen; Hao, Wei; Yu, Shengtao; Feng, Rui; Liu, Yanming; Yu, Fan; Tao, Peng; Shang, Wen; Wu, Jianbo; Song, Chengyi; Deng, Tao

2017-09-13

This paper explores a new propulsion mechanism that is based on the ejection of hot vapor jet to propel the motor at the liquid/air interface. For conventional photothermal motors, which mostly are driven by Marangoni effect, it is challenging to propel those motors at the surfaces of liquids with low surface tension due to the reduced Marangoni effect. With this new vapor-enabled propulsion mechanism, the motors can move rapidly at the liquid/air interface of liquids with a broad range of surface tensions. A design that can accumulate the hot vapor is further demonstrated to enhance both the propulsion force as well as the applicable range of liquids for such motors. This new propulsion mechanism will help open up new opportunities for the photothermal motors with desired motion controls at a wide range of liquid/air interfaces where hot vapor can be generated.

Ionic liquids for addressing unmet needs in healthcare

PubMed Central

Agatemor, Christian; Ibsen, Kelly N.; Tanner, Eden E. L.

2018-01-01

Abstract Advances in the field of ionic liquids have opened new applications beyond their traditional use as solvents into other fields especially healthcare. The broad chemical space, rich with structurally diverse ions, and coupled with the flexibility to form complementary ion pairs enables task‐specific optimization at the molecular level to design ionic liquids for envisioned functions. Consequently, ionic liquids now are tailored as innovative solutions to address many problems in medicine. To date, ionic liquids have been designed to promote dissolution of poorly soluble drugs and disrupt physiological barriers to transport drugs to targeted sites. Also, their antimicrobial activity has been demonstrated and could be exploited to prevent and treat infectious diseases. Metal‐containing ionic liquids have also been designed and offer unique features due to incorporation of metals. Here, we review application‐driven investigations of ionic liquids in medicine with respect to current status and future potential. PMID:29376130

Liquid-metal flows: Magnetohydrodynamics and applications; Proceedings of the Fifth Beersheba International Seminar on Magnetohydrodynamic Flows and Turbulence, University of the Negev, Beersheba, Israel, Mar. 2-6, 1987

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

Branover, H.; Mond, M.; Unger, Y.

The present collection of papers on MHD-related uses of liquid metal flows and their applications discusses topics in laminar MHD flows, MHD power generation, metallurgical MHD applications, and two-phase MHD flows. Attention is given to MHD flows with closed streamlines, nonlinear waves in liquid metals under a transverse magnetic field, liquid-metal MHD conversion of nuclear energy to electricity, the testing of optimized MHD conversion (OMACON) systems, and aspects of a liquid-metal induction generator. Also discussed are MHD effects in liquid-metal breeder reactors, a plasma-driven MHD powerplant, modeling the recirculating flows in channel-induction surfaces, the hydrodynamics of aluminum reduction cells, free-surfacemore » determination in a levitation-melting process, the parametric interactions of waves in bubbly liquid metals, and the occurrence of cavitation in water jets.« less

Super-cooled liquid water topped sub-arctic clouds and precipitation - investigation based on combination of ground-based in-situ and remote-sensing observations

NASA Astrophysics Data System (ADS)

Hirsikko, Anne; Brus, David; O'Connor, Ewan J.; Filioglou, Maria; Komppula, Mika; Romakkaniemi, Sami

2017-04-01

In the high and mid latitudes super-cooled liquid water layers are frequently observed on top of clouds. These layers are difficult to forecast with numerical weather prediction models, even though, they have strong influence on atmospheric radiative properties, cloud microphysical properties, and subsequently, precipitation. This work investigates properties of super-cooled liquid water layer topped sub-arctic clouds and precipitation observed with ground-based in-situ (cloud probes) and remote-sensing (a cloud radar, Doppler and multi-wavelength lidars) instrumentation during two-month long Pallas Cloud Experiment (PaCE 2015) in autumn 2015. Analysis is based on standard Cloudnet scheme supplemented with new retrieval products of the specific clouds and their properties. Combination of two scales of observation provides new information on properties of clouds and precipitation in the sub-arctic Pallas region. Current status of results will be presented during the conference. The authors acknowledge financial support by the Academy of Finland (Centre of Excellence Programme, grant no 272041; and ICINA project, grant no 285068), the ACTRIS2 - European Union's Horizon 2020 research and innovation programme under grant agreement No 654109, the KONE foundation, and the EU FP7 project BACCHUS (grant no 603445).

Surveillance and response for high-risk populations: what can malaria elimination programmes learn from the experience of HIV?

PubMed

Jacobson, Jerry O; Cueto, Carmen; Smith, Jennifer L; Hwang, Jimee; Gosling, Roly; Bennett, Adam

2017-01-18

To eliminate malaria, malaria programmes need to develop new strategies for surveillance and response appropriate for the changing epidemiology that accompanies transmission decline, in which transmission is increasingly driven by population subgroups whose behaviours place them at increased exposure. Conventional tools of malaria surveillance and response are likely not sufficient in many elimination settings for accessing high-risk population subgroups, such as mobile and migrant populations (MMPs), given their greater likelihood of asymptomatic infections, illegal risk behaviours, limited access to public health facilities, and high mobility including extended periods travelling away from home. More adaptive, targeted strategies are needed to monitor transmission and intervention coverage effectively in these groups. Much can be learned from HIV programmes' experience with "second generation surveillance", including how to rapidly adapt surveillance and response strategies to changing transmission patterns, biological and behavioural surveys that utilize targeted sampling methods for specific behavioural subgroups, and methods for population size estimation. This paper reviews the strategies employed effectively for HIV programmes and offers considerations and recommendations for adapting them to the malaria elimination context.

Rheological Properties of Quasi-2D Fluids in Microgravity

NASA Technical Reports Server (NTRS)

Trittel, Torsten; Stannarius, Ralf; Eremin, Alexey; Harth, Kirsten; Clark, Noel A.; Maclennan, Joseph; Glaser, Matthew; Park, Cheol; Hall, Nancy; Tin, Padetha

2016-01-01

Freely suspended smectic films of sub-micrometer thickness and lateral extensions of several millimeters are used to study thermally driven convection and diffusion in the film plane. The experiments were performed during a six minute microgravity phase of a TEXUS suborbital rocket flight (Texus 52, launched April 27, 2015). The project served as a preliminary test for a planned ISS Experiment with liquid crystal films (OASIS), and in addition it provided new experimental data on smectic films exposed to in-plane thermal gradients.We find an attraction of the smectic material towards the cold edge of the film in a temperature gradient, similar to a Soret effect. This process is reversed when this edge is heated up again. Thermal convection driven by two thermocontacts in the film is practically absent, even at temperature gradients up to 10 Kmm, thermally driven convection sets in when the hot post reaches the transition temperature to the nematic phase.An additional experiment was performed under microgravity conditions to test the stability of liquid crystal bridges in different smectic phases.

Manipulation of Micro Scale Particles in Optical Traps Using Programmable Spatial Light Modulation

NASA Technical Reports Server (NTRS)

Seibel, Robin E.; Decker, Arthur J. (Technical Monitor)

2003-01-01

1064 nm light, from an Nd:YAG laser, was polarized and incident upon a programmable parallel aligned liquid crystal spatial light modulator (PAL-SLM), where it was phase modulated according to the program controlling the PAL-SLM. Light reflected from the PAL-SLM was injected into a microscope and focused. At the focus, multiple optical traps were formed in which 9.975 m spheres were captured. The traps and the spheres were moved by changing the program of the PAL-SLM. The motion of ordered groups of micro particles was clearly demonstrated.

A Survey of ICT Competencies among Students in Teacher Preparation Programmes at the University of Benin, Benin City, Nigeria

ERIC Educational Resources Information Center

Danner, R. B.; Pessu, C. O. A.

2013-01-01

Today's fast-paced world is becoming increasingly characterized by technology driven communication, which has transformed the world into a large global connected community with ever-increasing outreach of information and communication technology (ICT). Technology plays an increasingly important role in people's lives, and it is envisaged that…

LIVING LAB: User-Driven Innovation for Sustainability

ERIC Educational Resources Information Center

Liedtke, Christa; Welfens, Maria Jolanta; Rohn, Holger; Nordmann, Julia

2012-01-01

Purpose: The purpose of this paper is to summarize and discuss the results from the LIVING LAB design study, a project within the 7th Framework Programme of the European Union. The aim of this project was to develop the conceptual design of the LIVING LAB Research Infrastructure that will be used to research human interaction with, and stimulate…

The Feasibility of Quality Function Deployment (QFD) as an Assessment and Quality Assurance Model

ERIC Educational Resources Information Center

Matorera, D.; Fraser, W. J.

2016-01-01

Business schools are globally often seen as structured, purpose-driven, multi-sector and multi-perspective organisations. This article is based on the response of a graduate school to an innovative industrial Quality Function Deployment-based model (QFD), which was to be adopted initially in a Master's degree programme for quality assurance…

Cholesteric metronomes with flexoelectrically programmable amplitude

NASA Astrophysics Data System (ADS)

Joshi, Vinay; Varanytsia, A.; Chang, Kai-Han; Paterson, Daniel A.; Storey, John M. D.; Imrie, Corrie T.; Chien, Liang-Chy

2018-02-01

We experimentally demonstrate fast flexoelectro-optic switching in a liquid crystal cell containing bimesogen-doped and polymer-stabilized cholesteric. The device exhibits a response time of less than 0.7 ms and with low hysteresis and color dispersion which is suitable for potential applications including field-sequential color displays.

Mechanisms of change of a novel weight loss programme provided by a third sector organisation: a qualitative interview study.

PubMed

McMahon, Naoimh E; Visram, Shelina; Connell, Louise A

2016-05-10

There is a need for theory-driven studies that explore the underlying mechanisms of change of complex weight loss programmes. Such studies will contribute to the existing evidence-base on how these programmes work and thus inform the future development and evaluation of tailored, effective interventions to tackle overweight and obesity. This study explored the mechanisms by which a novel weight loss programme triggered change amongst participants. The programme, delivered by a third sector organisation, addressed both diet and physical activity. Over a 26 week period participants engaged in three weekly sessions (education and exercise in a large group, exercise in a small group and a one-to-one education and exercise session). Novel aspects included the intensity and duration of the programme, a competitive selection process, milestone physical challenges (e.g. working up to a 5 K and 10 K walk/run during the programme), alumni support (face-to-face and online) and family attendance at exercise sessions. Data were collected through interviews with programme providers (n = 2) and focus groups with participants (n = 12). Discussions were audio-recorded, transcribed and analysed using NVivo10. Published behaviour change frameworks and behaviour change technique taxonomies were used to guide the coding process. Clients' interactions with components of the weight loss programme brought about a change in their commitment, knowledge, beliefs about capabilities and social and environmental contexts. Intervention components that generated these changes included the competitive selection process, group and online support, family involvement and overcoming milestone challenges over the 26 week programme. The mechanisms by which these components triggered change differed between participants. There is an urgent need to establish robust interventions that can support people who are overweight and obese to achieve a healthy weight and maintain this change. Third sector organisations may be a feasible alternative to private and public sector weight loss programmes. We have presented findings from one example of a novel community-based weight loss programme and identified how the programme components resulted in change amongst the participants. Further research is needed to robustly test the effectiveness, and cost-effectiveness, of this programme.

Liquid-liquid phase transition in an ionic model of silica

NASA Astrophysics Data System (ADS)

Chen, Renjie; Lascaris, Erik; Palmer, Jeremy C.

2017-06-01

Recent equation of state calculations [E. Lascaris, Phys. Rev. Lett. 116, 125701 (2016)] for an ionic model of silica suggest that it undergoes a density-driven, liquid-liquid phase transition (LLPT) similar to the controversial transition hypothesized to exist in deeply supercooled water. Here, we perform extensive free energy calculations to scrutinize the model's low-temperature phase behavior and confirm the existence of a first-order phase transition between two liquids with identical compositions but different densities. The low-density liquid (LDL) exhibits tetrahedral order, which is partially disrupted in the high-density liquid (HDL) by the intrusion of additional particles into the primary neighbor shell. Histogram reweighting methods are applied to locate conditions of HDL-LDL coexistence and the liquid spinodals that bound the two-phase region. Spontaneous liquid-liquid phase separation is also observed directly in large-scale molecular dynamics simulations performed inside the predicted two-phase region. Given its clear LLPT, we anticipate that this model may serve as a paradigm for understanding whether similar transitions occur in water and other tetrahedral liquids.

Microfluidics Transport and Path Control via Programmable Electrowetting on Dielectric

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

Theodore W. Von Bitner, Ph.D.

2002-08-22

This research was conducted in collaboration with Professor Chang-Jin Kim of the University of California, Los Angeles. In phase I, the IOS-UCLA collaboration demonstrated the transport and manipulation of insulting liquid droplets using the principles of EWOD. A postage stamp sized array of electronically addressable Teflon pads, whose surface tension characteristics could be altered on command through computer algorithms, was developed and tested using deionized water as the liquid. Going beyond the tasks originally proposed for Phase I, droplet manipulation was achieved and droplet stability in the EWOD device was examined.

Design considerations for a pressure-driven multi-stage rocket

NASA Astrophysics Data System (ADS)

Sauerwein, Steven Craig

2002-01-01

The purpose of this study was to examine the feasibility of using propellant tank pressurization to eliminate the use of high-pressure turbopumps in multi-stage liquid-fueled satellite launchers. Several new technologies were examined to reduce the mass of such a rocket. Composite materials have a greater strength-to-weight ratio than metals and can be used to reduce the weight of rocket propellant tanks and structure. Catalytically combined hydrogen and oxygen can be used to heat pressurization gas, greatly reducing the amount of gas required. Ablatively cooled rocket engines can reduce the complexity and cost of the rocket. Methods were derived to estimate the mass of the various rocket components. These included a method to calculate the amount of gas needed to pressurize a propellant tank by modeling the behavior of the pressurization gas as the liquid propellant flows out of the tank. A way to estimate the mass and size of a ablatively cooled composite cased rocket engine. And a method to model the flight of such a rocket through the atmosphere in conjunction with optimization of the rockets trajectory. The results show that while a liquid propellant rocket using tank pressurization are larger than solid propellant rockets and turbopump driven liquid propellant rockets, they are not impractically large.

High-performance beam steering using electrowetting-driven liquid prism fabricated by a simple dip-coating method

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

Enrico Clement, Carlos; Park, Sung-Yong, E-mail: mpeps@nus.edu.sg

2016-05-09

A high degree of beam steering is demonstrated using an electrowetting-driven liquid prism. While prism devices have typically relied on complex and expensive laboratory setups, such as high-vacuum facilities for fabrication of dielectric layers, this work utilizes a simple dip-coating method to provide an ion gel layer as a dielectric, offering 2 or 3 orders higher specific capacitance (c ≈ 10 μF/cm{sup 2}) than that of conventional dielectrics. Analytical studies present the effects of liquid selection and arrangement on overall prism performance. For experimental demonstrations of high-performance beam steering, we not only selected two immiscible liquids of water and 1-bromonaphthalene (1-BN)more » oil which provide the large refractive index difference (n{sub water} = 1.33 and n{sub 1-BN} = 1.65 at λ = 532 nm) between them, but also utilized a double-stacked prism configuration which increases the number of interfaces for incoming light to be steered. At a prism apex angle of φ = 27°, we were able to achieve significantly large beam steering of up to β = 19.06°, which is the highest beam steering performance ever demonstrated using electrowetting technology.« less

Time-dependent bubble motion through a liquid filled compliant channel

NASA Astrophysics Data System (ADS)

Halpern, David; Gaver, Donald; Jensen, Oliver

2000-11-01

Pulmonary airway closure occurs when the liquid lining layer occludes the airway and obstructs airflow. Meniscus formation is the result of a surface-tension driven instability within the liquid layer. Airway 'compliant collapse' may result, which leads to tube buckling with airway walls held in apposition. Airway closure is common in premature neonates who do not produce sufficient surfactant and those suffering from emphysema. To model the reopening of a collapsed airway flooded with fluid, we consider the time-dependent motion of an air-bubble driven by a positive bubble pressure Pb through a liquid filled compliant channel. The governing Stokes equations are solved using the boundary element method near the bubble tip, and lubrication theory sufficiently far ahead of the buble where the channel walls have a gentle taper. Results show that for Pb > P_crit, the bubble moves forward and converges to a steady velocity as the airway walls 'peel' open. For Pb < P_crit, no steady solutions are found because fluid continuously accummulates ahead of the bubble tip. This result validates the stability analysis of the previously steady wall peeling solution branch. The impact of the flow field on transport of surfactant and the applied shear and normal stresses on the wall as they relate to pulmonary reopening are also discussed.

Long-wavelength Instability in Surface-tension-driven Bénard Convection

NASA Astrophysics Data System (ADS)

van Hook, Stephen J.

1997-03-01

Laboratory experiments and numerical simulations reveal that a liquid layer heated from below and possessing a free upper surface can undergo a long-wavelength deformational instability that causes rupture of the interface.(S. J. VanHook, M. F. Schatz, W. D. McCormick, J. B. Swift, and H. L. Swinney, Phys. Rev. Lett.) 75, 4397 (1995). Depending on the depth and thermal conductivity of the liquid and the overlying gas layer, the interface can rupture downwards and form a dry spot or rupture upwards and form a high spot. This long-wavelength instability competes with the formation of Bénard hexagons for thin or viscous liquid layers, or for liquid layers in microgravity.

Flow Velocity Profiles in Actively-Driven 2D Nozzle Experiments using Freely-Suspended Smectic Liquid Crystal Films

NASA Astrophysics Data System (ADS)

Dutch, Evan; Briggs, Corrina; Ferguson, Kyle; Green, Adam; Park, Cheol; Glaser, Matt; Maclennan, Joe; Clark, Noel

Freely-suspended smectic A liquid crystal films have been used to explore a large range of interesting flow phenomena. Passive microrheology experiments have confirmed previously that such films are ideal systems with which to investigate two-dimensional (2D) hydrodynamics. Here we describe an experiment that uses smectic films to study actively-driven 2D flows. Flow excited by blowing air over a film of smectic liquid crystal material containing small inclusions is captured using digital video microscopy. The flow fields are extracted using particle imaging velocimetry. We have measured the velocity field generated by flow through a thin nozzle into a large rectangular reservoir and compared this to a theoretical model based on 2D complex potential flows. The observations confirm that there is parabolic flow in straight channels, and that the theory accurately models the film velocity flow field in the reservoir. This work was supported by NASA Grant No. NNX-13AQ81G, and NSF MRSEC Grants No. DMR-0820579 and DMR-1420736.

A magnetically driven piston pump for ultra-clean applications

NASA Astrophysics Data System (ADS)

LePort, F.; Neilson, R.; Barbeau, P. S.; Barry, K.; Bartoszek, L.; Counts, I.; Davis, J.; deVoe, R.; Dolinski, M. J.; Gratta, G.; Green, M.; Díez, M. Montero; Müller, A. R.; O'Sullivan, K.; Rivas, A.; Twelker, K.; Aharmim, B.; Auger, M.; Belov, V.; Benitez-Medina, C.; Breidenbach, M.; Burenkov, A.; Cleveland, B.; Conley, R.; Cook, J.; Cook, S.; Craddock, W.; Daniels, T.; Dixit, M.; Dobi, A.; Donato, K.; Fairbank, W.; Farine, J.; Fierlinger, P.; Franco, D.; Giroux, G.; Gornea, R.; Graham, K.; Green, C.; Hägemann, C.; Hall, C.; Hall, K.; Hallman, D.; Hargrove, C.; Herrin, S.; Hughes, M.; Hodgson, J.; Juget, F.; Kaufman, L. J.; Karelin, A.; Ku, J.; Kuchenkov, A.; Kumar, K.; Leonard, D. S.; Lutter, G.; Mackay, D.; MacLellan, R.; Marino, M.; Mong, B.; Morgan, P.; Odian, A.; Piepke, A.; Pocar, A.; Prescott, C. Y.; Pushkin, K.; Rollin, E.; Rowson, P. C.; Schmoll, B.; Sinclair, D.; Skarpaas, K.; Slutsky, S.; Stekhanov, V.; Strickland, V.; Swift, M.; Vuilleumier, J.-L.; Vuilleumier, J.-M.; Wichoski, U.; Wodin, J.; Yang, L.; Yen, Y.-R.

2011-10-01

A magnetically driven piston pump for xenon gas recirculation is presented. The pump is designed to satisfy extreme purity and containment requirements, as is appropriate for the recirculation of isotopically enriched xenon through the purification system and large liquid xenon time projection chamber of EXO-200. The pump, using sprung polymer gaskets, is capable of pumping more than 16 standard liters per minute of xenon gas with 750 Torr differential pressure.

A magnetically driven piston pump for ultra-clean applications.

PubMed

LePort, F; Neilson, R; Barbeau, P S; Barry, K; Bartoszek, L; Counts, I; Davis, J; deVoe, R; Dolinski, M J; Gratta, G; Green, M; Montero Díez, M; Müller, A R; O'Sullivan, K; Rivas, A; Twelker, K; Aharmim, B; Auger, M; Belov, V; Benitez-Medina, C; Breidenbach, M; Burenkov, A; Cleveland, B; Conley, R; Cook, J; Cook, S; Craddock, W; Daniels, T; Dixit, M; Dobi, A; Donato, K; Fairbank, W; Farine, J; Fierlinger, P; Franco, D; Giroux, G; Gornea, R; Graham, K; Green, C; Hägemann, C; Hall, C; Hall, K; Hallman, D; Hargrove, C; Herrin, S; Hughes, M; Hodgson, J; Juget, F; Kaufman, L J; Karelin, A; Ku, J; Kuchenkov, A; Kumar, K; Leonard, D S; Lutter, G; Mackay, D; MacLellan, R; Marino, M; Mong, B; Morgan, P; Odian, A; Piepke, A; Pocar, A; Prescott, C Y; Pushkin, K; Rollin, E; Rowson, P C; Schmoll, B; Sinclair, D; Skarpaas, K; Slutsky, S; Stekhanov, V; Strickland, V; Swift, M; Vuilleumier, J-L; Vuilleumier, J-M; Wichoski, U; Wodin, J; Yang, L; Yen, Y-R

2011-10-01

A magnetically driven piston pump for xenon gas recirculation is presented. The pump is designed to satisfy extreme purity and containment requirements, as is appropriate for the recirculation of isotopically enriched xenon through the purification system and large liquid xenon time projection chamber of EXO-200. The pump, using sprung polymer gaskets, is capable of pumping more than 16 standard liters per minute of xenon gas with 750 Torr differential pressure.

Decontamination of Water Containing Radiological Warfare Agents

DTIC Science & Technology

1975-03-01

debris was cond~ucted undcr Project Snowball. Open tanks of water were exposed to a 500- toxi TNT explosion 2 at varying distances from grouind zero...trailhr; 4-cylinder, 4-stroke, liquid- cooled gasoline engine: aluminum evaporator-conden ser; vapor complressor; watcr pumps; heat exchanger; cngine...field consists of a 10-kw gasoline -engine-driven generator and three electric-motor-driven pumps. See Figure 21 for a photograph of the cation and anion

Effects of capillary heterogeneity on vapor-liquid counterflow in porous media

NASA Astrophysics Data System (ADS)

Stubos, A. K.; Satik, C.; Yortsos, Y. C.

1992-06-01

Based on a continuum description, the effect of capillary heterogeneity, induced by variation in permeability, on the steady state, countercurrent, vapor-liquid flow in porous media is analyzed. It is shown that the heterogeneity acts as a body force that may enhance or diminish gravity effects on heat pipes. Selection rules that determine the steady states reached in homogeneous, gravity-driven heat pipes are also formulated. It is shown that the 'infinite' two-phase zone may terminate by a substantial change in the permeability somewhere in the medium. The two possible sequences, liquid-liquid dominated-dry, or liquid-vapor dominated-dry find applications in geothermal systems. Finally, it is shown that although weak heterogeneity affects only gravity controlled flows, stronger variations in permeability can give rise to significant capillary effects.

Voltage-programmable liquid optical interface

NASA Astrophysics Data System (ADS)

Brown, C. V.; Wells, G. G.; Newton, M. I.; McHale, G.

2009-07-01

Recently, there has been intense interest in photonic devices based on microfluidics, including displays and refractive tunable microlenses and optical beamsteerers that work using the principle of electrowetting. Here, we report a novel approach to optical devices in which static wrinkles are produced at the surface of a thin film of oil as a result of dielectrophoretic forces. We have demonstrated this voltage-programmable surface wrinkling effect in periodic devices with pitch lengths of between 20 and 240 µm and with response times of less than 40 µs. By a careful choice of oils, it is possible to optimize either for high-amplitude sinusoidal wrinkles at micrometre-scale pitches or more complex non-sinusoidal profiles with higher Fourier components at longer pitches. This opens up the possibility of developing rapidly responsive voltage-programmable, polarization-insensitive transmission and reflection diffraction devices and arbitrary surface profile optical devices.

Glass transition memorized by the enthalpy-entropy compensation in the shear thinning of supercooled metallic liquids.

PubMed

Zhang, Meng; Liu, Lin

2018-05-03

To unravel the true nature of glass transition, broader insights into glass forming have been gained by examining the stress-driven glassy systems, where strong shear thinning, i.e., a reduced viscosity under increasing shear rate, is encountered. It is argued that arbitrarily small stress-driven shear rates would "melt" the glass and erase any memory of its thermal history. In this work, we report a glass transition memorized by the enthalpy-entropy compensation in strongly shear-thinned supercooled metallic liquids, which coincides with the thermal glass transition in both the transition temperature and the activation Gibbs free energy. Our findings provide distinctive insights into both glass forming and shear thinning, and enrich current knowledge on the ubiquitous enthalpy-entropy compensation empirical law in condensed matter physics. © 2018 IOP Publishing Ltd.

Radiological Aspects of Heavy Metal Liquid Targets for Accelerator-Driven Systems as Intense Neutron Sources

NASA Astrophysics Data System (ADS)

Gai, E. V.; Ignatyuk, A. V.; Lunev, V. P.; Shubin, Yu. N.

2001-11-01

General problems arising in development of intense neutron sources as a part of accelerator-driven systems and first experience accumulated in IPPE during last several years are briefly discussed. The calculation and analysis of nuclear-physical properties of the targets, such as the accumulation of spallation reaction products, activity and heat release for various versions of heavy liquid metal targets were performed in IPPE. The sensitivity of the results of calculations to the various sets of nuclear data was considered. The main radiology characteristics of the lead-bismuth target, which is now under construction in the frame of ISTC Project # 559, are briefly described. The production of short-lived nuclides was estimated, the total activity and volatile nuclide accumulation, residual heat release, the energies of various decay modes were analysed.

Glass transition memorized by the enthalpy-entropy compensation in the shear thinning of supercooled metallic liquids

NASA Astrophysics Data System (ADS)

Zhang, Meng; Liu, Lin

2018-06-01

To unravel the true nature of glass transition, broader insights into glass forming have been gained by examining the stress-driven glassy systems, where strong shear thinning, i.e. a reduced viscosity under increasing shear rate, is encountered. It is argued that arbitrarily small stress-driven shear rates would ‘melt’ the glass and erase any memory of its thermal history. In this work, we report a glass transition memorized by the enthalpy-entropy compensation in strongly shear-thinned supercooled metallic liquids, which coincides with the thermal glass transition in both the transition temperature and the activation Gibbs free energy. Our findings provide distinctive insights into both glass forming and shear thinning, and enrich current knowledge on the ubiquitous enthalpy-entropy compensation empirical law in condensed matter physics.

Chemical and biological sensing using liquid crystals

PubMed Central

Carlton, Rebecca J.; Hunter, Jacob T.; Miller, Daniel S.; Abbasi, Reza; Mushenheim, Peter C.; Tan, Lie Na; Abbott, Nicholas L.

2014-01-01

The liquid crystalline state of matter arises from orientation-dependent, non-covalent interaction between molecules within condensed phases. Because the balance of intermolecular forces that underlies formation of liquid crystals is delicate, this state of matter can, in general, be easily perturbed by external stimuli (such as an electric field in a display). In this review, we present an overview of recent efforts that have focused on exploiting the responsiveness of liquid crystals as the basis of chemical and biological sensors. In this application of liquid crystals, the challenge is to design liquid crystalline systems that undergo changes in organization when perturbed by targeted chemical and biological species of interest. The approaches described below revolve around the design of interfaces that selectively bind targeted species, thus leading to surface-driven changes in the organization of the liquid crystals. Because liquid crystals possess anisotropic optical and dielectric properties, a range of different methods can be used to read out the changes in organization of liquid crystals that are caused by targeted chemical and biological species. This review focuses on principles for liquid crystal-based sensors that provide an optical output. PMID:24795857

Field alignment of bent-core smectic liquid crystals for analog optical phase modulation

NASA Astrophysics Data System (ADS)

Shen, Y.; Goodhew, L.; Shao, R.; Moran, M.; Korblova, E.; Walba, D. M.; Clark, N. A.; Maclennan, J. E.; Rudquist, P.

2015-05-01

A general method for aligning bent-core smectic liquid crystal materials is described. Alternating electric fields between interdigitated electrodes patterned on one cell surface create torques on the liquid crystal that result in uniform "bookshelf" orientation of the smectic layers. The aligned cell can then be driven in the conventional way by applying an electric field between all of the stripe electrodes connected together and a monolithic electrode on the other cell surface. Fast, analog, optical phase-only modulation is demonstrated in a device containing a polar, bent-core SmAPF material aligned using this technique.

2D THz-THz-Raman Photon-Echo Spectroscopy of Molecular Vibrations in Liquid Bromoform.

PubMed

Finneran, Ian A; Welsch, Ralph; Allodi, Marco A; Miller, Thomas F; Blake, Geoffrey A

2017-09-21

Fundamental properties of molecular liquids are governed by long-range interactions that most prominently manifest at terahertz (THz) frequencies. Here we report the detection of nonlinear THz photon-echo (rephasing) signals in liquid bromoform using THz-THz-Raman spectroscopy. Together, the many observed signatures span frequencies from 0.5 to 8.5 THz and result from couplings between thermally populated ladders of vibrational states. The strongest peaks in the spectrum are found to be multiquantum dipole and 1-quantum polarizability transitions and may arise from nonlinearities in the intramolecular dipole moment surface driven by intermolecular interactions.

Nonlinear dynamics of confined thin liquid-vapor bilayer systems with phase change

NASA Astrophysics Data System (ADS)

Kanatani, Kentaro; Oron, Alexander

2011-03-01

We numerically investigate the nonlinear evolution of the interface of a thin liquid-vapor bilayer system confined by rigid horizontal walls from both below and above. The lateral variation of the vapor pressure arising from phase change is taken into account in the present analysis. When the liquid (vapor) is heated (cooled) and gravity acts toward the liquid, the deflection of the interface monotonically grows, leading to a rupture of the vapor layer, whereas nonruptured stationary states are found when the liquid (vapor) is cooled (heated) and gravity acts toward the vapor. In the latter case, vapor-flow-driven convective cells are found in the liquid phase in the stationary state. The average vapor pressure and interface temperature deviate from their equilibrium values once the interface departs from the flat equilibrium state. Thermocapillarity does not have a significant effect near the thermodynamic equilibrium, but becomes important if the system significantly deviates from it.

Electrically Driven Thermal Management: Flight Validation, Experiment Development, Future Technologies

NASA Technical Reports Server (NTRS)

Didion, Jeffrey R.

2018-01-01

Electrically Driven Thermal Management is an active research and technology development initiative incorporating ISS technology flight demonstrations (STP-H5), development of Microgravity Science Glovebox (MSG) flight experiment, and laboratory-based investigations of electrically based thermal management techniques. The program targets integrated thermal management for future generations of RF electronics and power electronic devices. This presentation reviews four program elements: i.) results from the Electrohydrodynamic (EHD) Long Term Flight Demonstration launched in February 2017 ii.) development of the Electrically Driven Liquid Film Boiling Experiment iii.) two University based research efforts iv.) development of Oscillating Heat Pipe evaluation at Goddard Space Flight Center.

[An interactive three-dimensional model of the human body].

PubMed

Liem, S L

2009-01-01

Driven by advanced computer technology, it is now possible to show the human anatomy on a computer. On the internet, the Visible Body programme makes it possible to navigate in all directions through the anatomical structures of the human body, using mouse and keyboard. Visible Body is a wonderful tool to give insight in the human structures, body functions and organs.

Comparison of threshold hydrologic response across northern catchments

Treesearch

Genevieve Ali; Doerthe Tetzlaff; Jeffrey J. McDonnell; Chris Soulsby; Sean Carey; Hjalmar Laudon; Kevin McGuire; Jim Buttle; Jan Seibert; Jamie Shanley

2015-01-01

Nine mid-latitude to high-latitude headwater catchments – part of the Northern Watershed Ecosystem Response to Climate Change (North-Watch) programme – were used to analyze threshold response to rainfall and snowmelt-driven events and link the different responses to the catchment characteristics of the nine sites. The North-Watch data include daily time-series of...

Surfaces and Interfaces of Ceramic Materials. Programme

DTIC Science & Technology

1988-09-01

MOCELLIN , Ecole Polytechnque Fdlale, Lausanne, Switzerland 9.30-1030 ROUND TABLE . Sintering processes,(Discussion leader A MOCELLIN , Ecole...TABLE& Sinteringprocesses (second part) (Discussion leader A MOCELLIN , Ecole Polytechnique Fgdrale, Lausanne, Switzerland) P27 / Amrfialevidnesih A4... MOCELLIN Laboratoire de c6ramique Ecole Polytechnique F6d6rale de Lausanne ABSTRACT In polycrystalline ceramics, grain growth which is driven by the

Decision Aids Using Heterogeneous Intelligence Analysis

DTIC Science & Technology

2010-08-20

developing a Geocultural service, a software framework and inferencing engine for the Transparent Urban Structures program. The scope of the effort...has evolved as the program has matured and is including multiple data sources, as well as interfaces out to the ONR architectural framework . Tasks...Interface; Application Program Interface; Application Programmer Interface CAF Common Application Framework EDA Event Driven Architecture a 16. SECURITY

Engineering Skills Education: The Bachelor of Engineering Programme of the "Vrije Universiteit Brussel" as a Case Study

ERIC Educational Resources Information Center

Van Biesen, Leo Pierre; Rahier, Hubert; Vanherzeele, Herman; Willem, Rudolph; Hubin, Annick; Veretennicoff, Irina; Deblauwe, Nico; Ponet, Mireille

2009-01-01

The Bologna process has triggered an important change in the course outline towards a sustainable, transparent and quality-driven European education system. In Belgium, engineering education had to be completely revised. The transformation of the former system, leading to the degree of academic engineer after five years of study, into the typical…

Eco-Driven Chemical Research in the Boundary Between Academia and Industry. PhD Students' Views on Science and Society

NASA Astrophysics Data System (ADS)

Sjöström, Jesper

2013-10-01

This paper examines and discusses the views on science and society held among PhD students working in two different industrially and environmentally driven research programmes in the broad area of green chemistry. It is based on thirteen in-depth interviews. The analysis shows three main ways of handling the situation as "post-academic" PhD student: (1) the student sees the PhD work mainly as a job and does not reflect about his/her research or the research funding, (2) the student is satisfied with the post-academic situation, accepts the established innovation policy discourse and is sceptical to traditional academic research, and (3) the student sees collaborative research programmes as a way to get funding, which can be used for secretly done basic research. Most PhD students either emphasise usefulness—in line with the dominating research policy discourse—or they adopt the positivistic view of science as objective and independent of the surrounding society. However, there are only a few signs of "double problematisation", that is a critical view where both disciplinary-oriented and industry-dependent research are problematised.

Safety and efficacy for new techniques and imaging using new equipment to support European legislation: an EU coordination action.

PubMed

Zoetelief, J; Faulkner, K

2008-01-01

The past two decades have witnessed a technologically driven revolution in radiology. At the centre of these developments has been the use of computing. These developments have also been driven by the introduction of new detector and imaging devices in radiology and nuclear medicine, as well as the widespread application of computing techniques to enhance and extract information within the images acquired. Further advances have been introduced into digital practice. These technological developments, however, have not been matched by justification and optimisation studies to ensure that these new imaging devices and techniques are as effective as they might be, or performed at the lowest possible dose. The work programme of the SENTINEL Coordination Action was subdivided into eight work packages: functional performance and standards; efficacy and safety in digital radiology, dentistry and nuclear medicine, cardiology, interventional radiology, population screening/sensitive groups; justification, ethics and efficacy; good practice guidance and training; and project management. The intention of the work programme was to underwrite the safety, efficacy and ethical aspects of digital practice as well as to protect and add value to the equipment used in radiology.

Atomic Force Microscope Mediated Chromatography

NASA Technical Reports Server (NTRS)

Anderson, Mark S.

2013-01-01

The atomic force microscope (AFM) is used to inject a sample, provide shear-driven liquid flow over a functionalized substrate, and detect separated components. This is demonstrated using lipophilic dyes and normal phase chromatography. A significant reduction in both size and separation time scales is achieved with a 25-micron-length column scale, and one-second separation times. The approach has general applications to trace chemical and microfluidic analysis. The AFM is now a common tool for ultra-microscopy and nanotechnology. It has also been demonstrated to provide a number of microfluidic functions necessary for miniaturized chromatography. These include injection of sub-femtoliter samples, fluidic switching, and sheardriven pumping. The AFM probe tip can be used to selectively remove surface layers for subsequent microchemical analysis using infrared and tip-enhanced Raman spectroscopy. With its ability to image individual atoms, the AFM is a remarkably sensitive detector that can be used to detect separated components. These diverse functional components of microfluidic manipulation have been combined in this work to demonstrate AFM mediated chromatography. AFM mediated chromatography uses channel-less, shear-driven pumping. This is demonstrated with a thin, aluminum oxide substrate and a non-polar solvent system to separate a mixture of lipophilic dyes. In conventional chromatographic terms, this is analogous to thin-layer chromatography using normal phase alumina substrate with sheardriven pumping provided by the AFM tip-cantilever mechanism. The AFM detection of separated components is accomplished by exploiting the variation in the localized friction of the separated components. The AFM tip-cantilever provides the mechanism for producing shear-induced flows and rapid pumping. Shear-driven chromatography (SDC) is a relatively new concept that overcomes the speed and miniaturization limitations of conventional liquid chromatography. SDC is based on a sliding plate system, consisting of two flat surfaces, one of which has a recessed channel. A fluid flow is produced by axially sliding one plate past another, where the fluid has mechanical shear forces imposed at each point along the channel length. The shear-induced flow rates are very reproducible, and do not have pressure or voltage gradient limitations. SDC opens up a new range of enhanced separation kinetics by permitting the sample confinement with submicron dimensions. Small, highly confined liquid is advantageous for chromatographic separation because the separation rate is known to scale according to the square of the confined sample diameter. In addition, because shear-driven flows are not limited by fluid velocity, shear-driven liquid chromatography may provide up to 100,000 plate efficiency.

Dynamics of gas-driven eruptions: Experimental simulations using CO2-H2O-polymer system

NASA Astrophysics Data System (ADS)

Zhang, Youxue; Sturtevant, B.; Stolper, E. M.

1997-02-01

We report exploratory experiments simulating gas-driven eruptions using the CO2-H2O system at room temperature as an analog of natural eruptive systems. The experimental apparatus consists of a test cell and a large tank. Initially, up to 1.0 wt% of CO2 is dissolved in liquid water under a pressure of up to 735 kPa in the test cell. The experiment is initiated by suddenly reducing the pressure of the test cell to a typical tank pressure of 10 kPa. The following are the main results: (1) The style of the process depends on the decompression ratio. There is a threshold decompression ratio above which rapid eruption occurs. (2) During rapid eruption, there is always fragmentation at the liquid-vapor interface. Fragmentation may also occur in the flow interior. (3) Initially, the top of the erupting column ascends at a constant acceleration (instead of constant velocity). (4) Average bubble radius grows as t2/3. (5) When viscosity is 20 times that of pure water or greater, a static foam may be stable after expansion to 97% vesicularity. The experiments provide several insights into natural gas-driven eruptions, including (1) the interplay between bubble growth and ascent of the erupting column must be considered for realistic modeling of bubble growth during gas-driven eruptions, (2) buoyant rise of the bubbly magma is not necessary during an explosive volcanic eruption, and (3) CO2-driven limnic eruptions can be explosive. The violence increases with the initial CO2 content dissolved in water.

Thermally-Rechargeable Electrochemical Cell

NASA Technical Reports Server (NTRS)

Richter, R.

1985-01-01

Proposed liquid-sodium/sulfur electrochemical cell recharged by heat, rather than electric generator. Concept suitable for energy storage for utilites, mobile electronic equipment, and solar thermoelectric power systems. Sodium ions driven across membrane with aid of temperature differential.

Polymer-dispersed liquid crystal elastomers

NASA Astrophysics Data System (ADS)

Rešetič, Andraž; Milavec, Jerneja; Zupančič, Blaž; Domenici, Valentina; Zalar, Boštjan

2016-10-01

The need for mechanical manipulation during the curing of conventional liquid crystal elastomers diminishes their applicability in the field of shape-programmable soft materials and future applications in additive manufacturing. Here we report on polymer-dispersed liquid crystal elastomers, novel composite materials that eliminate this difficulty. Their thermal shape memory anisotropy is imprinted by curing in external magnetic field, providing for conventional moulding of macroscopically sized soft, thermomechanically active elastic objects of general shapes. The binary soft-soft composition of isotropic elastomer matrix, filled with freeze-fracture-fabricated, oriented liquid crystal elastomer microparticles as colloidal inclusions, allows for fine-tuning of thermal morphing behaviour. This is accomplished by adjusting the concentration, spatial distribution and orientation of microparticles or using blends of microparticles with different thermomechanical characteristics. We demonstrate that any Gaussian thermomechanical deformation mode (bend, cup, saddle, left and right twist) of a planar sample, as well as beat-like actuation, is attainable with bilayer microparticle configurations.

Boundary layers in turbulent convection for air, liquid gallium and liquid sodium

NASA Astrophysics Data System (ADS)

Scheel, Janet; Schumacher, Joerg

2017-11-01

The scaling of physical quantities that characterize the shape and dynamics of the viscous and thermal boundary layers with respect to the Rayleigh number will be presented for three series of three-dimensional high-resolution direct numerical simulations of Rayleigh-Benard convection (RBC) in a closed cylindrical cell of aspect ratio one. The simulations have been conducted for convection in air at a Prandtl number Pr = 0.7, in liquid gallium at Pr = 0.021 and in liquid sodium at Pr = 0.005. Then we discuss three statistical analysis methods which have been developed to predict the transition of turbulent RBC into the ultimate regime. The methods are based on the large-scale properties of the velocity profile. All three methods indicate that the range of critical Rayleigh numbers is shifted to smaller magnitudes as the Prandtl number becomes smaller. This work is supported by the Priority Programme SPP 1881 of the Deutsche Forschungsgemeinschaft.

The effect of surfactant on stratified and stratifying gas-liquid flows

NASA Astrophysics Data System (ADS)

Heiles, Baptiste; Zadrazil, Ivan; Matar, Omar

2013-11-01

We consider the dynamics of a stratified/stratifying gas-liquid flow in horizontal tubes. This flow regime is characterised by the thin liquid films that drain under gravity along the pipe interior, forming a pool at the bottom of the tube, and the formation of large-amplitude waves at the gas-liquid interface. This regime is also accompanied by the detachment of droplets from the interface and their entrainment into the gas phase. We carry out an experimental study involving axial- and radial-view photography of the flow, in the presence and absence of surfactant. We show that the effect of surfactant is to reduce significantly the average diameter of the entrained droplets, through a tip-streaming mechanism. We also highlight the influence of surfactant on the characteristics of the interfacial waves, and the pressure gradient that drives the flow. EPSRC Programme Grant EP/K003976/1.

Approaches to rationing antiretroviral treatment: ethical and equity implications.

PubMed Central

Bennett, Sara; Chanfreau, Catherine

2005-01-01

Despite a growing global commitment to the provision of antiretroviral therapy (ART), its availability is still likely to be less than the need. This imbalance raises ethical dilemmas about who should be granted access to publicly-subsidized ART programmes. This paper reviews the eligibility and targeting criteria used in four case-study countries at different points in the scale-up of ART, with the aim of drawing lessons regarding ethical approaches to rationing. Mexico, Senegal, Thailand and Uganda have each made an explicit policy commitment to provide antiretrovirals to all those in need, but are achieving this goal in steps--beginning with explicit rationing of access to care. Drawing upon the case-studies and experiences elsewhere, categories of explicit rationing criteria have been identified. These include biomedical factors, adherence to treatment, prevention-driven factors, social and economic benefits, financial factors and factors driven by ethical arguments. The initial criteria for determining eligibility are typically clinical criteria and assessment of adherence prospects, followed by a number of other factors. Rationing mechanisms reflect several underlying ethical theories and the ethical underpinnings of explicit rationing criteria should reflect societal values. In order to ensure this alignment, widespread consultation with a variety of stakeholders, and not only policy-makers or physicians, is critical. Without such explicit debate, more rationing will occur implicitly and this may be more inequitable. The effects of rationing mechanisms upon equity are critically dependent upon the implementation processes. As antiretroviral programmes are implemented it is crucial to monitor who gains access to these programmes. PMID:16175829

Measuring the Coefficient of Friction of a Small Floating Liquid Marble

PubMed Central

Ooi, Chin Hong; Nguyen, Anh Van; Evans, Geoffrey M.; Dao, Dzung Viet; Nguyen, Nam-Trung

2016-01-01

This paper investigates the friction coefficient of a moving liquid marble, a small liquid droplet coated with hydrophobic powder and floating on another liquid surface. A floating marble can easily move across water surface due to the low friction, allowing for the transport of aqueous solutions with minimal energy input. However, the motion of a floating marble has yet to be systematically characterised due to the lack of insight into key parameters such as the coefficient of friction between the floating marble and the carrier liquid. We measured the coefficient of friction of a small floating marble using a novel experimental setup that exploits the non-wetting properties of a liquid marble. A floating liquid marble pair containing a minute amount magnetite particles were immobilised and then released in a controlled manner using permanent magnets. The capillarity-driven motion was analysed to determine the coefficient of friction of the liquid marbles. The “capillary charge” model was used to fit the experimental results. We varied the marble content and carrier liquid to establish a relationship between the friction correction factor and the meniscus angle. PMID:27910916

Mechanisms of differentiation in the Skaergaard magma chamber

NASA Astrophysics Data System (ADS)

Tegner, C.; Lesher, C. E.; Holness, M. B.; Jakobsen, J. K.; Salmonsen, L. P.; Humphreys, M. C. S.; Thy, P.

2012-04-01

The Skaergaard intrusion is a superb natural laboratory for studying mechanisms of magma chamber differentiation. The magnificent exposures and new systematic sample sets of rocks that solidified inwards from the roof, walls and floor of the chamber provide means to test the relative roles of crystal settling, diffusion, convection, liquid immiscibility and compaction in different regions of the chamber and in opposite positions relative to gravity. Examination of the melt inclusions and interstitial pockets has demonstrated that a large portion of intrusion crystallized from an emulsified magma chamber composed of immiscible silica- and iron-rich melts. The similarity of ratios of elements with opposite partitioning between the immiscible melts (e.g. P and Rb) in wall, floor and roof rocks, however, indicate that large-scale separation did not occur. Yet, on a smaller scale of metres to hundred of metres and close to the interface between the roof and floor rocks (the Sandwich Horizon), irregular layers and pods of granophyre hosted by extremely iron-rich cumulates point to some separation of the two liquid phases. Similar proportions of the primocryst (cumulus) minerals in roof, wall and floor rocks indicate that crystal settling was not an important mechanism. Likewise, the lack of fractionation of elements with different behavior indicate that diffusion and fluid-driven metasomatism played relatively minor roles. Compositional convection and/or compaction within the solidifying crystal mush boundary layer are likely the most important mechanisms. A correlation of low trapped liquid fractions (calculated from strongly incompatible elements) in floor rocks with high fractionation density (the density difference between the crystal framework and the liquid) indicate that compaction is the dominating process in expelling evolved liquid from the crystal mush layer. This is supported by high and variable trapped liquid contents in the roof rocks, where gravity-driven compaction will not work.

Sustenance and sustainability: maximizing the impact of school gardens on health outcomes.

PubMed

Davis, Jaimie N; Spaniol, Mackenzie R; Somerset, Shawn

2015-09-01

School garden programmes have become popular action-oriented learning environments in many countries, often driven by converging priorities of environmental sustainability and healthful diets. Many of these programmes have assessed the impact on dietary intake, specifically fruit and vegetable intake, and related dietary behaviours, such as knowledge, preference, motivation, intention and self-efficacy to eat and prepare fruit and vegetables. The objective of the present study was twofold: (i) to review published garden-based programmes conducted in schools targeting dietary intake and/or determinants of dietary behaviour in children; and (ii) to identify similar strategies and components employed by these garden-based programmes. The review included thirteen studies that have examined the impact of garden-based programmes conducted in school, either during school hours or in after-school settings, on dietary behaviours in children (kindergarten through 8th grade students). Three of the reviewed studies did not have a comparison or control group and simply evaluated within-group changes after a garden intervention. None of the reviewed studies were randomized, but were assigned based on school's interest and timing of new school gardens being built. Out of the eleven programmes that examined dietary intake, six found that the programme resulted in increased vegetable intake, whereas four showed no effect. Seven of the eight studies that measured preference found that the programmes resulted in increased preference for vegetables. Gardening programmes also resulted in improved attitudes towards, willingness to taste, identification of and self-efficacy to prepare/cook fruit and vegetables. Similar strategies/components employed by the majority of the programmes included: 'hands on' curriculum, incorporation of a cooking component, providing the instructors, parental and stakeholder support, food provision and using the garden as the focal point for media promotion. Some of the garden programmes resulted in increased vegetable intake, which has positive implications for both environment sustainability and health-related outcomes. Further, the majority resulted in some improvement in behaviour determinants more generally. However, more research is warranted to understand how to achieve long-term improvements in dietary behaviours and how to sustain the garden-based programmes in schools.

Liquid-Crystal-Enabled Active Plasmonics: A Review

PubMed Central

Si, Guangyuan; Zhao, Yanhui; Leong, Eunice Sok Ping; Liu, Yan Jun

2014-01-01

Liquid crystals are a promising candidate for development of active plasmonics due to their large birefringence, low driving threshold, and versatile driving methods. We review recent progress on the interdisciplinary research field of liquid crystal based plasmonics. The research scope of this field is to build the next generation of reconfigurable plasmonic devices by combining liquid crystals with plasmonic nanostructures. Various active plasmonic devices, such as switches, modulators, color filters, absorbers, have been demonstrated. This review is structured to cover active plasmonic devices from two aspects: functionalities and driven methods. We hope this review would provide basic knowledge for a new researcher to get familiar with the field, and serve as a reference for experienced researchers to keep up the current research trends. PMID:28788515

Two-component Gaussian core model: Strong-coupling limit, Bjerrum pairs, and gas-liquid phase transition.

PubMed

Frydel, Derek; Levin, Yan

2018-01-14

In the present work, we investigate a gas-liquid transition in a two-component Gaussian core model, where particles of the same species repel and those of different species attract. Unlike a similar transition in a one-component system with particles having attractive interactions at long separations and repulsive interactions at short separations, a transition in the two-component system is not driven solely by interactions but by a specific feature of the interactions, the correlations. This leads to extremely low critical temperature, as correlations are dominant in the strong-coupling limit. By carrying out various approximations based on standard liquid-state methods, we show that a gas-liquid transition of the two-component system poses a challenging theoretical problem.

Two-component Gaussian core model: Strong-coupling limit, Bjerrum pairs, and gas-liquid phase transition

NASA Astrophysics Data System (ADS)

Frydel, Derek; Levin, Yan

2018-01-01

In the present work, we investigate a gas-liquid transition in a two-component Gaussian core model, where particles of the same species repel and those of different species attract. Unlike a similar transition in a one-component system with particles having attractive interactions at long separations and repulsive interactions at short separations, a transition in the two-component system is not driven solely by interactions but by a specific feature of the interactions, the correlations. This leads to extremely low critical temperature, as correlations are dominant in the strong-coupling limit. By carrying out various approximations based on standard liquid-state methods, we show that a gas-liquid transition of the two-component system poses a challenging theoretical problem.

Dynamical time-reversal symmetry breaking and photo-induced chiral spin liquids in frustrated Mott insulators

DOE PAGES

Claassen, Martin; Jiang, Hong -Chen; Moritz, Brian; ...

2017-10-30

The search for quantum spin liquids in frustrated quantum magnets recently has enjoyed a surge of interest, with various candidate materials under intense scrutiny. However, an experimental confirmation of a gapped topological spin liquid remains an open question. Here, we show that circularly polarized light can provide a knob to drive frustrated Mott insulators into a chiral spin liquid, realizing an elusive quantum spin liquid with topological order. We find that the dynamics of a driven Kagome Mott insulator is well-captured by an effective Floquet spin model, with heating strongly suppressed, inducing a scalar spin chirality S i · (Smore » j × S k) term which dynamically breaks time-reversal while preserving SU(2) spin symmetry. We fingerprint the transient phase diagram and find a stable photo-induced chiral spin liquid near the equilibrium state. Furthermore, the results presented suggest employing dynamical symmetry breaking to engineer quantum spin liquids and access elusive phase transitions that are not readily accessible in equilibrium.« less

Programmable fuzzy associative memory processor

NASA Astrophysics Data System (ADS)

Shao, Lan; Liu, Liren; Li, Guoqiang

1996-02-01

An optical system based on the method of spatial area-coding and multiple image scheme is proposed for fuzzy associative memory processing. Fuzzy maximum operation is accomplished by a ferroelectric liquid crystal PROM instead of a computer-based approach. A relative subsethood is introduced here to be used as a criterion for the recall evaluation.

Customizable 3D Printed ‘Plug and Play’ Millifluidic Devices for Programmable Fluidics

PubMed Central

Tsuda, Soichiro; Jaffery, Hussain; Doran, David; Hezwani, Mohammad; Robbins, Phillip J.; Yoshida, Mari; Cronin, Leroy

2015-01-01

Three dimensional (3D) printing is actively sought after in recent years as a promising novel technology to construct complex objects, which scope spans from nano- to over millimeter scale. Previously we utilized Fused deposition modeling (FDM)-based 3D printer to construct complex 3D chemical fluidic systems, and here we demonstrate the construction of 3D milli-fluidic structures for programmable liquid handling and control of biological samples. Basic fluidic operation devices, such as water-in-oil (W/O) droplet generators for producing compartmentalized mono-disperse droplets, sensor-integrated chamber for online monitoring of cellular growth, are presented. In addition, chemical surface treatment techniques are used to construct valve-based flow selector for liquid flow control and inter-connectable modular devices for networking fluidic parts. As such this work paves the way for complex operations, such as mixing, flow control, and monitoring of reaction / cell culture progress can be carried out by constructing both passive and active components in 3D printed structures, which designs can be shared online so that anyone with 3D printers can reproduce them by themselves. PMID:26558389

Active optics null test system based on a liquid crystal programmable spatial light modulator

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

Ares, Miguel; Royo, Santiago; Sergievskaya, Irina

2010-11-10

We present an active null test system adapted to test lenses and wavefronts with complex shapes and strong local deformations. This system provides greater flexibility than conventional static null tests that match only a precisely positioned, individual wavefront. The system is based on a cylindrical Shack-Hartmann wavefront sensor, a commercial liquid crystal programmable phase modulator (PPM), which acts as the active null corrector, enabling the compensation of large strokes with high fidelity in a single iteration, and a spatial filter to remove unmodulated light when steep phase changes are compensated. We have evaluated the PPM's phase response at 635 nmmore » and checked its performance by measuring its capability to generate different amounts of defocus aberration, finding root mean squared errors below {lambda}/18 for spherical wavefronts with peak-to-valley heights of up to 78.7{lambda}, which stands as the limit from which diffractive artifacts created by the PPM have been found to be critical under no spatial filtering. Results of a null test for a complex lens (an ophthalmic customized progressive addition lens) are presented and discussed.« less

Fabrication of heterogeneous nanomaterial array by programmable heating and chemical supply within microfluidic platform towards multiplexed gas sensing application

PubMed Central

Yang, Daejong; Kang, Kyungnam; Kim, Donghwan; Li, Zhiyong; Park, Inkyu

2015-01-01

A facile top-down/bottom-up hybrid nanofabrication process based on programmable temperature control and parallel chemical supply within microfluidic platform has been developed for the all liquid-phase synthesis of heterogeneous nanomaterial arrays. The synthesized materials and locations can be controlled by local heating with integrated microheaters and guided liquid chemical flow within microfluidic platform. As proofs-of-concept, we have demonstrated the synthesis of two types of nanomaterial arrays: (i) parallel array of TiO2 nanotubes, CuO nanospikes and ZnO nanowires, and (ii) parallel array of ZnO nanowire/CuO nanospike hybrid nanostructures, CuO nanospikes and ZnO nanowires. The laminar flow with negligible ionic diffusion between different precursor solutions as well as localized heating was verified by numerical calculation and experimental result of nanomaterial array synthesis. The devices made of heterogeneous nanomaterial array were utilized as a multiplexed sensor for toxic gases such as NO2 and CO. This method would be very useful for the facile fabrication of functional nanodevices based on highly integrated arrays of heterogeneous nanomaterials. PMID:25634814

Interfacial Dynamics of Condensing Vapor Bubbles in an Ultrasonic Acoustic Field

NASA Astrophysics Data System (ADS)

Boziuk, Thomas; Smith, Marc; Glezer, Ari

2016-11-01

Enhancement of vapor condensation in quiescent subcooled liquid using ultrasonic actuation is investigated experimentally. The vapor bubbles are formed by direct injection from a pressurized steam reservoir through nozzles of varying characteristic diameters, and are advected within an acoustic field of programmable intensity. While kHz-range acoustic actuation typically couples to capillary instability of the vapor-liquid interface, ultrasonic (MHz-range) actuation leads to the formation of a liquid spout that penetrates into the vapor bubble and significantly increases its surface area and therefore condensation rate. Focusing of the ultrasonic beam along the spout leads to ejection of small-scale droplets from that are propelled towards the vapor liquid interface and result in localized acceleration of the condensation. High-speed video of Schlieren images is used to investigate the effects of the ultrasonic actuation on the thermal boundary layer on the liquid side of the vapor-liquid interface and its effect on the condensation rate, and the liquid motion during condensation is investigated using high-magnification PIV measurements. High-speed image processing is used to assess the effect of the actuation on the dynamics and temporal variation in characteristic scale (and condensation rate) of the vapor bubbles.

Metrology in electricity and magnetism: EURAMET activities today and tomorrow

NASA Astrophysics Data System (ADS)

Piquemal, F.; Jeckelmann, B.; Callegaro, L.; Hällström, J.; Janssen, T. J. B. M.; Melcher, J.; Rietveld, G.; Siegner, U.; Wright, P.; Zeier, M.

2017-10-01

Metrology dedicated to electricity and magnetism has changed considerably in recent years. It encompasses almost all modern scientific, industrial, and societal challenges, e.g. the revision of the International System of Units, the profound transformation of industry, changes in energy use and generation, health, and environment, as well as nanotechnologies (including graphene and 2D materials) and quantum engineering. Over the same period, driven by the globalization of worldwide trade, the Mutual Recognition Arrangement (referred to as the CIPM MRA) was set up. As a result, the regional metrology organizations (RMOs) of national metrology institutes have grown in significance. EURAMET is the European RMO and has been very prominent in developing a strategic research agenda (SRA) and has established a comprehensive research programme. This paper reviews the highlights of EURAMET in electrical metrology within the European Metrology Research Programme and its main contributions to the CIPM MRA. In 2012 EURAMET undertook an extensive roadmapping exercise for proposed activities for the next decade which will also be discussed in this paper. This work has resulted in a new SRA of the second largest European funding programme: European Metrology Programme for Innovation and Research.

Sloshing dynamics modulated fluid angular momentum and moment fluctuations driven by orbital gravity gradient and jitter accelerations in microgravity

NASA Technical Reports Server (NTRS)

Hung, R. J.; Pan, H. L.

1995-01-01

The dynamical behavior of spacecraft propellant affected by the asymmetric combined gravity gradient and jitter accelerations, in particular the effect of surface tension on partially-filled rotating fluids applicable to a full-scale Gravity Probe-B Spacecraft dewar tank has been investigated. Three different cases of orbital accelerations: (1) gravity gradient-dominated, (2) equally weighted between gravity gradient and jitter, and (3) gravity jitter-dominated accelerations are studied. The results of slosh wave excitation along the liquid-vapor interface induced by gravity gradient-dominated accelerations provide a torsional moment with tidal motion of bubble oscillations in the rotating dewar. The results are clearly seen from the twisting shape of the bubble oscillations driven by gravity gradient-dominated acceleration. The results of slosh wave excitation along the liquid-vapor interface induced by gravity jitter-dominated acceleration indicate the results of bubble motion in a manner of down-and-up and leftward-and-rightward movement of oscillation when the bubble is rotating with respect to rotating dewar axis. Fluctuations of angular momentum, fluid moment and bubble mass center caused by slosh wave excitations driven by gravity gradient acceleration or gravity jitter acceleration are also investigated.

Possibility of H2O2 decomposition in thin liquid films on Mars

NASA Astrophysics Data System (ADS)

Kereszturi, Akos; Gobi, Sandor

2014-11-01

In this work the pathways and possibilities of H2O2 decomposition on Mars in microscopic liquid interfacial water were analyzed by kinetic calculations. Thermal and photochemical driven decomposition, just like processes catalyzed by various metal oxides, is too slow compared to the annual duration while such microscopic liquid layers exist on Mars today, to produce substantial decomposition. The most effective analyzed process is catalyzed by Fe ions, which could decompose H2O2 under pH<4.5 with a half life of 1-2 days. This process might be important during volcanically influenced periods when sulfur release produces acidic pH, and rotational axis tilt change driven climatic changes also influence the volatile circulation and spatial occurrence just like the duration of thin liquid layer. Under current conditions, using the value of 200 K as the temperature in interfacial water (at the southern hemisphere), and applying Phoenix lander's wet chemistry laboratory results, the pH is not favorable for Fe mobility and this kind of decomposition. Despite current conditions (especially pH) being unfavorable for H2O2 decomposition, microscopic scale interfacial liquid water still might support the process. By the reaction called heterogeneous catalysis, without acidic pH and mobile Fe, but with minerals surfaces containing Fe decomposition of H2O2 with half life of 20 days can happen. This duration is still longer but not several orders than the existence of springtime interfacial liquid water on Mars today. This estimation is relevant for activation energy controlled reaction rates. The other main parameter that may influence the reaction rate is the diffusion speed. Although the available tests and theoretical calculations do not provide firm values for the diffusion speed in such a “2-dimensional” environment, using relevant estimations this parameter in the interfacial liquid layer is smaller than in bulk water. But the 20 days' duration mentioned above is still relevant, as the activation energy driven reaction rate is the main limiting factor in the decomposition and not the diffusion speed. The duration of dozen(s) days is still longer but not with orders of magnitude than the expected duration for the existence of springtime interfacial liquid water on Mars today. The results suggest such decomposition may happen today, however, because of our limited knowledge on chemical processes in thin interfacial liquid layers, this possibility waits for confirmation - and also points to the importance of conducting laboratory tests to validate the possible process. Although some tests were already realized for diffusion in an almost 2-dimensional liquid, the same is not true for activation energy, where only the value from the “normal” measurements was applied. Even if H2O2 decomposition is too slow today, the analysis of such a process is important, as under volcanic influence more effective decomposition might take place in thin interfacial liquids close to the climate of today if released sulfur produces pH<4.5. Large quantity and widespread occurrence of bulk liquid phase are not expected in the Amazonian period, but interfacial liquid water probably appeared regularly, and its locations, especially during volcanically active periods, might make certain sites than others more interesting for astrobiology with the lower concentration of oxidizing H2O2.

Cryobot: an ice penetrating robotic vehicle for Mars and Europa

NASA Technical Reports Server (NTRS)

Zimmerman, W. F.; Bonitz, R.; Feldman, J.

2001-01-01

This paper describes the science driven requirements for a robotic vehicle, which utilizes gravity, and both passive and active heating systems to drive ice to a liquid phase change state, in order to facilitate mobility.

Surface tension-driven self-alignment.

PubMed

Mastrangeli, Massimo; Zhou, Quan; Sariola, Veikko; Lambert, Pierre

2017-01-04

Surface tension-driven self-alignment is a passive and highly-accurate positioning mechanism that can significantly simplify and enhance the construction of advanced microsystems. After years of research, demonstrations and developments, the surface engineering and manufacturing technology enabling capillary self-alignment has achieved a degree of maturity conducive to a successful transfer to industrial practice. In view of this transition, a broad and accessible review of the physics, material science and applications of capillary self-alignment is presented. Statics and dynamics of the self-aligning action of deformed liquid bridges are explained through simple models and experiments, and all fundamental aspects of surface patterning and conditioning, of choice, deposition and confinement of liquids, and of component feeding and interconnection to substrates are illustrated through relevant applications in micro- and nanotechnology. A final outline addresses remaining challenges and additional extensions envisioned to further spread the use and fully exploit the potential of the technique.

Shock driven melting and resolidification upon release in cerium

NASA Astrophysics Data System (ADS)

Bolme, Cindy; Bronkhorst, Curt; Brown, Don; Cherne, Frank; Cooley, Jason; Furlanetto, Michael; Gleason, Arianna; Jensen, Brian; Owens, Charles; Ali, Suzanne; Fratanduono, Dayne; Galtier, Eric; Granados, Eduardo; Lee, Hae Ja; Nagler, Bob

2017-06-01

The temperature rise due to increasing entropy during shock compression and the corresponding temperature decrease due to isentropic expansion upon release cause the physics of melting and solidification under dynamic pressure changes to differ fundamentally from the more common liquid-solid transitions governed by thermal diffusion. We investigated laser shock driven melting and resolidification during release in cerium to examine the dynamics of these processes. Cerium was selected as the material of study due to the low pressure at which γ-cerium melts along the principle Hugoniot and due to cerium's anomalous melt boundary at low pressure, which facilitates its transition from liquid to solid during isentropic release. The structural phase of cerium was probed with X-ray diffraction using the LCLS X-ray free electron laser, which provided in situ measurements of the transition dynamics. The experimental results will be presented showing the resolidification occurring over 10s of ns.

Azimuthal swirl in liquid metal electrodes and batteries

NASA Astrophysics Data System (ADS)

Ashour, Rakan; Kelley, Douglas

2016-11-01

Liquid metal batteries consist of two molten metals with different electronegativity separated by molten salt. In these batteries, critical performance related factors such as the limiting current density are governed by fluid mixing in the positive electrode. In this work we present experimental results of a swirling flow in a layer of molten lead-bismuth alloy driven by electrical current. Using in-situ ultrasound velocimetery, we show that poloidal circulation appears at low current density, whereas azimuthal swirl becomes dominant at higher current density. The presence of thermal gradients produces buoyant forces, which are found to compete with those produced by current injection. Taking the ratio of the characteristic electromagnetic to buoyant flow velocity, we are able to predict the current density at which the flow becomes electromagnetically driven. Scaling arguments are also used to show that swirl is generated through self-interaction between the electrical current in the electrode with its own magnetic field.

Surface-tension-driven flow in a glass melt

NASA Technical Reports Server (NTRS)

Mcneil, Thomas J.; Cole, Robert; Shankar Subramanian, R.

1985-01-01

Motion driven by surface tension gradients was observed in a vertical capillary liquid bridge geometry in a sodium borate melt. The surface tension gradients were introduced by maintaining a temperature gradient on the free melt surface. The flow velocities at the free surface of the melt, which were measured using a tracer technique, were found to be proportional to the applied temperature difference and inversely proportional to the melt viscosity. The experimentally observed velocities were in reasonable accord with predictions from a theoretical model of the system.

Dealing with locally-driven degradation: A quick start option under REDD+.

PubMed

Skutsch, Margaret M; Torres, Arturo Balderas; Mwampamba, Tuyeni H; Ghilardi, Adrian; Herold, Martin

2011-12-28

The paper reviews a number of challenges associated with reducing degradation and its related emissions through national approaches to REDD+ under UNFCCC policy. It proposes that in many countries, it may in the short run be easier to deal with the kinds of degradation that result from locally driven community over-exploitation of forest for livelihoods, than from selective logging or fire control. Such degradation is low-level, but chronic, and is experienced over very large forest areas. Community forest management programmes tend to result not only in reduced degradation, but also in forest enhancement; moreover they are often popular, and do not require major political shifts. In principle these approaches therefore offer a quick start option for REDD+. Developing reference emissions levels for low-level locally driven degradation is difficult however given that stock losses and gains are too small to be identified and measured using remote sensing, and that in most countries there is little or no forest inventory data available. We therefore propose that forest management initiatives at the local level, such as those promoted by community forest management programmes, should monitor, and be credited for, only the net increase in carbon stock over the implementation period, as assessed by ground level surveys at the start and end of the period. This would also resolve the problem of nesting (ensuring that all credits are accounted for against the national reference emission level), since communities and others at the local level would be rewarded only for increased sequestration, while the national reference emission level would deal only with reductions in emissions from deforestation and degradation.

True Shear Parallel Plate Viscometer

NASA Technical Reports Server (NTRS)

Ethridge, Edwin; Kaukler, William

2010-01-01

This viscometer (which can also be used as a rheometer) is designed for use with liquids over a large temperature range. The device consists of horizontally disposed, similarly sized, parallel plates with a precisely known gap. The lower plate is driven laterally with a motor to apply shear to the liquid in the gap. The upper plate is freely suspended from a double-arm pendulum with a sufficiently long radius to reduce height variations during the swing to negligible levels. A sensitive load cell measures the shear force applied by the liquid to the upper plate. Viscosity is measured by taking the ratio of shear stress to shear rate.

The identification of liquid ethane in Titan's Ontario Lacus

USGS Publications Warehouse

Brown, R.H.; Soderblom, L.A.; Soderblom, J.M.; Clark, R.N.; Jaumann, R.; Barnes, J.W.; Sotin, Christophe; Buratti, B.; Baines, K.H.; Nicholson, P.D.

2008-01-01

Titan was once thought to have global oceans of light hydrocarbons on its surface, but after 40 close flybys of Titan by the Cassini spacecraft, it has become clear that no such oceans exist. There are, however, features similar to terrestrial lakes and seas, and widespread evidence for fluvial erosion, presumably driven by precipitation of liquid methane from Titan's dense, nitrogen-dominated atmosphere. Here we report infrared spectroscopic data, obtained by the Visual and Infrared Mapping Spectrometer (VIMS) on board the Cassini spacecraft, that strongly indicate that ethane, probably in liquid solution with methane, nitrogen and other low-molecular-mass hydrocarbons, is contained within Titan's Ontario Lacus.

Large area projection liquid-crystal video display system with inherent grid pattern optically removed

NASA Technical Reports Server (NTRS)

Liu, Hua-Kuang (Inventor)

1992-01-01

A relatively small and low-cost system is provided for projecting a large and bright television image onto a screen. A miniature liquid crystal array is driven by video circuitry to produce a pattern of transparencies in the array corresponding to a television image. Light is directed against the rear surface of the array to illuminate it, while a projection lens lies in front of the array to project the image of the array onto a large screen. Grid lines in the liquid crystal array are eliminated by a spacial filter which comprises a negative of the Fourier transform of the grid.

Experimental Simulation of Turbine-Exhaust Oxygen Recovery

NASA Technical Reports Server (NTRS)

Clark, Jim A.; Branch, Ryan W.

2004-01-01

In some liquid-propellant rocket engines, the liquid-oxygen boost pump is driven by a turbine that is powered by high-pressure gaseous oxygen. Once it exits the turbine, this gaseous oxygen can be salvaged by injecting it into the subcooled liquid oxygen exiting the boost pump. If the main LOX pump is to function correctly under these circumstances, complete condensation of the gaseous oxygen must quickly follow its injection into the boost-pump discharge. The current investigation uses steam and water in a simple rig that allows the condensation process to be visualized and quantified. This paper offers dimensionless-parameter correlations of the data and trends observed.

Distributed Autonomous Control Action Based on Sensor and Mission Fusion

DTIC Science & Technology

2005-09-01

programmable control algorithm driven by the readings of two pressure switch sensors located on either side of the valve unit. Thus, a micro-controller...and Characterization The process of leak detection and characterization must be accomplished with a set of pressure switch sensors. This sensor...economically supplementing existing widely used pressure switch type sensors which are characterized by prohibitively long inertial lag responses

Empowering Women for Development through Community-Driven Sustainable Programmes: A Response to Traditional Patriarchal Power in the Southern African Region

ERIC Educational Resources Information Center

Braimoh, Dele; Lekoko, Rebecca; Alade, Eunice B.

2004-01-01

In the Southern Africa region, the act of prejudice against women mostly occurs where patriarchal power reigns. This type of power is felt in areas such as inheritance right, division of labour, access to political and economic resources and legal and social matters. Other areas of discrimination against women include access to educational and…

Where Am I in Our Schools' White Spaces? Social Justice for the Learners We Marginalise

ERIC Educational Resources Information Center

Milne, Ann

2016-01-01

We live in the world of the intensely market-driven lower case "i". Since the launch in 1998 of the "iMac", Apple Inc. has spawned a plethora of lower-case "i" devices and programmes. What do these mean? According to Steve Jobs (1998), the "i" signified "the marriage of the excitement of the internet,…

Data-Driven Learning and the Acquisition of Italian Collocations: From Design to Student Evaluation

ERIC Educational Resources Information Center

Forti, Luciana

2017-01-01

This paper looks at how corpus data was used to design an Italian as an L2 language learning programme and how it was evaluated by students. The study focuses on the acquisition of Italian verb-noun collocations by Chinese native students attending a ten month long Italian language course before enrolling at an Italian university. It describes how…

Thermally induced delay and reversal of liquid film dewetting on chemically patterned surfaces.

PubMed

Kalpathy, Sreeram K; Francis, Lorraine F; Kumar, Satish

2013-10-15

A thin liquid film resting on a solid substrate that is heated or cooled from below experiences surface tension gradients, which lead to Marangoni flows. We explore the behavior of such a film on a chemically patterned substrate which drives film dewetting in order to determine how surface patterning and applied temperature gradients can be designed to influence the behavior of thin-film coatings. A nonlinear partial differential equation for the film height based on lubrication theory is solved numerically for a broad range of problem parameters. Uniform cooling of the substrate is found to significantly delay dewetting that is driven by wettability gradients. Uniform heating speeds up dewetting but can destroy the near-perfect templating imposed by the surface patterning. However, localized heating and cooling together can accelerate dewetting while maintaining templating quality. Localized heating and cooling can also be used to drive liquid onto areas that it would dewet from in the absence of heating. Overall, these results indicate that applied temperature gradients can significantly influence dewetting driven by surface patterning, and suggest strategies for the creation of spatially patterned thin-film coatings and flow control in microfluidic devices. Copyright © 2013 Elsevier Inc. All rights reserved.

Air bio-battery with a gas/liquid porous diaphragm cell for medical and health care devices.

PubMed

Arakawa, Takahiro; Xie, Rui; Seshima, Fumiya; Toma, Koji; Mitsubayashi, Kohji

2018-04-30

Powering future generations of medical and health care devices mandates the transcutaneous transfer of energy or harvesting energy from the human body fluid. Glucose-driven bio fuel cells (bio-batteries) demonstrate promise as they produce electrical energy from glucose, which is a substrate presents in physiological fluids. Enzymatic biofuel cells can convert chemical energy into electrical energy using enzymes as catalysts. In this study, an air bio-battery was developed for healthcare and medical applications, consisting of a glucose-driven enzymatic biofuel cell using a direct gas-permeable membrane or a gas/liquid porous diaphragm. The power generation characteristics included a maximum current density of 285μA/cm 2 and maximum power density of 70.7μW/cm 2 in the presence of 5mmol/L of glucose in solution. In addition, high-performance, long-term-stabilized power generation was achieved using the gas/liquid porous diaphragm for the reactions between oxygen and enzyme. This system can be powered using 5mmol/L of glucose, the value of which is similar to that of the blood sugar range in humans. Copyright © 2017 Elsevier B.V. All rights reserved.

Numerical predictions of shock propagation through unreactive and reactive liquids with experimental validation

NASA Astrophysics Data System (ADS)

Stekovic, Svjetlana; Nissen, Erin; Bhowmick, Mithun; Stewart, Donald S.; Dlott, Dana D.

2017-06-01

The objective of this work is to numerically analyze shock behavior as it propagates through compressed, unreactive and reactive liquid, such as liquid water and liquid nitromethane. Parameters, such as pressure and density, are analyzed using the Mie-Gruneisen EOS and each multi-material system is modeled using the ALE3D software. The motivation for this study is based on provided high-resolution, optical interferometer (PDV) and optical pyrometer measurements. In the experimental set-up, a liquid is placed between an Al 1100 plate and Pyrex BK-7 glass. A laser-driven Al 1100 flyer impacts the plate, causing the liquid to be highly compressed. The numerical model investigates the influence of the high pressure, shock-compressed behavior in each liquid, the energy transfer, and the wave impedance at the interface of each material in contact. The numerical results using ALE3D will be validated by experimental data. This work aims to provide further understanding of shock-compressed behavior and how the shock influences phase transition in each liquid.

Light-directing self-organized 1D and 3D chiral liquid crystalline nanostructures

NASA Astrophysics Data System (ADS)

Li, Quan; Bisoyi, Hari K.

2015-03-01

A brief overview of recent research and developments in our laboratory toward the fabrication and application of photoresponsive cholesteric liquid crystals, microshells and microdroplets, and blue phase is presented here. We have designed and synthesized a variety of light-driven chiral molecular switches and doped into achiral nematic liquid crystals hosts to obtain photoresponsive cholesteric liquid crystals and blue phase. By irradiation with light of suitable wavelengths, it has been possible to tune the reflection color of cholesteric liquid crystals and blue phase over a wide range across the visible spectrum. By doping upconversion nanoparticles into photoresponsive cholesteric liquid crystals, the reflection color tuning has been accomplished by irradiation with near infrared light. Moreover, cholesteric microshells have been fabricated which exhibit omnidirectional lasing. Similarly, cholesteric microdroplets have been found to display omnidirectional selective reflection and photonic cross communication. Wide-range non-mechanical beam steering has been demonstrated in a phoresponsive cholesteric liquid crystal sample. This short summary of our recent research work shows that the century old fascinating cholesteric liquid crystals have diverse opportunities to offer.

Feasibility and indicative results from a 12-month low-energy liquid diet treatment and maintenance programme for severe obesity

PubMed Central

Lean, Michael; Brosnahan, Naomi; McLoone, Philip; McCombie, Louise; Higgs, Anna Bell; Ross, Hazel; Mackenzie, Mhairi; Grieve, Eleanor; Finer, Nick; Reckless, John; Haslam, David; Sloan, Billy; Morrison, David

2013-01-01

Background There is no established primary care solution for the rapidly increasing numbers of severely obese people with body mass index (BMI) > 40 kg/m2. Aim This programme aimed to generate weight losses of ≥15 kg at 12 months, within routine primary care. Design and setting Feasibility study in primary care. Method Patients with a BMI ≥40 kg/m2 commenced a micronutrient-replete 810–833 kcal/day low-energy liquid diet (LELD), delivered in primary care, for a planned 12 weeks or 20 kg weight loss (whichever was the sooner), with structured food reintroduction and then weight-loss maintenance, with optional orlistat to 12 months. Result Of 91 patients (74 females) entering the programme (baseline: weight 131 kg, BMI 48 kg/m2, age 46 years), 58/91(64%) completed the LELD stage, with a mean duration of 14.4 weeks (standard deviation [SD] = 6.0 weeks), and a mean weight loss of 16.9 kg (SD = 6.0 kg). Four patients commenced weight-loss maintenance omitting the food-reintroduction stage. Of the remaining 54, 37(68%) started and completed food reintroduction over a mean duration of 9.3 weeks (SD = 5.7 weeks), with a further mean weight loss of 2.1 kg (SD = 3.7 kg), before starting a long-term low-fat-diet weight-loss maintenance plan. A total of 44/91 (48%) received orlistat at some stage. At 12 months, weight was recorded for 68/91 (75%) patients, with a mean loss of 12.4 kg (SD = 11.4 kg). Of these, 30 (33% of all 91 patients starting the programme) had a documented maintained weight loss of ≥15 kg at 12 months, six (7%) had a 10–15 kg loss, and 11 (12%) had a 5–10 kg loss. The indicative cost of providing this entire programme for wider implementation would be £861 per patient entered, or £2611 per documented 15 kg loss achieved. Conclusion A care package within routine primary care for severe obesity, including LELD, food reintroduction, and weight-loss maintenance, was well accepted and achieved a 12-month-maintained weight loss of ≥15 kg for one-third of all patients entering the programme. PMID:23561690

Feasibility and indicative results from a 12-month low-energy liquid diet treatment and maintenance programme for severe obesity.

PubMed

Lean, Michael; Brosnahan, Naomi; McLoone, Philip; McCombie, Louise; Higgs, Anna Bell; Ross, Hazel; Mackenzie, Mhairi; Grieve, Eleanor; Finer, Nick; Reckless, John; Haslam, David; Sloan, Billy; Morrison, David

2013-02-01

There is no established primary care solution for the rapidly increasing numbers of severely obese people with body mass index (BMI) > 40 kg/m(2). This programme aimed to generate weight losses of ≥15 kg at 12 months, within routine primary care. Feasibility study in primary care. Patients with a BMI ≥40 kg/m(2) commenced a micronutrient-replete 810-833 kcal/day low-energy liquid diet (LELD), delivered in primary care, for a planned 12 weeks or 20 kg weight loss (whichever was the sooner), with structured food reintroduction and then weight-loss maintenance, with optional orlistat to 12 months. Of 91 patients (74 females) entering the programme (baseline: weight 131 kg, BMI 48 kg/m(2), age 46 years), 58/91(64%) completed the LELD stage, with a mean duration of 14.4 weeks (standard deviation [SD] = 6.0 weeks), and a mean weight loss of 16.9 kg (SD = 6.0 kg). Four patients commenced weight-loss maintenance omitting the food-reintroduction stage. Of the remaining 54, 37(68%) started and completed food reintroduction over a mean duration of 9.3 weeks (SD = 5.7 weeks), with a further mean weight loss of 2.1 kg (SD = 3.7 kg), before starting a long-term low-fat-diet weight-loss maintenance plan. A total of 44/91 (48%) received orlistat at some stage. At 12 months, weight was recorded for 68/91 (75%) patients, with a mean loss of 12.4 kg (SD = 11.4 kg). Of these, 30 (33% of all 91 patients starting the programme) had a documented maintained weight loss of ≥15 kg at 12 months, six (7%) had a 10-15 kg loss, and 11 (12%) had a 5-10 kg loss. The indicative cost of providing this entire programme for wider implementation would be £861 per patient entered, or £2611 per documented 15 kg loss achieved. A care package within routine primary care for severe obesity, including LELD, food reintroduction, and weight-loss maintenance, was well accepted and achieved a 12-month-maintained weight loss of ≥15 kg for one-third of all patients entering the programme.

An Effective Continuum Model for the Gas Evolution in Internal Steam Drives

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

Tsimpanogiannis, Ioannis N.; Yortsos, Yanis C.

This report examines the gas phase growth from a supersaturated, slightly compressible, liquid in a porous medium, driven by heat transfer and controlled by the application of a constant-rate decline of the system pressure.

Mainstreaming nutrition into maternal and child health programmes: scaling up of exclusive breastfeeding.

PubMed

Bhandari, Nita; Kabir, A K M Iqbal; Salam, Mohammed Abdus

2008-04-01

Interventions to promote exclusive breastfeeding have been estimated to have the potential to prevent 13% of all under-5 deaths in developing countries and are the single most important preventive intervention against child mortality. According to World Health Organization and United Nations Children Funds (UNICEF), only 39% infants are exclusively breastfed for less than 4 months. This review examines programme efforts to scale up exclusive breastfeeding in different countries and draws lesson for successful scale-up. Opportunities and challenges in scaling up of exclusive breastfeeding into Maternal and Child Health programmes are identified. The key processes required for exclusive breastfeeding scale-up are: (1) an evidence-based policy and science-driven technical guidelines; and (2) an implementation strategy and plan for achieving high exclusive breastfeeding rates in all strata of society, on a sustainable basis. Factors related to success include political will, strong advocacy, enabling policies, well-defined short- and long-term programme strategy, sustained financial support, clear definition of roles of multiple stakeholders and emphasis on delivery at the community level. Effective use of antenatal, birth and post-natal contacts at homes and through community mobilization efforts is emphasized. Formative research to ensure appropriate intervention design and delivery is critical particularly in areas with high HIV prevalence. Strong communication strategy and support, quality trainers and training contributed significantly to programme success. Monitoring and evaluation with feedback systems that allow for periodic programme corrections and continued innovation are central to very high coverage. Legal framework must make it possible for mothers to exclusively breastfeed for at least 4 months. Sustained programme efforts are critical to achieve high coverage and this requires strong national- and state-level leadership.

On-chip liquid storage and dispensing for lab-on-a-chip applications

NASA Astrophysics Data System (ADS)

Bodén, Roger; Lehto, Marcus; Margell, Joakim; Hjort, Klas; Schweitz, Jan-Åke

2008-07-01

This work presents novel components for on-chip storage and dispensing inside a lab-on-a-chip (LOC) for applications in immunoassay point-of-care testing (POCT), where incubation and washing steps are essential. It involves easy-to-use on-chip solutions for the sequential thermo-hydraulic actuation of liquids. The novel concept of combining the use of a rubber plug, both as a non-return valve cap and as a liquid injection interface of a sealed reservoir, allows simple filling of a sterilized cavity, as well as the storage and dispensing of reagent and washing buffer liquids. Segmenting the flow with air spacers enables effective rinsing and the use of small volumes of on-chip stored liquids. The chip uses low-resistance resistors as heaters in the paraffin actuator, providing the low-voltage actuation that is preferred for handheld battery driven instruments.

Breakdown of Landau Fermi liquid theory: Restrictions on the degrees of freedom of quantum electrons

NASA Astrophysics Data System (ADS)

Su, Yue-Hua; Lu, Han-Tao

2018-04-01

One challenge in contemporary condensed matter physics is to understand unconventional electronic physics beyond the paradigm of Landau Fermi-liquid theory. Here, we present a perspective that posits that most such examples of unconventional electronic physics stem from restrictions on the degrees of freedom of quantum electrons in Landau Fermi liquids. Since the degrees of freedom are deeply connected to the system's symmetries and topology, these restrictions can thus be realized by external constraints or by interaction-driven processes via the following mechanisms: (i) symmetry breaking, (ii) new emergent symmetries, and (iii) nontrivial topology. Various examples of unconventional electronic physics beyond the reach of traditional Landau Fermi liquid theory are extensively investigated from this point of view. Our perspective yields basic pathways to study the breakdown of Landau Fermi liquids and also provides a guiding principle in the search for novel electronic systems and devices.

Metallurgical technologies, energy conversion, and magnetohydrodynamic flows

NASA Astrophysics Data System (ADS)

Branover, Herman; Unger, Yeshajahu

The present volume discusses metallurgical applications of MHD, R&D on MHD devices employing liquid working medium for process applications, electromagnetic (EM) modulation of molten metal flow, EM pump performance of superconducting MHD devices, induction EM alkali-metal pumps, a physical model for EM-driven flow in channel-induction furnaces, grain refinement in Al alloys via EM vibrational method, dendrite growth of solidifying metal in dc magnetic field, MHD for mass and heat transfer in single-crystal melt growth, inverse EM shaping, and liquid-metal MHD development in Israel. Also discussed are the embrittlement of steel by lead, an open cycle MHD disk generator, the acceleration of gas-liquid piston flows for molten-metal MHD generators, MHD flow around a cylinder, new MHD drag coefficients, liquid-metal MHD two-phase flow, and two-phase liquid gas mixers for MHD energy conversion. (No individual items are abstracted in this volume)

Optofluidic lens actuated by laser-induced solutocapillary forces

NASA Astrophysics Data System (ADS)

Malyuk, A. Yu.; Ivanova, N. A.

2017-06-01

We demonstrate an adaptive liquid lens controlled by laser-induced solutocapillary forces. The liquid droplet serving as a lens is formed in a thin layer of binary liquid mixture by surface tension driven flows caused by the thermal action of laser irradiation. The shape of droplet, its aperture and the focal length are reversibly changed without hysteresis by varying the intensity of the laser beam. The focal length variation range of the droplet-lens lies in between infinity (a flat layer) to 15 mm (a curved interface). The droplet-lens is capable to adjust the in-plane lateral position in response to a displacement of the laser beam. The proposed laser controlled droplet-lens will enable to develop smart liquid optical devices, which can imitate the accommodation reflex and pupillary light reflex of the eye.

Energy driven self-organization in nanoscale metallic liquid films.

PubMed

Krishna, H; Shirato, N; Favazza, C; Kalyanaraman, R

2009-10-01

Nanometre thick metallic liquid films on inert substrates can spontaneously dewet and self-organize into complex nanomorphologies and nanostructures with well-defined length scales. Nanosecond pulses of an ultraviolet laser can capture the dewetting evolution and ensuing nanomorphologies, as well as introduce dramatic changes to dewetting length scales due to the nanoscopic nature of film heating. Here, we show theoretically that the self-organization principle, based on equating the rate of transfer of thermodynamic free energy to rate of loss in liquid flow, accurately describes the spontaneous dewetting. Experimental measurements of laser dewetting of Ag and Co liquid films on SiO(2) substrates confirm this principle. This energy transfer approach could be useful for analyzing the behavior of nanomaterials and chemical processes in which spontaneous changes are important.

Coherent Raman Studies of Shocked Liquids

NASA Astrophysics Data System (ADS)

McGrane, Shawn; Brown, Kathryn; Dang, Nhan; Bolme, Cynthia; Moore, David

2013-06-01

Transient vibrational spectroscopies offer the potential to directly observe time dependent shock induced chemical reaction kinetics. We report recent experiments that couple a hybrid picosecond/femtosecond coherent anti-Stokes Raman spectroscopy (CARS) diagnostic with our tabletop ultrafast laser driven shock platform. Initial results on liquids shocked to 20 GPa suggest that sub-picosecond dephasing at high pressure and temperature may limit the application of this nonresonant background free version of CARS. Initial results using interferometric CARS to increase sensitivity and overcome these limitations will be presented.

TEM Pump With External Heat Source And Sink

NASA Technical Reports Server (NTRS)

Nesmith, Bill J.

1991-01-01

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

Microgravity

NASA Image and Video Library

2004-04-15

Fluid Physics is study of the motion of fluids and the effects of such motion. When a liquid is heated from the bottom to the boiling point in Earth's microgravity, small bubbles of heated gas form near the bottom of the container and are carried to the top of the liquid by gravity-driven convective flows. In the same setup in microgravity, the lack of convection and buoyancy allows the heated gas bubbles to grow larger and remain attached to the container's bottom for a significantly longer period.

Biofuels: What Are They and How Can They Improve Practical Work and Discussions?

ERIC Educational Resources Information Center

MacLean, Tristan

2014-01-01

This article looks at the potential of bioenergy as a replacement for fossil fuels, the cutting-edge research being undertaken by scientists, and classroom resources available for teaching this topic. There is currently a large programme of scientific research aiming to develop advanced biofuels (replenishable liquid biofuels from non-food plants,…

Use of a micro programmable logic controller for oxygen monitoring and control in multiple tanks of a recirculating aquaculture system

USDA-ARS?s Scientific Manuscript database

In intensive recirculating aquaculture systems the use of supplemental oxygen, specifically pure liquid oxygen, increases the mass of fish that can be supported and eliminates oxygen as a major limiting factor to a system’s carrying capacity. The use of pure oxygen in a recirculating aquaculture sys...

Competition between Chaotic and Nonchaotic Phases in a Quadratically Coupled Sachdev-Ye-Kitaev Model.

PubMed

Chen, Xin; Fan, Ruihua; Chen, Yiming; Zhai, Hui; Zhang, Pengfei

2017-11-17

The Sachdev-Ye-Kitaev (SYK) model is a concrete solvable model to study non-Fermi liquid properties, holographic duality, and maximally chaotic behavior. In this work, we consider a generalization of the SYK model that contains two SYK models with a different number of Majorana modes coupled by quadratic terms. This model is also solvable, and the solution shows a zero-temperature quantum phase transition between two non-Fermi liquid chaotic phases. This phase transition is driven by tuning the ratio of two mode numbers, and a nonchaotic Fermi liquid sits at the critical point with an equal number of modes. At a finite temperature, the Fermi liquid phase expands to a finite regime. More intriguingly, a different non-Fermi liquid phase emerges at a finite temperature. We characterize the phase diagram in terms of the spectral function, the Lyapunov exponent, and the entropy. Our results illustrate a concrete example of the quantum phase transition and critical behavior between two non-Fermi liquid phases.

Thermocapillary droplet actuation on structured solid surfaces

NASA Astrophysics Data System (ADS)

Karapetsas, George; Chamakos, Nikolaos T.; Papathanasiou, Athanasios G.

2017-11-01

The present work investigates, through 2D and 3D finite element simulations, the thermocapillary-driven flow inside a droplet which resides on a non-uniformly heated patterned surface. We employ a recently proposed sharp-interface scheme capable of efficiently modelling the flow over complicate surfaces and consider a wide range of substrate wettabilities, i.e. from hydrophilic to super-hydrophobic surfaces. Our simulations indicate that due to the presence of the solid structures and the induced effect of contact angle hysteresis, inherently predicted by our model, a critical thermal gradient arises beyond which droplet migration is possible, in line with previous experimental observations. The migration velocity as well as the direction of motion depends on the combined action of the net mechanical force along the contact line and the thermocapillary induced flow at the liquid-air interface. We also show that through a proper control and design of the substrate wettability, the contact angle hysteresis and the induced flow field it is possible to manipulate the droplet dynamics, e.g. controlling its motion along a predefined track or entrapping by a wetting defect a droplet based on its size as well as providing appropriate conditions for enhanced mixing inside the droplet. Funding from the European Research Council under the Europeans Community's Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement no. [240710] is acknowledged.

Underground physics with DUNE

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

Kudryavtsev, Vitaly A.

2016-06-09

The Deep Underground Neutrino Experiment (DUNE) is a project to design, construct and operate a next-generation long-baseline neutrino detector with a liquid argon (LAr) target capable also of searching for proton decay and supernova neutrinos. It is a merger of previous efforts of the LBNE and LBNO collaborations, as well as other interested parties to pursue a broad programme with a staged 40-kt LAr detector at the Sanford Underground Research Facility (SURF) 1300 km from Fermilab. This programme includes studies of neutrino oscillations with a powerful neutrino beam from Fermilab, as well as proton decay and supernova neutrino burst searches.more » In this study, we will focus on the underground physics with DUNE.« less

Programmable Cadence Timer

NASA Technical Reports Server (NTRS)

Hall, William A.; Gilbert, John

1990-01-01

Electronic metronome paces users through wide range of exercise routines. Conceptual programmable cadence timer provides rhythmic aural and visual cues. Timer automatically changes cadence according to program entered by the user. It also functions as clock, stopwatch, or alarm. Modular pacer operated as single unit or as two units. With audiovisual module moved away from base module, user concentrates on exercise cues without distraction from information appearing on the liquid-crystal display. Variety of uses in rehabilitative medicine, experimental medicine, sports, and gymnastics. Used in intermittent positive-pressure breathing treatment, in which patient must rhythmically inhale and retain medication delivered under positive pressure; and in incentive spirometer treatment, in which patient must inhale maximally at regular intervals.

HOW DOES ADDING AND REMOVING LIQUID FROM SOCKET BLADDERS AFFECT RESIDUAL LIMB FLUID VOLUME?

PubMed Central

Sanders, JE; Cagle, JC; Harrison, DS; Myers, TR; Allyn, KJ

2015-01-01

Adding and removing liquid from socket bladders is a means for people with limb loss to accommodate residual limb volume change. Nineteen people with trans-tibial amputation using their regular prosthetic socket fitted with fluid bladders on the inside socket surface underwent cycles of bladder liquid addition and removal. In each cycle, subjects sat, stood, and walked for 90s with bladder liquid added and then sat, stood, and walking for 90s again with the bladder liquid removed. The amount of bladder liquid added was increased in each cycle. Bioimpedance analysis was implemented to measure residual limb fluid volume. Results showed that the preferred bladder liquid volume was 16.8 mL (s.d.8.4), corresponding to 1.7% (s.d.0.8%) of the average socket volume between the bioimpedance voltage-sensing electrodes. Limb fluid volume driven out of the residual limb when bladder liquid was added was typically not recovered upon subsequent bladder liquid removal. Fifteen of nineteen subjects experienced a gradual limb fluid volume loss over the test session. Care should be taken when implementing adjustable socket technologies in people with limb amputation. Reducing socket volume may accentuate limb fluid volume loss. PMID:24203546

A comprehensive review of the SLMTA literature part 2: Measuring success.

PubMed

Luman, Elizabeth T; Yao, Katy; Nkengasong, John N

2014-01-01

Since its introduction in 2009, the Strengthening Laboratory Management Toward Accreditation (SLMTA) programme has been implemented in 617 laboratories in 47 countries. We completed a systematic review of the published literature on SLMTA. The review consists of two companion papers; this article examines quantitative evidence presented in the publications along with a meta-analysis of selected results. We identified 28 published articles with data from SLMTA implementation. The SLMTA programme was evaluated through audits based on a standard checklist, which is divided into 12 sections corresponding to the 12 Quality System Essentials (QSEs). Several basic service delivery indicators reported by programmes were also examined. Results for various components of the programme were reviewed and summarised; a meta-analysis of QSE results grouped by the three stages of the quality cycle was conducted for 126 laboratories in 12 countries. Global programme data show improved quality in SLMTA laboratories in every country, with average improvements on audit scores of 25 percentage points. Meta-analysis identified Improvement Management as the weakest stage, with internal audit (8%) and occurrence management (16%) showing the lowest scores. Studies documented 19% - 95% reductions in turn-around times, 69% - 93% reductions in specimen rejection rates, 76% - 81% increases in clinician satisfaction rates, 67% - 85% improvements in external quality assessment results, 50% - 66% decreases in nonconformities and 67% increases in staff punctuality. The wide array of results reported provides a comprehensive picture of the SLMTA programme overall, suggesting a substantive impact on provision of quality laboratory services and patient care. These comprehensive results establish a solid data-driven foundation for program improvement and further expansion.

Formation of coffee-stain patterns at the nanoscale: The role of nanoparticle solubility and solvent evaporation rate.

PubMed

Zhang, Jianguo; Milzetti, Jasmin; Leroy, Frédéric; Müller-Plathe, Florian

2017-03-21

When droplets of nanoparticle suspension evaporate from surfaces, they leave behind a deposit of nanoparticles. The mechanism of evaporation-induced pattern formation in the deposit is studied by molecular dynamics simulations for sessile nanodroplets. The influence of the interaction between nanoparticles and liquid molecules and the influence of the evaporation rate on the final deposition pattern are addressed. When the nanoparticle-liquid interaction is weaker than the liquid-liquid interaction, an interaction-driven or evaporation-induced layer of nanoparticles appears at the liquid-vapor interface and eventually collapses onto the solid surface to form a uniform deposit independently of the evaporation rate. When the nanoparticle-liquid and liquid-liquid interactions are comparable, the nanoparticles are dispersed inside the droplet and evaporation takes place with the contact line pinned at a surface defect. In such a case, a pattern with an approximate ring-like shape is found with fast evaporation, while a more uniform distribution is observed with slower evaporation. When the liquid-nanoparticle interaction is stronger than the liquid-liquid interaction, evaporation always occurs with receding contact line. The final deposition pattern changes from volcano-like to pancake-like with decreasing evaporation rate. These findings might help to design nanoscale structures like nanopatterns or nanowires on surface through controlled solvent evaporation.

Formation of coffee-stain patterns at the nanoscale: The role of nanoparticle solubility and solvent evaporation rate

NASA Astrophysics Data System (ADS)

Zhang, Jianguo; Milzetti, Jasmin; Leroy, Frédéric; Müller-Plathe, Florian

2017-03-01

When droplets of nanoparticle suspension evaporate from surfaces, they leave behind a deposit of nanoparticles. The mechanism of evaporation-induced pattern formation in the deposit is studied by molecular dynamics simulations for sessile nanodroplets. The influence of the interaction between nanoparticles and liquid molecules and the influence of the evaporation rate on the final deposition pattern are addressed. When the nanoparticle-liquid interaction is weaker than the liquid-liquid interaction, an interaction-driven or evaporation-induced layer of nanoparticles appears at the liquid-vapor interface and eventually collapses onto the solid surface to form a uniform deposit independently of the evaporation rate. When the nanoparticle-liquid and liquid-liquid interactions are comparable, the nanoparticles are dispersed inside the droplet and evaporation takes place with the contact line pinned at a surface defect. In such a case, a pattern with an approximate ring-like shape is found with fast evaporation, while a more uniform distribution is observed with slower evaporation. When the liquid-nanoparticle interaction is stronger than the liquid-liquid interaction, evaporation always occurs with receding contact line. The final deposition pattern changes from volcano-like to pancake-like with decreasing evaporation rate. These findings might help to design nanoscale structures like nanopatterns or nanowires on surface through controlled solvent evaporation.

Building bridges: engaging medical residents in quality improvement and medical leadership.

PubMed

Voogt, Judith J; van Rensen, Elizabeth L J; van der Schaaf, Marieke F; Noordegraaf, Mirko; Schneider, Margriet Me

2016-12-01

To develop an educational intervention that targets residents' beliefs and attitudes to quality Improvement (QI) and leadership in order to demonstrate proactive behaviour. Theory-driven, mixed methods study including document analysis, interviews, observations and open-ended questionnaires. Six Dutch teaching hospitals. Using expertise from medicine, psychology, organizational and educational sciences we developed a situated learning programme named Ponder and IMProve (PIMP). The acronym PIMP reflects the original upbeat name in Dutch, Verwonder & Verbeter. It has a modern, positive meaning that relates to improving your current circumstances. In quarterly 1-h sessions residents are challenged to identify daily workplace frustrations and translate them into small-scale QI activities. Organizational awareness, beliefs and attitudes to QI and organizational responsibilities, resident behaviour, barriers and facilitators to successful learning and the programme's potential impact on the organization. Overall, 19 PIMP meetings were held over a period of 3 years. Residents defined 119 PIMP goals, resolved 37 projects and are currently working on another 39 projects. Interviews show that PIMP sessions make residents more aware of the organizational aspects of their daily work. Moreover, residents feel empowered to take up the role of change agent. Facilitators for success include a positive cost-benefit trade-off, a valuable group process and a safe learning environment. This article demonstrates the added value of multidisciplinary theory-driven research for the design, development and evaluation of educational programmes. Residents can be encouraged to develop organizational awareness and reshape their daily frustrations in QI work. © The Author 2016. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

The parser generator as a general purpose tool

NASA Technical Reports Server (NTRS)

Noonan, R. E.; Collins, W. R.

1985-01-01

The parser generator has proven to be an extremely useful, general purpose tool. It can be used effectively by programmers having only a knowledge of grammars and no training at all in the theory of formal parsing. Some of the application areas for which a table-driven parser can be used include interactive, query languages, menu systems, translators, and programming support tools. Each of these is illustrated by an example grammar.

Cryopreservation of human sperm: efficacy and use of a new nitrogen-free controlled rate freezer versus liquid nitrogen vapour freezing.

PubMed

Creemers, E; Nijs, M; Vanheusden, E; Ombelet, W

2011-12-01

Preservation of spermatozoa is an important aspect of assisted reproductive medicine. The aim of this study was to investigate the efficacy and use of a recently developed liquid nitrogen and cryogen-free controlled rate freezer and this compared with the classical liquid nitrogen vapour freezing method for the cryopreservation of human spermatozoa. Ten patients entering the IVF programme donated semen samples for the study. Samples were analysed according to the World Health Organization guidelines. No significant difference in total sperm motility after freeze-thawing between the new technique and classical technique was demonstrated. The advantage of the new freezing technique is that it uses no liquid nitrogen during the freezing process, hence being safer to use and clean room compatible. Investment costs are higher for the apparatus but running costs are only 1% in comparison with classical liquid nitrogen freezing. In conclusion, post-thaw motility of samples frozen with the classical liquid nitrogen vapour technique was comparable with samples frozen with the new nitrogen-free freezing technique. This latter technique can thus be a very useful asset to the sperm cryopreservation laboratory. © 2011 Blackwell Verlag GmbH.

Liquid rims collisions and the formation of fines

NASA Astrophysics Data System (ADS)

Néel, Baptiste; Villermaux, Emmanuel

2017-11-01

As an elementary mechanism for the formation of drops from liquid sheets, we investigate the collision of liquid cylinders. This results from the opening of two nearby holes on a liquid film, growing at a constant speed while collecting liquid into two rims, eventually colliding with each other. In this surface tension driven phenomenon, a unique Weber number We = ρ(2 V) 2 2 a / σ controls a variety of behaviors (ρ , σ are the liquid density and surface tension, and 2 V the relative velocity of the impinging rims, each of individual radius a). At low We , the rims merge through an inelastic, dissipative collision which produces a corrugated ligament, finally breaking into drops of size scaling like a, on average. Above a critical Wec 60 , the collision leads to a splash, with the formation of a thin transverse liquid sheet. We will describe the expansion-retraction dynamics of this secondary sheet and its destabilization, responsible for the production of a mist of finer droplets. These alter sensibly the mean, and overall drops size distribution, thus weighted by a substantial fraction of so-called fines.

Research on Liquid Management Technology in Water Tank and Reactor for Propulsion System with Hydrogen Production System Utilizing Aluminum and Water Reaction

NASA Astrophysics Data System (ADS)

Imai, Ryoji; Imamura, Takuya; Sugioka, Masatoshi; Higashino, Kazuyuki

2017-12-01

High pressure hydrogen produced by aluminum and water reaction is considered to be applied to space propulsion system. Water tank and hydrogen production reactor in this propulsion system require gas and liquid separation function under microgravity condition. We consider to install vane type liquid acquisition device (LAD) utilizing surface tension in the water tank, and install gas-liquid separation mechanism by centrifugal force which swirling flow creates in the hydrogen reactor. In water tank, hydrophilic coating was covered on both tank wall and vane surface to improve wettability. Function of LAD in water tank and gas-liquid separation in reaction vessel were evaluated by short duration microgravity experiments using drop tower facility. In the water tank, it was confirmed that liquid was driven and acquired on the outlet due to capillary force created by vanes. In addition of this, it was found that gas-liquid separation worked well by swirling flow in hydrogen production reactor. However, collection of hydrogen gas bubble was sometimes suppressed by aluminum alloy particles, which is open problem to be solved.

The latency validation of the optical link for the ATLAS Liquid Argon Calorimeter Phase-I trigger upgrade

NASA Astrophysics Data System (ADS)

Deng, B.; Xiao, L.; Zhao, X.; Baker, E.; Gong, D.; Guo, D.; He, H.; Hou, S.; Liu, C.; Liu, T.; Sun, Q.; Thomas, J.; Wang, J.; Xiang, A. C.; Yang, D.; Ye, J.; Zhou, W.

2018-05-01

Two optical data link data transmission Application Specific Integrated Circuits (ASICs), the baseline and its backup, have been designed for the ATLAS Liquid Argon (LAr) Calorimeter Phase-I trigger upgrade. The latency of each ASIC and that of its corresponding receiver implemented in a back-end Field-Programmable Gate Array (FPGA) are critical specifications. In this paper, we present the latency measurements and simulation of two ASICs. The measurement results indicate that both ASICs achieve their design goals and meet the latency specifications. The consistency between the simulation and measurements validates the ASIC latency characterization.

Achromatic diffractive lens written onto a liquid crystal display.

PubMed

Márquez, A; Iemmi, C; Campos, J; Yzuel, M J

2006-02-01

We propose a programmable diffractive lens written onto a liquid crystal display (LCD) that is able to provide equal focal lengths for several wavelengths simultaneously. To achieve this goal it is necessary that the LCD operate in the phase-only regime simultaneously for the different wavelengths. We design the appropriate lens for each wavelength, and then the lenses are spatially multiplexed onto the LCD. Various multiplexing schemes have been analyzed, and the random scheme shows the best performance. We further show the possibility of finely tuning the chromaticity of the focal spot by changing the relative weights of the multiplexing among the various wavelengths.

Numerical model for learning concepts of streamflow simulation

USGS Publications Warehouse

DeLong, L.L.; ,

1993-01-01

Numerical models are useful for demonstrating principles of open-channel flow. Such models can allow experimentation with cause-and-effect relations, testing concepts of physics and numerical techniques. Four PT is a numerical model written primarily as a teaching supplement for a course in one-dimensional stream-flow modeling. Four PT options particularly useful in training include selection of governing equations, boundary-value perturbation, and user-programmable constraint equations. The model can simulate non-trivial concepts such as flow in complex interconnected channel networks, meandering channels with variable effective flow lengths, hydraulic structures defined by unique three-parameter relations, and density-driven flow.The model is coded in FORTRAN 77, and data encapsulation is used extensively to simplify maintenance and modification and to enhance the use of Four PT modules by other programs and programmers.

The Principal Hugoniot of Forsterite to 950 GPa

NASA Astrophysics Data System (ADS)

Root, Seth; Townsend, Joshua P.; Davies, Erik; Lemke, Raymond W.; Bliss, David E.; Fratanduono, Dayne E.; Kraus, Richard G.; Millot, Marius; Spaulding, Dylan K.; Shulenburger, Luke; Stewart, Sarah T.; Jacobsen, Stein B.

2018-05-01

Forsterite (Mg2SiO4) single crystals were shock compressed to pressures between 200 and 950 GPa using independent plate-impact steady shocks and laser-driven decaying shock compression experiments. Additionally, we performed density functional theory-based molecular dynamics to aid interpretation of the experimental data and to investigate possible phase transformations and phase separations along the Hugoniot. We show that the experimentally obtained Hugoniot cannot distinguish between a pure liquid Mg2SiO4 and an assemblage of solid MgO plus liquid magnesium silicate. The measured reflectivity is nonzero and increases with pressure, which implies that the liquid is a poor electrical conductor at low pressures and that the conductivity increases with pressure.

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

Li, Yuzhan; Zhang, Yuehong; Rios, Orlando

The increasing demand for intelligent materials has driven the development of polymers with a variety of functionalities. However, combining multiple functionalities within one polymer is still challenging because of the difficulties encountered in coordinating different functional building blocks during fabrication. In this work, we demonstrate the fabrication of a multifunctional liquid crystalline epoxy network (LCEN) using the combination of thermotropic liquid crystals, photo-responsive azobenzene molecules, and exchangeable disulfide bonds. In addition to shape memory behavior enabled by the reversible liquid crystalline phase transition and photo-induced bending behavior resulting from the photo-responsive azobenzene molecules, the introduction of dynamic disulfide bonds intomore » the LCEN resulted in a structurally dynamic network, allowing the reshaping, repairing, and recycling of the material.« less

The identification of liquid ethane in Titan's Ontario Lacus

USGS Publications Warehouse

Brown, R.H.; Soderblom, L.A.; Soderblom, J.M.; Clark, R.N.; Jaumann, R.; Barnes, J.W.; Sotin, Christophe; Buratti, B.; Baines, K.H.; Nicholson, P.D.

2008-01-01

Titan was once thought to have global oceans of light hydrocarbons on its surface, but after 40 close flybys of Titan by the Cassini spacecraft, it has become clear that no such oceans exist. There are, however, features similar to terrestrial lakes and seas, and widespread evidence for fluvial erosion, presumably driven by precipitation of liquid methane from Titan's dense, nitrogen-dominated atmosphere. Here we report infrared spectroscopic data, obtained by the Visual and Infrared Mapping Spectrometer (VIMS) on board the Cassini spacecraft, that strongly indicate that ethane, probably in liquid solution with methane, nitrogen and other low-molecular-mass hydrocarbons, is contained within Titan's Ontario Lacus. ??2008 Macmillan Publishers Limited. All rights reserved.

Soldier-Warfighter Operationally Responsive Deployer for Space

NASA Technical Reports Server (NTRS)

Davis, Benny; Huebner, Larry; Kuhns, Richard

2015-01-01

The Soldier-Warfighter Operationally Responsive Deployer for Space (SWORDS) project was a joint project between the U.S. Army Space & Missile Defense Command (SMDC) and NASA. The effort, lead by SMDC, was intended to develop a three-stage liquid bipropellant (liquid oxygen/liquid methane), pressure-fed launch vehicle capable of inserting a payload of at least 25 kg to a 750-km circular orbit. The vehicle design was driven by low cost instead of high performance. SWORDS leveraged commercial industry standards to utilize standard hardware and technologies over customized unique aerospace designs. SWORDS identified broadly based global industries that have achieved adequate levels of quality control and reliability in their products and then designed around their expertise and business motivations.

Space shuttle auxiliary propulsion system design study. Phase D report: Oxygen-hydrogen special RCS studies

NASA Technical Reports Server (NTRS)

Baumann, T. L.; Pattern, T. C.; Mckee, H. B.

1972-01-01

Two alternate oxygen-hydrogen auxiliary propulsion system concepts for use with the space shuttle vehicle were evaluated. The two concepts considered were: (1) gaseous oxygen-hydrogen systems with electric or hydraulic motor driven pumps to provide system pressure and (2) liquid oxygen-hydrogen systems which delivered propellants to the engines in a liquid state without the need for pumps. The various means of implementing each of the concepts are compared on the basis of weight, technology requirements, and operational considerations. It was determined that the liquid oxygen-hydrogen system concepts have the potential to produce substantial weight reductions in the space shuttle orbiter total impulse range.

Method and apparatus for duct sealing using a clog-resistant insertable injector

DOEpatents

Wang, Duo; Modera, Mark P.

2007-01-02

A clog-resistant injector spray nozzle allows relatively unobtrusive insertion through a small access aperture into existing ductwork in occupied buildings for atomized particulate sealing of a ductwork. The spray nozzle comprises an easily cleaned and easily replaced straight liquid tube whose liquid contents are principally propelled by a heated propellant gas, such as heated air. Heat transfer is minimized from the heated propellant gas to the liquid tube until they both exit the injector, thereby greatly reducing the likelihood of nozzle clogging. A method of duct sealing using particles driven by heated propellant gas is described, whereby duct-sealing operations become both faster, and commercially practicable in inhabited commercial and residential buildings.

Automated dynamic liquid-liquid-liquid microextraction followed by high-performance liquid chromatography-ultraviolet detection for the determination of phenoxy acid herbicides in environmental waters.

PubMed

Wu, Jingming; Ee, Kim Huey; Lee, Hian Kee

2005-08-05

Automated dynamic liquid-liquid-liquid microextraction (D-LLLME) controlled by a programmable syringe pump and combined with HPLC-UV was investigated for the extraction and determination of 5 phenoxy acid herbicides in aqueous samples. In the extraction procedure, the acceptor phase was repeatedly withdrawn into and discharged from the hollow fiber by the syringe pump. The repetitive movement of acceptor phase into and out of the hollow fiber channel facilitated the transfer of analytes into donor phase, from the organic phase held in the pore of the fiber. Parameters such as the organic solvent, concentrations of the donor and acceptor phases, plunger movement pattern, speed of agitation and ionic strength of donor phase were evaluated. Good linearity of analytes was achieved in the range of 0.5-500 ng/ml with coefficients of determination, r2 > 0.9994. Good repeatabilities of extraction performance were obtained with relative standard deviations lower than 7.5%. The method provided up-to 490-fold enrichment within 13 min. In addition, the limits of detection (LODs) ranged from 0.1 to 0.4 ng/mL (S/N = 3). D-LLLME was successfully applied for the analysis of phenoxy acid herbicides from real environmental water samples.

Spatial correlations in driven-dissipative photonic lattices

NASA Astrophysics Data System (ADS)

Biondi, Matteo; Lienhard, Saskia; Blatter, Gianni; Türeci, Hakan E.; Schmidt, Sebastian

2017-12-01

We study the nonequilibrium steady-state of interacting photons in cavity arrays as described by the driven-dissipative Bose–Hubbard and spin-1/2 XY model. For this purpose, we develop a self-consistent expansion in the inverse coordination number of the array (∼ 1/z) to solve the Lindblad master equation of these systems beyond the mean-field approximation. Our formalism is compared and benchmarked with exact numerical methods for small systems based on an exact diagonalization of the Liouvillian and a recently developed corner-space renormalization technique. We then apply this method to obtain insights beyond mean-field in two particular settings: (i) we show that the gas–liquid transition in the driven-dissipative Bose–Hubbard model is characterized by large density fluctuations and bunched photon statistics. (ii) We study the antibunching–bunching transition of the nearest-neighbor correlator in the driven-dissipative spin-1/2 XY model and provide a simple explanation of this phenomenon.

Developing interface localized liquid dielectrophoresis for optical applications

NASA Astrophysics Data System (ADS)

McHale, Glen; Brown, Carl V.; Newton, Michael I.; Wells, Gary G.; Sampara, Naresh

2012-11-01

Electrowetting charges the solid-liquid interface to change the contact area of a droplet of a conducting liquid. It is a powerful technique used to create variable focus liquid lenses, electronic paper and other devices, but it depends upon ions within the liquid. Liquid dielectrophoresis (L-DEP) is a bulk force acting on the dipoles throughout a dielectric liquid and is not normally considered to be a localized effect acting at the interface between the liquid and a solid or other fluid. In this work, we show theoretically how non-uniform electric fields generated by interdigitated electrodes can effectively convert L-DEP into an interface localized form. We show that for droplets of sufficient thickness, the change in the cosine of the contact angle is proportional to the square of the applied voltage and so obeys a similar equation to that for electrowetting - this we call dielectrowetting. However, a major difference to electrowetting is that the strength of the effect is controlled by the electrode spacing and the liquid permittivity rather than the properties of an insulator in a sandwich structure. Experimentally, we show that that this dielectrowetting equation accurately describes the contact angle of a droplet of oil viewed across parallel interdigitated electrodes. Importantly, the induced spreading can be complete, such that contact angle saturation does not occur. We then show that for thin films, L-DEP can shape the liquid-air interface creating a spatially periodic wrinkle and that such a wrinkle can be used to create a voltage programmable phase diffraction grating.

Self-similarity of solitary waves on inertia-dominated falling liquid films.

PubMed

Denner, Fabian; Pradas, Marc; Charogiannis, Alexandros; Markides, Christos N; van Wachem, Berend G M; Kalliadasis, Serafim

2016-03-01

We propose consistent scaling of solitary waves on inertia-dominated falling liquid films, which accurately accounts for the driving physical mechanisms and leads to a self-similar characterization of solitary waves. Direct numerical simulations of the entire two-phase system are conducted using a state-of-the-art finite volume framework for interfacial flows in an open domain that was previously validated against experimental film-flow data with excellent agreement. We present a detailed analysis of the wave shape and the dispersion of solitary waves on 34 different water films with Reynolds numbers Re=20-120 and surface tension coefficients σ=0.0512-0.072 N m(-1) on substrates with inclination angles β=19°-90°. Following a detailed analysis of these cases we formulate a consistent characterization of the shape and dispersion of solitary waves, based on a newly proposed scaling derived from the Nusselt flat film solution, that unveils a self-similarity as well as the driving mechanism of solitary waves on gravity-driven liquid films. Our results demonstrate that the shape of solitary waves, i.e., height and asymmetry of the wave, is predominantly influenced by the balance of inertia and surface tension. Furthermore, we find that the dispersion of solitary waves on the inertia-dominated falling liquid films considered in this study is governed by nonlinear effects and only driven by inertia, with surface tension and gravity having a negligible influence.

Time-Dependent Thermally-Driven Interfacial Flows in Multilayered Fluid Structures

NASA Technical Reports Server (NTRS)

Haj-Hariri, Hossein; Borhan, A.

1996-01-01

A computational study of thermally-driven convection in multilayered fluid structures will be performed to examine the effect of interactions among deformable fluid-fluid interfaces on the structure of time-dependent flow in these systems. Multilayered fluid structures in two models configurations will be considered: the differentially heated rectangular cavity with a free surface, and the encapsulated cylindrical liquid bridge. An extension of a numerical method developed as part of our recent NASA Fluid Physics grant will be used to account for finite deformations of fluid-fluid interfaces.

GRADFLEX: Fluctuations in Microgravity

NASA Technical Reports Server (NTRS)

Vailati, A.; Cerbino, R.; Mazzoni, S.; Giglio, M.; Nikolaenko, G.; Cannell, D. S.; Meyer, W. V.; Smart, A. E.

2004-01-01

We present the results of experimental investigations of gradient driven fluctuations induced in a liquid mixture with a concentration gradient and in a single-component fluid with a temperature gradient. We also describe the experimental apparatus being developed to carry out similar measurement under microgravity conditions.

Compaction-Driven Evolution of Pluto's Rocky Core: Implications for Water-Rock Interactions

NASA Astrophysics Data System (ADS)

Gabasova, L. R.; Tobie, G.; Choblet, G.

2018-05-01

We model the compaction of Pluto's rocky core after accretion and explore the potential for hydrothermal circulation within the porous layer, as well as examine its effect on core cooling and the persistence of a liquid internal ocean.

Ag + reduction and silver nanoparticle synthesis at the plasma–liquid interface by an RF driven atmospheric pressure plasma jet: Mechanisms and the effect of surfactant

DOE PAGES

Kondeti, V. S. Santosh K.; Gangal, Urvashi; Yatom, Shurik; ...

2017-07-21

Here, the involvement of plasma produced species in the reduction of silver ions at the plasma–liquid interface is investigated using a well-characterized radio-frequency driven atmospheric pressure plasma jet. The absolute gas phase H density was measured using two photon absorption laser induced fluorescence in the free jet. Broadband absorption and transmission electron microscopy were used to study the synthesis of silver nanoparticles (AgNPs). It is shown that fructose, an often used surfactant/stabilizer for AgNP synthesis, also acts as a reducing agent after plasma exposure. Nonetheless, surfactant free AgNP synthesis is observed. Several experimental findings indicate that H plays an importantmore » role in the reduction of silver ions for the plasma conditions in this study. Vacuum ultraviolet photons generated by the plasma are able to reduce silver ions in the presence of fructose. Adding H2 to the argon feed gas leads to the production of a large amount of AgNPs having a particle size distribution with a maximum at a diameter of 2–3 nm, which is not observed for argon plasmas. This finding is consistent with a smaller concentration of reducing species at the plasma–liquid interface for Ar with the H2 admixture plasma. The smaller flux of reactive species to the liquid is in this case due to a less strong interaction of the plasma with the liquid. The formation of the nanoparticles was observed even at a distance of 6–7 mm below the tip of the plasma plume, conditions not favoring the injection of electrons.« less

Ag + reduction and silver nanoparticle synthesis at the plasma–liquid interface by an RF driven atmospheric pressure plasma jet: Mechanisms and the effect of surfactant

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

Kondeti, V. S. Santosh K.; Gangal, Urvashi; Yatom, Shurik

Here, the involvement of plasma produced species in the reduction of silver ions at the plasma–liquid interface is investigated using a well-characterized radio-frequency driven atmospheric pressure plasma jet. The absolute gas phase H density was measured using two photon absorption laser induced fluorescence in the free jet. Broadband absorption and transmission electron microscopy were used to study the synthesis of silver nanoparticles (AgNPs). It is shown that fructose, an often used surfactant/stabilizer for AgNP synthesis, also acts as a reducing agent after plasma exposure. Nonetheless, surfactant free AgNP synthesis is observed. Several experimental findings indicate that H plays an importantmore » role in the reduction of silver ions for the plasma conditions in this study. Vacuum ultraviolet photons generated by the plasma are able to reduce silver ions in the presence of fructose. Adding H2 to the argon feed gas leads to the production of a large amount of AgNPs having a particle size distribution with a maximum at a diameter of 2–3 nm, which is not observed for argon plasmas. This finding is consistent with a smaller concentration of reducing species at the plasma–liquid interface for Ar with the H2 admixture plasma. The smaller flux of reactive species to the liquid is in this case due to a less strong interaction of the plasma with the liquid. The formation of the nanoparticles was observed even at a distance of 6–7 mm below the tip of the plasma plume, conditions not favoring the injection of electrons.« less

ESF EUROCORES Programmes In Geosciences And Environmental Sciences

NASA Astrophysics Data System (ADS)

Jonckheere, I. G.

2007-12-01

In close cooperation with its Member Organisations, the European Science Foundation (ESF) has launched since late 2003 a series of European Collaborative Research (EUROCORES) Programmes. Their aim is to enable researchers in different European countries to develop cooperation and scientific synergy in areas where European scale and scope are required in a global context. The EUROCORES Scheme provides an open, flexible and transparent framework that allows national science funding and science performing agencies to join forces to support excellent European-led research, following a selection among many science-driven suggestions for new Programmes themes submitted by the scientific community. The EUROCORES instrument represents the first large scale attempt of national research (funding) agencies to act together against fragmentation, asynchronicity and duplication of research (funding) within Europe. There are presently 7 EUROCORES Programmes specifically dealing with cutting edge science in the fields of Earth, Climate and Environmental Sciences. The EUROCORES Programmes consist of a number of international, multidisciplinary collaborative research projects running for 3-4 years, selected through independent peer review. Under the overall responsibility of the participating funding agencies, those projects are coordinated and networked together through the scientific guidance of a Scientific Committee, with the support of a Programme Coordinator, responsible at ESF for providing planning, logistics, and the integration and dissemination of science. Strong links are aimed for with other major international programmes and initiatives worldwide. In this framework, linkage to IYPE would be of major interest for the scientific communities involved. Each Programme mobilises 5 to 13 million Euros in direct science funding from 9 to 27 national agencies from 8 to 20 countries. Additional funding for coordination, networking and dissemination is allocated by the ESF through these distinctive research initiatives, to build on the national research efforts and contribute to the capacity building, in relation with typically about 15-20 post-doc positions and/or PhD studentships supported nationally within each Programme. Typical networking activities are topical workshops, open sessions in a larger conference, Programme conference, (summer / winter) schools, exchange visits across projects or programmes. Overall, EUROCORES Programmes are supported by more than 60 national agencies from 30 countries and by the European Science Foundation (ESF) with support by the European Commission, DG Research (Sixth Framework Programme, contract ERAS-CT-2003-980409). In the framework of AGU, a series of present EUROCORES Programmes in the field of Geosciences and Environmental Sciences are presented (e.g., EuroDIVERSITY, EuroDEEP, EUROMARGINS, EuroCLIMATE, and EuroMinScI).

Dynamic Mass Transfer of Hemoglobin at the Aqueous/Ionic-Liquid Interface Monitored with Liquid Core Optical Waveguide.

PubMed

Chen, Xuwei; Yang, Xu; Zeng, Wanying; Wang, Jianhua

2015-08-04

Protein transfer from aqueous medium into ionic liquid is an important approach for the isolation of proteins of interest from complex biological samples. We hereby report a solid-cladding/liquid-core/liquid-cladding sandwich optical waveguide system for the purpose of monitoring the dynamic mass-transfer behaviors of hemoglobin (Hb) at the aqueous/ionic liquid interface. The optical waveguide system is fabricated by using a hydrophobic IL (1,3-dibutylimidazolium hexafluorophosphate, BBimPF6) as the core, and protein solution as one of the cladding layer. UV-vis spectra are recorded with a CCD spectrophotometer via optical fibers. The recorded spectra suggest that the mass transfer of Hb molecules between the aqueous and ionic liquid media involve accumulation of Hb on the aqueous/IL interface followed by dynamic extraction/transfer of Hb into the ionic liquid phase. A part of Hb molecules remain at the interface even after the accomplishment of the extraction/transfer process. Further investigations indicate that the mass transfer of Hb from aqueous medium into the ionic liquid phase is mainly driven by the coordination interaction between heme group of Hb and the cationic moiety of ionic liquid, for example, imidazolium cation in this particular case. In addition, hydrophobic interactions also contribute to the transfer of Hb.

Practical applications of injury surveillance: a brief 25-year history of the Connecticut Injury Prevention Center.

PubMed

Lapidus, Garry; Borrup, Kevin; DiVietro, Susan; Campbell, Brendan T; Beebe, Rebecca; Grasso, Damion; Rogers, Steven; Joseph, D'Andrea; Banco, Leonard

2016-04-01

The mission of the Connecticut Injury Prevention Center (CIPC), jointly housed in Connecticut Children's Medical Center and Hartford Hospital, is to reduce unintentional injury and violence among Connecticut residents, with a special focus on translating research into injury prevention programmes and policy. The CIPC engages in four core activities: research, education and training, community outreach programmes and public policy. As surveillance is an essential element of injury prevention, the CIPC has developed a robust statewide fatal and non-fatal injury surveillance system that has guided our prior work and continues to inform our current projects. The purpose of this article is to review the projects, programmes, and collaborative relationships that have made the CIPC successful in reducing unintentional injury and violence in Connecticut throughout the course of its 25 years history. Retrospective review of the application of injury surveillance. We believe that the application of our surveillance system can serve as a model for others who wish to engage in collaborative, community-based, data-driven injury prevention programmes in their own communities. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Convective mass transfer around a dissolving bubble

NASA Astrophysics Data System (ADS)

Duplat, Jerome; Grandemange, Mathieu; Poulain, Cedric

2017-11-01

Heat or mass transfer around an evaporating drop or condensing vapor bubble is a complex issue due to the interplay between the substrate properties, diffusion- and convection-driven mass transfer, and Marangoni effects, to mention but a few. In order to disentangle these mechanisms, we focus here mainly on the convective mass transfer contribution in an isothermal mass transfer problem. For this, we study the case of a millimetric carbon dioxide bubble which is suspended under a substrate and dissolved into pure liquid water. The high solubility of CO2 in water makes the liquid denser and promotes a buoyant-driven flow at a high (solutal) Rayleigh number (Ra˜104 ). The alteration of p H allows the concentration field in the liquid to be imaged by laser fluorescence enabling us to measure both the global mass flux (bubble volume, contact angle) and local mass flux around the bubble along time. After a short period of mass diffusion, where the boundary layer thickens like the square root of time, convection starts and the CO2 is carried by a plume falling at constant velocity. The boundary layer thickness then reaches a plateau which depends on the bubble cross section. Meanwhile the plume velocity scales like (dV /d t )1 /2 with V being the volume of the bubble. As for the rate of volume loss, we recover a constant mass flux in the diffusion-driven regime followed by a decrease in the volume V like V2 /3 after convection has started. We present a model which agrees well with the bubble dynamics and discuss our results in the context of droplet evaporation, as well as high Rayleigh convection.

Interactions between solidification and compositional convection in mushy layers

NASA Technical Reports Server (NTRS)

Worster, M. Grae

1994-01-01

Mushy layers are ubiquitous during the solidification of alloys. They are regions of mixed phase wherein solid crystals are bathed in the melt from which they grew. The matrix of crystals forms a porous medium through which the melt can flow, driven either by external forces or by its own buoyancy in a gravitational field. Buoyancy-driven convection of the melt depends both on temperature gradients, which are necessary for solidification, and on compositional gradients, which are generated as certain components of the alloy are preferentially incorporated in the solid phase and the remaining components are expelled into the melt. In fully liquid regions, the combined action of temperature and concentration on the density of the liquid can cause various forms of double-diffusive convection. However, in the interior of mushy regions the temperature and concentration are thermodynamically coupled so only single-diffusive convection can occur. Typically, the effect of composition on the buoyancy of the melt is much greater than the effect of temperature, and thus convection in mushy layers in driven primarily by the computational gradients within them. The rising interstitial liquid is relatively dilute, having come from colder regions of the mushy layer, where the liquidus concentration is lower, and can dissolve the crystal matrix through which it flows. This is the fundamental process by which chimneys are formed. It is a nonlinear process that requires the convective velocities to be sufficiently large, so fully fledged chimneys (narrow channels) might be avoided by means that weaken the flow. Better still would be to prevent convection altogether, since even weak convection will cause lateral, compositional inhomogeneities in castings. This report outlines three studies that examine the onset of convection within mushy layers.

A liquid crystal microlens array with aluminum and graphene electrodes for plenoptic imaging

NASA Astrophysics Data System (ADS)

Lei, Yu; Tong, Qing; Luo, Jun; Zhang, Xinyu; Sang, Hongshi; Xie, Changsheng

2015-12-01

Currently, several semiconducting oxide materials such as typical indium tin oxide are widely used as the transparent conducting electrodes (TCEs) in liquid crystal microlens arrays. In this paper, we fabricate a liquid crystal microlens array using graphene rather than semiconducting oxides as the TCE. Common optical experiments are carried out to acquire the focusing features of the graphene-based liquid crystal microlens array (GLCMLA) driven electrically. The acquired optical fields show that the GLCMLA can converge incident collimating lights efficiently. The relationship between the focal length and the applied voltage signal is presented. Then the GLCMLA is deployed in a plenoptic camera prototype and the raw images are acquired so as to verify their imaging capability. Our experiments demonstrate that graphene has already presented a broad application prospect in the area of adaptive optics.

Holographic optical tweezers for object manipulations at an air-liquid surface.

PubMed

Jesacher, Alexander; Fürhapter, Severin; Maurer, Christian; Bernet, Stefan; Ritsch-Marte, Monika

2006-06-26

We investigate holographic optical tweezers manipulating micro-beads at a suspended air-liquid interface. Axial confinement of the particles in the two-dimensional interface is maintained by the interplay between surface tension and gravity. Therefore, optical trapping of the micro-beads is possible even with a long distance air objective. Efficient micro-circulation of the liquid can be induced by fast rotating beads, driven by the orbital angular momentum transfer of incident Laguerre-Gaussian (doughnut) laser modes. Our setup allows various ways of creating a tailored dynamic flow of particles and liquid within the surface. We demonstrate examples of surface manipulations like efficient vortex pumps and mixers, interactive particle flow steering by arrays of vortex pumps, the feasibility of achieving a "clocked" traffic of micro beads, and size-selective guiding of beads along optical "conveyor belts".

Exploring bubble oscillation and mass transfer enhancement in acoustic-assisted liquid-liquid extraction with a microfluidic device

NASA Astrophysics Data System (ADS)

Xie, Yuliang; Chindam, Chandraprakash; Nama, Nitesh; Yang, Shikuan; Lu, Mengqian; Zhao, Yanhui; Mai, John D.; Costanzo, Francesco; Huang, Tony Jun

2015-07-01

We investigated bubble oscillation and its induced enhancement of mass transfer in a liquid-liquid extraction process with an acoustically-driven, bubble-based microfluidic device. The oscillation of individually trapped bubbles, of known sizes, in microchannels was studied at both a fixed frequency, and over a range of frequencies. Resonant frequencies were analytically identified and were found to be in agreement with the experimental observations. The acoustic streaming induced by the bubble oscillation was identified as the cause of this enhanced extraction. Experiments extracting Rhodanmine B from an aqueous phase (DI water) to an organic phase (1-octanol) were performed to determine the relationship between extraction efficiency and applied acoustic power. The enhanced efficiency in mass transport via these acoustic-energy-assisted processes was confirmed by comparisons against a pure diffusion-based process.

Dealing with locally-driven degradation: A quick start option under REDD+

PubMed Central

2011-01-01

The paper reviews a number of challenges associated with reducing degradation and its related emissions through national approaches to REDD+ under UNFCCC policy. It proposes that in many countries, it may in the short run be easier to deal with the kinds of degradation that result from locally driven community over-exploitation of forest for livelihoods, than from selective logging or fire control. Such degradation is low-level, but chronic, and is experienced over very large forest areas. Community forest management programmes tend to result not only in reduced degradation, but also in forest enhancement; moreover they are often popular, and do not require major political shifts. In principle these approaches therefore offer a quick start option for REDD+. Developing reference emissions levels for low-level locally driven degradation is difficult however given that stock losses and gains are too small to be identified and measured using remote sensing, and that in most countries there is little or no forest inventory data available. We therefore propose that forest management initiatives at the local level, such as those promoted by community forest management programmes, should monitor, and be credited for, only the net increase in carbon stock over the implementation period, as assessed by ground level surveys at the start and end of the period. This would also resolve the problem of nesting (ensuring that all credits are accounted for against the national reference emission level), since communities and others at the local level would be rewarded only for increased sequestration, while the national reference emission level would deal only with reductions in emissions from deforestation and degradation. PMID:22204698

Laser scanning confocal microscope with programmable amplitude, phase, and polarization of the illumination beam.

PubMed

Boruah, B R; Neil, M A A

2009-01-01

We describe the design and construction of a laser scanning confocal microscope with programmable beam forming optics. The amplitude, phase, and polarization of the laser beam used in the microscope can be controlled in real time with the help of a liquid crystal spatial light modulator, acting as a computer generated hologram, in conjunction with a polarizing beam splitter and two right angled prisms assembly. Two scan mirrors, comprising an on-axis fast moving scan mirror for line scanning and an off-axis slow moving scan mirror for frame scanning, configured in a way to minimize the movement of the scanned beam over the pupil plane of the microscope objective, form the XY scan unit. The confocal system, that incorporates the programmable beam forming unit and the scan unit, has been implemented to image in both reflected and fluorescence light from the specimen. Efficiency of the system to programmably generate custom defined vector beams has been demonstrated by generating a bottle structured focal volume, which in fact is the overlap of two cross polarized beams, that can simultaneously improve both the lateral and axial resolutions if used as the de-excitation beam in a stimulated emission depletion confocal microscope.

Programmable Self-Assembly of DNA-Dendrimer and DNA-Fullerene Nanostructures

DTIC Science & Technology

2004-10-01

separated by high pressure liquid chromatography ( HPLC ). The resulting material was analytically pure (99%) and monodisperse. Hybridization...bacterial and viral recognition, and gene expression analysis . These major accomplishments have been disseminated by various applications including 16...designing DNA strands with specific structural properties. The direct analysis of genomic DNA and RNA in an array format without labeling or

Designed cell consortia as fragrance-programmable analog-to-digital converters.

PubMed

Müller, Marius; Ausländer, Simon; Spinnler, Andrea; Ausländer, David; Sikorski, Julian; Folcher, Marc; Fussenegger, Martin

2017-03-01

Synthetic biology advances the rational engineering of mammalian cells to achieve cell-based therapy goals. Synthetic gene networks have nearly reached the complexity of digital electronic circuits and enable single cells to perform programmable arithmetic calculations or to provide dynamic remote control of transgenes through electromagnetic waves. We designed a synthetic multilayered gaseous-fragrance-programmable analog-to-digital converter (ADC) allowing for remote control of digital gene expression with 2-bit AND-, OR- and NOR-gate logic in synchronized cell consortia. The ADC consists of multiple sampling-and-quantization modules sensing analog gaseous fragrance inputs; a gas-to-liquid transducer converting fragrance intensity into diffusible cell-to-cell signaling compounds; a digitization unit with a genetic amplifier circuit to improve the signal-to-noise ratio; and recombinase-based digital expression switches enabling 2-bit processing of logic gates. Synthetic ADCs that can remotely control cellular activities with digital precision may enable the development of novel biosensors and may provide bioelectronic interfaces synchronizing analog metabolic pathways with digital electronics.

Surfactant effects on heat transfer at gas/liquid interfaces

NASA Astrophysics Data System (ADS)

Lopez, J. M.; Hirsa, A. H.

2000-01-01

A formulation of a canonical model to elucidate the interplay and competition between three primary sources of heat and mass transfer in non-isothermal systems with gas/liquid interfaces is presented. The nonlinear interaction between (i) buoyancy driven flow in the bulk, (ii) thermal Marangoni flow at the gas/liquid interface, and (iii) surfactant Marangoni flow at the interface is considered. A numerical model of the Navier-Stokes and energy equations is being developed for a simple, axisymmetric flow geometry. The boundary conditions for the Navier-Stokes equations are functions of the intrinsic viscoelastic properties of the interface, specifically the surface tension and the surface viscosities. A flow geometry which is amenable to both experiments and computations for elucidating the separate effects of the three mechanisms consists of an annular region bounded by a stationary inner and an outer cylinder and floor, and a free surface. The flow is driven by the temperature difference between the inner and outer cylinder which are set independently, and the floor is insulated. The predictions of the model for earth-g can be compared to laboratory measurements of the velocity field, and the surface temperature distribution. The predictions of the model for arbitrary gravity may be subsequently tested in the microgravity environment. .

Making waves in a photoactive polymer film

NASA Astrophysics Data System (ADS)

Gelebart, Anne Helene; Jan Mulder, Dirk; Varga, Michael; Konya, Andrew; Vantomme, Ghislaine; Meijer, E. W.; Selinger, Robin L. B.; Broer, Dirk J.

2017-06-01

Oscillating materials that adapt their shapes in response to external stimuli are of interest for emerging applications in medicine and robotics. For example, liquid-crystal networks can be programmed to undergo stimulus-induced deformations in various geometries, including in response to light. Azobenzene molecules are often incorporated into liquid-crystal polymer films to make them photoresponsive; however, in most cases only the bending responses of these films have been studied, and relaxation after photo-isomerization is rather slow. Modifying the core or adding substituents to the azobenzene moiety can lead to marked changes in photophysical and photochemical properties, providing an opportunity to circumvent the use of a complex set-up that involves multiple light sources, lenses or mirrors. Here, by incorporating azobenzene derivatives with fast cis-to-trans thermal relaxation into liquid-crystal networks, we generate photoactive polymer films that exhibit continuous, directional, macroscopic mechanical waves under constant light illumination, with a feedback loop that is driven by self-shadowing. We explain the mechanism of wave generation using a theoretical model and numerical simulations, which show good qualitative agreement with our experiments. We also demonstrate the potential application of our photoactive films in light-driven locomotion and self-cleaning surfaces, and anticipate further applications in fields such as photomechanical energy harvesting and miniaturized transport.

Event management for large scale event-driven digital hardware spiking neural networks.

PubMed

Caron, Louis-Charles; D'Haene, Michiel; Mailhot, Frédéric; Schrauwen, Benjamin; Rouat, Jean

2013-09-01

The interest in brain-like computation has led to the design of a plethora of innovative neuromorphic systems. Individually, spiking neural networks (SNNs), event-driven simulation and digital hardware neuromorphic systems get a lot of attention. Despite the popularity of event-driven SNNs in software, very few digital hardware architectures are found. This is because existing hardware solutions for event management scale badly with the number of events. This paper introduces the structured heap queue, a pipelined digital hardware data structure, and demonstrates its suitability for event management. The structured heap queue scales gracefully with the number of events, allowing the efficient implementation of large scale digital hardware event-driven SNNs. The scaling is linear for memory, logarithmic for logic resources and constant for processing time. The use of the structured heap queue is demonstrated on a field-programmable gate array (FPGA) with an image segmentation experiment and a SNN of 65,536 neurons and 513,184 synapses. Events can be processed at the rate of 1 every 7 clock cycles and a 406×158 pixel image is segmented in 200 ms. Copyright © 2013 Elsevier Ltd. All rights reserved.

KNMI DataLab experiences in serving data-driven innovations

NASA Astrophysics Data System (ADS)

Noteboom, Jan Willem; Sluiter, Raymond

2016-04-01

Climate change research and innovations in weather forecasting rely more and more on (Big) data. Besides increasing data from traditional sources (such as observation networks, radars and satellites), the use of open data, crowd sourced data and the Internet of Things (IoT) is emerging. To deploy these sources of data optimally in our services and products, KNMI has established a DataLab to serve data-driven innovations in collaboration with public and private sector partners. Big data management, data integration, data analytics including machine learning and data visualization techniques are playing an important role in the DataLab. Cross-domain data-driven innovations that arise from public-private collaborative projects and research programmes can be explored, experimented and/or piloted by the KNMI DataLab. Furthermore, advice can be requested on (Big) data techniques and data sources. In support of collaborative (Big) data science activities, scalable environments are offered with facilities for data integration, data analysis and visualization. In addition, Data Science expertise is provided directly or from a pool of internal and external experts. At the EGU conference, gained experiences and best practices are presented in operating the KNMI DataLab to serve data-driven innovations for weather and climate applications optimally.

Usability-driven evolution of a space instrument

NASA Astrophysics Data System (ADS)

McCalden, Alec

2012-09-01

The use of resources in the cradle-to-grave timeline of a space instrument might be significantly improved by considering the concept of usability from the start of the mission. The methodology proposed here includes giving early priority in a programme to the iterative development of a simulator that models instrument operation, and allowing this to evolve ahead of the actual instrument specification and fabrication. The advantages include reduction of risk in software development by shifting much of it to earlier in a programme than is typical, plus a test programme that uses and thereby proves the same support systems that may be used for flight. A new development flow for an instrument is suggested, showing how the system engineering phases used by the space agencies could be reworked in line with these ideas. This methodology is also likely to contribute to a better understanding between the various disciplines involved in the creation of a new instrument. The result should better capture the science needs, implement them more accurately with less wasted effort, and more fully allow the best ideas from all team members to be considered.

Method for controlling protein crystallization

NASA Technical Reports Server (NTRS)

Noever, David A. (Inventor)

1993-01-01

A method and apparatus for controlling the crystallization of protein by solvent evaporation including placing a drop of protein solution between and in contact with a pair of parallel plates and driving one of the plates toward and away from the other plate in a controlled manner to adjust the spacing between the plates is presented. The drop of solution forms a liquid cylinder having a height dependent upon the plate spacing thereby effecting the surface area available for solvent evaporation. When the spacing is close, evaporation is slow. Evaporation is increased by increasing the spacing between the plates until the breaking point of the liquid cylinder. One plate is mounted upon a fixed post while the other plate is carried by a receptacle movable relative to the post and driven by a belt driven screw drive. The temperature and humidity of the drop of protein solution are controlled by sealing the drop within the receptacle and mounting a heater and dessicant within the receptacle.

An evaluation of a hubless inducer and a full flow hydraulic turbine driven inducer boost pump

NASA Technical Reports Server (NTRS)

Lindley, B. K.; Martinson, A. R.

1971-01-01

The purpose of the study was to compare the performance of several configurations of hubless inducers with a hydrodynamically similar conventional inducer and to demonstrate the performance of a full flow hydraulic turbine driven inducer boost pump using these inducers. A boost pump of this type consists of an inducer connected to a hydraulic turbine with a high speed rotor located in between. All the flow passes through the inducer, rotor, and hydraulic turbine, then into the main pump. The rotor, which is attached to the main pump shaft, provides the input power to drive the hydraulic turbine which, in turn, drives the inducer. The inducer, rotating at a lower speed, develops the necessary head to prevent rotor cavitation. The rotor speed is consistent with present main engine liquid hydrogen pump designs and the overall boost pump head rise is sufficient to provide adequate main pump suction head. This system would have the potential for operating at lower liquid hydrogen tank pressures.

Valving for controlling a fluid-driven reciprocating apparatus

DOEpatents

Whitehead, John C.

1995-01-01

A pair of control valve assemblies for alternately actuating a pair of fluid-driven free-piston devices by using fluid pressure communication therebetween. Each control valve assembly is switched by a pressure signal depending on the state of its counterpart's piston. The communication logic is arranged to provide overlap of the forward strokes of the pistons, so that at least one of the pair will always be pressurized. Thus, uninterrupted pumping of liquid is made possible from a pair of free-piston pumps. In addition, the speed and frequency of piston stroking is entirely dependent on the mechanical power load applied. In the case of a pair of pumps, this enables liquid delivery at a substantially constant pressure over the full range of flow rates, from zero to maximum flow. Each of the valve assemblies uses an intake-exhaust valve and a signal valve with the signal valve of one pump being connected to be pressure responsive to the piston of the opposite cylinder or pump.

Valving for controlling a fluid-driven reciprocating apparatus

DOEpatents

Whitehead, J.C.

1995-06-27

A pair of control valve assemblies is described for alternately actuating a pair of fluid-driven free-piston devices by using fluid pressure communication therebetween. Each control valve assembly is switched by a pressure signal depending on the state of its counterpart`s piston. The communication logic is arranged to provide overlap of the forward strokes of the pistons, so that at least one of the pair will always be pressurized. Thus, uninterrupted pumping of liquid is made possible from a pair of free-piston pumps. In addition, the speed and frequency of piston stroking is entirely dependent on the mechanical power load applied. In the case of a pair of pumps, this enables liquid delivery at a substantially constant pressure over the full range of flow rates, from zero to maximum flow. Each of the valve assemblies uses an intake-exhaust valve and a signal valve with the signal valve of one pump being connected to be pressure responsive to the piston of the opposite cylinder or pump. 15 figs.

Simulation of sloshing dynamics induced forces and torques actuated on dewar container driven by gravity gradient and jitter accelerations in microgravity

NASA Technical Reports Server (NTRS)

Hung, R. J.; Pan, H. L.

1993-01-01

Some experimental spacecraft use superconducting sensors for gyro read-out and so must be maintained at a very low temperature. The boil-off from the cryogenic liquid used to cool the sensors can also be used, as the Gravity Probe B (GP-B) spacecraft does, as propellant to maintain attitude control and drag-free operation of the spacecraft. The cryogenic liquid for such spacecraft is, however, susceptible to both slosh-like motion and non-axisymmetric configurations under the influence of various kinds of gravity jitter and gravity gradient accelerations. Hence, it is important to quantify the magnitude of the liquid-induced perturbations on the spacecraft. We use the example of the GP-B to investigate such perturbations by numerical simulations. For this spacecraft disturbances can be imposed on the liquid by atmospheric drag, spacecraft attitude control maneuvers, and the earth's gravity gradient. More generally, onboard machinery vibrations and crew motion can also create disturbances. Recent studies suggest that high frequency disturbances are relatively unimportant in causing liquid motions in comparison to low frequency ones. The results presented here confirm this conclusion. After an initial calibration period, the GP-B spacecraft rotates in orbit at 0.1 rpm about the tank symmetry axis. For this rotation rate, the equilibrium liquid free surface shape is a 'doughnut' configuration for all residual gravity levels of 10(exp -6) g(sub 0) or less, as shown by experiments and by numerical simulations; furthermore, the superfluid behavior of the 1.8 K liquid helium used in GP-B eliminates temperature gradients and therefore such effects as Marangoni convection do not have to be considered. Classical fluid dynamics theory is used as the basis of the numerical simulations here, since Mason's experiments show that the theory is applicable for cryogenic liquid helium in large containers. To study liquid responses to various disturbances, we investigate and simulate three levels of gravity jitter (10(exp -6), 10(exp -7), and 10(exp -8) g(sub 0)) each at three predominant frequencies (0.1, 1.0, and 10 Hz), combined with a gravity gradient appropriate for the GP-B orbit. Dynamical evolution of sloshing dynamics excited fluid forces and torque fluctuations exerted on the dewar container driven by the combined gravity gradient and jitter accelerations are also investigated and simulated.

Turbo Pascal Implementation of a Distributed Processing Network of MS-DOS Microcomputers Connected in a Master-Slave Configuration

DTIC Science & Technology

1989-12-01

Interrupt Procedures ....... 29 13. Support for a Larger Memory Model ................ 29 C. IMPLEMENTATION ........................................ 29...describe the programmer’s model of the hardware utilized in the microcomputers and interrupt driven serial communication considerations. Chapter III...Central Processor Unit The programming model of Table 2.1 is common to the Intel 8088, 8086 and 80x86 series of microprocessors used in the IBM PC/AT

Dynamics of poroelastocapillary rise

NASA Astrophysics Data System (ADS)

Nasouri, Babak; Elfring, Gwynn

2017-11-01

The surface-tension-driven rise of a liquid between two elastic sheets can result in their deformation or coalescence depending on their flexibility. When the sheets are poroelastic, the flexibility of the immersed parts of the sheets can change considerably thereby altering the dynamical behavior of the system. To better understand this phenomenon, we study the poroelastocapillary rise of a wetting liquid between poroelastic sheets. Using the lubrication theory and linear elasticity, we quantify the effects of the change in material properties of the wet sheets on the capillary rise and the equilibrium state of the system.

Crystalline nucleation in undercooled liquids: a Bayesian data-analysis approach for a nonhomogeneous Poisson process.

PubMed

Filipponi, A; Di Cicco, A; Principi, E

2012-12-01

A Bayesian data-analysis approach to data sets of maximum undercooling temperatures recorded in repeated melting-cooling cycles of high-purity samples is proposed. The crystallization phenomenon is described in terms of a nonhomogeneous Poisson process driven by a temperature-dependent sample nucleation rate J(T). The method was extensively tested by computer simulations and applied to real data for undercooled liquid Ge. It proved to be particularly useful in the case of scarce data sets where the usage of binned data would degrade the available experimental information.

Recent and future liquid metal experiments on homogeneous dynamo action and magnetic instabilities

NASA Astrophysics Data System (ADS)

Stefani, Frank; Gerbeth, Gunter; Giesecke, Andre; Gundrum, Thomas; Kirillov, Oleg; Seilmayer, Martin; Gellert, Marcus; Rüdiger, Günther; Gailitis, Agris

2011-10-01

The present status of the Riga dynamo experiment is summarized and the prospects for its future exploitation are evaluated. We further discuss the plans for a large-scale precession driven dynamo experiment to be set-up in the framework of the new installation DRESDYN (DREsden Sodium facility for dynamo and thermohydraulic studies) at Helmholtz-Zentrum Dresden-Rossendorf. We report recent investigations of the magnetorotational instability and the Tayler instability and sketch the plans for another large-scale liquid sodium facility devoted to the combined study of both effects.

Spontaneous mode-selection in the self-propelled motion of a solid/liquid composite driven by interfacial instability

NASA Astrophysics Data System (ADS)

Takabatake, Fumi; Magome, Nobuyuki; Ichikawa, Masatoshi; Yoshikawa, Kenichi

2011-03-01

Spontaneous motion of a solid/liquid composite induced by a chemical Marangoni effect, where an oil droplet attached to a solid soap is placed on a water phase, was investigated. The composite exhibits various characteristic motions, such as revolution (orbital motion) and translational motion. The results showed that the mode of this spontaneous motion switches with a change in the size of the solid scrap. The essential features of this mode-switching were reproduced by ordinary differential equations by considering nonlinear friction with proper symmetry.

Vibration isolation technology: Sensitivity of selected classes of space experiments to residual accelerations

NASA Technical Reports Server (NTRS)

Alexander, J. Iwan D.; Zhang, Y. Q.; Adebiyi, Adebimpe

1989-01-01

Progress performed on each task is described. Order of magnitude analyses related to liquid zone sensitivity and thermo-capillary flow sensitivity are covered. Progress with numerical models of the sensitivity of isothermal liquid zones is described. Progress towards a numerical model of coupled buoyancy-driven and thermo-capillary convection experiments is also described. Interaction with NASA personnel is covered. Results to date are summarized and they are discussed in terms of the predicted space station acceleration environment. Work planned for the second year is also discussed.

Quantifying Instability Sources in Liquid Rocket Engines

NASA Technical Reports Server (NTRS)

Farmer, Richard C.; Cheng, Gary C.

2000-01-01

Computational fluid dynamics methodology to predict the effects of combusting flows on acoustic pressure oscillations in liquid rocket engines (LREs) is under development. 'Me intent of the investigation is to develop the causal physics of combustion driven acoustic resonances in LREs. The crux of the analysis is the accurate simulation of pressure/density/sound speed in a combustor which when used by the FDNS-RFV CFD code will produce realistic flow phenomena. An analysis of a gas generator considered for the Fastrac engine will be used as a test validation case.

Novel Directional Solidification Processing of Hypermonotectic Alloys

NASA Technical Reports Server (NTRS)

Grugel, Richard N.

1999-01-01

Gravity driven separation precludes uniform microstructural development during controlled directional solidification (DS) processing of hypermonotectic alloys. It is well established that liquid/liquid suspensions, in which the respective components are immiscible and have significant density differences, can be established and maintained by utilizing ultrasound. A historical introduction to this work is presented with the intent of establishing the basis for applying the phenomena to promote microstructural uniformity during controlled directional solidification processing of immiscible mixtures. Experimental work based on transparent organics, as well as salt systems, will be presented in view of the processing parameters.

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.

Pressure Profiles in a Loop Heat Pipe Under Gravity Influence

NASA Technical Reports Server (NTRS)

Ku, Jentung

2015-01-01

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

Pressure Profiles in a Loop Heat Pipe under Gravity Influence

NASA Technical Reports Server (NTRS)

Ku, Jentung

2015-01-01

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

Programmable masks for optical information processing

NASA Technical Reports Server (NTRS)

Goebel, J. H.; Matsumoto, T.; Mina, C.; Welch, J.

1984-01-01

Research in progress at NASA Ames Research Center on programmable masks is discussed in this paper. One type is a large area format liquid crystal mask intended for binary optical computation problems. To date, an on-off contrast ratio of 500:1 has been achieved at a switching rate of 1 Hz. With a 32 x 32 format, a ratio 10 to the 4th power:1 is desirable. The switching contrast is entirely dependent on the polarized quality; therefore, it is believed that 10 to the 4th power:1 in transmission is possible. Larger format masks are under development. An application to Hadamard transform polarized imagery at wavelengths of 1.0 to 2.0 micrometers, which is competitive with the best monolithic infrared detector arrays, is discussed.

Measuring and modelling the quality of 40 post-disaster mental health and psychosocial support programmes.

PubMed

Dückers, Michel L A; Thormar, Sigridur B; Juen, Barbara; Ajdukovic, Dean; Newlove-Eriksson, Lindy; Olff, Miranda

2018-01-01

Disasters can have an enormous impact on the health and well-being of those affected. Internationally, governments and service providers are often challenged to address complex psychosocial problems. Ideally, the potentially broad range of support activities include a coherent, high-quality mental health and psychosocial support (MHPSS) programme. We present a theory-driven quantitative analysis of the quality of 40 MHPSS programmes, mostly implemented in European disaster settings. The objective is to measure quality domains recognized as relevant in the literature and to empirically test associations. During the EU project "Operationalizing Psychosocial Support in Crisis" (OPSIC) an evaluation survey was designed and developed for this purpose and completed by 40 MHPSS programme coordinators involved in different mass emergencies and disasters. We analysed the survey data in two steps. Firstly, we used the data to operationalize quality domains of a MHPSS programme, tested constructs and assessed their internal consistency reliability. A total of 26 out of 44 survey items clustered into three of the four domains identified within the theoretical framework: "planning and delivery system" (Cronbach's alpha 0.82); "general evaluation criteria" (Cronbach's alpha 0.82); and "essential psychosocial principles" (Cronbach's alpha 0.75). "Measures and interventions applied", theoretically a potential fourth domain, could not be confirmed to empirically cluster together. Secondly, several models with associations between domains and measures and interventions were tested and compared. The model with the best fit suggests that in MHPSS programmes with a higher planning and delivery systems score, a larger number of measures and interventions from evidence-informed guidelines are applied. In such programmes, coordinators are more positive about general evaluation criteria and the realization of essential psychosocial principles. Moreover, the analyses showed that some measures and interventions are more likely to be applied in programmes with more evolved planning and delivery systems, yet for most measures and interventions the likelihood of being applied is not linked to planning and delivery system status, nor to coordinator perceptions concerning psychosocial principles and evaluation criteria. Further research is necessary to validate and expand the findings and to learn more about success factors and obstacles for MHPSS programme implementation.

Innovative health systems projects.

PubMed

Green, Michael; Amad, Mansoor; Woodland, Mark

2015-02-01

Residency programmes struggle with the systems-based practice and improvement competency promoted by the Accreditation Council for Graduate Medical Education. The development of Innovative Health Systems Projects (IHelP) was driven by the need for better systems-based initiatives at an institutional level. Our objective was to develop a novel approach that successfully incorporates systems-based practice in our Graduate Medical Education (GME) programmes, while tracking our impact on health care delivery as an academic medical centre. We started the IHelP programme as a 'volunteer initiative' in 2010. A detailed description of the definition, development and implementation of the IHelP programme, along with our experience of the first year, is described. Residents, fellows and faculty mentors all played an important role in establishing the foundation of this initiative. Following the positive response, we have now incorporated IHelP into all curricula as a graduating requirement. IHelP has promoted scholarly activity and faculty mentorship, [and] has improved aspects of patient care and safety A total of 123 residents and fellows, representing 26 specialties, participated. We reviewed 145 projects that addressed topics ranging from administrative and departmental improvements to clinical care algorithms. The projects by area of focus were: patient care - clinical care, 38 per cent; patient care - quality, 27 per cent; resident education, 21 per cent; and a cumulative 16 per cent among pharmacy, department activities, patient education, medical records and clinical facility. We are pleased with the results of our first year of incorporating a systems-based improvement programme into the GME programmes. This initiative has promoted scholarly activity and faculty mentorship, has improved aspects of patient care and safety, and has led to the development of many practical innovations. © 2015 John Wiley & Sons Ltd.

A comprehensive review of the SLMTA literature part 2: Measuring success

PubMed Central

Yao, Katy; Nkengasong, John N.

2014-01-01

Background Since its introduction in 2009, the Strengthening Laboratory Management Toward Accreditation (SLMTA) programme has been implemented in 617 laboratories in 47 countries. Objective We completed a systematic review of the published literature on SLMTA. The review consists of two companion papers; this article examines quantitative evidence presented in the publications along with a meta-analysis of selected results. Methods We identified 28 published articles with data from SLMTA implementation. The SLMTA programme was evaluated through audits based on a standard checklist, which is divided into 12 sections corresponding to the 12 Quality System Essentials (QSEs). Several basic service delivery indicators reported by programmes were also examined. Results for various components of the programme were reviewed and summarised; a meta-analysis of QSE results grouped by the three stages of the quality cycle was conducted for 126 laboratories in 12 countries. Results Global programme data show improved quality in SLMTA laboratories in every country, with average improvements on audit scores of 25 percentage points. Meta-analysis identified Improvement Management as the weakest stage, with internal audit (8%) and occurrence management (16%) showing the lowest scores. Studies documented 19% – 95% reductions in turn-around times, 69% – 93% reductions in specimen rejection rates, 76% – 81% increases in clinician satisfaction rates, 67% – 85% improvements in external quality assessment results, 50% – 66% decreases in nonconformities and 67% increases in staff punctuality. Conclusions The wide array of results reported provides a comprehensive picture of the SLMTA programme overall, suggesting a substantive impact on provision of quality laboratory services and patient care. These comprehensive results establish a solid data-driven foundation for program improvement and further expansion. PMID:29043201

Scale-up of a comprehensive harm reduction programme for people injecting opioids: lessons from north-eastern India

PubMed Central

Lalmuanpuii, Melody; Biangtung, Langkham; Mishra, Ritu Kumar; Reeve, Matthew J; Tzudier, Sentimoa; Singh, Angom L; Sinate, Rebecca

2013-01-01

Abstract Problem Harm reduction packages for people who inject illicit drugs, including those infected with human immunodeficiency virus (HIV), are cost-effective but have not been scaled up globally. In the north-eastern Indian states of Manipur and Nagaland, the epidemic of HIV infection is driven by the injection of illicit drugs, especially opioids. These states needed to scale up harm reduction programmes but faced difficulty doing so. Approach In 2004, the Bill & Melinda Gates Foundation funded Project ORCHID to scale up a harm reduction programme in Manipur and Nagaland. Local setting In 2003, an estimated 10 000 and 16 000 people were injecting drugs in Manipur and Nagaland, respectively. The prevalence of HIV infection among people injecting drugs was 24.5% in Manipur and 8.4% in Nagaland. Relevant changes By 2012, the harm reduction programme had been scaled up to an average of 9011 monthly contacts outside clinics (80% of target); an average of 1709 monthly clinic visits (15% of target, well above the 5% monthly goal) and an average monthly distribution of needles and syringes of 16 each per programme participant. Opioid agonist maintenance treatment coverage was 13.7% and retention 6 months after enrolment was 63%. Antiretroviral treatment coverage for HIV-positive participants was 81%. Lessons learnt A harm reduction model consisting of community-owned, locally relevant innovations and business approaches can result in good harm reduction programme scale-up and influence harm reduction policy. Project ORCHID has influenced national harm reduction policy in India and contributed to the development of harm reduction guidelines. PMID:23599555

A community continuity programme: volunteer faculty mentors and continuity learning.

PubMed

McGeehan, John; English, Richard; Shenberger, Keith; Tracy, Gerald; Smego, Raymond

2013-02-01

Longitudinal generalist preceptorship experiences early in medical education can have beneficial effects on how students practise the art and science of medicine, regardless of their eventual career choices. We evaluated the first 2 years of implementation of an integrated, regional campus-based, early clinical experience programme, the Community Continuity Program, at our new community-based medical school that is under the supervision of volunteer primary care faculty members acting as continuity mentors (CMs). Curricular components for years 1 and 2 consisted of three annual 1-week community-based experiences with CMs, extensive physical diagnosis practice, interprofessional learning activities, a multigenerational family care experience, a mandatory Community Health Research Project (CHRP) in year 1 and a mandatory Quality Improvement Project in year 2. Outcome measures included student, faculty member and programme evaluations, student reflective narratives in portal-based e-journals, a Liaison Committee on Medical Education (LCME) self-study student survey and serial level-of-empathy surveys.   Students found all elements of this integrated community experience programme beneficial and worthwhile, especially the CMs and the use of standardised and real-life patients. CMs noted effective and professional student-patient interactions. The number of reflective e-journal postings per student during year1 ranged from 14 to 81 (mean, 47). Serial empathy questionnaires administered over 2 years demonstrated preservation of student empathy, and students believed that the programme had a positive effect on their personal level of empathy.   An integrative, longitudinal, community-based, early clinical experience programme driven by volunteer CMs provides patient-centered instruction for preclinical students in the clinical, social, behavioural, ethical and research foundations of medicine. © Blackwell Publishing Ltd 2013.

Human Apolipoprotein A1 at Solid/Liquid and Liquid/Gas Interfaces.

PubMed

Dogan, Susanne; Paulus, Michael; Forov, Yury; Weis, Christopher; Kampmann, Matthias; Cewe, Christopher; Kiesel, Irena; Degen, Patrick; Salmen, Paul; Rehage, Heinz; Tolan, Metin

2018-04-12

An X-ray reflectivity study on the adsorption behavior of human apolipoprotein A1 (apoA1) at hydrophilic and hydrophobic interfaces is presented. It is shown that the protein interacts via electrostatic and hydrophobic interactions with the interfaces, resulting in the absorption of the protein. pH dependent measurements at the solid/liquid interface between silicon dioxide and aqueous protein solution show that in a small pH range between pH 4 and 6, adsorption is increased due to electrostatic attraction. Here, the native shape of the protein seems to be conserved. In contrast, the adsorption at the liquid/gas interface is mainly driven by hydrophobic effects, presumably by extending the hydrophobic regions of the amphipathic helices, and results in a conformational change of the protein during adsorption. However, the addition of differently charged membrane-forming lipids at the liquid/gas interface illustrates the ability of apoA1 to include lipids, resulting in a depletion of the lipids from the interface.

FAST TRACK COMMUNICATION: Gas liquid phase coexistence in a tetrahedral patchy particle model

NASA Astrophysics Data System (ADS)

Romano, Flavio; Tartaglia, Piero; Sciortino, Francesco

2007-08-01

We evaluate the location of the gas-liquid coexistence line and of the associated critical point for the primitive model for water (PMW), introduced by Kolafa and Nezbeda (1987 Mol. Phys. 61 161). Besides being a simple model for a molecular network forming liquid, the PMW is representative of patchy proteins and novel colloidal particles interacting with localized directional short-range attractions. We show that the gas-liquid phase separation is metastable, i.e. it takes place in the region of the phase diagram where the crystal phase is thermodynamically favoured, as in the case of particles interacting via short-range attractive spherical potentials. We do not observe crystallization close to the critical point. The region of gas-liquid instability of this patchy model is significantly reduced as compared to that from equivalent models of spherically interacting particles, confirming the possibility of observing kinetic arrest in a homogeneous sample driven by bonding as opposed to packing.

The jABC Approach to Rigorous Collaborative Development of SCM Applications

NASA Astrophysics Data System (ADS)

Hörmann, Martina; Margaria, Tiziana; Mender, Thomas; Nagel, Ralf; Steffen, Bernhard; Trinh, Hong

Our approach to the model-driven collaborative design of IKEA's P3 Delivery Management Process uses the jABC [9] for model driven mediation and choreography to complement a RUP-based (Rational Unified Process) development process. jABC is a framework for service development based on Lightweight Process Coordination. Users (product developers and system/software designers) easily develop services and applications by composing reusable building-blocks into (flow-) graph structures that can be animated, analyzed, simulated, verified, executed, and compiled. This way of handling the collaborative design of complex embedded systems has proven to be effective and adequate for the cooperation of non-programmers and non-technical people, which is the focus of this contribution, and it is now being rolled out in the operative practice.

Design features and operational characteristics of the Langley pilot transonic cryogenic tunnel

NASA Technical Reports Server (NTRS)

Kilgore, R. A.

1974-01-01

A fan-driven transonic cryogenic tunnel was designed, and its purging, cooldown, and warmup times were determined satisfactory. Cooling with liquid nitrogen is at the power levels required for transonic testing. Good temperature distributions are obtained by using a simple nitrogen injection system.

Confinement-Driven Phase Separation of Quantum Liquid Mixtures

NASA Astrophysics Data System (ADS)

Prisk, T. R.; Pantalei, C.; Kaiser, H.; Sokol, P. E.

2012-08-01

We report small-angle neutron scattering studies of liquid helium mixtures confined in Mobil Crystalline Material-41 (MCM-41), a porous silica glass with narrow cylindrical nanopores (d=3.4nm). MCM-41 is an ideal model adsorbent for fundamental studies of gas sorption in porous media because its monodisperse pores are arranged in a 2D triangular lattice. The small-angle scattering consists of a series of diffraction peaks whose intensities are determined by how the imbibed liquid fills the pores. Pure He4 adsorbed in the pores show classic, layer-by-layer film growth as a function of pore filling, leaving the long range symmetry of the system intact. In contrast, the adsorption of He3-He4 mixtures produces a structure incommensurate with the pore lattice. Neither capillary condensation nor preferential adsorption of one helium isotope to the pore walls can provide the symmetry-breaking mechanism. The scattering is consistent with the formation of randomly distributed liquid-liquid microdomains ˜2.3nm in size, providing evidence that confinement in a nanometer scale capillary can drive local phase separation in quantum liquid mixtures.

Extraction and Esterification of Low-Titer Short-Chain Volatile Fatty Acids from Anaerobic Fermentation with Ionic Liquids.

PubMed

Andersen, Stephen J; Berton, Jan K E T; Naert, Pieter; Gildemyn, Sylvia; Rabaey, Korneel; Stevens, Christian V

2016-08-23

Ionic liquids can both act as a solvent and mediate esterification to valorize low-titer volatile fatty acids and generate organic solvents from renewable carbon sources including biowaste and CO2 . In this study, four phosphonium ionic liquids were tested for single-stage extraction of acetic acid from a dilute stream and esterification to ethyl acetate with added ethanol and heat. The esterification proceeded with a maximum conversion of 85.9±1.3 % after 30 min at 75 °C at a 1:1 stoichiometric ratio of reactants. Extraction and esterification can be tailored using mixed-anion ionic liquids; this is demonstrated herein using a common trihexyl(tetradecyl)phosphonium cation and a mixed chloride and bis(trifluoromethylsulfonyl)imide anion ionic liquid. As a further proof-of-concept, ethyl acetate was generated from an ionic liquid-driven esterification of an acetic acid extractant generated using CO2 as the only carbon source by microbial electrosynthesis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Concept of a self-pressurized feed system for liquid rocket engines and its fundamental experiment results

NASA Astrophysics Data System (ADS)

Matsumoto, Jun; Okaya, Shunichi; Igoh, Hiroshi; Kawaguchi, Junichiro

2017-04-01

A new propellant feed system referred to as a self-pressurized feed system is proposed for liquid rocket engines. The self-pressurized feed system is a type of gas-pressure feed system; however, the pressurization source is retained in the liquid state to reduce tank volume. The liquid pressurization source is heated and gasified using heat exchange from the hot propellant using a regenerative cooling strategy. The liquid pressurization source is raised to critical pressure by a pressure booster referred to as a charger in order to avoid boiling and improve the heat exchange efficiency. The charger is driven by a part of the generated pressurization gas using a closed-loop self-pressurized feed system. The purpose of this study is to propose a propellant feed system that is lighter and simpler than traditional gas pressure feed systems. The proposed system can be applied to all liquid rocket engines that use the regenerative cooling strategy. The concept and mathematical models of the self-pressurized feed system are presented first. Experiment results for verification are then shown and compared with the mathematical models.

Transient natural and surface-tension-driven convection in a two-layer gas-and-liquid enclosure with nonuniform radiative transfer

NASA Technical Reports Server (NTRS)

Abramzon, B.; Edwards, D. K.; Sirignano, W. A.

1986-01-01

A numerical study has been made of transient heat transfer and fluid flow in a cylindrical enclosure containing a two-layer gas-and-liquid system. The geometric configuration and the boundary conditions of the problem are relevant to the analysis of the preignition processes during the fire accident situation involving a pool of liquid fuel in the vicinity of an ignition source. It is demonstrated that the effects of the natural and thermocapillary convection, radiative transfer, thermal inertia and conduction of the walls bounding the enclosure, as well as, the magnitude of the gravity field play important roles in the development of the temperature and velocity fields in the container.

Generation mechanism of hydrogen peroxide in dc plasma with a liquid electrode

NASA Astrophysics Data System (ADS)

Takeuchi, Nozomi; Ishibashi, Naoto

2018-04-01

The production mechanism of liquid-phase H2O2 in dc driven plasma in O2 and Ar with a water electrode was investigated. When a water anode was used, the concentration of H2O2 increased linearly with the treatment time. The production rate was proportional to the discharge current, and there was no dependence on the gap distance. On the other hand, the production rate was much smaller with a water anode. We concluded that the production of gas-phase H2O2 in the cathode sheath just above a water cathode and diffusion of this H2O2 into the water constitute the key mechanism in the production of liquid-phase H2O2.

The Principal Hugoniot of Forsterite to 950 GPa

DOE PAGES

Root, Seth; Townsend, Joshua P.; Davies, Erik; ...

2018-04-27

Forsterite (Mg 2SiO 4) single crystals were shock compressed to pressures between 200 and 950 GPa using independent plate–impact steady shocks and laser–driven decaying shock compression experiments. Additionally, we performed density functional theory–based molecular dynamics to aid interpretation of the experimental data and to investigate possible phase transformations and phase separations along the Hugoniot. We show that the experimentally obtained Hugoniot cannot distinguish between a pure liquid Mg 2SiO 4 and an assemblage of solid MgO plus liquid magnesium silicate. In conclusion, the measured reflectivity is nonzero and increases with pressure, which implies that the liquid is a poor electricalmore » conductor at low pressures and that the conductivity increases with pressure.« less

The influence of negative current collector size on a liquid metal positive electrode

NASA Astrophysics Data System (ADS)

Mohammad, Ibrahim; Ashour, Rakan; Kelley, Douglas

2017-11-01

Fluid mixing in the positive electrode of a liquid metal battery (LMB) governs some performance-related factors such as the rate of charge and discharge of the battery. The negative current collector (NCC) of a LMB is always smaller than the positive current collector, implying that current is convergent at the NCC. Also, different NCC sizes introduce different thermal, electromagnetic, and flow boundary conditions. In this talk, I will show how our lab studies the influence of NCC diameter on the flow in a liquid metal positive electrode driven by electrical current. I will present measurements of the flow velocity taken via Ultrasonic Doppler Velocimetry (UDV) over a range of different currents, at different NCC diameters.

Electric field-driven, magnetically-stabilized ferro-emulsion phase contactor

DOEpatents

Scott, T.C.

1990-07-17

Methods and systems are disclosed for interfacial surface area contact between a dispersed phase liquid and a continuous phase liquid in counter-current flow for purposes such as solvent extraction. Initial droplets of a dispersed phase liquid material containing ferromagnetic particles functioning as a packing'' are introduced to a counter-current flow of the continuous phase. A high intensity pulsed electric field is applied so as to shatter the initial droplets into a ferromagnetic emulsion comprising many smaller daughter droplets having a greater combined total surface area than that of the initial droplets in contact with the continuous phase material. A magnetic field is applied to control the position of the ferromagnetic emulsion for enhanced coalescence of the daughter droplets into larger reformed droplets. 2 figs.

Electric field-driven, magnetically-stabilized ferro-emulsion phase contactor

DOEpatents

Scott, Timothy C.

1990-01-01

Methods and systems for interfacial surface area contact between a dispersed phase liquid and a continuous phase liquid in counter-current flow for purposes such as solvent extraction. Initial droplets of a dispersed phase liquid material containing ferromagnetic particles functioning as a "packing" are introduced to a counter-current flow of the continuous phase. A high intensity pulsed electric field is applied so as to shatter the initial droplets into a ferromagnetic emulsion comprising many smaller daughter droplets having a greater combined total surface area than that of the initial droplets in contact with the continuous phase material. A magnetic field is applied to control the position of the ferromagnetic emulsion for enhanced coalescence of the daughter droplets into larger reformed droplets.

The Principal Hugoniot of Forsterite to 950 GPa

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

Root, Seth; Townsend, Joshua P.; Davies, Erik

Forsterite (Mg 2SiO 4) single crystals were shock compressed to pressures between 200 and 950 GPa using independent plate–impact steady shocks and laser–driven decaying shock compression experiments. Additionally, we performed density functional theory–based molecular dynamics to aid interpretation of the experimental data and to investigate possible phase transformations and phase separations along the Hugoniot. We show that the experimentally obtained Hugoniot cannot distinguish between a pure liquid Mg 2SiO 4 and an assemblage of solid MgO plus liquid magnesium silicate. In conclusion, the measured reflectivity is nonzero and increases with pressure, which implies that the liquid is a poor electricalmore » conductor at low pressures and that the conductivity increases with pressure.« less

Elimination of image flicker in a fringe-field switching liquid crystal display by applying a bipolar voltage wave.

PubMed

Oh, Seung-Won; Park, Jun-Hee; Lee, Ji-Hoon; Yoon, Tae-Hoon

2015-09-07

Recently, low-frequency driving of liquid crystal display (LCD) panels to minimize power consumption has drawn much attention. In the case in which an LCD panel is driven by a fringe-field at a low frequency, the image flickering phenomenon occurs when the sign of the applied electric field is reversed. We investigated image flickering induced by the flexoelectric effect in a fringe-field switching (FFS) liquid crystal cell in terms of the transmittance difference between frames and the ripple phenomenon. Experimental results show that image flicker due to transmittance difference can be eliminated completely and that the ripple phenomena can be reduced significantly by applying a bipolar voltage wave to the FFS cell.

A history of the UK liquid hydrogen programme

NASA Astrophysics Data System (ADS)

Harlow, J.

1992-07-01

A review is presented of the evolution of UK liquid hydrogen (LH2) programs into the testing of low- and higher-pressure engines for upper stage applications with attention given to the production of LH2. The engine requirements are examined of launchers such as the Black Knight and Black Prince vehicles and LOX/LH2 upper stages for the European Launcher Development Organization (ELDO). High-energy second and third stages are described for the ELDO vehicles, and injector types and thrust-chamber designs are illustrated for the use of LH2/LOX. Successful firings of the RZ-20 chamber are reported, and the production of liquid hydrogen is shown to be adequate for testing and usage over all of the experimental phases. Developments from the LH2 programs in the UK can provide technologies for current items such as the propellant feed lines for the Ariane program.

A High-Voltage Integrated Circuit Engine for a Dielectrophoresis-based Programmable Micro-Fluidic Processor

PubMed Central

Current, K. Wayne; Yuk, Kelvin; McConaghy, Charles; Gascoyne, Peter R. C.; Schwartz, Jon A.; Vykoukal, Jody V.; Andrews, Craig

2010-01-01

A high-voltage (HV) integrated circuit has been demonstrated to transport droplets on programmable paths across its coated surface. This chip is the engine for a dielectrophoresis (DEP)-based micro-fluidic lab-on-a-chip system. This chip creates DEP forces that move and help inject droplets. Electrode excitation voltage and frequency are variable. With the electrodes driven with a 100V peak-to-peak periodic waveform, the maximum high-voltage electrode waveform frequency is about 200Hz. Data communication rate is variable up to 250kHz. This demonstration chip has a 32×32 array of nominally 100V electrode drivers. It is fabricated in a 130V SOI CMOS fabrication technology, dissipates a maximum of 1.87W, and is about 10.4 mm × 8.2 mm. PMID:23989241

Development of an active structure flight experiment

NASA Astrophysics Data System (ADS)

Manning, R. A.; Wyse, R. E.; Schubert, S. R.

1993-02-01

The design and development of the Air Force and TRW's Advanced Control Technology Experiment (ACTEX) flight experiment is described in this paper. The overall objective of ACTEX is to provide an active structure trailblazer which will demonstrate the compatibility of active structures with operational spacecraft performance and lifetime measures. At the heart of the experiment is an active tripod driven by a digitally-programmable analog control electronics subsystem. Piezoceramic sensors and actuators embedded in a graphite epoxy host material provide the sensing and actuation mechanism for the active tripod. Low noise ground-programmable electronics provide a virtually unlimited number of control schemes that can be implemented in the space environment. The flight experiment program provides the opportunity to gather performance, reliability, adaptability, and lifetime performance data on vibration suppression hardware for the next generation of DoD and NASA spacecraft.

Tuning and Freezing Disorder in Photonic Crystals using Percolation Lithography.

PubMed

Burgess, Ian B; Abedzadeh, Navid; Kay, Theresa M; Shneidman, Anna V; Cranshaw, Derek J; Lončar, Marko; Aizenberg, Joanna

2016-01-21

Although common in biological systems, synthetic self-assembly routes to complex 3D photonic structures with tailored degrees of disorder remain elusive. Here we show how liquids can be used to finely control disorder in porous 3D photonic crystals, leading to complex and hierarchical geometries. In these optofluidic crystals, dynamically tunable disorder is superimposed onto the periodic optical structure through partial wetting or evaporation. In both cases, macroscopic symmetry breaking is driven by subtle sub-wavelength variations in the pore geometry. These variations direct site-selective infiltration of liquids through capillary interactions. Incorporating cross-linkable resins into our liquids, we developed methods to freeze in place the filling patterns at arbitrary degrees of partial wetting and intermediate stages of drying. These percolation lithography techniques produced permanent photonic structures with adjustable disorder. By coupling strong changes in optical properties to subtle differences in fluid behavior, optofluidic crystals may also prove useful in rapid analysis of liquids.

Superphobicity/philicity Janus Fabrics with Switchable, Spontaneous, Directional Transport Ability to Water and Oil Fluids

PubMed Central

Zhou, Hua; Wang, Hongxia; Niu, Haitao; Lin, Tong

2013-01-01

Herein we demonstrate that switchable, spontaneous, directional-transport ability to both water and oil fluids can be created on fabric materials through wet-chemistry coating and successive UV irradiation treatment. When the fabric showed directional transport to a liquid, it prevented liquids of higher surface tension from penetration, but allowed liquids of lower surface tension to permeate, from either side. The directional transport ability can be switched from one fluid to another simply by heating the fabric at an elevated temperature and then re-irradiating the fabric with UV light for required period of time. By attaching liquid drops vertically upwards to a horizontally-laid fabric, we further demonstrated that this novel directional fluid transport was an automatic process driven by surface property alone, irrespective of gravity's effect. This novel fabric may be useful for development of “smart” textiles and functional membranes for various applications. PMID:24129357

A weighted multiple-relaxation-time lattice Boltzmann method for multiphase flows and its application to partial coalescence cascades

NASA Astrophysics Data System (ADS)

Fakhari, Abbas; Bolster, Diogo; Luo, Li-Shi

2017-07-01

We present a lattice Boltzmann method (LBM) with a weighted multiple-relaxation-time (WMRT) collision model and an adaptive mesh refinement (AMR) algorithm for direct numerical simulation of two-phase flows in three dimensions. The proposed WMRT model enhances the numerical stability of the LBM for immiscible fluids at high density ratios, particularly on the D3Q27 lattice. The effectiveness and efficiency of the proposed WMRT-LBM-AMR is validated through simulations of (a) buoyancy-driven motion and deformation of a gas bubble rising in a viscous liquid; (b) the bag-breakup mechanism of a falling drop; (c) crown splashing of a droplet on a wet surface; and (d) the partial coalescence mechanism of a liquid drop at a liquid-liquid interface. The numerical simulations agree well with available experimental data and theoretical approximations where applicable.

Ionic liquid thermal stabilities: decomposition mechanisms and analysis tools.

PubMed

Maton, Cedric; De Vos, Nils; Stevens, Christian V

2013-07-07

The increasing amount of papers published on ionic liquids generates an extensive quantity of data. The thermal stability data of divergent ionic liquids are collected in this paper with attention to the experimental set-up. The influence and importance of the latter parameters are broadly addressed. Both ramped temperature and isothermal thermogravimetric analysis are discussed, along with state-of-the-art methods, such as TGA-MS and pyrolysis-GC. The strengths and weaknesses of the different methodologies known to date demonstrate that analysis methods should be in line with the application. The combination of data from advanced analysis methods allows us to obtain in-depth information on the degradation processes. Aided with computational methods, the kinetics and thermodynamics of thermal degradation are revealed piece by piece. The better understanding of the behaviour of ionic liquids at high temperature allows selective and application driven design, as well as mathematical prediction for engineering purposes.

Laser measurement of the spectral extinction coefficients of fluorescent, highly absorbing liquids. [crude petroleum oils

NASA Technical Reports Server (NTRS)

Hoge, F. E.

1982-01-01

A conceptual method is developed to deduce rapidly the spectral extinction coefficient of fluorescent, highly absorbing liquids, such as crude or refined petroleum oils. The technique offers the advantage of only requiring one laser wavelength and a single experimental assembly and execution for any specific fluorescent liquid. The liquid is inserted into an extremely thin wedge-shaped cavity for stimulation by a laser from one side and flurescence measurement on the other side by a monochromator system. For each arbitrarily selected extinction wavelength, the wedge is driven slowly to increasing thicknesses until the fluorescence extinguishes. The fluorescence as a function of wedge thickness permits a determination of the extinction coefficient using an included theoretical model. When the monochromator is set to the laser emission wavelength, the extinction coefficient is determined using the usual on-wavelength signal extinction procedure.

Investigation Of Vapor Explosion Mechanisms Using High Speed Photography

NASA Astrophysics Data System (ADS)

Armstrong, Donn R.; Anderson, Richard P.

1983-03-01

The vapor explosion, a physical interaction between hot and cold liquids that causes the explosive vaporization of the cold liquid, is a hazard of concern in such diverse industries as metal smelting and casting, paper manufacture, and nuclear power generation. Intensive work on this problem worldwide, for the past 25 years has generated a number of theories and mechanisms proposed to explain vapor explosions. High speed photography has been the major instrument used to test the validity of the theories and to provide the observations that have lead to new theories. Examples are given of experimental techniques that have been used to investigate vapor explosions. Detailed studies of specific mechanisms have included microsecond flash photograph of contact boiling and high speed cinematography of shock driven breakup of liquid drops. Other studies looked at the explosivity of various liquid pairs using cinematography inside a pulsed nuclear reactor and x-ray cinematography of a thermite-sodium interaction.

Superphobicity/philicity Janus Fabrics with Switchable, Spontaneous, Directional Transport Ability to Water and Oil Fluids

NASA Astrophysics Data System (ADS)

Zhou, Hua; Wang, Hongxia; Niu, Haitao; Lin, Tong

2013-10-01

Herein we demonstrate that switchable, spontaneous, directional-transport ability to both water and oil fluids can be created on fabric materials through wet-chemistry coating and successive UV irradiation treatment. When the fabric showed directional transport to a liquid, it prevented liquids of higher surface tension from penetration, but allowed liquids of lower surface tension to permeate, from either side. The directional transport ability can be switched from one fluid to another simply by heating the fabric at an elevated temperature and then re-irradiating the fabric with UV light for required period of time. By attaching liquid drops vertically upwards to a horizontally-laid fabric, we further demonstrated that this novel directional fluid transport was an automatic process driven by surface property alone, irrespective of gravity's effect. This novel fabric may be useful for development of ``smart'' textiles and functional membranes for various applications.

Liquid electrolyte informatics using an exhaustive search with linear regression.

PubMed

Sodeyama, Keitaro; Igarashi, Yasuhiko; Nakayama, Tomofumi; Tateyama, Yoshitaka; Okada, Masato

2018-06-14

Exploring new liquid electrolyte materials is a fundamental target for developing new high-performance lithium-ion batteries. In contrast to solid materials, disordered liquid solution properties have been less studied by data-driven information techniques. Here, we examined the estimation accuracy and efficiency of three information techniques, multiple linear regression (MLR), least absolute shrinkage and selection operator (LASSO), and exhaustive search with linear regression (ES-LiR), by using coordination energy and melting point as test liquid properties. We then confirmed that ES-LiR gives the most accurate estimation among the techniques. We also found that ES-LiR can provide the relationship between the "prediction accuracy" and "calculation cost" of the properties via a weight diagram of descriptors. This technique makes it possible to choose the balance of the "accuracy" and "cost" when the search of a huge amount of new materials was carried out.

Exploring bubble oscillation and mass transfer enhancement in acoustic-assisted liquid-liquid extraction with a microfluidic device

PubMed Central

Xie, Yuliang; Chindam, Chandraprakash; Nama, Nitesh; Yang, Shikuan; Lu, Mengqian; Zhao, Yanhui; Mai, John D.; Costanzo, Francesco; Huang, Tony Jun

2015-01-01

We investigated bubble oscillation and its induced enhancement of mass transfer in a liquid-liquid extraction process with an acoustically-driven, bubble-based microfluidic device. The oscillation of individually trapped bubbles, of known sizes, in microchannels was studied at both a fixed frequency, and over a range of frequencies. Resonant frequencies were analytically identified and were found to be in agreement with the experimental observations. The acoustic streaming induced by the bubble oscillation was identified as the cause of this enhanced extraction. Experiments extracting Rhodanmine B from an aqueous phase (DI water) to an organic phase (1-octanol) were performed to determine the relationship between extraction efficiency and applied acoustic power. The enhanced efficiency in mass transport via these acoustic-energy-assisted processes was confirmed by comparisons against a pure diffusion-based process. PMID:26223474

PANEL LIBRARY AND EDITOR

NASA Technical Reports Server (NTRS)

Raible, E.

1994-01-01

The Panel Library and Editor is a graphical user interface (GUI) builder for the Silicon Graphics IRIS workstation family. The toolkit creates "widgets" which can be manipulated by the user. Its appearance is similar to that of the X-Windows System. The Panel Library is written in C and is used by programmers writing user-friendly mouse-driven applications for the IRIS. GUIs built using the Panel Library consist of "actuators" and "panels." Actuators are buttons, dials, sliders, or other mouse-driven symbols. Panels are groups of actuators that occupy separate windows on the IRIS workstation. The application user can alter variables in the graphics program, or fire off functions with a click on a button. The evolution of data values can be tracked with meters and strip charts, and dialog boxes with text processing can be built. Panels can be stored as icons when not in use. The Panel Editor is a program used to interactively create and test panel library interfaces in a simple and efficient way. The Panel Editor itself uses a panel library interface, so all actions are mouse driven. Extensive context-sensitive on-line help is provided. Programmers can graphically create and test the user interface without writing a single line of code. Once an interface is judged satisfactory, the Panel Editor will dump it out as a file of C code that can be used in an application. The Panel Library (v9.8) and Editor (v1.1) are written in C-Language (63%) and Scheme, a dialect of LISP, (37%) for Silicon Graphics 4D series workstations running IRIX 3.2 or higher. Approximately 10Mb of disk space is required once compiled. 1.5Mb of main memory is required to execute the panel editor. This program is available on a .25 inch streaming magnetic tape cartridge in UNIX tar format for an IRIS, and includes a copy of XScheme, the public-domain Scheme interpreter used by the Panel Editor. The Panel Library Programmer's Manual is included on the distribution media. The Panel Library and Editor were released to COSMIC in 1991. Silicon Graphics, IRIS, and IRIX are trademarks of Silicon Graphics, Inc. X-Window System is a trademark of Massachusetts Institute of Technology.

Flow behaviour and transitions in surfactant-laden gas-liquid vertical flows

NASA Astrophysics Data System (ADS)

Zadrazil, Ivan; Chakraborty, Sourojeet; Matar, Omar; Markides, Christos

2016-11-01

The aim of this work is to elucidate the effect of surfactant additives on vertical gas-liquid counter-current pipe flows. Two experimental campaigns were undertaken, one with water and one with a light oil (Exxsol D80) as the liquid phase; in both cases air was used as the gaseous phase. Suitable surfactants were added to the liquid phase up to the critical micelle concentration (CMC); measurements in the absence of additives were also taken, for benchmarking. The experiments were performed in a 32-mm bore and 5-m long vertical pipe, over a range of superficial velocities (liquid: 1 to 7 m/s, gas: 1 to 44 m/s). High-speed axial- and side-view imaging was performed at different lengths along the pipe, together with pressure drop measurements. Flow regime maps were then obtained describing the observed flow behaviour and related phenomena, i.e., downwards/upwards annular flow, flooding, bridging, gas/liquid entrainment, oscillatory film flow, standing waves, climbing films, churn flow and dryout. Comparisons of the air-water and oil-water results will be presented and discussed, along with the role of the surfactants in affecting overall and detailed flow behaviour and transitions; in particular, a possible mechanism underlying the phenomenon of flooding will be presented. EPSRC UK Programme Grant EP/K003976/1.

A more rational, theory-driven approach to analysing the factor structure of the Edinburgh Postnatal Depression Scale.

PubMed

Kozinszky, Zoltan; Töreki, Annamária; Hompoth, Emőke A; Dudas, Robert B; Németh, Gábor

2017-04-01

We endeavoured to analyze the factor structure of the Edinburgh Postnatal Depression Scale (EPDS) during a screening programme in Hungary, using exploratory (EFA) and confirmatory factor analysis (CFA), testing both previously published models and newly developed theory-driven ones, after a critical analysis of the literature. Between April 2011 and January 2015, a sample of 2967 pregnant women (between 12th and 30th weeks of gestation) and 714 women 6 weeks after delivery completed the Hungarian version of the EPDS in South-East Hungary. EFAs suggested unidimensionality in both samples. 33 out of 42 previously published models showed good and 6 acceptable fit with our antepartum data in CFAs, whilst 10 of them showed good and 28 acceptable fit in our postpartum sample. Using multiple fit indices, our theory-driven anhedonia (items 1,2) - anxiety (items 4,5) - low mood (items 8,9) model provided the best fit in the antepartum sample. In the postpartum sample, our theory-driven models were again among the best performing models, including an anhedonia and an anxiety factor together with either a low mood or a suicidal risk factor (items 3,6,10). The EPDS showed moderate within- and between-culture invariability, although this would also need to be re-examined with a theory-driven approach. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Numerical simulation of drop impact on a thin film: the origin of the droplets in the splashing regime

NASA Astrophysics Data System (ADS)

Xie, Zhihua; Che, Zhizhao; Ismail, Renad; Pain, Chris; Matar, Omar

2015-11-01

Drop impact on a liquid layer is a feature of numerous multiphase flow problems, and has been the subject of numerous theoretical, experimental and numerical investigations. In the splashing regime, however, little attention has been focused on the origin of the droplets that are formed during the splashing process. The objective of this study is to investigate this issue numerically in order to improve our understanding of the mechanisms underlying splashing as a function of the relevant system parameters. In contrast to the conventional two-phase flow approach, commonly used to simulate splashing, here, a three-dimensional, three-phase flow model, with adaptive, unstructured meshing, is employed to study the liquid (droplet) - gas (surrounding air) - liquid (thin film) system. In the cases to be presented, both liquid phases have the same fluid property, although, clearly, our method can be used in the more general case of two different liquids. Numerical results of droplet impact on a thin film are analysed to determine whether the origin of the droplets following impact corresponds to the mother drop, or the thin film, or both. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

Valorization of biogas into liquid hydrocarbons in plasma-catalyst reactor

NASA Astrophysics Data System (ADS)

Nikravech, Mehrdad; Rahmani, Abdelkader; Labidi, Sana; Saintini, Noiric

2016-09-01

Biogas represents an important source of renewable energy issued from biological degradation of biomass. It is planned to produce in Europe the amount of biogas equivalent to 6400 kWh electricity and 4500 kteo (kilo tons equivalent oil) in 2020. Currently the biogas is used in cogeneration engines to produce heat and electricity directly in farms or it is injected in gas networks after purification and odorisation. The aim of this work is to propose a third option that consists of valorization of biogas by transformation into liquid hydrocarbons like acetone, methanol, ethanol, acetic acid etc. These chemicals, among the most important feed materials for chemical industries, retain CO2 molecules participating to reduce the greenhouse gas emissions and have high storage energy capacity. We developed a low temperature atmospheric plasma-catalyst reactor (surface dielectric barrier discharge) to transform biogas into chemicals. The conversion rates of CH4 and CO2 are respectively about 50% and 30% depending on operational conditions. The energetic cost is 25 eV/molecule. The yields of liquid hydrocarbon reaches currently 10% wt. More the 11 liquid chemicals are observed in the liquid fraction. Acknowledgements are due to SPC Programme Energie de demain.

Thermodynamic Insight into the Solvation and Complexation Behavior of U(VI) in Ionic Liquid: Binding of CMPO with U(VI) Studied by Optical Spectroscopy and Calorimetry.

PubMed

Wu, Qi; Sun, Taoxiang; Meng, Xianghai; Chen, Jing; Xu, Chao

2017-03-06

The complexation of U(VI) with octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO, denoted as L) in ionic liquid (IL) C 4 mimNTf 2 was investigated by UV-vis absorption spectrophotometry and isothermal titration calorimetry. Spectro-photometric titration suggests that three successive complexes, UO 2 L j 2+ (j = 1-3), formed both in "dry" (water content < 250 ppm) and "wet" (water content ≈ 12 500 ppm) ionic liquid. However, the thermodynamic parameters are distinctly different in the two ILs. In dry IL, the complexation strength between CMPO and U(VI) is much stronger, with stability constants of the respective complexes more than 1 order of magnitude higher than that in wet IL. Energetically, the complexation of U(VI) with CMPO in dry IL is mainly driven by negative enthalpies. In contrast, the complexation in wet IL is overwhelmingly driven by highly positive entropies as a result of the release of a large amount of water molecules from the solvation sphere of U(VI). Moreover, comparisons between the fitted absorption spectra of complexes in wet IL and that of extractive samples from solvent extraction have identified the speciation involved in the extraction of U(VI) by CMPO in ionic liquid. The results from this study not only offer a thermodynamic insight into the complexation behavior of U(VI) with CMPO in IL but also provide valuable information for understanding the extraction behavior in the corresponding solvent extraction system.

Sink or Swim: Ions and Organics at the Ice-Air Interface.

PubMed

Hudait, Arpa; Allen, Michael T; Molinero, Valeria

2017-07-26

The ice-air interface is an important locus of environmental chemical reactions. The structure and dynamics of the ice surface impact the uptake of trace gases and kinetics of reactions in the atmosphere and snowpack. At tropospheric temperatures, the ice surface is partially premelted. Experiments indicate that ions increase the liquidity of the ice surface but hydrophilic organics do not. However, it is not yet known the extent of the perturbation solutes induce at the ice surface and what is the role of the disordered liquid-like layer in modulating the interaction between solutes and their mobility and aggregation at the ice surface. Here we use large-scale molecular simulations to investigate the effect of ions and glyoxal, one of the most abundant oxygenated volatile organic compounds in the atmosphere, on the structure, dynamics, and solvation properties of the ice surface. We find that the premelted surface of ice has unique solvation properties, different from those of liquid water. The increase in surface liquidity resulting from the hydration of ions leads to a water-mediated attraction of ions at the ice surface. Glyoxal molecules, on the other hand, perturb only slightly the surface of ice and do not experience water-driven attraction. They nonetheless accumulate as dry agglomerates at the ice surface, driven by direct interactions between the organic molecules. The enhanced attraction and clustering of ions and organics at the ice surface may play a significant role in modulating the mechanism and rate of heterogeneous chemical reactions occurring at the surface of atmospheric ice particles.

Critical mingling and universal correlations in model binary active liquids

NASA Astrophysics Data System (ADS)

Bain, Nicolas; Bartolo, Denis

2017-06-01

Ensembles of driven or motile bodies moving along opposite directions are generically reported to self-organize into strongly anisotropic lanes. Here, building on a minimal model of self-propelled bodies targeting opposite directions, we first evidence a critical phase transition between a mingled state and a phase-separated lane state specific to active particles. We then demonstrate that the mingled state displays algebraic structural correlations also found in driven binary mixtures. Finally, constructing a hydrodynamic theory, we single out the physical mechanisms responsible for these universal long-range correlations typical of ensembles of oppositely moving bodies.

Ion transfer through solvent polymeric membranes driven by an exponential current flux.

PubMed

Molina, A; Torralba, E; González, J; Serna, C; Ortuño, J A

2011-03-21

General analytical equations which govern ion transfer through liquid membranes with one and two polarized interfaces driven by an exponential current flux are derived. Expressions for the transient and stationary E-t, dt/dE-E and dI/dE-E curves are obtained, and the evolution from transient to steady behaviour has been analyzed in depth. We have also shown mathematically that the voltammetric and stationary chronopotentiometric I(N)-E curves are identical (with E being the applied potential for voltammetric techniques and the measured potential for chronopotentiometric techniques), and hence, their derivatives provide identical information.

Electrowetting-driven variable-focus microlens on flexible surfaces

NASA Astrophysics Data System (ADS)

Li, Chenhui; Jiang, Hongrui

2012-06-01

We demonstrate a flexible, electrowetting-driven, variable-focus liquid microlens. The microlens is fabricated using a soft polymer polydimethylsiloxane. The lens can be smoothly wrapped onto a curved surface. A low-temperature fabrication process was developed to reduce the stress on and to avoid any damage to the polymer. The focal length of the microlens varies between -15.0 mm to +28.0 mm, depending on the applied voltage. The resolving power of the microlens is 25.39 line pairs per mm using a 1951 United States Air Force resolution chart. The typical response time of the lens is around 50 ms.

A novel pressure-driven piezodispenser for nanoliter volumes.

PubMed

McGuire, Shawn; Fisher, Charles; Holl, Mark; Meldrum, Deirdre

2008-08-01

A successful dispensing device has been built for use in biotechnology applications requiring nanoliter volume liquid transfer. Air pressure is used as the primary driving force and is controlled via a high speed miniature solenoid valve as opposed to many existing systems that use a valve in line with constantly pressurized fluid to start and stop the dispensing action. This automated pressure-driven system is used to improve a typical piezodriven microdispenser. The resulting system is much less prone to failures resulting from air entrainment and can dispense much higher viscosity fluids than the microdispenser alone.

Zero curvature-surface driven small objects

NASA Astrophysics Data System (ADS)

Dou, Xiaoxiao; Li, Shanpeng; Liu, Jianlin

2017-08-01

In this study, we investigate the spontaneous migration of small objects driven by surface tension on a catenoid, formed by a layer of soap constrained by two rings. Although the average curvature of the catenoid is zero at each point, the small objects always migrate to the position near the ring. The force and energy analyses have been performed to uncover the mechanism, and it is found that the small objects distort the local shape of the liquid film, thus making the whole system energetically favorable. These findings provide some inspiration to design microfluidics, aquatic robotics, and miniature boats.

School Area Road Safety Assessment and Improvements (SARSAI) programme reduces road traffic injuries among children in Tanzania.

PubMed

Poswayo, Ayikai; Kalolo, Simon; Rabonovitz, Katheryn; Witte, Jeffrey; Guerrero, Alejandro

2018-05-19

To determine the impact of a paediatric road traffic injury (RTI) prevention programme in urban Sub-Saharan Africa. Dares Salaam, Republic of Tanzania. Household surveys were conducted in catchment areas around 18 primary schools in Dar es Salaam, Republic of Tanzania; the catchment areas were divided into control and intervention groups. Collected data included basic demographic information on all school-aged household members and whether or not they had been involved in an RTI in the previous 12 months, and, if so, what the characteristics of that RTI were. Based on these findings, a separate road safety engineering site analysis and consultation with the communities and other stakeholders, an injury-prevention programme was developed and implemented, consisting of infrastructure enhancements and a site-specific educational programme. The programme was initially implemented at the intervention schools. After 1 year, data were collected in the same manner. The control group received the same intervention after follow-up data were collected. Data were collected on 12 957 school-aged children in the baseline period and 13 555 school-aged children in the post-intervention period, in both the control and intervention communities. There was a statistically significant reduction in RTIs in the intervention group and a non-significant increase in RTI in the control group. The greatest reduction was in motorcycle-pedestrian RTI, private vehicle-pedestrian RTI and morning RTI. The programme demonstrated a significant reduction in paediatric RTI after its implementation, in very specific ways. This study demonstrates that for a reasonable investment, scientifically driven injury-prevention programmes are feasible in resource-limited settings with high paediatric RTI rates. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

49 CFR 178.338-17 - Pumps and compressors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.338-17 Pumps and compressors. (a) Liquid pumps and gas compressors, if used, must be of suitable design, adequately protected against breakage by collision, and kept in good condition. They may be driven by motor vehicle power take...

49 CFR 178.337-15 - Pumps and compressors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.337-15 Pumps and compressors. (a) Liquid pumps or gas compressors, if used, must be of suitable design, adequately protected against breakage by collision, and kept in good condition. They may be driven by motor vehicle power take...

A Novel Liquid-Liquid Transition in Undercooled Ti-Zr-Ni Liquids

NASA Technical Reports Server (NTRS)

Lee, G. W.; Gangopadhyay, A. K.; Kelton, K. F.; Bradshaw, R. C.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.

2004-01-01

If crystallization can be avoided, liquids enter a metastable (undercooled) state below their equilibrium liquidus temperatures, T(sub l), finally 'freezing' into a glass below a characteristic temperature called the glass transition temperature, T(sub g). In rare cases, the undercooled liquid may undergo a liquid-liquid phase transition (liquid polymorphism) before entering the glassy state. This has been suggested from experimental studies of H2O and Si. Such phase transitions have been predicted in some stable liquids, ie. above T(sub l) at atmospheric pressure, for SiO2 and BeF2, but these have not been verified experimentally. They have been observed in liquids of P, Si and C, but only under high pressure. In this letter we present the first experimental evidence for a phase transition in a low viscosity metallic liquid that is driven by an approach to a constant entropy configuration state and correlated with a growing icosahedral order in the liquid. A maximum in the specific heat at constant pressure, similar to what is normally observed near T(sub g), is reported for undercooled liquids of quasicrystal-forming Ti-Zr-Ni alloys. A two-state excitation model that includes cooperativity by incorporating a temperature-dependent excitation energy, fits the specific heat data well, signaling a phase transition. An inflection in the liquid density with decreasing temperature instead of a discontinuity indicates that this is not a typical first order phase transition; it could be a weakly first order or higher order transition. While showing many similarities to a glass transition, this liquid-liquid phase transition occurs in a mobile liquid, making it novel.

Digital holographic characterization of liquid microlenses array fabricated in electrode-less configuration

NASA Astrophysics Data System (ADS)

Miccio, L.; Vespini, V.; Grilli, S.; Paturzo, M.; Finizio, A.; De Nicola, S.; Ferraro, P.

2009-06-01

We show how thin liquid film on polar dielectric substrate can form an array of liquid micro-lenses. The effect is driven by the pyroelectric effect leading to a new concept in electro-wetting (EW). EW is a viable method for actuation of liquids in microfluidic systems and requires the design and fabrication of complex electrodes for suitable actuation of liquids. When compared to conventional electrowetting devices, the pyroelectric effect allowed to have an electrode-less and circuitless configuration. In our case the surface electric charge induced by the thermal stimulus is able to pattern selectively the surface wettability according to geometry of the ferroelectric domains micro-engineered into the lithium niobate crystal. We show that different geometries of liquid microlenses can be obtained showing also a tuneability of the focal lenses down to 1.6 mm. Thousand of liquid microlenses, each with 100 μm diameter, can be formed and actuated. Also different geometries such as hemi-cylindrical and toroidal liquid structures can be easily obtained. By means of a digital holography method, an accurate characterization of the micro-lenses curvature is performed and presented. The preliminary results concerning the imaging capability of the micro-lens array are also reported. Microlens array can find application in medical stereo-endoscopy, imaging, telecommunication and optical data storage too.

Polydopamine-Coated Main-Chain Liquid Crystal Elastomer as Optically Driven Artificial Muscle.

PubMed

Tian, Hongmiao; Wang, Zhijian; Chen, Yilong; Shao, Jinyou; Gao, Tong; Cai, Shengqiang

2018-03-07

Optically driven active materials have received much attention because their deformation and motion can be controlled remotely, instantly, and precisely in a contactless way. In this study, we investigated an optically actuated elastomer with rapid response: polydopamine (PDA)-coated liquid crystal elastomer (LCE). Because of the photothermal effect of PDA coating and thermal responsiveness of LCE, the elastomer film contracted significantly with near-infrared (NIR) irradiation. With a fixed strain, light-induced actuating stress in the film could be as large as 1.5 MPa, significantly higher than the maximum stress generated by most mammalian skeletal muscle (0.35 MPa). The PDA-coated LCE films could also bend or roll up by surface scanning of an NIR laser. The response time of the film to light exposure could be as short as 1/10 of a second, comparable to or even faster than that of mammalian skeletal muscle. Using the PDA-coated LCE film, we designed and fabricated a prototype of robotic swimmer that was able to swim near the water-air interface by performing "swimming strokes" through reversible bending and unbending motions induced and controlled by an NIR laser. The results presented in this study clearly demonstrated that PDA-coated LCE is a promising optically driven artificial muscle, which may have great potential for applications of soft robotics and optomechanical coupling devices.

Design and dynamic analysis of a piezoelectric linear stage for pipetting liquid samples

NASA Astrophysics Data System (ADS)

Yu-Jen, Wang; Chien, Lee; Yi-Bin, Jiang; Kuo-Chieh, Fu

2017-06-01

Piezoelectric actuators have been widely used in positioning stages because of their compact size, stepping controllability, and holding force. This study proposes a piezoelectric-driven stage composed of a bi-electrode piezoelectric slab, capacitive position sensor, and capillary filling detector for filling liquid samples into nanopipettes using capillary flow. This automatic sample-filling device is suitable for transmission electron microscopy image-based quantitative analysis of aqueous products with added nanoparticles. The step length of the actuator is adjusted by a pulse width modulation signal that depends on the stage position; the actuator stops moving once the capillary filling has been detected. A novel dynamic model of the piezoelectric-driven stage based on collision interactions between the piezoelectric actuator and the sliding clipper is presented. Unknown model parameters are derived from the steady state solution of the equivalent steady phase angle. The output force of the piezoelectric actuator is formulated using the impulse and momentum principle. Considering the applied forces and related velocity between the sliding clipper and the piezoelectric slab, the stage dynamic response is confirmed with the experimental results. Moreover, the model can be used to explain the in-phase slanted trajectories of piezoelectric slab to drive sliders, but not elliptical trajectories. The maximum velocity and minimum step length of the piezoelectric-driven stage are 130 mm s-1 and 1 μm respectively.

Th and U fuel photofission study by NTD for AD-MSR subcritical assembly

NASA Astrophysics Data System (ADS)

Sajo-Bohus, Laszlo; Greaves, Eduardo D.; Davila, Jesus; Barros, Haydn; Pino, Felix; Barrera, Maria T.; Farina, Fulvio

2015-07-01

During the last decade a considerable effort has been devoted for developing energy generating systems based on advanced nuclear technology within the design concepts of GEN-IV. Thorium base fuel systems such as accelerator driven nuclear reactors are one of the often mentioned attractive and affordable options. Several radiotherapy linear accelerators are on the market and due to their reliability, they could be employed as drivers for subcritical liquid fuel assemblies. Bremsstrahlung photons with energies above 5.5MeV, induce (γ,n) and (e,e'n) reactions in the W-target. Resulting gamma radiation and photo or fission neutrons may be absorbed in target materials such as thorium and uranium isotopes to induce sustained fission or nuclear transmutation in waste radioactive materials. Relevant photo driven and photo-fission reaction cross sections are important for actinides 232Th, 238U and 237Np in the radiotherapy machines energy range of 10-20 MV. In this study we employ passive nuclear track detectors (NTD) to determine fission rates and neutron production rates with the aim to establish the feasibility for gamma and photo-neutron driven subcritical assemblies. To cope with these objectives a 20 MV radiotherapy machine has been employed with a mixed fuel target. Results will support further development for a subcritical assembly employing a thorium containing liquid fuel. It is expected that acquired technological knowledge will contribute to the Venezuelan nuclear energy program.

A qualitative evaluation of the Scottish Staff and Associate Specialist Development Programme.

PubMed

Cleland, Jennifer; Burr, Jacqueline; Johnston, Peter

2016-05-01

The continued professional development of staff and associate specialist doctors in the UK was ill served prior to the introduction of the new staff and associate specialist doctor's contract in 2008. The aim of this study was to independently evaluate NHS Education for Scotland's approach to improving professional development for staff and associate specialist doctors, the staff and associate specialist Professional Development Fund. Semi-structured telephone interviews with key stakeholders, framed by a realistic approach to evaluate what works, for whom and in how and under what circumstances. An inductive and data-driven thematic analysis was carried out and then the realist framework was applied to the data. We interviewed 22 key stakeholders: staff and associate specialist doctors, staff and associate specialist educational advisors, programme architects and clinical directors, between end February and May 2014. The resultant data indicated five broad themes: organisational barriers to continued professional development for staff and associate specialist doctors, the purpose of funding, gains from funding, the need for better communication about the staff and associate specialist Programme Development Fund, and the interplay between individual and systems factors. The staff and associate specialist Programme Development Fund has changed the opportunities available to staff and associate specialist doctors in Scotland and, in that sense, has changed the context for this group - or at least those who have realised the opportunities. © The Author(s) 2016.

Evaluation of an online master's programme in Somaliland. A phenomenographic study on the experience of professional and personal development among midwifery faculty.

PubMed

Erlandsson, Kerstin; Osman, Fatumo; Hatakka, Mathias; Egal, Jama Ali; Byrskog, Ulrika; Pedersen, Christina; Klingberg-Allvin, Marie

2017-07-01

To record the variation of perceptions of midwifery faculty in terms of the possibilities and challenges related to the completion of their first online master's level programme in Sexual and Reproductive Health and Rights in Somaliland. The informants included in this phenomenongraphical focus group study were those well-educated professional women and men who completed the master's program. The informant perceived that this first online master's level programme provided tools for independent use of the Internet and independent searching for evidence-based information, enhanced professional development, was challenge-driven and evoked curiosity, challenged professional development, enhanced personal development and challenged context-bound career paths. Online education makes it possible for well-educated professional women to continue higher education. It furthermore increased the informants' confidence in their use of Internet, software and databases and in the use of evidence in both their teaching and their clinical practice. Programmes such as the one described in this paper could counter the difficulties ensuring best practice by having a critical mass of midwives who will be able to continually gather contemporary midwifery evidence and use it to ensure best practice. An increase of online education is suggested in South-central Somalia and in similar settings globally. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Lightwave programme and roadshow: an overview and update

NASA Astrophysics Data System (ADS)

Wong, Nicholas H. L.; Posner, Matthew T.; John, Pearl V.

2015-10-01

While optics and photonics are exciting disciplines with much research, industrial, and economic potential in the 21st century, this appreciation is only shared by a limited number of science, technology, engineering, and mathematics (STEM) experts, and there is a recognized STEM skills shortage. To widen the pool of talent, it is essential to expose students to optics and photonics throughout their education and particularly starting at a young age. The Lightwave programme, consisting of an interactive collection of photonics demonstrations and experiments targeted for primary school students, was thus created to facilitate this endeavor. The programme is run by doctoral students forming a team of "Lightwave ambassadors". All the demonstrations that comprise Lightwave can be easily integrated into a physics curriculum, enabling educators to generate more student interest and enhance the image of science through an interactive pedagogy. We provide a description of the programme at its initial inception, and report on the recent additions and updates that have brought about its success, moving from a purely outreach driven focus to engaging pupils with our own research. We also discuss our approach to ensuring that our team of ambassadors are from diverse backgrounds and use both male and female students as role models. Finally, we reflect on how evaluation methods to obtain feedback from our activities are key to Lightwave's sustainability and in improving the perception of optics and photonics.

Water-driven micromotors.

PubMed

Gao, Wei; Pei, Allen; Wang, Joseph

2012-09-25

We demonstrate the first example of a water-driven bubble-propelled micromotor that eliminates the requirement for the common hydrogen peroxide fuel. The new water-driven Janus micromotor is composed of a partially coated Al-Ga binary alloy microsphere prepared via microcontact mixing of aluminum microparticles and liquid gallium. The ejection of hydrogen bubbles from the exposed Al-Ga alloy hemisphere side, upon its contact with water, provides a powerful directional propulsion thrust. Such spontaneous generation of hydrogen bubbles reflects the rapid reaction between the aluminum alloy and water. The resulting water-driven spherical motors can move at remarkable speeds of 3 mm s(-1) (i.e., 150 body length s(-1)), while exerting large forces exceeding 500 pN. Factors influencing the efficiency of the aluminum-water reaction and the resulting propulsion behavior and motor lifetime, including the ionic strength and environmental pH, are investigated. The resulting water-propelled Al-Ga/Ti motors move efficiently in different biological media (e.g., human serum) and hold considerable promise for diverse biomedical or industrial applications.

Identifying effective pathways in a successful continuous quality improvement programme: the GEDAPS study.

PubMed

Bodicoat, Danielle H; Mundet, Xavier; Gray, Laura J; Cos, Xavier; Davies, Melanie J; Khunti, Kamlesh; Cano, Juan-Franciso

2014-12-01

Continuous quality improvement programmes often target several aspects of care, some of which may be more effective meaning that resources could be focussed on these. The objective was to identify the effective and ineffective aspects of a successful continuous quality improvement programme for individuals with type 2 diabetes in primary care. Data were from a series of cross-sectional studies (GEDAPS) in primary care, Catalonia, Spain, in 55 centres (2239 participants) in 1993, and 92 centres (5819 participants) in 2002. A structural equation modelling approach was used. The intervention was associated with improved microvascular outcomes through microalbuminuria and funduscopy screening, which had a direct effect on microvascular outcomes, and through attending 2-4 nurse visits and having ≥1 blood pressure measurement, which acted through reducing systolic blood pressure. The intervention was associated with improved macrovascular outcomes through blood pressure measurement and attending 2-4 nurse visits (through systolic blood pressure) and having ≥3 education topics, ≥1 HbA1c measurement and adequate medication (through HbA1c). Cholesterol measurement, weight measurement and foot examination did not contribute towards the effectiveness of the intervention. The pathways through which a continuous quality improvement programme appeared to act to reduce microvascular and macrovascular complications were driven by reductions in systolic blood pressure and HbA1c, which were attained through changes in nurse and education visits, measurement and medication. This suggests that these factors are potential areas on which future quality improvement programmes should focus. © 2014 John Wiley & Sons, Ltd.

Bouncing and coalescence of droplets on falling liquid films

NASA Astrophysics Data System (ADS)

Che, Zhizhao; Deygas, Amandine; Matar, Omar

2014-11-01

When a droplet impacts on a falling liquid film, the outcome depends on the fluid properties of the droplet, its speed, and angle of incidence, as well as on the film flow rate and associated flow regimes. In this study, the oblique impact of droplets on a falling liquid film is investigated experimentally. The falling film is created on an inclined substrate and the Reynolds number is varied. Droplets with different sizes and different speeds are used to study the impact process for different Weber and Ohnesorge numbers. Different phenomena of droplet impact are identified and analysed, such as bouncing, partial coalescence, total coalescence, and splashing. An impact regime map is generated, and the effects of droplet impact speed and size, and the film flow rates are studied. The propagation of waves on the liquid film post-impact is analysed. The results show that the flowing film can significantly affect the impact process of droplets, and the latter can alter the propagation of waves on the falling film. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

Refrigeration system with a compressor-pump unit and a liquid-injection desuperheating line

DOEpatents

Gaul, Christopher J.

2001-01-01

The refrigeration system includes a compressor-pump unit and/or a liquid-injection assembly. The refrigeration system is a vapor-compression refrigeration system that includes an expansion device, an evaporator, a compressor, a condenser, and a liquid pump between the condenser and the expansion device. The liquid pump improves efficiency of the refrigeration system by increasing the pressure of, thus subcooling, the liquid refrigerant delivered from the condenser to the expansion device. The liquid pump and the compressor are driven by a single driving device and, in this regard, are coupled to a single shaft of a driving device, such as a belt-drive, an engine, or an electric motor. While the driving device may be separately contained, in a preferred embodiment, the liquid pump, the compressor, and the driving device (i.e., an electric motor) are contained within a single sealable housing having pump and driving device cooling paths to subcool liquid refrigerant discharged from the liquid pump and to control the operating temperature of the driving device. In another aspect of the present invention, a liquid injection assembly is included in a refrigeration system to divert liquid refrigerant from the discharge of a liquid pressure amplification pump to a compressor discharge pathway within a compressor housing to desuperheat refrigerant vapor to the saturation point within the compressor housing. The liquid injection assembly includes a liquid injection pipe with a control valve to meter the volume of diverted liquid refrigerant. The liquid injection assembly may also include a feedback controller with a microprocessor responsive to a pressure sensor and a temperature sensor both positioned between the compressor to operate the control valve to maintain the refrigerant at or near saturation.

A reconfigurable continuous-flow fluidic routing fabric using a modular, scalable primitive.

PubMed

Silva, Ryan; Bhatia, Swapnil; Densmore, Douglas

2016-07-05

Microfluidic devices, by definition, are required to move liquids from one physical location to another. Given a finite and frequently fixed set of physical channels to route fluids, a primitive design element that allows reconfigurable routing of that fluid from any of n input ports to any n output ports will dramatically change the paradigms by which these chips are designed and applied. Furthermore, if these elements are "regular" regarding their design, the programming and fabrication of these elements becomes scalable. This paper presents such a design element called a transposer. We illustrate the design, fabrication and operation of a single transposer. We then scale this design to create a programmable fabric towards a general-purpose, reconfigurable microfluidic platform analogous to the Field Programmable Gate Array (FPGA) found in digital electronics.

Thermally driven electrokinetic energy conversion with liquid water microjets

DOE PAGES

Lam, Royce K.; Gamlieli, Zach; Harris, Stephen J.; ...

2015-11-01

One goal of current energy research is to design systems and devices that can efficiently exploit waste heat and utilize solar or geothermal heat energy for electrical power generation. We demonstrate a novel technique exploiting water's large coefficient of thermal expansion, wherein modest thermal gradients produce the requisite high pressure for driving fast-flowing liquid water microjets, which can effect the direct conversion of the kinetic energy into electricity and gaseous hydrogen. Waste heat in thermoelectric generating plants and combustion engines, as well as solar and geothermal energy could be used to drive these systems.

Dynamic integral imaging technology for 3D applications (Conference Presentation)

NASA Astrophysics Data System (ADS)

Huang, Yi-Pai; Javidi, Bahram; Martínez-Corral, Manuel; Shieh, Han-Ping D.; Jen, Tai-Hsiang; Hsieh, Po-Yuan; Hassanfiroozi, Amir

2017-05-01

Depth and resolution are always the trade-off in integral imaging technology. With the dynamic adjustable devices, the two factors of integral imaging can be fully compensated with time-multiplexed addressing. Those dynamic devices can be mechanical or electrical driven. In this presentation, we will mainly focused on discussing various Liquid Crystal devices which can change the focal length, scan and shift the image position, or switched in between 2D/3D mode. By using the Liquid Crystal devices, dynamic integral imaging have been successfully applied on 3D Display, capturing, and bio-imaging applications.

Crash test of a liquid hydrogen automobile

NASA Technical Reports Server (NTRS)

Finegold, J. G.; Van Vorst, W. D.

1976-01-01

Details of the conversion of a U.S. Postal Service mail truck to hydrogen-fueled operation are given. Specific reference is made to design safety considerations. A traffic accident is described that caused the mail truck (mounted on a trailer) to turn on its side at approximately 20 mph and to finally slide to a stop and turn upside down. No one was injured, and there was essentially no damage to the liquid hydrogen fuel system. The mail truck was driven away from the scene of the accident. Suggestions to insure the safety of hydrogen-fueled experimental vehicles are made.

ADMiER-ing thin but complex fluids

NASA Astrophysics Data System (ADS)

McDonnell, Amarin G.; Bhattacharjee, Pradipto K.; Pan, Sharadwata; Hill, David; Danquah, Michael K.; Friend, James R.; Yeo, Leslie Y.; Prabhakar, Ranganathan

2011-12-01

The Acoustics Driven Microfluidic Extensional Rheometer (ADMiER) utilises micro litre volumes of liquid, with viscosities as low as that of water, to create valid and observable extensional flows, liquid bridges that pinch off due to capillary forces in this case. ADMiER allows the study fluids that have been beyond conventional methods and also study more subtle fluid properties. We can observe polymeric fluids with solvent viscosities far below those previously testable, accentuating elastic effects. Also, it has enabled the testing of aqueous solutions of living motile particles, which significantly change fluid properties, opening up the potential for diagnostic applications.

Thermally driven electrokinetic energy conversion with liquid water microjets

NASA Astrophysics Data System (ADS)

Lam, Royce K.; Gamlieli, Zach; Harris, Stephen J.; Saykally, Richard J.

2015-11-01

A goal of current energy research is to design systems and devices that can efficiently exploit waste heat and utilize solar or geothermal heat energy for electrical power generation. We demonstrate a novel technique exploiting water's large coefficient of thermal expansion, wherein modest thermal gradients produce the requisite high pressure for driving fast-flowing liquid water microjets, which can effect the direct conversion of the kinetic energy into electricity and gaseous hydrogen. Waste heat in thermoelectric generating plants and combustion engines, as well as solar and geothermal energy could be used to drive these systems.

Marshburn works with Marangoni Experiment Hardware in Kibo

NASA Image and Video Library

2013-03-19

ISS035e006147 (19 March 2013) --- NASA astronaut Tom Marshburn, Expedition 35 flight engineer, works on the Marangoni Inside core cleaning in the Kibo Japanese Experiment Module onboard the Earth-orbiting International Space Station. Marangoni convection is the flow driven by the presence of a surface tension gradient which can be produced by temperature difference at a liquid/gas interface. The convection in liquid bridge of silicone oil is generated by heating the one disc higher than the other. Scientists are observing flow patterns of how fluids move to learn more about how heat is transferred in microgravity.

The Spectrum of Single Bubble Sonoluminescence.

NASA Astrophysics Data System (ADS)

Hiller, Robert Anthony

1995-01-01

An acoustically levitated bubble in a liquid may be driven to produce short flashes of light synchronous with the sound field in a process called sonoluminescence. The spectrum of the emitted light is measured with a grating monochromator and calibrated for absolute spectral radiance. The spectrum has been measured for various gases dissolved in pure water and heavy water, and alcohols and other hydrocarbon liquids. At a bandpass of 10nm EWHM the spectra are broad -band, showing no sign of lines or absorptions, with a peak in the ultraviolet. The experimental apparatus, including a system for producing sonoluminescence in a sealed container, is described.

Trends in long-period seismicity related to magmatic fluid compositions

USGS Publications Warehouse

Morrissey, M.M.; Chouet, B.A.

2001-01-01

Sound speeds and densities are calculated for three different types of fluids: gas-gas mixture; ash-gas mixture; and bubbly liquid. These fluid properties are used to calculate the impedance contrast (Z) and crack stiffness (C) in the fluid-driven crack model (Chouet: J. Geophys. Res., 91 (1986) 13,967; 101 (1988) 4375; A seismic model for the source of long-period events and harmonic tremor. In: Gasparini, P., Scarpa, R., Aki, K. (Eds.), Volcanic Seismology, IAVCEI Proceedings in Volcanology, Springer, Berlin, 3133). The fluid-driven crack model describes the far-field spectra of long-period (LP) events as modes of resonance of the crack. Results from our calculations demonstrate that ash-laden gas mixtures have fluid to solid density ratios comparable to, and fluid to solid velocity ratios lower than bubbly liquids (gas-volume fractions 20% gas-volume fraction yields values of Q-1r similar to those for a rectangular crack. As with gas-gas and ash-gas mixtures, an increase in mass fraction narrows the bandwidth of the dominant mode and shifts the spectra to lower frequencies. Including energy losses due to dissipative processes in a bubbly liquid increases attenuation. Attenuation may also be higher in ash-gas mixtures and foams if the effects of momentum and mass transfer between the phases were considered in the calculations. ?? 2001 Elsevier Science B. V. All rights reserved.

Operando chemistry of catalyst surfaces during catalysis.

PubMed

Dou, Jian; Sun, Zaicheng; Opalade, Adedamola A; Wang, Nan; Fu, Wensheng; Tao, Franklin Feng

2017-04-03

Chemistry of a catalyst surface during catalysis is crucial for a fundamental understanding of mechanism of a catalytic reaction performed on the catalyst in the gas or liquid phase. Due to the pressure- or molecular density-dependent entropy contribution of gas or liquid phase of the reactants and the potential formation of a catalyst surface during catalysis different from that observed in an ex situ condition, the characterization of the surface of a catalyst under reaction conditions and during catalysis can be significant and even necessary for understanding the catalytic mechanism at a molecular level. Electron-based analytical techniques are challenging for studying catalyst nanoparticles in the gas or liquid phase although they are necessary techniques to employ. Instrumentation and further development of these electron-based techniques have now made in situ/operando studies of catalysts possible. New insights into the chemistry and structure of catalyst nanoparticles have been uncovered over the last decades. Herein, the origin of the differences between ex situ and in situ/operando studies of catalysts, and the technical challenges faced as well as the corresponding instrumentation and innovations utilized for characterizing catalysts under reaction conditions and during catalysis, are discussed. The restructuring of catalyst surfaces driven by the pressure of reactant(s) around a catalyst, restructuring in reactant(s) driven by reaction temperature and restructuring during catalysis are also reviewed herein. The remaining challenges and possible solutions are briefly discussed.

Power games: The political use of solar technology in northern Thailand

NASA Astrophysics Data System (ADS)

Green, Donna Lisa

This dissertation politicises and historically situates the transfer of an environmental technology to a less developed country, a transfer that has occurred under the rubric of sustainable development. The case study explores the social and political context of two solar battery charging station programmes selected to provide electrification in rural Northern Thailand beginning in the 1980s. It places these rural electrification programmes in the context of previous rural electrification policies in northern Thailand in the 1960s and 1970s which were driven by an explicitly state-serving agenda: an agenda that aimed to expand the centralised state's ability to pacify and control remote areas of the country. However, it is clear that the technology and implementation strategies selected for the new electrification programmes could not fulfil their community-serving objectives; furthermore, these systems could not meet the actual energy needs of the programmes' intended beneficiaries. I argue that we need to consider whether the objectives that motivated previous rural electrification programmes may be continuing to play a role in the promotion of these new rural electrification programmes, a motivation that would contradict the philosophy behind the choice of the solar battery charging stations. Specifically, I show how the new rural electrification strategy has been de-politicised through its framing within the sustainable development discourses. This thesis highlights how the rush to promote environmental technologies through the rubric of sustainable development may limit a proper consideration of the social and political dynamics that motivated these decisions, resulting in the uncritical justification of technology selection. Scholars have critiqued the social ramifications of, and the political motivations behind, earlier technocentric rural development strategies, showing how they can exacerbate social inequalities. I argue that in this situation, the alleged environmental benefits of using an environmental technology in a sustainable development programme may have served to shelter it from similar critique. The assessment reveals and emphasises the need to query the validity of the objectives motivating other technocentric rural development programmes that transfer environmental technologies as part of the practice of sustainable development.

Acoustic wave-driven oxidized liquid metal-based energy harvester

NASA Astrophysics Data System (ADS)

Jeon, Jinpyo; Chung, Sang Kug; Lee, Jeong-Bong; Doo, Seok Joo; Kim, Daeyoung

2018-06-01

We report an oxidized liquid metal droplet-based energy harvester that converts acoustic energy into electrical energy by modulating an electrical double layer that originates from the deformation of the oxidized liquid metal droplet. Gallium-based liquid metal alloy has been developed for various applications owing to the outstanding material properties, such as its high electrical conductivity (metallic property) and unlimited deformability (liquid property). In this study, we demonstrated energy harvesting using an electrical double layer between the acoustic wave-modulated liquid metal droplet and two electrodes. The proposed energy harvester consisted of top and bottom electrodes covered with the dielectric layer and a Gallium-based liquid metal droplet placed between the electrodes. When we applied an external bias voltage and acoustic wave to the proposed device, the contact area between the liquid metal droplet and the electrodes changed, leading to the variation of the capacitance in the electrical double layer and the generation of electrical output current. Using the proposed energy harvester, the maximum output current of 41.2 nA was generated with an applied acoustic wave of 30 Hz. In addition, we studied the relationships between the maximum output current and a variety of factors, such as the size of the liquid metal droplet, the thickness of the hydrophobic layer, and the distance between the top and bottom electrode plates.

Energy minimization in nematic liquid crystal systems driven by geometric confinement and temperature gradients with applications in colloidal systems

NASA Astrophysics Data System (ADS)

Kolacz, Jakub

We first explore the topology of liquid crystals and look at the fundamental limitations of liquid crystals in confined geometries. The properties of liquid crystal droplets are studied both theoretically and through simulations. We then demonstrate a method of chemically patterning surfaces that allows us to generate periodic arrays of micron-sized liquid crystal droplets and compare them to our simulation results. The parallelizable method of self-localizing liquid crystals using 2D chemical patterning developed here has applications in liquid crystal biosensors and lens arrays. We also present the first work looking at colloidal liquid crystals under the guise of thermophoresis. We observe that strong negative thermophoresis occurs in these systems and develop a theory based on elastic energy minimization. We also calculate a Soret coefficient two orders of magnitude larger than those present in the literature. This large Soret coefficient has considerable potential for improving thermophoretic sorting mechanisms such as Thermal-Field Flow Fractionation and MicroScale Thermophoresis. The final piece of this work demonstrates a method of using projection lithography to polymerize liquid crystal colloids with a defined internal director. While still a work in progress, there is potential for generating systems of active colloids that can change shape upon external stimulus and in the generation of self-folding shapes by selective polymerization and director predetermination in the vain of micro-kirigami.

Microencapsulation and Electrostatic Processing Method

NASA Technical Reports Server (NTRS)

Morrison, Dennis R. (Inventor); Mosier, Benjamin (Inventor)

2000-01-01

Methods are provided for forming spherical multilamellar microcapsules having alternating hydrophilic and hydrophobic liquid layers, surrounded by flexible, semi-permeable hydrophobic or hydrophilic outer membranes which can be tailored specifically to control the diffusion rate. The methods of the invention rely on low shear mixing and liquid-liquid diffusion process and are particularly well suited for forming microcapsules containing both hydrophilic and hydrophobic drugs. These methods can be carried out in the absence of gravity and do not rely on density-driven phase separation, mechanical mixing or solvent evaporation phases. The methods include the process of forming, washing and filtering microcapsules. In addition, the methods contemplate coating microcapsules with ancillary coatings using an electrostatic field and free fluid electrophoresis of the microcapsules. The microcapsules produced by such methods are particularly useful in the delivery of pharmaceutical compositions.

Inorganic Surface Coating with Fast Wetting-Dewetting Transitions for Liquid Manipulations.

PubMed

Yang, Yajie; Zhang, Liaoliao; Wang, Jue; Wang, Xinwei; Duan, Libing; Wang, Nan; Xiao, Fajun; Xie, Yanbo; Zhao, Jianlin

2018-06-06

Liquid manipulation is a fundamental issue for microfluidics and miniaturized sensors. Fast wetting-state transitions by optical methods have proven being efficient for liquid manipulations by organic surface coatings, however rarely been achieved by using inorganic coatings. Here, we report a fast optical-induced wetting-state transition surface achieved by inorganic coating, enabling tens of second transitions for a wetting-dewetting cycle, shortened from an hour, as typically reported. Here, we demonstrate a gravity-driven microfluidic reactor and switch it to a mixer after a second-step exposure in a minimum of within 80 s of UV exposure. The fast wetting-dewetting transition surfaces enable the fast switchable or erasable smart surfaces for water collection, miniature chemical reaction, or sensing systems by using inorganic surface coatings.

Experimental evidence for a transient Tayler instability in a cylindrical liquid-metal column.

PubMed

Seilmayer, Martin; Stefani, Frank; Gundrum, Thomas; Weier, Tom; Gerbeth, Gunter; Gellert, Marcus; Rüdiger, Günther

2012-06-15

In the current-driven, kink-type Tayler instability (TI) a sufficiently strong azimuthal magnetic field becomes unstable against nonaxisymmetric perturbations. The TI has been discussed as a possible ingredient of the solar dynamo mechanism and a source of the helical structures in cosmic jets. It is also considered as a size-limiting factor for liquid metal batteries. We report on a liquid metal TI experiment using a cylindrical column of the eutectic alloy GaInSn to which electrical currents of up to 8 kA are applied. We present results of external magnetic field measurements that indicate the transient occurrence of the TI in good agreement with numerical predictions. The interference of TI with the competing large-scale convection, resulting from Joule heating, is also discussed.

Stretched Inertial Jets

NASA Astrophysics Data System (ADS)

Ghabache, Elisabeth; Antkowiak, Arnaud; Seon, Thomas; Villermaux, Emmanuel

2015-11-01

Liquid jets often arise as short-lived bursting liquid flows. Cavitation or impact-driven jets, bursting champagne bubbles, shaped-charge jets, ballistospores or drop-on-demand inkjet printing are a few examples where liquid jets are suddenly released. The trademark of all these discharge jets is the property of being stretched, due to the quenching injection. the present theoretical and experimental investigation, the structure of the jet flow field will be unraveled experimentally for a few emblematic occurrences of discharge jets. Though the injection markedly depends on each flow configuration, the jet velocity field will be shown to be systematically and rapidly attracted to the universal stretching flow z/t. The emergence of this inertial attractor actually only relies on simple kinematic ingredients, and as such is fairly generic. The universality of the jet velocity structure will be discussed.

Manipulation of Liquids Using Phased Array Generation of Acoustic Radiation Pressure

NASA Technical Reports Server (NTRS)

Oeftering, Richard C. (Inventor)

2000-01-01

A phased array of piezoelectric transducers is used to control and manipulate contained as well as uncontained fluids in space and earth applications. The transducers in the phased array are individually activated while being commonly controlled to produce acoustic radiation pressure and acoustic streaming. The phased array is activated to produce a single pulse, a pulse burst or a continuous pulse to agitate, segregate or manipulate liquids and gases. The phased array generated acoustic radiation pressure is also useful in manipulating a drop, a bubble or other object immersed in a liquid. The transducers can be arranged in any number of layouts including linear single or multi- dimensional, space curved and annular arrays. The individual transducers in the array are activated by a controller, preferably driven by a computer.

Soap films burst like flapping flags.

PubMed

Lhuissier, Henri; Villermaux, Emmanuel

2009-07-31

When punctured, a flat soap film bursts by opening a hole driven by liquid surface tension. The hole rim does not, however, remain smooth but soon develops indentations at the tip of which ligaments form, ultimately breaking and leaving the initially connex film into a mist of disjointed drops. We report on original observations showing that these indentations result from a flaglike instability between the film and the surrounding atmosphere inducing an oscillatory motion out of its plane. Just like a flag edge flaps in the wind, the film is successively accelerated on both sides perpendicularly to its plane, inducing film thickness modulations and centrifuging liquid ligaments that finally pinch off to form the observed spray. This effect exemplifies how the dynamics of fragile objects such as thin liquid films is sensitive to their embedding medium.

The destabilization of an initially thick liquid sheet edge

NASA Astrophysics Data System (ADS)

Lhuissier, Henri; Villermaux, Emmanuel

2011-09-01

By forcing the sudden dewetting of a free soap film attached on one edge to a straight solid wire, we study the recession and subsequent destabilization of its free edge. The newly formed rim bordering the sheet is initially thicker than the film to which it is attached, because of the Plateau border preexisting on the wire. The initial condition is thus that of an immobile massive toroidal rim connected to a thin liquid film of thickness h. The terminal Taylor-Culick receding velocity V =√2σ/ρh , where σ and ρ are the liquid surface tension and density, respectively, is only reached after a transient acceleration period which promotes the rim destabilization. The selected wavelength and associated growth time coincide with those of an inertial instability driven by surface tension.

Ultrafast nonthermal heating of water initiated by an X-ray Free-Electron Laser.

PubMed

Beyerlein, Kenneth R; Jönsson, H Olof; Alonso-Mori, Roberto; Aquila, Andrew; Bajt, Saša; Barty, Anton; Bean, Richard; Koglin, Jason E; Messerschmidt, Marc; Ragazzon, Davide; Sokaras, Dimosthenis; Williams, Garth J; Hau-Riege, Stefan; Boutet, Sébastien; Chapman, Henry N; Tîmneanu, Nicuşor; Caleman, Carl

2018-05-29

The bright ultrafast pulses of X-ray Free-Electron Lasers allow investigation into the structure of matter under extreme conditions. We have used single pulses to ionize and probe water as it undergoes a phase transition from liquid to plasma. We report changes in the structure of liquid water on a femtosecond time scale when irradiated by single 6.86 keV X-ray pulses of more than 10 6 J/cm 2 These observations are supported by simulations based on molecular dynamics and plasma dynamics of a water system that is rapidly ionized and driven out of equilibrium. This exotic ionic and disordered state with the density of a liquid is suggested to be structurally different from a neutral thermally disordered state.

Star-shaped oscillations of Leidenfrost drops

NASA Astrophysics Data System (ADS)

Ma, Xiaolei; Liétor-Santos, Juan-José; Burton, Justin C.

2017-03-01

We experimentally investigate the self-sustained, star-shaped oscillations of Leidenfrost drops. The drops levitate on a cushion of evaporated vapor over a heated, curved surface. We observe modes with n =2 -13 lobes around the drop periphery. We find that the wavelength of the oscillations depends only on the capillary length of the liquid and is independent of the drop radius and substrate temperature. However, the number of observed modes depends sensitively on the liquid viscosity. The dominant frequency of pressure variations in the vapor layer is approximately twice the drop oscillation frequency, consistent with a parametric forcing mechanism. Our results show that the star-shaped oscillations are driven by capillary waves of a characteristic wavelength beneath the drop and that the waves are generated by a large shear stress at the liquid-vapor interface.

Electrokinetic Microactuator Arrays for Control of Vehicles

DTIC Science & Technology

2002-08-01

programmable logic array (PLA) content in each unit cell....................46 Chapter 4 4.1 Schematic showing electroosmotic flow induced by an...control situations involved in propulsion systems, spanning from con- trol of mixing in advanced gas turbine combustors, to active control of surge and... electroosmotic flow, shown schematically in Fig. 4.1, results when an electric field is applied to a liquid electrolyte in contact with a charged solid

Pneumatically Modulated Liquid Delivery System for Nebulizers

DTIC Science & Technology

2011-12-02

VII. Acknowledgements 18 APPENDIX A: Complete Parts List 19 APPENDIX B: Source code for the Arduino Uno microcontroller (CD) 23 1 I...implemented. The Arduino Uno is a well-established hobbyist microcontroller, focused on ease-of-use and teaching non-computer programmers about embedded...circuits. The Arduino Uno uses an Atmega328 microcontroller with thirteen digital TTL control lines, six 10-bit resolution 0-5 V analog inputs, TTL

Determination of pesticides in composite dietary samples by gas chromatography/mass spectrometry in the selected ion monitoring mode by using a temperature-programmable large volume injector with preseparation column.

PubMed

Rosenblum, L; Hieber, T; Morgan, J

2001-01-01

Use of a temperature-programmable preseparation column in the gas chromatographic (GC) injection port permits determination of a wide range of semi-volatile pesticides including organochlorines, organophosphates, triazines, and anilines in fatty composite dietary samples while reducing sample preparation time and solvent consumption. Dietary samples are mixed with diatomaceous earth and are Soxhlet-extracted with an azeotropic solution of hexane and acetone. Sample preparation uses liquid-liquid partitioning over diatomaceous earth followed by normal phase chromatography over partially deactivated alumina. The final cleanup step occurs in a preseparation column in the GC injector, which is able to perform splitless transfer of the analytes to the analytical column and purge 99% of the high molecular weight residue. Detection is performed by GC/mass spectrometry (MS) in the selected ion monitoring mode. Method detection limits were at or below 2 ng/g for 24 of 35 pesticides studied, with recovery between 70 and 125% for 27 pesticides in samples fortified at 10 ng/g. Recovery was not dependent on fat content when measured in laboratory fortified samples containing 1, 5, and 10% fat by weight. Precision over multiple injections was acceptable, with a relative standard deviation of 2.6-15% for 25 analytes.

Programmable Regulation of DNA Conjugation to Gold Nanoparticles via Strand Displacement.

PubMed

Zhang, Cheng; Wu, Ranfeng; Li, Yifan; Zhang, Qiang; Yang, Jing

2017-10-31

Methods for conjugating DNA to gold nanoparticles (AuNPs) have recently attracted considerable attention. The ability to control such conjugation in a programmable way is of great interest. Here, we have developed a logic-based method for manipulating the conjugation of thiolated DNA species to AuNPs via cascading DNA strand displacement. Using this method, several logic-based operation systems are established and up to three kinds of DNA signals are introduced at the same time. In addition, a more sensitive catalytic logic-based operation is also achieved based on an entropy-driven process. In the experiment, all of the DNA/AuNPs conjugation results are verified by agrose gel. This strategy promises great potential for automatically conjugating DNA stands onto label-free gold nanoparticles and can be extended to constructing DNA/nanoparticle devices for applications in diagnostics, biosensing, and molecular robotics.

A 45 ps time digitizer with a two-phase clock and dual-edge two-stage interpolation in a field programmable gate array device

NASA Astrophysics Data System (ADS)

Szplet, R.; Kalisz, J.; Jachna, Z.

2009-02-01

We present a time digitizer having 45 ps resolution, integrated in a field programmable gate array (FPGA) device. The time interval measurement is based on the two-stage interpolation method. A dual-edge two-phase interpolator is driven by the on-chip synthesized 250 MHz clock with precise phase adjustment. An improved dual-edge double synchronizer was developed to control the main counter. The nonlinearity of the digitizer's transfer characteristic is identified and utilized by the dedicated hardware code processor for the on-the-fly correction of the output data. Application of presented ideas has resulted in the measurement uncertainty of the digitizer below 70 ps RMS over the time interval ranging from 0 to 1 s. The use of the two-stage interpolation and a fast FIFO memory has allowed us to obtain the maximum measurement rate of five million measurements per second.

Learning from recovery after Hurricane Mitch.

PubMed

Christoplos, Ian; Rodríguez, Tomás; Schipper, E Lisa F; Narvaez, Eddy Alberto; Bayres Mejia, Karla Maria; Buitrago, Rolando; Gómez, Ligia; Pérez, Francisco J

2010-04-01

This paper reviews how Nicaragua has recovered from Hurricane Mitch of October 1998. In particular, it examines how the assumptions and claims that were made during initial recovery planning have proven relevant in light of subsequent development. One must consider the response to Hurricane Mitch from the perspective of the broader trends that have driven recovery, including household, community and government initiatives and the wider economic context. Recovery efforts have not 'transformed' Nicaragua. In fact, market upheavals and livelihood changes in rural areas have had a more profound impact on poverty profiles than recovery programmes. Social protection programmes have been piloted, but patron-client ties and relations with aid providers are still more reliable sources of support in a time of crisis. Risk reduction has become more deeply integrated into the rural development discourse than was the case before the disaster, but risk reduction initiatives continue to place undue emphasis on hazard response rather than addressing vulnerability.

Programmable and reversible plasmon mode engineering.

PubMed

Yang, Ankun; Hryn, Alexander J; Bourgeois, Marc R; Lee, Won-Kyu; Hu, Jingtian; Schatz, George C; Odom, Teri W

2016-12-13

Plasmonic nanostructures with enhanced localized optical fields as well as narrow linewidths have driven advances in numerous applications. However, the active engineering of ultranarrow resonances across the visible regime-and within a single system-has not yet been demonstrated. This paper describes how aluminum nanoparticle arrays embedded in an elastomeric slab may exhibit high-quality resonances with linewidths as narrow as 3 nm at wavelengths not accessible by conventional plasmonic materials. We exploited stretching to improve and tune simultaneously the optical response of as-fabricated nanoparticle arrays by shifting the diffraction mode relative to single-particle dipolar or quadrupolar resonances. This dynamic modulation of particle-particle spacing enabled either dipolar or quadrupolar lattice modes to be selectively accessed and individually optimized. Programmable plasmon modes offer a robust way to achieve real-time tunable materials for plasmon-enhanced molecular sensing and plasmonic nanolasers and opens new possibilities for integrating with flexible electronics.

Spectral linewidth preservation in parametric frequency combs seeded by dual pumps.

PubMed

Tong, Zhi; Wiberg, Andreas O J; Myslivets, Evgeny; Kuo, Bill P P; Alic, Nikola; Radic, Stojan

2012-07-30

We demonstrate new technique for generation of programmable-pitch, wideband frequency combs with low phase noise. The comb generation was achieved using cavity-less, multistage mixer driven by two tunable continuous-wave pump seeds. The approach relies on phase-correlated continuous-wave pumps in order to cancel spectral linewidth broadening inherent to parametric comb generation. Parametric combs with over 200-nm bandwidth were obtained and characterized with respect to phase noise scaling to demonstrate linewidth preservation over 100 generated tones.

Macro-actor execution on multilevel data-driven architectures

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

Gaudiot, J.L.; Najjar, W.

1988-12-31

The data-flow model of computation brings to multiprocessors high programmability at the expense of increased overhead. Applying the model at a higher level leads to better performance but also introduces loss of parallelism. We demonstrate here syntax directed program decomposition methods for the creation of large macro-actors in numerical algorithms. In order to alleviate some of the problems introduced by the lower resolution interpretation, we describe a multi-level of resolution and analyze the requirements for its actual hardware and software integration.

Programmable Colored Illumination Microscopy (PCIM): A practical and flexible optical staining approach for microscopic contrast enhancement

NASA Astrophysics Data System (ADS)

Zuo, Chao; Sun, Jiasong; Feng, Shijie; Hu, Yan; Chen, Qian

2016-03-01

Programmable colored illumination microscopy (PCIM) has been proposed as a flexible optical staining technique for microscopic contrast enhancement. In this method, we replace the condenser diaphragm of a conventional microscope with a programmable thin film transistor-liquid crystal display (TFT-LCD). By displaying different patterns on the LCD, numerous established imaging modalities can be realized, such as bright field, dark field, phase contrast, oblique illumination, and Rheinberg illuminations, which conventionally rely on intricate alterations in the respective microscope setups. Furthermore, the ease of modulating both the color and the intensity distribution at the aperture of the condenser opens the possibility to combine multiple microscopic techniques, or even realize completely new methods for optical color contrast staining, such as iridescent dark-field and iridescent phase-contrast imaging. The versatility and effectiveness of PCIM is demonstrated by imaging of several transparent colorless specimens, such as unstained lung cancer cells, diatom, textile fibers, and a cryosection of mouse kidney. Finally, the potentialities of PCIM for RGB-splitting imaging with stained samples are also explored by imaging stained red blood cells and a histological section.

The introduction of dengue vaccine may temporarily cause large spikes in prevalence.

PubMed

Pandey, A; Medlock, J

2015-04-01

A dengue vaccine is expected to be available within a few years. Once vaccine is available, policy-makers will need to develop suitable policies to allocate the vaccine. Mathematical models of dengue transmission predict complex temporal patterns in prevalence, driven by seasonal oscillations in mosquito abundance. In particular, vaccine introduction may induce a transient period immediately after vaccine introduction where prevalence can spike higher than in the pre-vaccination period. These spikes in prevalence could lead to doubts about the vaccination programme among the public and even among decision-makers, possibly impeding the vaccination programme. Using simple dengue transmission models, we found that large transient spikes in prevalence are robust phenomena that occur when vaccine coverage and vaccine efficacy are not either both very high or both very low. Despite the presence of transient spikes in prevalence, the models predict that vaccination does always reduce the total number of infections in the 15 years after vaccine introduction. We conclude that policy-makers should prepare for spikes in prevalence after vaccine introduction to mitigate the burden of these spikes and to accurately measure the effectiveness of the vaccine programme.

Demonstration of a wireless driven MEMS pond skater that uses EWOD technology

NASA Astrophysics Data System (ADS)

Mita, Y.; Li, Y.; Kubota, M.; Morishita, S.; Parkes, W.; Haworth, L. I.; Flynn, B. W.; Terry, J. G.; Tang, T.-B.; Ruthven, A. D.; Smith, S.; Walton, A. J.

2009-07-01

A silicon swimming robot or pond skating device has been demonstrated. It floats on liquid surfaces using surface tension and is capable of movement using electrowetting on dielectric (EWOD) based propulsion. Its dimensions are 6 × 9 mm and the driving mechanism involves first trapping air bubbles within the liquid onto the hydrophobic surface of the device. The air bubbles are then moved using EWOD, which provides the propulsion. The device employs a recently reported TaO EWOD technology enabling a driving voltage of ≈15 V, which is low enough for RF power transmission, thus facilitating wire-free movement. A wired version has been measured to move 1.35 mm in 168 ms (a speed of 8 mm s -1). This low voltage-EWOD (<15 V) device, fabricated using a CMOS compatible process, is believed to be the world's smallest swimming MEMS device that has no mechanical moving parts. The paper also reports results of EWOD droplet operation driven by wireless power transmission and demonstrates that such a wireless design can be successfully mounted on a floating EWOD device to produce movement.

Reversible switching of liquid crystalline order permits synthesis of homogeneous populations of dipolar patchy microparticles

DOE PAGES

Wang, Xiaoguang; Miller, Daniel S.; de Pablo, Juan J.; ...

2014-08-15

The spontaneous positioning of colloids on the surfaces of micrometer-sized liquid crystal (LC) droplets and their subsequent polymerization offers the basis of a general and facile method for the synthesis of patchy microparticles. The existence of multiple local energetic minima, however, can generate kinetic traps for colloids on the surfaces of the LC droplets and result in heterogeneous populations of patchy microparticles. To address this issue, in this paper it is demonstrated that adsorbate-driven switching of the internal configurations of LC droplets can be used to sweep colloids to a single location on the LC droplet surfaces, thus resulting inmore » the synthesis of homogeneous populations of patchy microparticles. The surface-driven switching of the LC can be triggered by addition of surfactant or salts, and permits the synthesis of dipolar microparticles as well as “Janus-like” microparticles. Finally, by using magnetic colloids, the utility of the approach is illustrated by synthesizing magnetically responsive patchy microdroplets of LC with either dipolar or quadrupolar symmetry that exhibit distinct optical responses upon application of an external magnetic field.« less

Ring waves as a mass transport mechanism in air-driven core-annular flows.

PubMed

Camassa, Roberto; Forest, M Gregory; Lee, Long; Ogrosky, H Reed; Olander, Jeffrey

2012-12-01

Air-driven core-annular fluid flows occur in many situations, from lung airways to engineering applications. Here we study, experimentally and theoretically, flows where a viscous liquid film lining the inside of a tube is forced upwards against gravity by turbulent airflow up the center of the tube. We present results on the thickness and mean speed of the film and properties of the interfacial waves that develop from an instability of the air-liquid interface. We derive a long-wave asymptotic model and compare properties of its solutions with those of the experiments. Traveling wave solutions of this long-wave model exhibit evidence of different mass transport regimes: Past a certain threshold, sufficiently large-amplitude waves begin to trap cores of fluid which propagate upward at wave speeds. This theoretical result is then confirmed by a second set of experiments that show evidence of ring waves of annular fluid propagating over the underlying creeping flow. By tuning the parameters of the experiments, the strength of this phenomenon can be adjusted in a way that is predicted qualitatively by the model.

Measurements of droplet size in shear-driven atomization using ultra-small angle x-ray scattering

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

Kastengren, A.; Ilavsky, J.; Viera, Juan Pablo

Measurements of droplet size in optically-thick, non-evaporating, shear-driven sprays have been made using ultra-small angle x-ray scattering (USAXS). The sprays are produced by orifice-type nozzles coupled to diesel injectors, with measurements conducted from 1 – 24 mm from the orifice, spanning from the optically-dense near-nozzle region to more dilute regions where optical diagnostics are feasible. The influence of nozzle diameter, liquid injection pressure, and ambient density were examined. The USAXS measurements reveal few if any nanoscale droplets, in conflict with a popular computational model of diesel spray breakup. The average droplet diameter rapidly decreases with downstream distance from the nozzlemore » until a plateau value is reached, after which only small changes are seen in droplet diameter. This plateau droplet size is consistent with the droplets being small enough to be stable with respect to further breakup. As a result, liquid injection pressure and nozzle diameter have the biggest impact on droplet size, while ambient density has a smaller effect.« less

Water imbibition by mica pores: what happens when capillary flow is suppressed?

NASA Astrophysics Data System (ADS)

Fang, Chao; Qiao, Rui

2017-11-01

The imbibition of liquids into porous media plays a critical role in numerous applications. Most prior studies focused on imbibition driven by capillary flows. In this work, we study the imbibition of water into slit-shaped mica pores filled with pressurized methane using molecular simulations. Despite that capillary flow is suppressed by the high gas pressure, water is imbibed into the pore as monolayer liquid films. Since the classical hydrodynamic flow is not readily applicable for the monolayer water film propagating on the mica wall and the imbibition is driven by the strong affinity of water molecules to the mica walls, the observed imbibition is best taken as surface hydration. We show that the dynamics of water's imbibition front follows a simple diffusive scaling law. The effective diffusion coefficient of the imbibition front, however, is more than ten times larger than the diffusion coefficient of the water molecules in the water film adsorbed on the mica walls. Using a molecular theory originally developed for the spreading of monolayer films on solid substrates, we clarify the mechanism underlying the rapid water imbibition observed here.

Physical cleaning by bubbly streaming flow in an ultrasound field

NASA Astrophysics Data System (ADS)

Yamashita, Tatsuya; Ando, Keita

2017-11-01

Low-intensity ultrasonic cleaning with gas-supersaturated water is a promising method of physical cleaning without erosion; we are able to trigger cavitation bubble nucleation by weak ultrasound under gas supersaturation and thus clean material surfaces by mild bubble dynamics. Here, we perform particle image velocimetry (PIV) measurement of liquid flow and cavitation bubble translation in an ultrasonic cleaning bath driven at 28 kHz and then relate it to cleaning tests using glass slides at which silica particles are attached. The ultrasound pressure amplitude at the cleaning spot is set at 1.4 atm. We select the supersaturation level of dissolved oxygen (DO) as a parameter and control it by oxygen microbubble aeration. It follows from the PIV measurement that the liquid flow is enhanced by the cavitation bubble translation driven by acoustic radiation force; this trend becomes clearer when the bubbles appear more densely as the DO supersaturation increases. In the cleaning tests, the cleaned areas appear as straight streaks. This suggests that physical cleaning is achieved mainly by cavitation bubbles that translate in ultrasound fields.

Geothermal energy control system and method

DOEpatents

Matthews, Hugh B.

1977-01-01

A geothermal energy transfer and utilization system makes use of thermal energy stored in hot solute-bearing well water to generate super-heated steam from an injected flow of clean water; the super-heated steam is then used for operating a turbine-driven pump at the well bottom for pumping the hot solute-bearing water at high pressure and in liquid state to the earth's surface, where it is used by transfer of its heat to a closed-loop boiler-turbine-alternator combination for the generation of electrical or other power. Residual concentrated solute-bearing water is pumped back into the earth. The clean cooled water is regenerated at the surface-located system and is returned to the deep well pumping system also for lubrication of a novel bearing arrangement supporting the turbine-driven pump system. The bearing system employs liquid lubricated thrust and radial bearings with all bearing surfaces bathed in clean water serving as a lubricant and maintained under pressure to prevent entry into the bearings of contaminated geothermal fluid, an auxiliary thrust ball bearing arrangement comes into operation when starting or stopping the pumping system.

Measurements of droplet size in shear-driven atomization using ultra-small angle x-ray scattering

DOE PAGES

Kastengren, A.; Ilavsky, J.; Viera, Juan Pablo; ...

2017-03-16

Measurements of droplet size in optically-thick, non-evaporating, shear-driven sprays have been made using ultra-small angle x-ray scattering (USAXS). The sprays are produced by orifice-type nozzles coupled to diesel injectors, with measurements conducted from 1 – 24 mm from the orifice, spanning from the optically-dense near-nozzle region to more dilute regions where optical diagnostics are feasible. The influence of nozzle diameter, liquid injection pressure, and ambient density were examined. The USAXS measurements reveal few if any nanoscale droplets, in conflict with a popular computational model of diesel spray breakup. The average droplet diameter rapidly decreases with downstream distance from the nozzlemore » until a plateau value is reached, after which only small changes are seen in droplet diameter. This plateau droplet size is consistent with the droplets being small enough to be stable with respect to further breakup. As a result, liquid injection pressure and nozzle diameter have the biggest impact on droplet size, while ambient density has a smaller effect.« less

Emerging Applications of Liquid Crystals Based on Nanotechnology

PubMed Central

Sohn, Jung Inn; Hong, Woong-Ki; Choi, Su Seok; Coles, Harry J.; Welland, Mark E.; Cha, Seung Nam; Kim, Jong Min

2014-01-01

Diverse functionalities of liquid crystals (LCs) offer enormous opportunities for their potential use in advanced mobile and smart displays, as well as novel non-display applications. Here, we present snapshots of the research carried out on emerging applications of LCs ranging from electronics to holography and self-powered systems. In addition, we will show our recent results focused on the development of new LC applications, such as programmable transistors, a transparent and active-type two-dimensional optical array and self-powered display systems based on LCs, and will briefly discuss their novel concepts and basic operating principles. Our research will give insights not only into comprehensively understanding technical and scientific applications of LCs, but also developing new discoveries of other LC-based devices. PMID:28788555

A new electrowetting lab-on-a-chip platform based on programmable and virtual wall-less channels

NASA Astrophysics Data System (ADS)

Banerjee, Ananda; Kreit, Eric; Dhindsa, Manjeet; Heikenfeld, Jason; Papautsky, Ian

2011-02-01

Microscale liquid handling based on electrowetting has been previously demonstrated by several groups. Such liquid manipulation however is limited to control of individual droplets, aptly termed digital microfluidics. The inability to form continuous channels thus prevents conventional microfluidic sample manipulation and analysis approaches, such as electroosmosis and electrophoresis. In this paper, we discuss our recent progress on the development of electrowettingbased virtual channels. These channels can be created and reconfigured on-demand and preserve their shape without external stimulus. We also discuss recent progress towards demonstrating electroosmotic flows in such microchannels for fluid transport. This would permit a variety of basic functionalities in this new platform including sample transport and mixing between various functional areas of the chip.

Additive Manufacturing a Liquid Hydrogen Rocket Engine

NASA Technical Reports Server (NTRS)

Jones, Carl P.; Robertson, Elizabeth H.; Koelbl, Mary Beth; Singer, Chris

2016-01-01

Space Propulsion is a 5 day event being held from 2nd May to the 6th May 2016 at the Rome Marriott Park Hotel in Rome, Italy. This event showcases products like Propulsion sub-systems and components, Production and manufacturing issues, Liquid, Solid, Hybrid and Air-breathing Propulsion Systems for Launcher and Upper Stages, Overview of current programmes, AIV issues and tools, Flight testing and experience, Technology building blocks for Future Space Transportation Propulsion Systems : Launchers, Exploration platforms & Space Tourism, Green Propulsion for Space Transportation, New propellants, Rocket propulsion & global environment, Cost related aspects of Space Transportation propulsion, Modelling, Pressure-Thrust oscillations issues, Impact of new requirements and regulations on design etc. in the Automotive, Manufacturing, Fabrication, Repair & Maintenance industries.

Non-invasive energy meter for fixed and variable flow systems

DOEpatents

Menicucci, David F.; Black, Billy D.

2005-11-01

An energy metering method and apparatus for liquid flow systems comprising first and second segments of one or more conduits through which a liquid flows, comprising: attaching a first temperature sensor for connection to an outside of the first conduit segment; attaching a second temperature sensor for connection to an outside of the second conduit segment; via a programmable control unit, receiving data from the sensors and calculating energy data therefrom; and communicating energy data from the meter; whereby the method and apparatus operate without need to temporarily disconnect or alter the first or second conduit segments. The invention operates with both variable and fixed flow systems, and is especially useful for both active and passive solar energy systems.

Marangoni-Benard Convection in a Evaporating Liquid Thin Layer

NASA Technical Reports Server (NTRS)

Chai, An-Ti; Zhang, Nengli

1996-01-01

Marangoni-Benard convection in evaporating liquid thin layers has been investigated through flow visualization and temperature profile measurement. Twelve liquids, namely ethyl alcohol, methanol, chloroform, acetone, cyclohexane, benzine, methylene chloride, carbon tetrachloride, ethyl acetate, n-pentane, silicone oil (0.65 cSt.), and freon-113, were tested and convection patterns in thin layers of these samples were observed. Comparison among these tested samples shows that some liquids are sensitive to surface contamination from aluminum powder but some are not. The latter is excellent to be used for the investigation of surface-tension driven convection through visualization using the tracer. Two sample liquids, alcohol and freon-113 were particularly selected for systematic study. It was found that the wavelength of Benard cells would not change with thickness of the layer when it evaporates at room temperature. Special attention was focused on cases in which a liquid layer was cooled from below, and some interesting results were obtained. Convection patterns were recorded during the evaporation process and the patterns at certain time frame were compared. Benard cells were observed in thin layers with a nonlinear temperature profile and even with a zero or positive temperature gradient. Wavelength of the cells was found to increase as the evaporation progressed.

Double-duct liquid metal magnetohydrodynamic engine

DOEpatents

Haaland, Carsten M.

1995-01-01

An internal combustion, liquid metal (LM) magnetohydrodynamic (MHD) engine and an alternating current (AC) magnetohydrodynamic generator, are used in combination to provide useful AC electric energy output. The engine design has-four pistons and a double duct configuration, with each duct containing sodium potassium liquid metal confined between free pistons located at either end of the duct. The liquid metal is forced to flow back and forth in the duct by the movement of the pistons, which are alternatively driven by an internal combustion process. In the MHD generator, the two LM-MHD ducts pass in close proximity through a Hartmann duct with output transformer. AC power is produced by operating the engine with the liquid metal in the two generator ducts always flowing in counter directions. The amount of liquid metal maintained in the ducts may be varied. This provides a variable stroke length for the pistons. The engine/generator provides variable AC power at variable frequencies that correspond to the power demands of the vehicular propulsion. Also the engine should maintain nearly constant efficiency throughout the range of power usage. Automobiles and trucks could be powered by the invention, with no transmission or power converter devices being required.

Double-duct liquid metal magnetohydrodynamic engine

DOEpatents

Haaland, Carsten M.

1997-01-01

An internal combustion, liquid metal (LM) magnetohydrodynamic (MHD) engine and an alternating current (AC) magnetohydrodynamic generator, are used in combination to provide useful AC electric energy output. The engine design has four pistons and a double duct configuration, with each duct containing sodium potassium liquid metal confined between free pistons located at either end of the duct. The liquid metal is forced to flow back and forth in the duct by the movement of the pistons, which are alternatively driven by an internal combustion process. In the MHD generator, the two LM-MHD ducts pass in close proximity through a Hartmann duct with output transformer. AC power is produced by operating the engine with the liquid metal in the two generator ducts always flowing in counter directions. The amount of liquid metal maintained in the ducts may be varied. This provides a variable stroke length for the pistons. The engine/generator provides variable AC power at variable frequencies that correspond to the power demands of the vehicular propulsion. Also the engine should maintain nearly constant efficiency throughout the range of power usage. Automobiles and trucks could be powered by the invention, with no transmission or power converter devices being required.

Molecular modeling of field-driven ion emission from ionic liquids

NASA Astrophysics Data System (ADS)

Zhang, Fei; He, Yadong; Qiao, Rui

2017-11-01

Traditionally, operating electrosprays in the purely ionic mode is challenging, but recent experiments confirmed that such operation can be achieved using room-temperature ionic liquids as working electrolytes. Such electrosprays have shown promise in applications including chemical analysis, nanomanufacturing, and space propulsion. The mechanistic and quantitative understanding of such electrosprays at the molecular level, however, remain limited at present. In this work, we simulated ion emission from EMIM-PF6 ionic liquid films using the molecular dynamics method. We show that, when the surface electric field is smaller than 1.5V/nm, the ion emission current predicted using coarse-grained ionic liquid model observes the classical scaling law by J. V. Iribarne and B. A. Thomson, i.e., ln(Je/ σ) En1/2. These simulations, however, cannot capture the co-emission of cations and anions from ionic liquid surface observed in some experiments. Such co-emission was successfully captured when united-atom models were adopted for the ionic liquids. By examining the co-emission events with picosecond, sub-angstrom resolution, we clarified the origins of the co-emission phenomenon and delineate the molecular events leading to ion emission.

Design and Modeling of a Liquid Lithium LiMIT Loop

NASA Astrophysics Data System (ADS)

Szott, Matthew; Christenson, Michael; Stemmley, Steven; Ahn, Chisung; Andruczyk, Daniel; Ruzic, David

2017-10-01

The use of flowing liquid lithium in plasma facing components has been shown to reduce erosion and thermal stress damage, prolong device lifetime, decrease edge recycling, reduce impurities, and increase plasma performance, all while providing a clean and self-healing surface. The Liquid Metal Infused Trench (LiMIT) system has proven the concept of controlled thermoelectric magnetohydrodynamic-driven lithium flow for use in fusion relevant conditions, through tests at UIUC, HT-7, and Magnum PSI. As the use of liquid lithium in fusion devices progresses, emphasis must now be placed on full systems integration of flowing liquid metal concepts. The LiMIT system will be upgraded to include a full liquid lithium loop, which will pump lithium into the fusion device, utilize TEMHD to drive lithium through the vessel, and remove lithium for filtration and degassing. Flow control concepts recently developed at UIUC - including wetting control, dryout control, and flow velocity control - will be tested in conjunction in order to demonstrate a robust system. Lithium loop system requirements, designs, and modeling work will be presented, along with plans for installation and testing on the HIDRA device at UIUC. This work is supported by DOE/ALPS DE-FG02-99ER54515.

Experimental investigation on structures and velocity of liquid jets in a supersonic crossflow

NASA Astrophysics Data System (ADS)

Wang, Zhen-guo; Wu, Liyin; Li, Qinglian; Li, Chun

2014-09-01

Particle image velocimetry was applied in the study focusing on the structure and velocity of water jets injected into a Ma = 2.1 crossflow. The instantaneous structures of the jet, including surface waves in the near-injector region and vortices in the far-field, were visualized clearly. Spray velocity increases rapidly to 66% of the mainstream velocity in the region of x/d < 15, owing to the strong gas-liquid interaction near the orifice. By contrast, the velocity grows slowly in the far-field region, where the liquid inside the spray is accelerated mainly by the continuous driven force provided by the mainstream with the gas-liquid shear. The injection and atomization of liquid jet in a supersonic crossflow serves as a foundation of scramjet combustion process, by affecting the combustion efficiency and some other performances. With various forces acting on the liquid jet (Mashayek et al. [AIAA J. 46, 2674-2686 (2008)] and Wang et al. [AIAA J. 50, 1360-1366 (2012)]), the atomization process involves very complex flow physics. These physical processes include strong vortical structures, small-scale wave formation, stripping of small droplets from the jet surface, formations of ligaments, and droplets with a wide range of sizes.

Fluid dynamics of liquids on Titans surface

NASA Astrophysics Data System (ADS)

Ori, Gian Gabriele; Marinangeli, Lucia; Baliva, Antonio; Bressan, Mario; Strom, Robert G.

1998-10-01

On the surface of Titan liquids can be present in three types of environments : (i) oceans, (ii) seas and lakes, and (iii) fluvial channels. The liquid in these environments will be affected by several types of motion: progressive (tidal) waves, wind-generated waves and unidirectional currents. The physical parameters of the liquid on Titans surface can be reconstructed using the Peng-Robinson equation of state. The total energy of the waves, both tidal and wind, depends on the gravity and liquid density ; both values are lower on Titan than on Earth. Thus, the same total energy will produce larger waves on Titan. This is also valid also for the progressive waves, as it is confirmed by the physical relationship between horizontal velocity, wave amplitude, and depth of the liquid. Wind-driven waves also will tend to be larger, because the viscosity of the liquid (which is lower on Titan) controls the deformation of the liquid under shear stress. Wind-generated waves would be rather large, but the dimension of the liquid basin limits the size of the waves ; in small lakes or seas the wave power cannot reach large values. Unidirectional currents are also affected by the liquid properties. Both the relations from driving and resting forces and the Reynolds number suggests that the flows exhibit a large erosional capacity and that, theoretically, a true fluvial network could be formed. However, caution should be exercised, because the cohesion of the sedimentary interface can armour bottom and induce laterally extensive, unchanelled sheet flows with small erosional capacity.

Liquid phase sintered compacts in space

NASA Technical Reports Server (NTRS)

Mookherji, T. K.; Mcanelly, W. B.

1974-01-01

A model that will explain the effect of gravity on liquid phase sintering was developed. Wetting characteristics and density segregation which are the two important phenomena in liquid phase sintering are considered in the model development. Experiments were conducted on some selected material combinations to study the gravity effects on liquid phase sintering, and to verify the validity of the model. It is concluded that: (1) The surface tension forces acting on solid particles in a one-g environment are not appreciably different from those anticipated in a 0.00001g/g sub 0 (or lower) environment. (2) The capillary forces are dependent on the contact angle, the quantity of the liquid phase, and the distance between solid particles. (3) The pores (i.e., bubbles) do not appear to be driven to the surface by gravity-produced buoyancy forces. (4) The length of time to produce the same degree of settling in a low-gravity environment will be increased significantly. (5) A low gravity environment would appear to offer a unique means of satisfactorily infiltrating a larger and/or complex shaped compact.

Spontaneous Self-Formation of 3D Plasmonic Optical Structures.

PubMed

Choi, Inhee; Shin, Yonghee; Song, Jihwan; Hong, SoonGweon; Park, Younggeun; Kim, Dongchoul; Kang, Taewook; Lee, Luke P

2016-08-23

Self-formation of colloidal oil droplets in water or water droplets in oil not only has been regarded as fascinating fundamental science but also has been utilized in an enormous number of applications in everyday life. However, the creation of three-dimensional (3D) architectures by a liquid droplet and an immiscible liquid interface has been less investigated than other applications. Here, we report interfacial energy-driven spontaneous self-formation of a 3D plasmonic optical structure at room temperature without an external force. Based on the densities and interfacial energies of two liquids, we simulated the spontaneous formation of a plasmonic optical structure when a water droplet containing metal ions meets an immiscible liquid polydimethylsiloxane (PDMS) interface. At the interface, the metal ions in the droplet are automatically reduced to form an interfacial plasmonic layer as the liquid PDMS cures. The self-formation of both an optical cavity and integrated plasmonic nanostructure significantly enhances the fluorescence by a magnitude of 1000. Our findings will have a huge impact on the development of various photonic and plasmonic materials as well as metamaterials and devices.

Noncontact thermophysical property measurement by levitation of a thin liquid disk.

PubMed

Lee, Sungho; Ohsaka, Kenichi; Rednikov, Alexei; Sadhal, Satwindar Singh

2006-09-01

The purpose of the current research program is to develop techniques for noncontact measurement of thermophysical properties of highly viscous liquids. The application would be for undercooled liquids that remain liquid even below the freezing point when suspended without a container. The approach being used here consists of carrying out thermocapillary flow and temperature measurements in a horizontally levitated, laser-heated thin glycerin disk. In a levitated state, the disk is flattened by an intense acoustic field. Such a disk has the advantage of a relatively low gravitational potential over the thickness, thus mitigating the buoyancy effects, and helping isolate the thermocapillary-driven flows. For the purpose of predicting the thermal properties from these measurements, it is necessary to develop a theoretical model of the thermal processes. Such a model has been developed, and, on the basis of the observed shape, the thickness is taken to be a minimum at the center with a gentle parabolic profile at both the top and the bottom surfaces. This minimum thickness is much smaller than the radius of disk drop and the ratio of thickness to radius becomes much less than unity. It is heated by laser beam in normal direction to the edge. A general three-dimensional momentum equation is transformed into a two-variable vorticity equation. For the highly viscous liquid, a few millimeters in size, Stokes equations adequately describe the flow. Additional approximations are made by considering average flow properties over the disk thickness in a manner similar to lubrication theory. In the same way, the three-dimensional energy equation is averaged over the disk thickness. With convection boundary condition at the surfaces, we integrate a general three-dimensional energy equation to get an averaged two-dimensional energy equation that has convection terms, conduction terms, and additional source terms corresponding to a Biot number. A finite-difference numerical approach is used to solve these steady-state governing equations in the cylindrical coordinate system. The calculations yield the temperature distribution and the thermally driven flow field. These results have been used to formulate a model that, in conjunction with experiments, has enabled the development of a method for the noncontact thermophysical property measurement of liquids.

Electrowetting-driven variable-focus microlens on flexible surfaces.

PubMed

Li, Chenhui; Jiang, Hongrui

2012-06-04

We demonstrate a flexible, electrowetting-driven, variable-focus liquid microlens. The microlens is fabricated using a soft polymer polydimethylsiloxane. The lens can be smoothly wrapped onto a curved surface. A low-temperature fabrication process was developed to reduce the stress on and to avoid any damage to the polymer. The focal length of the microlens varies between -15.0 mm to +28.0 mm, depending on the applied voltage. The resolving power of the microlens is 25.39 line pairs per mm using a 1951 United States Air Force resolution chart. The typical response time of the lens is around 50 ms.

Electrowetting-driven variable-focus microlens on flexible surfaces

PubMed Central

Li, Chenhui; Jiang, Hongrui

2012-01-01

We demonstrate a flexible, electrowetting-driven, variable-focus liquid microlens. The microlens is fabricated using a soft polymer polydimethylsiloxane. The lens can be smoothly wrapped onto a curved surface. A low-temperature fabrication process was developed to reduce the stress on and to avoid any damage to the polymer. The focal length of the microlens varies between −15.0 mm to +28.0 mm, depending on the applied voltage. The resolving power of the microlens is 25.39 line pairs per mm using a 1951 United States Air Force resolution chart. The typical response time of the lens is around 50 ms. PMID:22904571

Highly anisotropic mobility in solution processed TIPS-pentacene film studied by independently driven four GaIn probes

NASA Astrophysics Data System (ADS)

Yoshimoto, Shinya; Takahashi, Kohtaro; Suzuki, Mitsuharu; Yamada, Hiroko; Miyahara, Ryosuke; Mukai, Kozo; Yoshinobu, Jun

2017-08-01

We have studied in-plane anisotropy in the field-effect mobility of solution-processed organic semiconductor 6,13-bis(triisopropylsilylethynyl)pentacene by using independently driven four gallium indium (Ga-In) probes. Liquid-metal Ga-In probes are highly effective for reproducible conductivity measurements of organic thin films. We demonstrated that a high mobility anisotropy of 44 was obtained by using a square four-probe method and a feedback circuit to keep the channel potential constant. The present method minimized the influences of the contact resistance and the insensitivity of anisotropy in a linear arrangement in two-dimensional field-effect transistors.

Restructured low-fat cooked ham containing liquid whey fortified with lactulose.

PubMed

Oliveira, Cristiane A; Massingue, Armando A; Moura, Ana Paula R; Fontes, Paulo Rogério; Ramos, Alcinéia Ls; Ramos, Eduardo M

2018-01-01

Current health concerns have driven consumers to request products with nutritional and physiological advantages, which can be achieved by using prebiotic ingredients. Lactulose is a prebiotic with excellent functional properties and can be easily incorporated into meat products through the addition of liquid whey. This study investigated the technological and sensorial quality of restructured cooked ham elaborated without liquid whey added (control) and with liquid whey containing different contents (0, 30, 60 and 100 g kg -1 ) of lactulose. Liquid whey did not change any technological or sensorial characteristics of the product, but the general acceptability decreased due to addition of lactulose. Samples with higher lactulose concentrations had lower moisture content, pH and refreezing loss and increased carbohydrate content. Control and whey added samples had higher lightness and lower intense color than samples with lactulose. Liquid whey additions with higher lactulose content increased hardness and chewiness of the samples. Restructured cooked hams formulated with liquid whey and 30 g kg -1 of lactulose had minimal effects on the technological properties and sensory characteristics and, due to the possible benefits conferred by the prebiotic, is a potential alternative to provide meat products with prebiotic activity. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Thermal Rayleigh-Marangoni convection in a three-layer liquid-metal-battery model.

PubMed

Köllner, Thomas; Boeck, Thomas; Schumacher, Jörg

2017-05-01

The combined effects of buoyancy-driven Rayleigh-Bénard convection (RC) and surface tension-driven Marangoni convection (MC) are studied in a triple-layer configuration which serves as a simplified model for a liquid metal battery (LMB). The three-layer model consists of a liquid metal alloy cathode, a molten salt separation layer, and a liquid metal anode at the top. Convection is triggered by the temperature gradient between the hot electrolyte and the colder electrodes, which is a consequence of the release of resistive heat during operation. We present a linear stability analysis of the state of pure thermal conduction in combination with three-dimensional direct numerical simulations of the nonlinear turbulent evolution on the basis of a pseudospectral method. Five different modes of convection are identified in the configuration, which are partly coupled to each other: RC in the upper electrode, RC with internal heating in the molten salt layer, and MC at both interfaces between molten salt and electrode as well as anticonvection in the middle layer and lower electrode. The linear stability analysis confirms that the additional Marangoni effect in the present setup increases the growth rates of the linearly unstable modes, i.e., Marangoni and Rayleigh-Bénard instability act together in the molten salt layer. The critical Grashof and Marangoni numbers decrease with increasing middle layer thickness. The calculated thresholds for the onset of convection are found for realistic current densities of laboratory-sized LMBs. The global turbulent heat transfer follows scaling predictions for internally heated RC. The global turbulent momentum transfer is comparable with turbulent convection in the classical Rayleigh-Bénard case. In summary, our studies show that incorporating Marangoni effects generates smaller flow structures, alters the velocity magnitudes, and enhances the turbulent heat transfer across the triple-layer configuration.

Thermal Rayleigh-Marangoni convection in a three-layer liquid-metal-battery model

NASA Astrophysics Data System (ADS)

Köllner, Thomas; Boeck, Thomas; Schumacher, Jörg

2017-05-01

The combined effects of buoyancy-driven Rayleigh-Bénard convection (RC) and surface tension-driven Marangoni convection (MC) are studied in a triple-layer configuration which serves as a simplified model for a liquid metal battery (LMB). The three-layer model consists of a liquid metal alloy cathode, a molten salt separation layer, and a liquid metal anode at the top. Convection is triggered by the temperature gradient between the hot electrolyte and the colder electrodes, which is a consequence of the release of resistive heat during operation. We present a linear stability analysis of the state of pure thermal conduction in combination with three-dimensional direct numerical simulations of the nonlinear turbulent evolution on the basis of a pseudospectral method. Five different modes of convection are identified in the configuration, which are partly coupled to each other: RC in the upper electrode, RC with internal heating in the molten salt layer, and MC at both interfaces between molten salt and electrode as well as anticonvection in the middle layer and lower electrode. The linear stability analysis confirms that the additional Marangoni effect in the present setup increases the growth rates of the linearly unstable modes, i.e., Marangoni and Rayleigh-Bénard instability act together in the molten salt layer. The critical Grashof and Marangoni numbers decrease with increasing middle layer thickness. The calculated thresholds for the onset of convection are found for realistic current densities of laboratory-sized LMBs. The global turbulent heat transfer follows scaling predictions for internally heated RC. The global turbulent momentum transfer is comparable with turbulent convection in the classical Rayleigh-Bénard case. In summary, our studies show that incorporating Marangoni effects generates smaller flow structures, alters the velocity magnitudes, and enhances the turbulent heat transfer across the triple-layer configuration.