On the mechanism of the ring zone effect obtained with the mixed haemadsorption technique

PubMed Central

Jonsson, J.; Fagraeus, Astrid

1969-01-01

A ring zone effect noted with the radial diffusion disc test modification of the mixed haemadsorption technique has been studied using human anti-thyroid sera reacting with thyroid monolayer cultures. Results are presented which suggest that the `empty' centre of the ring zones is due to an excess of attached antibody. Sera giving the ring zone effect contain a larger number of antibody specificities than those producing filled zones. The appearance of ring zones is favoured by a low density of antigens on the culture. These findings and a number of synergistic effects produced by mixing ring and filled zone reactions are compatible with the hypothesis that the ring zone is produced when several antibodies of different specificities react with restricted antigenic areas carrying densely located clusters of antigenic determinants representing the different specificities contained in the ring zone sera. The crowding of antibodies on the clusters in the centre of the ring zones creates a steric hindrance for the indicator cells so that they are not firmly attached in this area. The antibody zone is therefore indicated as a peripheral haemadsorption ring. ImagesFIG. 1FIG. 2FIG. 4FIG. 6FIG. 7FIG. 9 PMID:5307718

Tank 241-AZ-101 criticality assessment resulting from pump jet mixing: Sludge mixing simulation

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

Onishi, Y.; Recknagle, K.

Tank 241-AZ-101 (AZ-101) is one of 28 double-shell tanks located in the AZ farm in the Hanford Site`s 200 East Area. The tank contains a significant quantity of fissile materials, including an estimated 9.782 kg of plutonium. Before beginning jet pump mixing for mitigative purposes, the operations must be evaluated to demonstrate that they will be subcritical under both normal and credible abnormal conditions. The main objective of this study was to address a concern about whether two 300-hp pumps with four rotating 18.3-m/s (60-ft/s) jets can concentrate plutonium in their pump housings during mixer pump operation and cause amore » criticality. The three-dimensional simulation was performed with the time-varying TEMPEST code to determine how much the pump jet mixing of Tank AZ-101 will concentrate plutonium in the pump housing. The AZ-101 model predicted that the total amount of plutonium within the pump housing peaks at 75 g at 10 simulation seconds and decreases to less than 10 g at four minutes. The plutonium concentration in the entire pump housing peaks at 0.60 g/L at 10 simulation seconds and is reduced to below 0.1 g/L after four minutes. Since the minimum critical concentration of plutonium is 2.6 g/L, and the minimum critical plutonium mass under idealized plutonium-water conditions is 520 g, these predicted maximums in the pump housing are much lower than the minimum plutonium conditions needed to reach a criticality level. The initial plutonium maximum of 1.88 g/L still results in safety factor of 4.3 in the pump housing during the pump jet mixing operation.« less

Comparison of Anaerobic Susceptibility Results Obtained by Different Methods

PubMed Central

Rosenblatt, J. E.; Murray, P. R.; Sonnenwirth, A. C.; Joyce, J. L.

1979-01-01

Susceptibility tests using 7 antimicrobial agents (carbenicillin, chloramphenicol, clindamycin, penicillin, cephalothin, metronidazole, and tetracycline) were run against 35 anaerobes including Bacteroides fragilis (17), other gram-negative bacilli (7), clostridia (5), peptococci (4), and eubacteria (2). Results in triplicate obtained by the microbroth dilution method and the aerobic modification of the broth disk method were compared with those obtained with an agar dilution method using Wilkins-Chalgren agar. Media used in the microbroth dilution method included Wilkins-Chalgren broth, brain heart infusion broth, brucella broth, tryptic soy broth, thioglycolate broth, and Schaedler's broth. A result differing by more than one dilution from the Wilkins-Chalgren agar result was considered a discrepancy, and when there was a change in susceptibility status this was termed a significant discrepancy. The microbroth dilution method using Wilkins-Chalgren broth and thioglycolate broth produced the fewest total discrepancies (22 and 24, respectively), and Wilkins-Chalgren broth, thioglycolate, and Schaedler's broth had the fewest significant discrepancies (6, 5, and 5, respectively). With the broth disk method, there were 15 significant discrepancies, although half of these were with tetracycline, which was the antimicrobial agent associated with the highest number of significant discrepancies (33), considering all of the test methods and media. PMID:464560

Application of the Fokker-Planck molecular mixing model to turbulent scalar mixing using moment methods

NASA Astrophysics Data System (ADS)

Madadi-Kandjani, E.; Fox, R. O.; Passalacqua, A.

2017-06-01

An extended quadrature method of moments using the β kernel density function (β -EQMOM) is used to approximate solutions to the evolution equation for univariate and bivariate composition probability distribution functions (PDFs) of a passive scalar for binary and ternary mixing. The key element of interest is the molecular mixing term, which is described using the Fokker-Planck (FP) molecular mixing model. The direct numerical simulations (DNSs) of Eswaran and Pope ["Direct numerical simulations of the turbulent mixing of a passive scalar," Phys. Fluids 31, 506 (1988)] and the amplitude mapping closure (AMC) of Pope ["Mapping closures for turbulent mixing and reaction," Theor. Comput. Fluid Dyn. 2, 255 (1991)] are taken as reference solutions to establish the accuracy of the FP model in the case of binary mixing. The DNSs of Juneja and Pope ["A DNS study of turbulent mixing of two passive scalars," Phys. Fluids 8, 2161 (1996)] are used to validate the results obtained for ternary mixing. Simulations are performed with both the conditional scalar dissipation rate (CSDR) proposed by Fox [Computational Methods for Turbulent Reacting Flows (Cambridge University Press, 2003)] and the CSDR from AMC, with the scalar dissipation rate provided as input and obtained from the DNS. Using scalar moments up to fourth order, the ability of the FP model to capture the evolution of the shape of the PDF, important in turbulent mixing problems, is demonstrated. Compared to the widely used assumed β -PDF model [S. S. Girimaji, "Assumed β-pdf model for turbulent mixing: Validation and extension to multiple scalar mixing," Combust. Sci. Technol. 78, 177 (1991)], the β -EQMOM solution to the FP model more accurately describes the initial mixing process with a relatively small increase in computational cost.

Investigation of fatigue failure in bituminous base mixes.

DOT National Transportation Integrated Search

1980-01-01

A correlation between the results obtained with the fatigue test and those from the indirect tensile test on two base mixes was attempted in anticipation of the possible use of the latter test to design base mixes for maximum fatigue life. Two base m...

Integrating Quantitative and Qualitative Results in Health Science Mixed Methods Research Through Joint Displays

PubMed Central

Guetterman, Timothy C.; Fetters, Michael D.; Creswell, John W.

2015-01-01

PURPOSE Mixed methods research is becoming an important methodology to investigate complex health-related topics, yet the meaningful integration of qualitative and quantitative data remains elusive and needs further development. A promising innovation to facilitate integration is the use of visual joint displays that bring data together visually to draw out new insights. The purpose of this study was to identify exemplar joint displays by analyzing the various types of joint displays being used in published articles. METHODS We searched for empirical articles that included joint displays in 3 journals that publish state-of-the-art mixed methods research. We analyzed each of 19 identified joint displays to extract the type of display, mixed methods design, purpose, rationale, qualitative and quantitative data sources, integration approaches, and analytic strategies. Our analysis focused on what each display communicated and its representation of mixed methods analysis. RESULTS The most prevalent types of joint displays were statistics-by-themes and side-by-side comparisons. Innovative joint displays connected findings to theoretical frameworks or recommendations. Researchers used joint displays for convergent, explanatory sequential, exploratory sequential, and intervention designs. We identified exemplars for each of these designs by analyzing the inferences gained through using the joint display. Exemplars represented mixed methods integration, presented integrated results, and yielded new insights. CONCLUSIONS Joint displays appear to provide a structure to discuss the integrated analysis and assist both researchers and readers in understanding how mixed methods provides new insights. We encourage researchers to use joint displays to integrate and represent mixed methods analysis and discuss their value. PMID:26553895

Atomization and Mixing Study

NASA Technical Reports Server (NTRS)

Ferrenberg, A.; Hunt, K.; Duesberg, J.

1985-01-01

The primary objective was the obtainment of atomization and mixing performance data for a variety of typical liquid oxygen/hydrocarbon injector element designs. Such data are required to establish injector design criteria and to provide critical inputs to liquid rocket engine combustor performance and stability analysis, and computational codes and methods. Deficiencies and problems with the atomization test equipment were identified, and action initiated to resolve them. Test results of the gas/liquid mixing tests indicated that an assessment of test methods was required. A series of 71 liquid/liquid tests were performed.

Preliminary Results from Duplex Procedure for Obtain of Fe Based Materials for Automotive Applications

NASA Astrophysics Data System (ADS)

Crăciun, R. C.; Stanciu, S.; Geantă, V.; Voiculescu, I.; Manole, V.; Gârneţ, I. A.; Alexandru, A.; Cimpoesu, N.; Săndulache, F.

2017-06-01

Abstract Iron based materials still represent a high percentage from metallic materials used in industry, in general, and in automotive industry, in particular. In this case we used a duplex process in order to obtain the FeMnSiAl experimental alloy for a more efficient use of various units. In the first stage iron, manganese, silicon and aluminum were melted and mixed together using arc melting technology and for the second stage the alloy was re-melt for homogeneity in an induction furnace. Chemical composition, after each melting step, was analyzed using EDS Bruker detector for various areas and microstructural characterization using SEM, VegaTescan LMH II with SE detector, equipment. This alloy is proposed as a metallic approach of mechanical dumpers used in automotive industry for low and medium impact contacts.

Is recurrence in major depressive disorder related to bipolarity and mixed features? Results from the BRIDGE-II-Mix study.

PubMed

Mazzarini, Lorenzo; Kotzalidis, Georgios D; Piacentino, Daria; Rizzato, Salvatore; Angst, Jules; Azorin, Jean-Michel; Bowden, Charles L; Mosolov, Sergey; Young, Allan H; Vieta, Eduard; Girardi, Paolo; Perugi, Giulio

2018-03-15

Current classifications separate Bipolar (BD) from Major Depressive Disorder (MDD) based on polarity rather than recurrence. We aimed to determine bipolar/mixed feature frequency in a large MDD multinational sample with (High-Rec) and without (Low-Rec) >3 recurrences, comparing the two subsamples. We measured frequency of bipolarity/hypomanic features during current depressive episodes (MDEs) in 2347 MDD patients from the BRIDGE-II-mix database, comparing High-Rec with Low-Rec. We used Bonferroni-corrected Student's t-test for continuous, and chi-squared test, for categorical variables. Logistic regression estimated the size of the association between clinical characteristics and High-Rec MDD. Compared to Low-Rec (n = 1084, 46.2%), High-Rec patients (n = 1263, 53.8%) were older, with earlier depressive onset, had more family history of BD, more atypical features, suicide attempts, hospitalisations, and treatment resistance and (hypo)manic switches when treated with antidepressants, higher comorbidity with borderline personality disorder, and more hypomanic symptoms during current MDE, resulting in higher rates of mixed depression according to both DSM-5 and research-based diagnostic (RBDC) criteria. Logistic regression showed age at first symptoms < 30 years, current MDE duration ≤ 1 month, hypomania/mania among first-degree relatives, past suicide attempts, treatment-resistance, antidepressant-induced swings, and atypical, mixed, or psychotic features during MDE to associate with High-Rec. Number of MDEs for defining recurrence was arbitrary; cross-sectionality did not allow assessment of conversion from MDD to BD. High-Rec MDD differed from Low-Rec group for several clinical/epidemiological variables, including bipolar/mixed features. Bipolarity specifier and RBDC were more sensitive than DSM-5 criteria in detecting bipolar and mixed features in MDD. Copyright © 2017. Published by Elsevier B.V.

Development of a microfluidic device for simultaneous mixing and pumping

NASA Astrophysics Data System (ADS)

Kim, Byoung Jae; Yoon, Sang Youl; Lee, Kyung Heon; Sung, Hyung Jin

2009-01-01

We conducted experimental and numerical studies aimed at developing a microfluidic device capable of simultaneous mixing while pumping. The proposed multifunctional device makes use of alternating current electroosmotic flow and adopts an array of planar asymmetric microelectrodes with a diagonal or herringbone shape. The pumping performance was assessed in terms of the fluid velocity at the center of the microchannel, obtained by micro PIV. To assess the mixing, flow visualizations were carried out over the electrodes to verify the lateral flows. The mixing degree was quantified in terms of a mixing efficiency obtained by three-dimensional numerical simulations. The results showed that simultaneous mixing and pumping was achieved in the channels with diagonal or herringbone electrode configurations. A herringbone electrode configuration showed better pumping compared with a reference, as well as enhanced mixing.

A New Method to Obtain the Black Carbon Mixing State of Biomass and Combustion Aerosols

NASA Astrophysics Data System (ADS)

Irwin, M.; Liu, D.; Joshi, R.; Allan, J. D.; Coe, H.; Flynn, M.; Olfert, J. S.; Broda, K.; Fu, P.; Sun, Y.; Ge, X.; Wang, J.

2017-12-01

Black carbon particles (BC) significantly contribute to warming effects in the atmosphere, altering weather systems, and pose significant health risks. These impacts are especially efficient at regional hotspots with high emissions of pollutants, such as in fast-developing megacities. These urban environments have the most population exposure, and improving the understanding of the sources and the processing of pollutants in these environments is critical in guiding policy making. Here we present the results of BC characterization in Beijing during the winter of 2016 (10th Nov-10th Dec), as part of a large joint UK-China field experiment. During this experiment, we successfully gathered 4 weeks of continuous measurements, including several severe pollution events in Beijing. MethodologyThe mixing state of BC, which is how BC is associated with non-BC material (its coating) within a particle, is crucial to determine its lifetime in the atmosphere and also its optical properties. However precisely quantifying the BC mixing state has posed a challenge, in part due to complex particle morphology. We have applied morphology-independent measurements of BC mixing state on a single-particle basis throughout this experiment: mono-dispersed particle mass (MP) is selected using a Centrifugal Particle Mass Analyser (CPMA, Cambustion Ltd) and a single particle soot photometer (SP2, DMT inc.) was used downstream of the CPMA to measure the refractory BC mass (MrBC). The full scan of CPMA masses (21 mass bins covering most of MP) are performed every half hour, following polydispersed particles measured without running CPMA.

A Lagrangian mixing frequency model for transported PDF modeling

NASA Astrophysics Data System (ADS)

Turkeri, Hasret; Zhao, Xinyu

2017-11-01

In this study, a Lagrangian mixing frequency model is proposed for molecular mixing models within the framework of transported probability density function (PDF) methods. The model is based on the dissipations of mixture fraction and progress variables obtained from Lagrangian particles in PDF methods. The new model is proposed as a remedy to the difficulty in choosing the optimal model constant parameters when using conventional mixing frequency models. The model is implemented in combination with the Interaction by exchange with the mean (IEM) mixing model. The performance of the new model is examined by performing simulations of Sandia Flame D and the turbulent premixed flame from the Cambridge stratified flame series. The simulations are performed using the pdfFOAM solver which is a LES/PDF solver developed entirely in OpenFOAM. A 16-species reduced mechanism is used to represent methane/air combustion, and in situ adaptive tabulation is employed to accelerate the finite-rate chemistry calculations. The results are compared with experimental measurements as well as with the results obtained using conventional mixing frequency models. Dynamic mixing frequencies are predicted using the new model without solving additional transport equations, and good agreement with experimental data is observed.

Preliminary results of lab-scale investigations of products of incomplete combustion during incineration of primary and mixed digested sludge.

PubMed

Braguglia, C M; Bagnuolo, G; Gianico, A; Mininni, G; Pastore, C; Mascolo, G

2016-03-01

Separation between primary and secondary sludge treatment could be a valuable solution for sludge management. According to this approach, secondary sludge can be conveniently used in agriculture while primary sludge could be easily dried and incinerated. It follows that some concern may arise from incinerating primary sludge with respect to the current practice to incinerate mixed digested sludge. Incineration of primary and mixed digested municipal sludge was investigated with a lab-scale equipment in terms of emissions of products of incomplete combustion (PICs) during incineration failure modes. PICs can be grouped in three sub-categories, namely aliphatic hydrocarbons (alkanes and alkenes), compounds with a single aromatic ring, and polycyclic aromatic hydrocarbons (PAHs). After-burning temperature was the most important parameter to be controlled in order to minimize emissions of alkanes and alkenes. As for mono-aromatic compounds, benzene and toluene are the most thermally resistant compounds, and in some cases, an after-burning temperature of 1100 °C was not enough to get the complete destruction of benzene leading to a residual emission of 18 mg/kgsludge. PAHs showed an opposite trend with respect to aliphatic and mono-aromatic hydrocarbons being the thermal failure mode the main responsible of PIC emissions. A proper oxygen concentration is more important than elevated temperature thus reflecting the high thermal stability of PAHs. Overall, obtained results, even though obtained under flameless conditions that are different from those of the industrial plants, demonstrated that separation of primary and secondary sludge does not pose any drawbacks or concern regarding primary sludge being disposed of by incineration even though it is more contaminated than mixed digested sludge in terms of organic pollutants.

Results of a study on polarization mix selection for the NSCAT scatterometer

NASA Technical Reports Server (NTRS)

Long, David G.; Dunbar, R. Scott; Shaffer, Scott; Freilich, Michael H.; Hsiao, S. Vincent

1989-01-01

The NASA scatterometer (NSCAT) is an instrument designed to measure the radar backscatter of the ocean's surface for estimating the near-surface wind velocity. A given resolution element is observed from several different azimuth angles. From these measurements the near-surface vector wind over the ocean may be inferred using a geophysical model function relating the normalized radar backscatter coefficient (sigma0) to the near-surface wind. The results of a study to select a polarization mix for NSCAT using an end-to-end simulation of the NSCAT scatterometer and ground processing of the sigma0 measurements into unambiguous wind fields using a median-filter-based ambiguity-removal algorithm are presented. The system simulation was used to compare the wind measurement accuracy and ambiguity removal skill over a set of realistic mesoscale wind fields for various polarization mixes. Considerations in the analysis and simulation are discussed, and a recommended polarization mix is given.

Synthesis and characterization of binary titania-silica mixed oxides

NASA Astrophysics Data System (ADS)

Budhi, Sridhar

A series of binary titania-silica mixed oxides were synthesized by the sol-gel method at room temperature. The mixed oxides were prepared that involved the hydrolysis of titanium isopropoxide and tetraethylorthosilicate (TEOS) by co-solvent induced gelation usually in acidic media. The resulting gels were dried, calcined and then characterized by powder X-ray diffractometric studies, nitrogen sorption studies (at 77K), diffuse reflectance spectroscopy, Raman microscopy and transmission electron microscopic studies. The nitrogen sorption studies indicate that the specific surface areas, pore volume, pore diameter and pore size distribution of the mixed oxides were substantially enhanced when non-polar solvents such as toluene, p-xylene or mesitylene were added as co-solvents to the synthesis gel. Transmission electron microscopic (TEM) studies confirm the results obtained from the nitrogen sorption studies. Our results indicate that we can obtain binary metal oxides possessing high surface area and large pore volumes with tunable pore size distribution at room temperature. Photocatalytic evaluation of the mixed oxides is currently in progress.

Layered Na‐Ion Cathodes with Outstanding Performance Resulting from the Synergetic Effect of Mixed P‐ and O‐Type Phases

PubMed Central

Keller, Marlou

2015-01-01

Herein, the synthesis of new quaternary layered Na‐based oxides of the type NaxMnyNizFe0.1Mg0.1O2 (0.67≤ x ≤ 1.0; 0.5≤ y ≤ 0.7; 0.1≤ z ≤ 0.3) is described. The synthesis can be tuned to obtain P2‐ and O3‐type as well as mixed P‐/O‐type phases as demonstrated by structural, morphological, and electrochemical properties characterization. Although all materials show good electrochemical performance, the simultaneous presence of the P‐ and O‐type phases is found to have a synergetic effect resulting in outstanding performance of the mixed phase material as a sodium‐ion cathode. The mixed P3/P2/O3‐type material, having an average elemental composition of Na0.76Mn0.5Ni0.3Fe0.1Mg0.1O2, overcomes the specific drawbacks associated with the P2‐ and O3‐type materials, allowing the outstanding electrochemical performance. In detail, the mixed phase material is able to deliver specific discharge capacities of up to 155 mAh g−1 (18 mA g−1) in the potential range of 2.0–4.3 V. In the narrower potential range of 2.5–4.3 V the material exhibits high average discharge potential (3.4 V versus Na/Na+), exceptional average coulombic efficiencies (>99.9%), and extraordinary capacity retention (90.2% after 601 cycles). The unexplored class of P‐/O‐type mixed phases introduces new perspectives for the development of layered positive electrode materials and powerful Na‐ion batteries. PMID:27134617

On the coalescence-dispersion modeling of turbulent molecular mixing

NASA Technical Reports Server (NTRS)

Givi, Peyman; Kosaly, George

1987-01-01

The general coalescence-dispersion (C/D) closure provides phenomenological modeling of turbulent molecular mixing. The models of Curl and Dopazo and O'Brien appear as two limiting C/D models that bracket the range of results one can obtain by various models. This finding is used to investigate the sensitivtiy of the results to the choice of the model. Inert scalar mixing is found to be less model-sensitive than mixing accompanied by chemical reaction. Infinitely fast chemistry approximation is used to relate the C/D approach to Toor's earlier results. Pure mixing and infinite rate chemistry calculations are compared to study further a recent result of Hsieh and O'Brien who found that higher concentration moments are not sensitive to chemistry.

Paramagnetic particles and mixing in micro-scale flows.

PubMed

Calhoun, R; Yadav, A; Phelan, P; Vuppu, A; Garcia, A; Hayes, M

2006-02-01

Mixing in microscale flows with rotating chains of paramagnetic particles can be enhanced by adjusting the ratio of viscous to magnetic forces so that chains dynamically break and reform. Lattice Boltzmann (LB) simulations were used to calculate the interaction between the fluid and suspended paramagnetic particles under the influence of a rotating magnetic field. Fluid velocities obtained from the LB simulations are used to solve the advection diffusion equation for massless tracer particles. At relatively high Mason numbers, small chains result in low edge velocities, and hence mixing is slower than at other Mason numbers. At low Mason numbers, long, stable chains form and produce little mixing toward the center of the chains. A peak in mixing rate is observed when chains break and reform. The uniformity of mixing is greater at higher Mason numbers because more small chains result in a larger number of small mixing areas.

Transport and Mixing Induced by Beating Cilia in Human Airways

PubMed Central

Chateau, Sylvain; D'Ortona, Umberto; Poncet, Sébastien; Favier, Julien

2018-01-01

The fluid transport and mixing induced by beating cilia, present in the bronchial airways, are studied using a coupled lattice Boltzmann—Immersed Boundary solver. This solver allows the simulation of both single and multi-component fluid flows around moving solid boundaries. The cilia are modeled by a set of Lagrangian points, and Immersed Boundary forces are computed onto these points in order to ensure the no-slip velocity conditions between the cilia and the fluids. The cilia are immersed in a two-layer environment: the periciliary layer (PCL) and the mucus above it. The motion of the cilia is prescribed, as well as the phase lag between two cilia in order to obtain a typical collective motion of cilia, known as metachronal waves. The results obtained from a parametric study show that antiplectic metachronal waves are the most efficient regarding the fluid transport. A specific value of phase lag, which generates the larger mucus transport, is identified. The mixing is studied using several populations of tracers initially seeded into the pericilary liquid, in the mucus just above the PCL-mucus interface, and in the mucus far away from the interface. We observe that each zone exhibits different chaotic mixing properties. The larger mixing is obtained in the PCL layer where only a few beating cycles of the cilia are required to obtain a full mixing, while above the interface, the mixing is weaker and takes more time. Almost no mixing is observed within the mucus, and almost all the tracers do not penetrate the PCL layer. Lyapunov exponents are also computed for specific locations to assess how the mixing is performed locally. Two time scales are introduced to allow a comparison between mixing induced by fluid advection and by molecular diffusion. These results are relevant in the context of respiratory flows to investigate the transport of drugs for patients suffering from chronic respiratory diseases. PMID:29559920

Transport and Mixing Induced by Beating Cilia in Human Airways.

PubMed

Chateau, Sylvain; D'Ortona, Umberto; Poncet, Sébastien; Favier, Julien

2018-01-01

The fluid transport and mixing induced by beating cilia, present in the bronchial airways, are studied using a coupled lattice Boltzmann-Immersed Boundary solver. This solver allows the simulation of both single and multi-component fluid flows around moving solid boundaries. The cilia are modeled by a set of Lagrangian points, and Immersed Boundary forces are computed onto these points in order to ensure the no-slip velocity conditions between the cilia and the fluids. The cilia are immersed in a two-layer environment: the periciliary layer (PCL) and the mucus above it. The motion of the cilia is prescribed, as well as the phase lag between two cilia in order to obtain a typical collective motion of cilia, known as metachronal waves. The results obtained from a parametric study show that antiplectic metachronal waves are the most efficient regarding the fluid transport. A specific value of phase lag, which generates the larger mucus transport, is identified. The mixing is studied using several populations of tracers initially seeded into the pericilary liquid, in the mucus just above the PCL-mucus interface, and in the mucus far away from the interface. We observe that each zone exhibits different chaotic mixing properties. The larger mixing is obtained in the PCL layer where only a few beating cycles of the cilia are required to obtain a full mixing, while above the interface, the mixing is weaker and takes more time. Almost no mixing is observed within the mucus, and almost all the tracers do not penetrate the PCL layer. Lyapunov exponents are also computed for specific locations to assess how the mixing is performed locally. Two time scales are introduced to allow a comparison between mixing induced by fluid advection and by molecular diffusion. These results are relevant in the context of respiratory flows to investigate the transport of drugs for patients suffering from chronic respiratory diseases.

Retrieval of constituent mixing ratios from limb thermal emission spectra

NASA Technical Reports Server (NTRS)

Shaffer, William A.; Kunde, Virgil G.; Conrath, Barney J.

1988-01-01

An onion-peeling iterative, least-squares relaxation method to retrieve mixing ratio profiles from limb thermal emission spectra is presented. The method has been tested on synthetic data, containing various amounts of added random noise for O3, HNO3, and N2O. The retrieval method is used to obtain O3 and HNO3 mixing ratio profiles from high-resolution thermal emission spectra. Results of the retrievals compare favorably with those obtained previously.

Mixing Silicate Melts with High Viscosity Contrast by Chaotic Dynamics: Results from a New Experimental Device

NASA Astrophysics Data System (ADS)

de Campos, Cristina; Perugini, Diego; Ertel-Ingrisch, Werner; Dingwell, Donald B.; Poli, Giampiero

2010-05-01

A new experimental device has been developed to perform chaotic mixing between high viscosity melts under controlled fluid-dynamic conditions. The apparatus is based on the Journal Bearing System (JBS). It consists of an outer cylinder hosting the melts of interest and an inner cylinder, which is eccentrically located. Both cylinders can be independently moved to generate chaotic streamlines in the mixing system. Two experiments were performed using as end-members different proportions of a peralkaline haplogranite and a mafic melt, corresponding to the 1 atm eutectic composition in the An-Di binary system. The two melts were stirred together in the JBS for ca. two hours, at 1,400° C and under laminar fluid dynamic condition (Re of the order of 10-7). The viscosity ratio between the two melts, at the beginning of the experiment, was of the order of 103. Optical analyses of experimental samples revealed, at short length scale (of the order of μm), a complex pattern of mixed structures. These consisted of an intimate distribution of filaments; a complex inter-fingering of the two melts. Such features are typically observed in rocks thought to be produced by magma mixing processes. Stretching and folding dynamics between the melts induced chaotic flow fields and generated wide compositional interfaces. In this way, chemical diffusion processes become more efficient, producing melts with highly heterogeneous compositions. A remarkable modulation of compositional fields has been obtained by performing short time-scale experiments and using melts with a high viscosity ratio. This indicates that chaotic mixing of magmas can be a very efficient process in modulating compositional variability in igneous systems, especially under high viscosity ratios and laminar fluid-dynamic regimes. Our experimental device may replicate magma mixing features, observed in natural rocks, and therefore open new frontiers in the study of this important petrologic and volcanological process.

Mixing times in quantum walks on two-dimensional grids

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

Marquezino, F. L.; Portugal, R.; Abal, G.

2010-10-15

Mixing properties of discrete-time quantum walks on two-dimensional grids with toruslike boundary conditions are analyzed, focusing on their connection to the complexity of the corresponding abstract search algorithm. In particular, an exact expression for the stationary distribution of the coherent walk over odd-sided lattices is obtained after solving the eigenproblem for the evolution operator for this particular graph. The limiting distribution and mixing time of a quantum walk with a coin operator modified as in the abstract search algorithm are obtained numerically. On the basis of these results, the relation between the mixing time of the modified walk and themore » running time of the corresponding abstract search algorithm is discussed.« less

Mixing times in quantum walks on two-dimensional grids

NASA Astrophysics Data System (ADS)

Marquezino, F. L.; Portugal, R.; Abal, G.

2010-10-01

Mixing properties of discrete-time quantum walks on two-dimensional grids with toruslike boundary conditions are analyzed, focusing on their connection to the complexity of the corresponding abstract search algorithm. In particular, an exact expression for the stationary distribution of the coherent walk over odd-sided lattices is obtained after solving the eigenproblem for the evolution operator for this particular graph. The limiting distribution and mixing time of a quantum walk with a coin operator modified as in the abstract search algorithm are obtained numerically. On the basis of these results, the relation between the mixing time of the modified walk and the running time of the corresponding abstract search algorithm is discussed.

Integrating Quantitative and Qualitative Results in Health Science Mixed Methods Research Through Joint Displays.

PubMed

Guetterman, Timothy C; Fetters, Michael D; Creswell, John W

2015-11-01

Mixed methods research is becoming an important methodology to investigate complex health-related topics, yet the meaningful integration of qualitative and quantitative data remains elusive and needs further development. A promising innovation to facilitate integration is the use of visual joint displays that bring data together visually to draw out new insights. The purpose of this study was to identify exemplar joint displays by analyzing the various types of joint displays being used in published articles. We searched for empirical articles that included joint displays in 3 journals that publish state-of-the-art mixed methods research. We analyzed each of 19 identified joint displays to extract the type of display, mixed methods design, purpose, rationale, qualitative and quantitative data sources, integration approaches, and analytic strategies. Our analysis focused on what each display communicated and its representation of mixed methods analysis. The most prevalent types of joint displays were statistics-by-themes and side-by-side comparisons. Innovative joint displays connected findings to theoretical frameworks or recommendations. Researchers used joint displays for convergent, explanatory sequential, exploratory sequential, and intervention designs. We identified exemplars for each of these designs by analyzing the inferences gained through using the joint display. Exemplars represented mixed methods integration, presented integrated results, and yielded new insights. Joint displays appear to provide a structure to discuss the integrated analysis and assist both researchers and readers in understanding how mixed methods provides new insights. We encourage researchers to use joint displays to integrate and represent mixed methods analysis and discuss their value. © 2015 Annals of Family Medicine, Inc.

Coolant mixing in LMFBR rod bundles and outlet plenum mixing transients. Final report

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

Todreas, N.E.; Cheng, S.K.; Basehore, K.

1984-08-01

This project principally undertook the investigation of the thermal hydraulic performance of wire wrapped fuel bundles of LMFBR configuration. Results obtained included phenomenological models for friction factors, flow split and mixing characteristics; correlations for predicting these characteristics suitable for insertion in design codes; numerical codes for analyzing bundle behavior both of the lumped subchannel and distributed parameter categories and experimental techniques for pressure velocity, flow split, salt conductivity and temperature measurement in water cooled mockups of bundles and subchannels. Flow regimes investigated included laminar, transition and turbulent flow under forced convection and mixed convection conditions. Forced convections conditions were emphasized.more » Continuing efforts are underway at MIT to complete the investigation of the mixed convection regime initiated here. A number of investigations on outlet plenum behavior were also made. The reports of these investigations are identified.« less

Mixed-Strategy Chance Constrained Optimal Control

NASA Technical Reports Server (NTRS)

Ono, Masahiro; Kuwata, Yoshiaki; Balaram, J.

2013-01-01

This paper presents a novel chance constrained optimal control (CCOC) algorithm that chooses a control action probabilistically. A CCOC problem is to find a control input that minimizes the expected cost while guaranteeing that the probability of violating a set of constraints is below a user-specified threshold. We show that a probabilistic control approach, which we refer to as a mixed control strategy, enables us to obtain a cost that is better than what deterministic control strategies can achieve when the CCOC problem is nonconvex. The resulting mixed-strategy CCOC problem turns out to be a convexification of the original nonconvex CCOC problem. Furthermore, we also show that a mixed control strategy only needs to "mix" up to two deterministic control actions in order to achieve optimality. Building upon an iterative dual optimization, the proposed algorithm quickly converges to the optimal mixed control strategy with a user-specified tolerance.

Chemical compatibility screening results of plastic packaging to mixed waste simulants

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

Nigrey, P.J.; Dickens, T.G.

1995-12-01

We have developed a chemical compatibility program for evaluating transportation packaging components for transporting mixed waste forms. We have performed the first phase of this experimental program to determine the effects of simulant mixed wastes on packaging materials. This effort involved the screening of 10 plastic materials in four liquid mixed waste simulants. The testing protocol involved exposing the respective materials to {approximately}3 kGy of gamma radiation followed by 14 day exposures to the waste simulants of 60 C. The seal materials or rubbers were tested using VTR (vapor transport rate) measurements while the liner materials were tested using specificmore » gravity as a metric. For these tests, a screening criteria of {approximately}1 g/m{sup 2}/hr for VTR and a specific gravity change of 10% was used. It was concluded that while all seal materials passed exposure to the aqueous simulant mixed waste, EPDM and SBR had the lowest VTRs. In the chlorinated hydrocarbon simulant mixed waste, only VITON passed the screening tests. In both the simulant scintillation fluid mixed waste and the ketone mixture simulant mixed waste, none of the seal materials met the screening criteria. It is anticipated that those materials with the lowest VTRs will be evaluated in the comprehensive phase of the program. For specific gravity testing of liner materials the data showed that while all materials with the exception of polypropylene passed the screening criteria, Kel-F, HDPE, and XLPE were found to offer the greatest resistance to the combination of radiation and chemicals.« less

Diffusive mixing through velocity profile variation in microchannels

NASA Astrophysics Data System (ADS)

Yakhshi-Tafti, Ehsan; Cho, Hyoung J.; Kumar, Ranganathan

2011-03-01

Rapid mixing does not readily occur at low Reynolds number flows encountered in microdevices; however, it can be enhanced by passive diffusive mixing schemes. This study of micromixing of two miscible fluids is based on the principle that (1) increased velocity at the interface of co-flowing fluids results in increased diffusive mass flux across their interface, and (2) diffusion interfaces between two liquids progress transversely as the flow proceeds downstream. A passive micromixer is proposed that takes advantage of the peak velocity variation, inducing diffusive mixing. The effect of flow variation on the enhancement of diffusive mixing is investigated analytically and experimentally. Variation of the flow profile is confirmed using micro-Particle Image Velocimetry (μPIV) and mixing is evaluated by color variations resulting from the mixing of pH indicator and basic solutions. Velocity profile variations obtained from μPIV show a shift in peak velocities. The mixing efficiency of the Σ-micromixer is expected to be higher than that for a T-junction channel and can be as high as 80%. The mixing efficiency decreases with Reynolds number and increases with downstream length, exhibiting a power law.

Estimation of proportions in mixed pixels through their region characterization

NASA Technical Reports Server (NTRS)

Chittineni, C. B. (Principal Investigator)

1981-01-01

A region of mixed pixels can be characterized through the probability density function of proportions of classes in the pixels. Using information from the spectral vectors of a given set of pixels from the mixed pixel region, expressions are developed for obtaining the maximum likelihood estimates of the parameters of probability density functions of proportions. The proportions of classes in the mixed pixels can then be estimated. If the mixed pixels contain objects of two classes, the computation can be reduced by transforming the spectral vectors using a transformation matrix that simultaneously diagonalizes the covariance matrices of the two classes. If the proportions of the classes of a set of mixed pixels from the region are given, then expressions are developed for obtaining the estmates of the parameters of the probability density function of the proportions of mixed pixels. Development of these expressions is based on the criterion of the minimum sum of squares of errors. Experimental results from the processing of remotely sensed agricultural multispectral imagery data are presented.

Effects of vigorous mixing of blood vacuum tubes on laboratory test results.

PubMed

Lima-Oliveira, Gabriel; Lippi, Giuseppe; Salvagno, Gian Luca; Montagnana, Martina; Gelati, Matteo; Volanski, Waldemar; Boritiza, Katia Cristina; Picheth, Geraldo; Guidi, Gian Cesare

2013-02-01

To evaluate the effect of tubes mixing (gentle vs. vigorous) on diagnostic blood specimens collected in vacuum tube systems by venipuncture. Blood was collected for routine coagulation, immunochemistry and hematological testing from one hundred volunteers into six vacuum tubes: two 3.6 mL vacuum tubes containing 0.4 mL of buffered sodium citrate (9NC) 0.109 mol/L: 3.2 W/V%; two 3.5 mL vacuum tubes with clot activator and gel separator; and two 3.0 mL vacuum tubes containing 5.9 mg K(2)EDTA (Terumo Europe, Belgium). Immediately after the venipuncture all vacuum tubes (each of one additive type) were processed through two different procedures: i) Standard: blood specimens in K(2)EDTA- or sodium citrate-vacuum tubes were gently inverted five times whereas the specimens in tubes with clot activator and gel separator were gently inverted ten times, as recommended by the manufacturer; ii) Vigorous mix: all blood specimens were shaken up vigorously during 3-5s independently of the additive type inside the tubes. The significance of the differences between samples was assessed by Student's t-test or Wilcoxon ranked-pairs test after checking for normality. The level of statistical significance was set at P<0.05. No significant difference (P<0.05) was detected between the procedures for all tested parameters. Surprisingly only a visual alteration (presence of foam on the top) was shown by all the tubes mixed vigorously before centrifugation (Fig. 1 A, B and C). Moreover the serum tubes from vigorous mixing procedure shows a "blood ring" on the tube top after stopper removal (Fig. 1 D). Our results drop out a paradigm suggesting that the incorrect primary blood tubes mixing promotes laboratory variability. We suggest that similar evaluation should be done using other brands of vacuum tubes by each laboratory manager. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Patch testing with fragrance mix II: results of the IVDK 2005-2008.

PubMed

Krautheim, Andrea; Uter, Wolfgang; Frosch, Peter; Schnuch, Axel; Geier, Johannes

2010-11-01

The fragrance mix (FM I), established in 1977, detects the majority, but not all cases of contact allergy to fragrances. Based on European research 2002/2003, fragrance mix II (FM II) was developed to supplement FM I. In 2005, the German Contact Dermatitis Research Group (DKG) added FM II to their baseline series. To evaluate reactions to FM II and its constituents in routine patch testing. Retrospective data analysis of the Information Network of Departments of Dermatology (IVDK), 2005-2008, of patch test results with FM II and its constituents. A total of 35 633 patients were patch tested with FM II as part of the DKG baseline series. Of these, 1742 (4.9%) reacted positively. Concomitant reactions to FM I were observed in 41.9% of the patients reacting to FM II. In 367 FM II-positive patients, a full breakdown test of the mix was performed. Of these, 47.7% reacted to hydroxyisohexyl 3-cyclohexene carboxaldehyde, 16.1% to citral, 11.4% to farnesol, 3.8% to hexyl cinnamal, 2.7% to coumarin, and 2.5% to citronellol. FM II is an important screening and diagnostic tool to detect fragrance allergy. Hydroxyisohexyl 3-cyclohexene carboxaldehyde is the most important fragrance allergen in FM II. © 2010 John Wiley & Sons A/S.

A New Expanded Mixed Element Method for Convection-Dominated Sobolev Equation

PubMed Central

Wang, Jinfeng; Li, Hong; Fang, Zhichao

2014-01-01

We propose and analyze a new expanded mixed element method, whose gradient belongs to the simple square integrable space instead of the classical H(div; Ω) space of Chen's expanded mixed element method. We study the new expanded mixed element method for convection-dominated Sobolev equation, prove the existence and uniqueness for finite element solution, and introduce a new expanded mixed projection. We derive the optimal a priori error estimates in L 2-norm for the scalar unknown u and a priori error estimates in (L 2)2-norm for its gradient λ and its flux σ. Moreover, we obtain the optimal a priori error estimates in H 1-norm for the scalar unknown u. Finally, we obtained some numerical results to illustrate efficiency of the new method. PMID:24701153

Mutagenic substances in pyrolysate obtained by burning polyvinylchloride-product at 1000 degrees C.

PubMed

Yonezawa, Y; Saigusa, S; Takahagi, M; Nishioka, H

1999-06-25

In order to detect possible mutagenic substances in pyrolysate obtained by burning polyvinyl chloride product (PVC-P) at approximately 1000 degrees C, mutagenicity of rough extracts obtained by extraction with various solvents for the products was investigated by means of reversion mutation assay using Salmonella typhimurium TA98 and TA100 with or without microsomal metabolic activation (S9 mix). Strong mutagenicity in TA98 without S9 mix was observed in acetone-extract of PVC-P. The extract was fractionated into acidic, neutral and basic by liquid-liquid distribution and the mutagenicity in TA98 without S9 mix was found in the neutral fraction. Identification of mutagenic substances in the neutral fraction from acetone extract, which showed the strongest mutagenicity, was attempted by means of thin layer chromatography and capillary gas chromatography. The results suggest that mutagenic substances from pyrolysate of PVC-P are benzanthrone and an isomer of benzo(c)cinnoline. The results also suggest that burning wastes containing plastic products is not always safe even if at 1000 degrees C and further research on the problem is necessary. Copyright 1999 Elsevier Science B.V.

Mixed Material Plasma-Surface Interactions in ITER: Recent Results from the PISCES Group

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

Tynan, George R.; Baldwin, Matthew; Doerner, Russell

This paper summarizes recent PISCES studies focused on the effects associated with mixed species plasmas that are similar in composition to what one might expect in ITER. Formation of nanometer scale whiskerlike features occurs in W surfaces exposed to pure He and mixed D/He plasmas and appears to be associated with the formation of He nanometer-scaled bubbles in the W surface. Studies of Be-W alloy formation in Be-seeded D plasmas suggest that this process may be important in ITER all metal wall operational scenarios. Studies also suggest that BeD formation via chemical sputtering of Be walls may be an importantmore » first wall erosion mechanism. D retention in ITER mixed materials has also been studied. The D release behavior from beryllium co-deposits does not appear to be a diffusion dominated process, but instead is consistent with thermal release from a number of variable trapping energy sites. As a result, the amount of tritium remaining in codeposits in ITER after baking will be determined by the maximum temperature achieved, rather than by the duration of the baking cycle.« less

Endoscopic Histologic Mapping of a Mixed Germ Pineal Tumor.

PubMed

Velásquez, Carlos; Rivero-Garvía, Mónica; Rivas, Eloy; Cañizares, María de Los Angeles; Mayorga-Buiza, María José; Márquez-Rivas, Javier

2016-11-01

The accurate histologic diagnosis of germ cell tumors in the pineal region is a keystone for determining the best treatment strategy and prognosis. This situation poses a challenge for the neuropathologist, considering the lack of a standarized procedure to obtain biopsy samples, which results in few and small specimens, which are not suitable for diagnosis. We report a case in which a pineal region mixed germ cell tumor was accurately diagnosed by performing histologic mapping through a dual burr-hole endoscopic approach. The technical pitfalls and other considerations necessary for obtaining an accurate diagnosis in this tumor subgroup are specified. In addition, the histologic analysis regarding the sampling technique used is described. The supraorbital frontal endoscopic approach enables the surgeon to perform histologic mapping of pineal region tumors, allowing standarization of the procedure used to obtain the specimens. This approach could result in a more accurate diagnosis, especially in mixed germ cell neoplasms. Copyright © 2016 Elsevier Inc. All rights reserved.

High-resolution diapycnal mixing map of the Alboran Sea thermocline from seismic reflection images

NASA Astrophysics Data System (ADS)

Mojica, Jhon F.; Sallarès, Valentí; Biescas, Berta

2018-06-01

The Alboran Sea is a dynamically active region where the salty and warm Mediterranean water first encounters the incoming milder and cooler Atlantic water. The interaction between these two water masses originates a set of sub-mesoscale structures and a complex sequence of processes that entail mixing close to the thermocline. Here we present a high-resolution map of the diapycnal diffusivity around the thermocline depth obtained using acoustic data recorded with a high-resolution multichannel seismic system. The map reveals a patchy thermocline, with spots of strong diapycnal mixing juxtaposed with areas of weaker mixing. The patch size is of a few kilometers in the horizontal scale and of 10-15 m in the vertical one. The comparison of the obtained maps with the original acoustic images shows that mixing tends to concentrate in areas where internal waves, which are ubiquitous in the surveyed area, become unstable and shear instabilities develop, enhancing energy transfer towards the turbulent regime. These results are also compared with others obtained using more conventional oceanographic probes. The values estimated based on the seismic data are within the ranges of values obtained from oceanographic data analysis, and they are also consistent with reference theoretical values. Overall, our results demonstrate that high-resolution seismic systems allow the remote quantification of mixing at the thermocline depth with unprecedented resolution.

The next step toward end-result specifications for hot-mix asphalt materials and construction.

DOT National Transportation Integrated Search

2007-01-01

In 2000, the Virginia Department of Transportation's (VDOT) Chief Engineer asked the Virginia Transportation Research Council to develop a vision of how and when VDOT would have a working end-result specification for hot-mix asphalt. The response to ...

Search for the sterile neutrino mixing with the ICAL detector at INO

NASA Astrophysics Data System (ADS)

Behera, S. P.; Ghosh, Anushree; Choubey, Sandhya; Datar, V. M.; Mishra, D. K.; Mohanty, A. K.

2017-05-01

The study has been carried out on the prospects of probing the sterile neutrino mixing with the magnetized iron calorimeter (ICAL) at the India-based Neutrino Observatory (INO), using atmospheric neutrinos as a source. The so-called 3 + 1 scenario is considered for active-sterile neutrino mixing and lead to projected exclusion curves in the sterile neutrino mass and mixing angle plane. The analysis is performed using the neutrino event generator NUANCE, modified for ICAL, and folded with the detector resolutions obtained by the INO collaboration from a full GEANT4-based detector simulation. A comparison has been made between the results obtained from the analysis considering only the energy and zenith angle of the muon and combined with the hadron energy due to the neutrino induced event. A small improvement has been observed with the addition of the hadron information to the muon. In the analysis we consider neutrinos coming from all zenith angles and the Earth matter effects are also included. The inclusion of events from all zenith angles improves the sensitivity to sterile neutrino mixing by about 35% over the result obtained using only down-going events. The improvement mainly stems from the impact of Earth matter effects on active-sterile mixing. The expected precision of ICAL on the active-sterile mixing is explored and the allowed confidence level (C.L.) contours presented. At the assumed true value of 10° for the sterile mixing angles and marginalization over Δ m^2_{41} and the sterile mixing angles, the upper bound at 90% C.L. (from two-parameter plots) is around 20^deg; for θ _{14} and θ _{34}, and about 12°c for θ _{24}.

Degradation of polycyclic aromatic hydrocarbons (PAHs) by a mixed culture and its component pure cultures, obtained from PAH-contaminated soil.

PubMed

Trzesicka-Mlynarz, D; Ward, O P

1995-06-01

A mixed culture, isolated from soil contaminated with polycyclic aromatic hydrocarbons (PAHs), grew on and degraded fluoranthene in aqueous media supplemented with glucose, yeast extract, and peptone. Increased complex nitrogen levels in the medium promoted bacterial growth and a greater extent of fluoranthene degradation. Amendment of the media with high glucose levels also diminished specific fluoranthene degradation. The mixed culture was capable of degrading a range of other PAHs, including benzo[a]pyrene, anthracene, phenanthrene, acenaphthene, and fluorene. The mixed culture contained four predominant isolates, all of which were Gram-negative rods, three of which were identified as Pseudomonas putida, Flavobacterium sp., and Pseudomonas aeruginosa. Better degradation of a defined PAH mixture was observed with the mixed culture than with individual isolates. A reconstituted culture, prepared by combining the four individual isolates, manifested a similar PAH biodegradation performance to the original mixed culture. When compared with the mixed culture, individual isolates exhibited a relatively good capacity to remove more water-soluble PAHs (acenaphthene, fluorene, phenanthrene, fluoranthene). In contrast, removal of less water-soluble PAHs (anthracene and pyrene) was low or negligible with isolated cultures compared with the mixed culture.

Marked heterogeneity in growth characteristics of myoblast clonal cultures and myoblast mixed cultures obtained from the same individual.

PubMed

Maier, Andrea B; Cohen, Ron; Blom, Joke; van Heemst, Diana; Westendorp, Rudi G J

2012-01-01

Sarcopenia is defined as an age-related decrease in skeletal muscle mass and function while adjacent satellite cells are unable to compensate for this loss. However, myoblast cultures can be established even in the presence of sarcopenia. It is yet unknown whether satellite cells from failing muscle in older age are equally affected, as human satellite cells have been assessed using myoblast mixed cultures and not by using myoblast clonal cultures. We questioned to what extent myoblast mixed cultures reflect the in vivo characteristics of single satellite cells from adult skeletal muscle. We established a myoblast mixed culture and three myoblast clonal cultures out of the same muscle biopsy and cultured these cells for 100 days. Replicative capacity and oxidative stress resistance were compared. We found marked heterogeneity between the myoblast clonal cultures that all had a significantly lower replicative capacity when compared to the mixed culture. Replicative capacity of the clonal cultures was inversely related to the β-galactosidase activity after exposure to oxidative stress. Addition of L-carnosine enhanced the remaining replicative capacity in all cultures with a concomitant marginal decrease in β-galactosidase activity. It is concluded that myoblast mixed cultures in vitro do not reflect the marked heterogeneity between single isolated satellite cells. The consequences of the heterogeneity on muscle performance remain to be established. Copyright © 2011 S. Karger AG, Basel.

Mixing and overshooting in surface convection zones of DA white dwarfs: first results from ANTARES

NASA Astrophysics Data System (ADS)

Kupka, F.; Zaussinger, F.; Montgomery, M. H.

2018-03-01

We present results of a large, high-resolution 3D hydrodynamical simulation of the surface layers of a DA white dwarf (WD) with Teff = 11 800 K and log (g) = 8 using the ANTARES code, the widest and deepest such simulation to date. Our simulations are in good agreement with previous calculations in the Schwarzschild-unstable region and in the overshooting region immediately beneath it. Farther below, in the wave-dominated region, we find that the rms horizontal velocities decay with depth more rapidly than the vertical ones. Since mixing requires both vertical and horizontal displacements, this could have consequences for the size of the region that is well mixed by convection, if this trend is found to hold for deeper layers. We discuss how the size of the mixed region affects the calculated settling times and inferred steady-state accretion rates for WDs with metals observed in their atmospheres.

Mixing Efficiency in the Ocean.

PubMed

Gregg, M C; D'Asaro, E A; Riley, J J; Kunze, E

2018-01-03

Mixing efficiency is the ratio of the net change in potential energy to the energy expended in producing the mixing. Parameterizations of efficiency and of related mixing coefficients are needed to estimate diapycnal diffusivity from measurements of the turbulent dissipation rate. Comparing diffusivities from microstructure profiling with those inferred from the thickening rate of four simultaneous tracer releases has verified, within observational accuracy, 0.2 as the mixing coefficient over a 30-fold range of diapycnal diffusivities. Although some mixing coefficients can be estimated from pycnocline measurements, at present mixing efficiency must be obtained from channel flows, laboratory experiments, and numerical simulations. Reviewing the different approaches demonstrates that estimates and parameterizations for mixing efficiency and coefficients are not converging beyond the at-sea comparisons with tracer releases, leading to recommendations for a community approach to address this important issue.

Mixing Efficiency in the Ocean

NASA Astrophysics Data System (ADS)

Gregg, M. C.; D'Asaro, E. A.; Riley, J. J.; Kunze, E.

2018-01-01

Mixing efficiency is the ratio of the net change in potential energy to the energy expended in producing the mixing. Parameterizations of efficiency and of related mixing coefficients are needed to estimate diapycnal diffusivity from measurements of the turbulent dissipation rate. Comparing diffusivities from microstructure profiling with those inferred from the thickening rate of four simultaneous tracer releases has verified, within observational accuracy, 0.2 as the mixing coefficient over a 30-fold range of diapycnal diffusivities. Although some mixing coefficients can be estimated from pycnocline measurements, at present mixing efficiency must be obtained from channel flows, laboratory experiments, and numerical simulations. Reviewing the different approaches demonstrates that estimates and parameterizations for mixing efficiency and coefficients are not converging beyond the at-sea comparisons with tracer releases, leading to recommendations for a community approach to address this important issue.

Groverian measure of entanglement for mixed states

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

Shapira, Daniel; Shimoni, Yishai; Biham, Ofer

2006-04-15

The Groverian entanglement measure, introduced earlier for pure quantum states of multiple qubits [O. Biham, M.A. Nielsen, and T. Osborne, Phys. Rev. A 65, 062312 (2002)], is generalized to the case of mixed states. The Groverian measure of a mixed state of n qubits is obtained by a purification procedure into a pure state of 2n qubits, followed by an optimization process, before the resulting state is fed into Grover's search algorithm. It is expressed in terms of the maximal success probability of the algorithm and in this sense provides an operational measure of entanglement.

Toward topology-based characterization of small-scale mixing in compressible turbulence

NASA Astrophysics Data System (ADS)

Suman, Sawan; Girimaji, Sharath

2011-11-01

Turbulent mixing rate at small scales of motion (molecular mixing) is governed by the steepness of the scalar-gradient field which in turn is dependent upon the prevailing velocity gradients. Thus motivated, we propose a velocity-gradient topology-based approach for characterizing small-scale mixing in compressible turbulence. We define a mixing efficiency metric that is dependent upon the topology of the solenoidal and dilatational deformation rates of a fluid element. The mixing characteristics of solenoidal and dilatational velocity fluctuations are clearly delineated. We validate this new approach by employing mixing data from direct numerical simulations (DNS) of compressible decaying turbulence with passive scalar. For each velocity-gradient topology, we compare the mixing efficiency predicted by the topology-based model with the corresponding conditional scalar variance obtained from DNS. The new mixing metric accurately distinguishes good and poor mixing topologies and indeed reasonably captures the numerical values. The results clearly demonstrate the viability of the proposed approach for characterizing and predicting mixing in compressible flows.

Solar neutrino masses and mixing from bilinear R-parity broken supersymmetry: Analytical versus numerical results

NASA Astrophysics Data System (ADS)

Díaz, M.; Hirsch, M.; Porod, W.; Romão, J.; Valle, J.

2003-07-01

We give an analytical calculation of solar neutrino masses and mixing at one-loop order within bilinear R-parity breaking supersymmetry, and compare our results to the exact numerical calculation. Our method is based on a systematic perturbative expansion of R-parity violating vertices to leading order. We find in general quite good agreement between the approximate and full numerical calculations, but the approximate expressions are much simpler to implement. Our formalism works especially well for the case of the large mixing angle Mikheyev-Smirnov-Wolfenstein solution, now strongly favored by the recent KamLAND reactor neutrino data.

Numerical analysis of mixing enhancement for micro-electroosmotic flow

NASA Astrophysics Data System (ADS)

Tang, G. H.; He, Y. L.; Tao, W. Q.

2010-05-01

Micro-electroosmotic flow is usually slow with negligible inertial effects and diffusion-based mixing can be problematic. To gain an improved understanding of electroosmotic mixing in microchannels, a numerical study has been carried out for channels patterned with wall blocks, and channels patterned with heterogeneous surfaces. The lattice Boltzmann method has been employed to obtain the external electric field, electric potential distribution in the electrolyte, the flow field, and the species concentration distribution within the same framework. The simulation results show that wall blocks and heterogeneous surfaces can significantly disturb the streamlines by fluid folding and stretching leading to apparently substantial improvements in mixing. However, the results show that the introduction of such features can substantially reduce the mass flow rate and thus effectively prolongs the available mixing time when the flow passes through the channel. This is a non-negligible factor on the effectiveness of the observed improvements in mixing efficiency. Compared with the heterogeneous surface distribution, the wall block cases can achieve more effective enhancement in the same mixing time. In addition, the field synergy theory is extended to analyze the mixing enhancement in electroosmotic flow. The distribution of the local synergy angle in the channel aids to evaluate the effectiveness of enhancement method.

Computational analysis of electrokinetically driven flow mixing in microchannels with patterned blocks

NASA Astrophysics Data System (ADS)

Chang, C.-C.; Yang, R.-J.

2004-04-01

Electroosmotic flow in microchannels is restricted to low Reynolds number regimes characterized by extremely weak inertia forces and laminar flow. Consequently, the mixing of different species occurs primarily through diffusion, and hence cannot readily be achieved within a short mixing channel. The current study presents a numerical investigation of electrokinetically driven flow mixing in microchannels with various numbers of incorporated patterned rectangular blocks. Furthermore, a novel approach is introduced which patterns heterogeneous surfaces on the upper faces of these rectangular blocks in order to enhance species mixing. The simulation results confirm that the introduction of rectangular blocks within the mixing channel slightly enhances species mixing by constricting the bulk flow, hence creating a stronger diffusion effect. However, it is noted that a large number of blocks and hence a long mixing channel are required if a complete mixing of the species is to be obtained. The results also indicate that patterning heterogeneous upper surfaces on the rectangular blocks is an effective means of enhancing the species mixing. It is shown that increasing the magnitude of the heterogeneous surface zeta potential enables a reduction in the mixing channel length and an improved degree of mixing efficiency.

Microfluidic mixing using orbiting magnetic microbeads

NASA Astrophysics Data System (ADS)

Ballard, Matthew; Owen, Drew; Mao, Wenbin; Hesketh, Peter; Alexeev, Alexander

2013-11-01

Using three-dimensional simulations and experiments, we examine mixing in a microfluidic channel that incorporates a hybrid passive-active micromixer. The passive part of the mixer consists of a series of angled parallel ridges lining the top microchannel wall. The active component of the mixer is made up of microbeads rotating around small pillars on the bottom of the microchannel. In our simulations, we use a binary fluid lattice Boltzmann model to simulate the system and characterize the microfluidic mixing in the system. We consider the passive and active micromixers separately and evaluate their combined effect on the mixing of binary fluids. We compare our simulations with the experimental results obtained in a microchannel with magnetically actuated microbeads. Our findings guide the design of an efficient micromixer to be used in sampling in complex fluids. Financial support from NSF (CBET-1159726) is gratefully acknowledged.

Mixing order of glidant and lubricant – Influence on powder and tablet properties

PubMed Central

Pingali, Kalyana; Mendez, Rafael; Lewis, Daniel; Michniak-Kohn, Bozena; Cuitino, Alberto; Muzzio, Fernando

2014-01-01

The main objective of the present work was to study the effect of mixing order of Cab-O-Sil (CS) and magnesium stearate (MgSt) and microlayers during mixing on blend and tablet properties. A first set of pharmaceutical blend containing Avicel PH200, Pharmatose and micronized acetaminophen was prepared with three mixing orders (mixing order-1: CS added first; mixing order-2: MgSt added first; mixing order-3: CS and MgSt added together). All the blends were subjected to a shear rate of 80 rpm and strain of 40, 160 and 640 revolutions in a controlled shear environment resulting in nine different blends. A second set of nine blends was prepared by replacing Avicel PH200 with Avicel PH102. A total of eighteen blends thus prepared were tested for powder hydrophobicity, powder flow, tablet weight, tablet hardness and tablet dissolution. Results indicated that powder hydrophobicity increased significantly for mixing order-1. Intermediate hydrophobic behavior was found for mixing order-3. Additionally, mixing order 1 resulted in improved powder flow properties, low weight variability, higher average tablet weight and slow drug release rates. Dissolution profiles obtained were found to be strongly dependent not only on the mixing order of flowing agents, but also on the strain and the resulting hydrophobicity. PMID:21356286

The numerical modelling of mixing phenomena of nanofluids in passive micromixers

NASA Astrophysics Data System (ADS)

Milotin, R.; Lelea, D.

2018-01-01

The paper deals with the rapid mixing phenomena in micro-mixing devices with four tangential injections and converging tube, considering nanoparticles and water as the base fluid. Several parameters like Reynolds number (Re = 6 - 284) or fluid temperature are considered in order to optimize the process and obtain fundamental insight in mixing phenomena. The set of partial differential equations is considered based on conservation of momentum and species. Commercial package software Ansys-Fluent is used for solution of differential equations, based on a finite volume method. The results reveal that mixing index and mixing process is strongly dependent both on Reynolds number and heat flux. Moreover there is a certain Reynolds number when flow instabilities are generated that intensify the mixing process due to the tangential injections of the fluids.

GHEP-ISFG collaborative exercise on mixture profiles (GHEP-MIX06). Reporting conclusions: Results and evaluation.

PubMed

Barrio, P A; Crespillo, M; Luque, J A; Aler, M; Baeza-Richer, C; Baldassarri, L; Carnevali, E; Coufalova, P; Flores, I; García, O; García, M A; González, R; Hernández, A; Inglés, V; Luque, G M; Mosquera-Miguel, A; Pedrosa, S; Pontes, M L; Porto, M J; Posada, Y; Ramella, M I; Ribeiro, T; Riego, E; Sala, A; Saragoni, V G; Serrano, A; Vannelli, S

2018-07-01

One of the main goals of the Spanish and Portuguese-Speaking Group of the International Society for Forensic Genetics (GHEP-ISFG) is to promote and contribute to the development and dissemination of scientific knowledge in the field of forensic genetics. Due to this fact, GHEP-ISFG holds different working commissions that are set up to develop activities in scientific aspects of general interest. One of them, the Mixture Commission of GHEP-ISFG, has organized annually, since 2009, a collaborative exercise on analysis and interpretation of autosomal short tandem repeat (STR) mixture profiles. Until now, six exercises have been organized. At the present edition (GHEP-MIX06), with 25 participant laboratories, the exercise main aim was to assess mixture profiles results by issuing a report, from the proposal of a complex mock case. One of the conclusions obtained from this exercise is the increasing tendency of participating laboratories to validate DNA mixture profiles analysis following international recommendations. However, the results have shown some differences among them regarding the edition and also the interpretation of mixture profiles. Besides, although the last revision of ISO/IEC 17025:2017 gives indications of how results should be reported, not all laboratories strictly follow their recommendations. Regarding the statistical aspect, all those laboratories that have performed statistical evaluation of the data have employed the likelihood ratio (LR) as a parameter to evaluate the statistical compatibility. However, LR values obtained show a wide range of variation. This fact could not be attributed to the software employed, since the vast majority of laboratories that performed LR calculation employed the same software (LRmixStudio). Thus, the final allelic composition of the edited mixture profile and the parameters employed in the software could explain this data dispersion. This highlights the need, for each laboratory, to define through internal

Obtaining patient test results from clinical laboratories: a survey of state law for pharmacists.

PubMed

Witry, Matthew J; Doucette, William R

2009-01-01

To identify states with laws that restrict to whom clinical laboratories may release copies of laboratory test results and to describe how these laws may affect pharmacists' ability to obtain patient laboratory test results. Researchers examined state statutes and administrative codes for all 50 states and the District of Columbia at the University of Iowa Law Library between June and July 2007. Researchers also consulted with lawyers, state Clinical Laboratory Improvement Amendments officers, and law librarians. Laws relating to the study objective were analyzed. 34 jurisdictions do not restrict the release of laboratory test results, while 17 states have laws that restrict to whom clinical laboratories can send copies of test results. In these states, pharmacists will have to use alternative sources, such as physician offices, to obtain test results. Pharmacists must consider state law before requesting copies of laboratory test results from clinical laboratories. This may be an issue that state pharmacy associations can address to increase pharmacist access to important patient information.

Mixed-mode oscillations in memristor emulator based Liénard system

NASA Astrophysics Data System (ADS)

Kingston, S. Leo; Suresh, K.; Thamilmaran, K.

2018-04-01

We report the existence of mixed-mode oscillations in memristor emulator based Liénard system which is externally driven by sinusoidal force. The charge and flux relationship of memristor emulator device explored based on the smooth cubic nonlinear element. The system exhibits the successive period adding sequences of mixed-mode oscillations in the wide parameter region. The electronics circuit of the memristor emulator is successfully implemented through PSpice simulation and mixed mode oscillations are observed through PSpice experiment and the obtained results are qualitatively matches with the numerical simulation.

Modeling molecular mixing in a spatially inhomogeneous turbulent flow

NASA Astrophysics Data System (ADS)

Meyer, Daniel W.; Deb, Rajdeep

2012-02-01

Simulations of spatially inhomogeneous turbulent mixing in decaying grid turbulence with a joint velocity-concentration probability density function (PDF) method were conducted. The inert mixing scenario involves three streams with different compositions. The mixing model of Meyer ["A new particle interaction mixing model for turbulent dispersion and turbulent reactive flows," Phys. Fluids 22(3), 035103 (2010)], the interaction by exchange with the mean (IEM) model and its velocity-conditional variant, i.e., the IECM model, were applied. For reference, the direct numerical simulation data provided by Sawford and de Bruyn Kops ["Direct numerical simulation and lagrangian modeling of joint scalar statistics in ternary mixing," Phys. Fluids 20(9), 095106 (2008)] was used. It was found that velocity conditioning is essential to obtain accurate concentration PDF predictions. Moreover, the model of Meyer provides significantly better results compared to the IECM model at comparable computational expense.

An experimental study of reactive turbulent mixing

NASA Technical Reports Server (NTRS)

Cooper, L. P.; Marek, C. J.; Strehlow, R. A.

1977-01-01

An experimental study of two coaxial gas streams, which react very rapidly, was performed to investigate the mixing characteristics of turbulent flow fields. The center stream consisted of a CO-N2 mixture and the outer annular stream consisted of air vitiated by H2 combustion. The streams were at equal velocity (50 m/sec) and temperature (1280 K). Turbulence measurements were obtained using hot film anemometry. A sampling probe was used to obtain time averaged gas compositions. Six different turbulence generators were placed in the annular passage to alter the flow field mixing characteristics. The turbulence generators affected the bulk mixing of the streams and the extent of CO conversion to different degrees. The effects can be related to the average eddy size (integral scale) and the bulk mixing. Higher extents of conversion of CO to CO2 were found be increasing the bulk mixing and decreasing the average eddy size.

Combustion Diagnostics and Flow Visualization of Hypergolic Combustion and Gelled Mixing Behavior

DTIC Science & Technology

1997-12-19

difference. Also, Exciplex Flourescence imaging has been implented to visualize diffusion layers which form at the contact interface of mixing...have been implemented and developed as a result of this effort. Among these techniques the most noteworthy involves a unique application of Exciplex ...fluorescence for visualization of diffusion layers formed between mixing liquids. Time resolved images of Exciplex fluorescence have been obtained

Modeling of mixing processes: Fluids, particulates, and powders

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

Ottino, J.M.; Hansen, S.

Work under this grant involves two main areas: (1) Mixing of Viscous Liquids, this first area comprising aggregation, fragmentation and dispersion, and (2) Mixing of Powders. In order to produce a coherent self-contained picture, we report primarily on results obtained under (1), and within this area, mostly on computational studies of particle aggregation in regular and chaotic flows. Numerical simulations show that the average cluster size of compact clusters grows algebraically, while the average cluster size of fractal clusters grows exponentially; companion mathematical arguments are used to describe the initial growth of average cluster size and polydispersity. It is foundmore » that when the system is well mixed and the capture radius independent of mass, the polydispersity is constant for long-times and the cluster size distribution is self-similar. Furthermore, our simulations indicate that the fractal nature of the clusters is dependent upon the mixing.« less

Distilling perfect GHZ states from two copies of non-GHZ-diagonal mixed states

NASA Astrophysics Data System (ADS)

Wang, Xin-Wen; Tang, Shi-Qing; Yuan, Ji-Bing; Zhang, Deng-Yu

2017-06-01

It has been shown that a nearly pure Greenberger-Horne-Zeilinger (GHZ) state could be distilled from a large (even infinite) number of GHZ-diagonal states that can be obtained by depolarizing general multipartite mixed states (non-GHZ-diagonal states) through sequences of (probabilistic) local operations and classical communications. We here demonstrate that perfect GHZ states can be extracted, with certain probabilities, from two copies of non-GHZ-diagonal mixed states when some conditions are satisfied. This result implies that it is not necessary to depolarize these entangled mixed states to the GHZ-diagonal type, and that they are better than GHZ-diagonal states for distillation of pure GHZ states. We find a wide class of multipartite entangled mixed states that fulfill the requirements. Moreover, we display that the obtained result can be applied to practical noisy environments, e.g., amplitude-damping channels. Our findings provide an important complementarity to conventional GHZ-state distillation protocols (designed for GHZ-diagonal states) in theory, as well as having practical applications.

Experiments in dilution jet mixing

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Srinivasan, R.; Berenfeld, A.

1983-01-01

Experimental results are given on the mixing of a single row of jets with an isothermal mainstream in a straight duct, to include flow and geometric variations typical of combustion chambers in gas turbine engines. The principal conclusions reached from these experiments were: at constant momentum ratio, variations in density ratio have only a second-order effect on the profiles; a first-order approximation to the mixing of jets with a variable temperature mainstream can be obtained by superimposing the jets-in-an isothermal-crossflow and mainstream profiles; flow area convergence, especially injection-wall convergence, significantly improves the mixing; for opposed rows of jets, with the orifice centerlines in-line, the optimum ratio of orifice spacing to duct height is one half of the optimum value for single side injection at the same momentum ratio; and for opposed rows of jets, with the orifice centerlines staggered, the optimum ratio of orifice spacing to duct height is twice the optimum value for single side injection at the same momentum ratio.

Experiments in dilution jet mixing

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Srinivasan, R.; Berenfeld, A.

1983-01-01

Experimental results are presented on the mixing of a single row of jets with an isothermal mainstream in a straight duct, with flow and geometric variations typical of combustion chambers in gas turbine engines included. It is found that at a constant momentum ratio, variations in the density ratio have only a second-order effect on the profiles. A first-order approximation to the mixing of jets with a variable temperature mainstream can, it is found, be obtained by superimposing the jets-in-an-isothermal-crossflow and mainstream profiles. Another finding is that the flow area convergence, especially injection-wall convergence, significantly improves the mixing. For opposed rows of jets with the orifice cone centerlines in-line, the optimum ratio of orifice spacing to duct height is determined to be 1/2 of the optimum value for single injection at the same momentum ratio. For opposed rows of jets with the orifice centerlines staggered, the optimum ratio of orifice spacing to duct height is found to be twice the optimum value for single side injection at the same momentum ratio.

Mixing properties of the one-atom maser

NASA Astrophysics Data System (ADS)

Bruneau, Laurent

2014-06-01

We study the relaxation properties of the quantized electromagnetic field in a cavity under repeated interactions with single two-level atoms, so-called one-atom maser. We improve the ergodic results obtained in Bruneau and Pillet (J Stat Phys 134(5-6):1071-1095, 2009) and prove that, whenever the atoms are initially distributed according to the canonical ensemble at temperature , all the invariant states are mixing. Under some non-resonance condition this invariant state is known to be thermal equilibirum at some renormalized temperature and we prove that the mixing is then arbitrarily slow, in other words that there is no lower bound on the relaxation speed.

Performance Evaluation of Hot Mix Asphalt with Different Proportions of RAP Content

NASA Astrophysics Data System (ADS)

Kamil Arshad, Ahmad; Awang, Haryati; Shaffie, Ekarizan; Hashim, Wardati; Rahman, Zanariah Abd

2018-03-01

Reclaimed Asphalt Pavement (RAP) is old asphalt pavement that has been removed from a road by milling or full depth removal. The use of RAP in hot mix asphalt (HMA) eliminates the need to dispose old asphalt pavements and conserves asphalt binders and aggregates, resulting in significant cost savings and benefits to society. This paper presents a study on HMA with different RAP proportions carried out to evaluate the volumetric properties and performance of asphalt mixes containing different proportions of RAP. Marshall Mix Design Method was used to produce control mix (0% RAP) and asphalt mixes containing 15% RAP, 25% RAP and 35% RAP in accordance with Specifications for Road Works of Public Works Department, Malaysia for AC14 dense graded asphalt gradation. Volumetric analysis was performed to ensure that the result is compliance with specification requirements. The resilient modulus test was performed to measure the stiffness of the mixes while the Modified Lottman test was conducted to evaluate the moisture susceptibility of these mixes. The Hamburg wheel tracking test was used to evaluate the rutting performance of these mixes. The results obtained showed that there were no substantial difference in Marshall Properties, moisture susceptibility, resilient modulus and rutting resistance between asphalt mixes with RAP and the control mix. The test results indicated that recycled mixes performed as good as the performance of conventional HMA in terms of moisture susceptibility and resilient modulus. It is recommended that further research be carried out for asphalt mixes containing more than 35% RAP material.

The influence of inoculum composition on selected bioactive and nutritional parameters of grass pea tempeh obtained by mixed-culture fermentation with Rhizopus oligosporus and Aspergillus oryzae strains.

PubMed

Starzynska-Janiszewska, A; Stodolak, B; Dulinski, R; Mickowska, B

2012-04-01

Tempeh is a popular Indonesian product obtained from legume seeds by solid-state fermentation with Rhizopus sp. The aim of this research was to study the effect of simultaneous mixed-culture fermentation of grass pea seeds on selected parameters of products as compared to traditional tempeh. The inoculum contained different ratios of Rhizopus oligosporus and Aspergillus oryzae spores. The simultaneous fermentation of grass pea seeds with inoculum consisting of 1.2 × 10(6) R. oligosporus and 0.6 × 10(6) A. oryzae spores (per 60 g of seeds) resulted in a product of improved quality, as compared with traditionally made tempeh (obtained after inoculation with 1.2 × 10(6) R. oligosporus spores), at the same fermentation time. This product had radical scavenging ability 70% higher than the one obtained with pure R. oligosporus culture and contained 2.23 g/kg dm of soluble phenols. The thiamin and riboflavin levels were above three (340 µg/g dm) and two (50.50 µg/g dm) folds higher than in traditionally made tempeh, respectively. The product had 65% in vitro bioavailability of proteins and 33% in vitro bioavailability of sugars. It also contained 40% less 3-N-oxalyl-L-2, 3-diaminopropionic acid (0.074 g/kg dm), as compared to traditional tempeh.

Concentration variance decay during magma mixing: a volcanic chronometer

PubMed Central

Perugini, Diego; De Campos, Cristina P.; Petrelli, Maurizio; Dingwell, Donald B.

2015-01-01

The mixing of magmas is a common phenomenon in explosive eruptions. Concentration variance is a useful metric of this process and its decay (CVD) with time is an inevitable consequence during the progress of magma mixing. In order to calibrate this petrological/volcanological clock we have performed a time-series of high temperature experiments of magma mixing. The results of these experiments demonstrate that compositional variance decays exponentially with time. With this calibration the CVD rate (CVD-R) becomes a new geochronometer for the time lapse from initiation of mixing to eruption. The resultant novel technique is fully independent of the typically unknown advective history of mixing – a notorious uncertainty which plagues the application of many diffusional analyses of magmatic history. Using the calibrated CVD-R technique we have obtained mingling-to-eruption times for three explosive volcanic eruptions from Campi Flegrei (Italy) in the range of tens of minutes. These in turn imply ascent velocities of 5-8 meters per second. We anticipate the routine application of the CVD-R geochronometer to the eruptive products of active volcanoes in future in order to constrain typical “mixing to eruption” time lapses such that monitoring activities can be targeted at relevant timescales and signals during volcanic unrest. PMID:26387555

Concentration variance decay during magma mixing: a volcanic chronometer.

PubMed

Perugini, Diego; De Campos, Cristina P; Petrelli, Maurizio; Dingwell, Donald B

2015-09-21

The mixing of magmas is a common phenomenon in explosive eruptions. Concentration variance is a useful metric of this process and its decay (CVD) with time is an inevitable consequence during the progress of magma mixing. In order to calibrate this petrological/volcanological clock we have performed a time-series of high temperature experiments of magma mixing. The results of these experiments demonstrate that compositional variance decays exponentially with time. With this calibration the CVD rate (CVD-R) becomes a new geochronometer for the time lapse from initiation of mixing to eruption. The resultant novel technique is fully independent of the typically unknown advective history of mixing - a notorious uncertainty which plagues the application of many diffusional analyses of magmatic history. Using the calibrated CVD-R technique we have obtained mingling-to-eruption times for three explosive volcanic eruptions from Campi Flegrei (Italy) in the range of tens of minutes. These in turn imply ascent velocities of 5-8 meters per second. We anticipate the routine application of the CVD-R geochronometer to the eruptive products of active volcanoes in future in order to constrain typical "mixing to eruption" time lapses such that monitoring activities can be targeted at relevant timescales and signals during volcanic unrest.

Criteria for quantitative and qualitative data integration: mixed-methods research methodology.

PubMed

Lee, Seonah; Smith, Carrol A M

2012-05-01

Many studies have emphasized the need and importance of a mixed-methods approach for evaluation of clinical information systems. However, those studies had no criteria to guide integration of multiple data sets. Integrating different data sets serves to actualize the paradigm that a mixed-methods approach argues; thus, we require criteria that provide the right direction to integrate quantitative and qualitative data. The first author used a set of criteria organized from a literature search for integration of multiple data sets from mixed-methods research. The purpose of this article was to reorganize the identified criteria. Through critical appraisal of the reasons for designing mixed-methods research, three criteria resulted: validation, complementarity, and discrepancy. In applying the criteria to empirical data of a previous mixed methods study, integration of quantitative and qualitative data was achieved in a systematic manner. It helped us obtain a better organized understanding of the results. The criteria of this article offer the potential to produce insightful analyses of mixed-methods evaluations of health information systems.

A Mixed Micelle Formulation for Oral Delivery of Vitamin K.

PubMed

Sun, Feilong; Jaspers, Tessa C C; van Hasselt, Peter M; Hennink, Wim E; van Nostrum, Cornelus F

2016-09-01

To develop a stable micellar formulation of vitamin K for oral delivery, because the commercial and clinically used formulation of vitamin K (Konakion® MM) destabilizes at gastric pH resulting in low bioavailability of this vitamin in neonates with cholestasis. Mixed micelles composed of EPC, DSPE-PEG 2000 and glycocholic acid, with and without vitamin K, were prepared by a film hydration method. The influence of pH on the stability of the micelles was analyzed by dynamic light scattering (DLS). The critical micelle concentration (CMC) was determined by fluorescence spectroscopy using pyrene and the morphology was evaluated by transmission electron microscopy . Caco-2 cells were used to study the cytocompatibilty. Mixed micelles with mean diameters from 7.1 to 11.0 nm and a narrow size distribution (PDI < 0.2) were obtained after 3 membrane extrusion cycles. Konakion® MM formed aggregated particles at gastric pH, which was avoided through steric stabilization by introducing PEG. TEM showed that mixed micelles had a spherical size (diameter of around 10 nm) with a narrow size distribution in agreement with the DLS results. The loading capacities for vitamin K of mixed micelles with varying molar fractions of DSPE-PEG and EPC (from 0/100 to 50/50 (mol/mol)) were 10.8-5.0 w%, respectively. The mixed micelles showed good cytocompatibility at concentrations of glycocholic acid between 0.12 and 1.20 mM. Mixed micelles with superior stability to Konakion® MM at low pH were obtained by introducing DSPE-PEG 2000. These are therefore attractive oral formulations for vitamin K.

Mixed Emotions and Coping: The Benefits of Secondary Emotions

PubMed Central

Braniecka, Anna; Trzebińska, Ewa; Dowgiert, Aneta; Wytykowska, Agata

2014-01-01

The existing empirical literature suggests that during difficult situations, the concurrent experience of positive and negative affects may be ideal for ensuring successful adaptation and well-being. However, different patterns of mixed emotions may have different adaptive consequences. The present research tested the proposition that experiencing a pattern of secondary mixed emotion (i.e., secondary emotion that embrace both positive and negative affects) more greatly promotes adaptive coping than experiencing two other patterns of mixed emotional experiences: simultaneous (i.e., two emotions of opposing affects taking place at the same time) and sequential (i.e., two emotions of opposing affects switching back and forth). Support for this hypothesis was obtained from two experiments (Studies 1 and 2) and a longitudinal survey (Study 3). The results revealed that secondary mixed emotions predominate over sequential and simultaneous mixed emotional experiences in promoting adaptive coping through fostering the motivational and informative functions of emotions; this is done by providing solution-oriented actions rather than avoidance, faster decisions regarding coping strategies (Study 1), easier access to self-knowledge, and better narrative organization (Study 2). Furthermore, individuals characterized as being prone to feeling secondary mixed emotions were more resilient to stress caused by transitions than those who were characterized as being prone to feeling opposing emotions separately (Study 3). Taken together, the preliminary results indicate that the pattern of secondary mixed emotion provides individuals with a higher capacity to handle adversity than the other two patterns of mixed emotional experience. PMID:25084461

Mixed emotions and coping: the benefits of secondary emotions.

PubMed

Braniecka, Anna; Trzebińska, Ewa; Dowgiert, Aneta; Wytykowska, Agata

2014-01-01

The existing empirical literature suggests that during difficult situations, the concurrent experience of positive and negative affects may be ideal for ensuring successful adaptation and well-being. However, different patterns of mixed emotions may have different adaptive consequences. The present research tested the proposition that experiencing a pattern of secondary mixed emotion (i.e., secondary emotion that embrace both positive and negative affects) more greatly promotes adaptive coping than experiencing two other patterns of mixed emotional experiences: simultaneous (i.e., two emotions of opposing affects taking place at the same time) and sequential (i.e., two emotions of opposing affects switching back and forth). Support for this hypothesis was obtained from two experiments (Studies 1 and 2) and a longitudinal survey (Study 3). The results revealed that secondary mixed emotions predominate over sequential and simultaneous mixed emotional experiences in promoting adaptive coping through fostering the motivational and informative functions of emotions; this is done by providing solution-oriented actions rather than avoidance, faster decisions regarding coping strategies (Study 1), easier access to self-knowledge, and better narrative organization (Study 2). Furthermore, individuals characterized as being prone to feeling secondary mixed emotions were more resilient to stress caused by transitions than those who were characterized as being prone to feeling opposing emotions separately (Study 3). Taken together, the preliminary results indicate that the pattern of secondary mixed emotion provides individuals with a higher capacity to handle adversity than the other two patterns of mixed emotional experience.

Application of zero-inflated poisson mixed models in prognostic factors of hepatitis C.

PubMed

Akbarzadeh Baghban, Alireza; Pourhoseingholi, Asma; Zayeri, Farid; Jafari, Ali Akbar; Alavian, Seyed Moayed

2013-01-01

In recent years, hepatitis C virus (HCV) infection represents a major public health problem. Evaluation of risk factors is one of the solutions which help protect people from the infection. This study aims to employ zero-inflated Poisson mixed models to evaluate prognostic factors of hepatitis C. The data was collected from a longitudinal study during 2005-2010. First, mixed Poisson regression (PR) model was fitted to the data. Then, a mixed zero-inflated Poisson model was fitted with compound Poisson random effects. For evaluating the performance of the proposed mixed model, standard errors of estimators were compared. The results obtained from mixed PR showed that genotype 3 and treatment protocol were statistically significant. Results of zero-inflated Poisson mixed model showed that age, sex, genotypes 2 and 3, the treatment protocol, and having risk factors had significant effects on viral load of HCV patients. Of these two models, the estimators of zero-inflated Poisson mixed model had the minimum standard errors. The results showed that a mixed zero-inflated Poisson model was the almost best fit. The proposed model can capture serial dependence, additional overdispersion, and excess zeros in the longitudinal count data.

Integrated aeroelastic vibrator for fluid mixing in open microwells

NASA Astrophysics Data System (ADS)

Xia, H. M.; Jin, X.; Zhang, Y. Y.; Wu, J. W.; Zhang, J.; Wang, Z. P.

2018-01-01

Fluid mixing in micro-wells/chambers is required in a variety of biological and biochemical processes. However, mixing fluids of small volumes is usually difficult due to increased viscous effects. In this study, we propose a new method for mixing enhancement in microliter-scale open wells. A thin elastic diaphragm is used to seal the bottom of the mixing microwell, underneath which an air chamber connects an aeroelastic vibrator. Driven by an air flow, the vibrator produces self-excited vibrations and causes pressure oscillations in the air chamber. Then the elastic diaphragm is actuated to mix the fluids in the microwell. Two designs that respectively have one single well and 2  ×  2 wells were prototyped. Testing results show that for liquids with a volume ranging from 10-60 µl and viscosity ranging from 1-5 cP, complete mixing can be obtained within 5-20 s. Furthermore, the device is operable with an air micropump, and hence facilitating the miniaturization and integration of lab-on-a-chip and microbioreactor systems.

Clustering of Variables for Mixed Data

NASA Astrophysics Data System (ADS)

Saracco, J.; Chavent, M.

2016-05-01

This chapter presents clustering of variables which aim is to lump together strongly related variables. The proposed approach works on a mixed data set, i.e. on a data set which contains numerical variables and categorical variables. Two algorithms of clustering of variables are described: a hierarchical clustering and a k-means type clustering. A brief description of PCAmix method (that is a principal component analysis for mixed data) is provided, since the calculus of the synthetic variables summarizing the obtained clusters of variables is based on this multivariate method. Finally, the R packages ClustOfVar and PCAmixdata are illustrated on real mixed data. The PCAmix and ClustOfVar approaches are first used for dimension reduction (step 1) before applying in step 2 a standard clustering method to obtain groups of individuals.

Evaluating the influences of mixing strategies on the Biochemical Methane Potential test.

PubMed

Wang, Bing; Björn, Annika; Strömberg, Sten; Nges, Ivo Achu; Nistor, Mihaela; Liu, Jing

2017-01-01

Mixing plays an important role in the Biochemical Methane Potential (BMP) test, but only limited efforts have been put into it. In this study, various mixing strategies were applied to evaluate the influences on the BMP test, i.e., no mixing, shaking in water bath, shake manually once per day (SKM), automated unidirectional and bidirectional mixing. The results show that the effects of mixing are prominent for the most viscous substrate investigated, as both the highest methane production and highest maximal daily methane production were obtained at the highest mixing intensity. However, the organic removal efficiencies were not affected, which might offer evidence that mixing helps the release of gases trapped in digester liquid. Moreover, mixing is required for improved methane production when the digester content is viscous, conversely, mixing is unnecessary or SKM might be sufficient for the BMP test if the digester content is quite dilute or the substrate is easily degraded. Copyright © 2016 Elsevier Ltd. All rights reserved.

Continuous synthesis of drug-loaded nanoparticles using microchannel emulsification and numerical modeling: effect of passive mixing

PubMed Central

Ortiz de Solorzano, Isabel; Uson, Laura; Larrea, Ane; Miana, Mario; Sebastian, Victor; Arruebo, Manuel

2016-01-01

By using interdigital microfluidic reactors, monodisperse poly(d,l lactic-co-glycolic acid) nanoparticles (NPs) can be produced in a continuous manner and at a large scale (~10 g/h). An optimized synthesis protocol was obtained by selecting the appropriated passive mixer and fluid flow conditions to produce monodisperse NPs. A reduced NP polydispersity was obtained when using the microfluidic platform compared with the one obtained with NPs produced in a conventional discontinuous batch reactor. Cyclosporin, an immunosuppressant drug, was used as a model to validate the efficiency of the microfluidic platform to produce drug-loaded monodisperse poly(d,l lactic-co-glycolic acid) NPs. The influence of the mixer geometries and temperatures were analyzed, and the experimental results were corroborated by using computational fluid dynamic three-dimensional simulations. Flow patterns, mixing times, and mixing efficiencies were calculated, and the model supported with experimental results. The progress of mixing in the interdigital mixer was quantified by using the volume fractions of the organic and aqueous phases used during the emulsification–evaporation process. The developed model and methods were applied to determine the required time for achieving a complete mixing in each microreactor at different fluid flow conditions, temperatures, and mixing rates. PMID:27524896

Continuous synthesis of drug-loaded nanoparticles using microchannel emulsification and numerical modeling: effect of passive mixing.

PubMed

Ortiz de Solorzano, Isabel; Uson, Laura; Larrea, Ane; Miana, Mario; Sebastian, Victor; Arruebo, Manuel

2016-01-01

By using interdigital microfluidic reactors, monodisperse poly(d,l lactic-co-glycolic acid) nanoparticles (NPs) can be produced in a continuous manner and at a large scale (~10 g/h). An optimized synthesis protocol was obtained by selecting the appropriated passive mixer and fluid flow conditions to produce monodisperse NPs. A reduced NP polydispersity was obtained when using the microfluidic platform compared with the one obtained with NPs produced in a conventional discontinuous batch reactor. Cyclosporin, an immunosuppressant drug, was used as a model to validate the efficiency of the microfluidic platform to produce drug-loaded monodisperse poly(d,l lactic-co-glycolic acid) NPs. The influence of the mixer geometries and temperatures were analyzed, and the experimental results were corroborated by using computational fluid dynamic three-dimensional simulations. Flow patterns, mixing times, and mixing efficiencies were calculated, and the model supported with experimental results. The progress of mixing in the interdigital mixer was quantified by using the volume fractions of the organic and aqueous phases used during the emulsification-evaporation process. The developed model and methods were applied to determine the required time for achieving a complete mixing in each microreactor at different fluid flow conditions, temperatures, and mixing rates.

Quick-Mixing Studies Under Reacting Conditions

NASA Technical Reports Server (NTRS)

Leong, May Y.; Samuelsen, G. S.

1996-01-01

The low-NO(x) emitting potential of rich-burn/quick-mix/lean-burn )RQL) combustion makes it an attractive option for engines of future stratospheric aircraft. Because NO(x) formation is exponentially dependent on temperature, the success of the RQL combustor depends on minimizing high temperature stoichiometric pocket formation in the quick-mixing section. An experiment was designed and built, and tests were performed to characterize reaction and mixing properties of jets issuing from round orifices into a hot, fuel-rich crossflow confined in a cylindrical duct. The reactor operates on propane and presents a uniform, non-swirling mixture to the mixing modules. Modules consisting of round orifice configurations of 8, 9, 10, 12, 14, and 18 holes were evaluated at a momentum-flux ratio of 57 and jet-to-mainstream mass-flaw ratio of 2.5. Temperatures and concentrations of O2, CO2, CO, HC, and NO(x) were obtained upstream, down-stream, and within the orifice plane to determine jet penetration as well as reaction processes. Jet penetration was a function of the number of orifices and affected the mixing in the reacting system. Of the six configurations tested, the 14-hole module produced jet penetration close to the module half-radius and yielded the best mixing and most complete combustion at a plane one duct diameter from the orifice leading edge. The results reveal that substantial reaction and heat release occur in the jet mixing zone when the entering effluent is hot and rich, and that the experiment as designed will serve to explore satisfactorily jet mixing behavior under realistic reacting conditions in future studies.

Jet Mixing in a Reacting Cylindrical Crossflow

NASA Technical Reports Server (NTRS)

Leong, M. Y.; Samuelsen, G. S.; Holdeman, J. D.

1995-01-01

This paper addresses the mixing of air jets into the hot, fuel-rich products of a gas turbine primary zone. The mixing, as a result, occurs in a reacting environment with chemical conversion and substantial heat release. The geometry is a crossflow confined in a cylindrical duct with side-wall injection of jets issuing from round orifices. A specially designed reactor, operating on propane, presents a uniform mixture without swirl to mixing modules consisting of 8, 9, 10, and 12 holes at a momentum-flux ratio of 57 and a jet-to-mainstream mass-flow ratio of 2.5. Concentrations of O2, CO2, CO, and HC are obtained upstream, downstream, and within the orifice plane. O2 profiles indicate jet penetration while CO2, CO, and HC profiles depict the extent of reaction. Jet penetration is observed to be a function of the number of orifices and is found to affect the mixing in the reacting system. The results demonstrate that one module (the 12-hole) produces near-optimal penetration defined here as a jet penetration closest to the module half-radius, and hence the best uniform mixture at a plane one duct radius from the orifice leading edge.

Analytical Solution for Reactive Solute Transport Considering Incomplete Mixing

NASA Astrophysics Data System (ADS)

Bellin, A.; Chiogna, G.

2013-12-01

The laboratory experiments of Gramling et al. (2002) showed that incomplete mixing at the pore scale exerts a significant impact on transport of reactive solutes and that assuming complete mixing leads to overestimation of product concentration in bimolecular reactions. We consider here the family of equilibrium reactions for which the concentration of the reactants and the product can be expressed as a function of the mixing ratio, the concentration of a fictitious non reactive solute. For this type of reactions we propose, in agreement with previous studies, to model the effect of incomplete mixing at scales smaller than the Darcy scale assuming that the mixing ratio is distributed within an REV according to a Beta distribution. We compute the parameters of the Beta model by imposing that the mean concentration is equal to the value that the concentration assumes at the continuum Darcy scale, while the variance decays with time as a power law. We show that our model reproduces the concentration profiles of the reaction product measured in the Gramling et al. (2002) experiments using the transport parameters obtained from conservative experiments and an instantaneous reaction kinetic. The results are obtained applying analytical solutions both for conservative and for reactive solute transport, thereby providing a method to handle the effect of incomplete mixing on multispecies reactive solute transport, which is simpler than other previously developed methods. Gramling, C. M., C. F. Harvey, and L. C. Meigs (2002), Reactive transport in porous media: A comparison of model prediction with laboratory visualization, Environ. Sci. Technol., 36(11), 2508-2514.

Mixed Schools versus Single-Sex Schools: Are There Differences in the Academic Results for Boys and Girls in Catalonia?

ERIC Educational Resources Information Center

Garcia-Gracia, Maribel; Donoso Vázquez, Trinidad

2016-01-01

This study carries out a comparative analysis of achievement according to gender between mixed and single-sex schools in the region of Catalonia, Spain, for the subjects of Spanish, Catalan, English and Mathematics. After a brief contextualisation, a review of the main findings from international studies on differences in results for mixed schools…

Hydrogen Production by Geobacter Species and a Mixed Consortium in a Microbial Electrolysis Cell▿

PubMed Central

Call, Douglas F.; Wagner, Rachel C.; Logan, Bruce E.

2009-01-01

A hydrogen utilizing exoelectrogenic bacterium (Geobacter sulfurreducens) was compared to both a nonhydrogen oxidizer (Geobacter metallireducens) and a mixed consortium in order to compare the hydrogen production rates and hydrogen recoveries of pure and mixed cultures in microbial electrolysis cells (MECs). At an applied voltage of 0.7 V, both G. sulfurreducens and the mixed culture generated similar current densities (ca. 160 A/m3), resulting in hydrogen production rates of ca. 1.9 m3 H2/m3/day, whereas G. metallireducens exhibited lower current densities and production rates of 110 ± 7 A/m3 and 1.3 ± 0.1 m3 H2/m3/day, respectively. Before methane was detected in the mixed-culture MEC, the mixed consortium achieved the highest overall energy recovery (relative to both electricity and substrate energy inputs) of 82% ± 8% compared to G. sulfurreducens (77% ± 2%) and G. metallireducens (78% ± 5%), due to the higher coulombic efficiency of the mixed consortium. At an applied voltage of 0.4 V, methane production increased in the mixed-culture MEC and, as a result, the hydrogen recovery decreased and the overall energy recovery dropped to 38% ± 16% compared to 80% ± 5% for G. sulfurreducens and 76% ± 0% for G. metallireducens. Internal hydrogen recycling was confirmed since the mixed culture generated a stable current density of 31 ± 0 A/m3 when fed hydrogen gas, whereas G. sulfurreducens exhibited a steady decrease in current production. Community analysis suggested that G. sulfurreducens was predominant in the mixed-culture MEC (72% of clones) despite its relative absence in the mixed-culture inoculum obtained from a microbial fuel cell reactor (2% of clones). These results demonstrate that Geobacter species are capable of obtaining similar hydrogen production rates and energy recoveries as mixed cultures in an MEC and that high coulombic efficiencies in mixed culture MECs can be attributed in part to the recycling of hydrogen into current. PMID:19820150

Hydrogen production by geobacter species and a mixed consortium in a microbial electrolysis cell.

PubMed

Call, Douglas F; Wagner, Rachel C; Logan, Bruce E

2009-12-01

A hydrogen utilizing exoelectrogenic bacterium (Geobacter sulfurreducens) was compared to both a nonhydrogen oxidizer (Geobacter metallireducens) and a mixed consortium in order to compare the hydrogen production rates and hydrogen recoveries of pure and mixed cultures in microbial electrolysis cells (MECs). At an applied voltage of 0.7 V, both G. sulfurreducens and the mixed culture generated similar current densities (ca. 160 A/m3), resulting in hydrogen production rates of ca. 1.9 m(3) H2/m3/day, whereas G. metallireducens exhibited lower current densities and production rates of 110 +/- 7 A/m3 and 1.3 +/- 0.1 m3 H2/m3/day, respectively. Before methane was detected in the mixed-culture MEC, the mixed consortium achieved the highest overall energy recovery (relative to both electricity and substrate energy inputs) of 82% +/- 8% compared to G. sulfurreducens (77% +/- 2%) and G. metallireducens (78% +/- 5%), due to the higher coulombic efficiency of the mixed consortium. At an applied voltage of 0.4 V, methane production increased in the mixed-culture MEC and, as a result, the hydrogen recovery decreased and the overall energy recovery dropped to 38% +/- 16% compared to 80% +/- 5% for G. sulfurreducens and 76% +/- 0% for G. metallireducens. Internal hydrogen recycling was confirmed since the mixed culture generated a stable current density of 31 +/- 0 A/m3 when fed hydrogen gas, whereas G. sulfurreducens exhibited a steady decrease in current production. Community analysis suggested that G. sulfurreducens was predominant in the mixed-culture MEC (72% of clones) despite its relative absence in the mixed-culture inoculum obtained from a microbial fuel cell reactor (2% of clones). These results demonstrate that Geobacter species are capable of obtaining similar hydrogen production rates and energy recoveries as mixed cultures in an MEC and that high coulombic efficiencies in mixed culture MECs can be attributed in part to the recycling of hydrogen into current.

Results obtained with a low cost software-based audiometer for hearing screening.

PubMed

Ferrari, Deborah Viviane; Lopez, Esteban Alejandro; Lopes, Andrea Cintra; Aiello, Camila Piccini; Jokura, Pricila Reis

2013-07-01

 The implementation of hearing screening programs can be facilitated by reducing operating costs, including the cost of equipment. The Telessaúde (TS) audiometer is a low-cost, software-based, and easy-to-use piece of equipment for conducting audiometric screening.  To evaluate the TS audiometer for conducting audiometric screening.  A prospective randomized study was performed. Sixty subjects, divided into those who did not have (group A, n = 30) and those who had otologic complaints (group B, n = 30), underwent audiometric screening with conventional and TS audiometers in a randomized order. Pure tones at 25 dB HL were presented at frequencies of 500, 1000, 2000, and 4000 Hz. A "fail" result was considered when the individual failed to respond to at least one of the stimuli. Pure-tone audiometry was also performed on all participants. The concordance of the results of screening with both audiometers was evaluated. The sensitivity, specificity, and positive and negative predictive values of screening with the TS audiometer were calculated.  For group A, 100% of the ears tested passed the screening. For group B, "pass" results were obtained in 34.2% (TS) and 38.3% (conventional) of the ears tested. The agreement between procedures (TS vs. conventional) ranged from 93% to 98%. For group B, screening with the TS audiometer showed 95.5% sensitivity, 90.4% sensitivity, and positive and negative predictive values equal to 94.9% and 91.5%, respectively.  The results of the TS audiometer were similar to those obtained with the conventional audiometer, indicating that the TS audiometer can be used for audiometric screening.

Circumpolar Estimates of Isopycnal Mixing in the ACC from Argo Floats

NASA Astrophysics Data System (ADS)

Roach, C. J.; Balwada, D.; Speer, K. G.

2015-12-01

There are few direct observations of cross-stream isopycnal mixing in the interior of the Southern Ocean, yet such measurements are needed to determine the role of eddies transporting properties across the ACC, and key to progress toward testing theories of meridional overturning. In light of this we examine if it is possible to obtain estimates of mixing from Argo float trajectories. We divided the Southern Ocean into overlapping 15ο longitude bins before estimating mixing. Resulting diffusivities ranged from 300 to 3000 m2s-1, with peaks corresponding to the Scotia Sea; Kerguelen and Campbell Plateaus. Comparison of our diffusivities with previous regional studies demonstrated good agreement. Tests of the methodology in the DIMES region found that mixing from Argo floats agreed closely with mixing from RAFOS floats. To further test the method we used the Southern Ocean State Estimate velocity fields to advect particles with Argo and RAFOS float like behaviours. Stirring estimates from the particles agreed well with each other in the Kerguelen Island region, South Pacific and Scotia Sea, despite the differences in the imposed behaviour. Finally, these estimates were compared to mixing length suppression theory presented in Ferrari and Nikurashin 2010. This mixing length suppression theory quantifies horizontal diffusivity similar to Prandtl (1925), but the mixing length is suppressed in the presence of mean flows and eddy phase speeds. Our results suggest that the theory can explain both the structure and magnitude of mixing using mean flow data. An exception is near the Kerguelen and Campbell Plateaus where theory under-estimates mixing relative to our results.

Sidestream superoxygenation for wastewater treatment: Oxygen transfer in clean water and mixed liquor.

PubMed

Barreto, Carlos M; Ochoa, Ivania M; Garcia, Hector A; Hooijmans, Christine M; Livingston, Dennis; Herrera, Aridai; Brdjanovic, Damir

2018-08-01

The performance of a pilot-scale superoxygenation system was evaluated in clean water and mixed liquor. A mass balance was applied over the pilot-scale system to determine the overall oxygen mass transfer rate coefficient (K L a, h -1 ), the standard oxygen transfer rate (SOTR, kg O 2 d -1 ), and the standard oxygen transfer efficiency (SOTE, %). Additionally, the alpha factor (α) was determined at a mixed liquor suspend solids (MLSS) concentration of approximately 5 g L -1 . SOTEs of nearly 100% were obtained in clean water and mixed liquor. The results showed that at higher oxygen flowrates, higher transfer rates could be achieved; this however, at expenses of the transfer efficiency. As expected, lower transfer efficiencies were observed in mixed liquor compared to clean water. Alpha factors varied between 0.6 and 1.0. However, values of approximately 1.0 can be obtained in all cases by fine tuning the oxygen flowrate delivered to the system. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparisons Between NO PLIF Imaging and CFD Simulations of Mixing Flowfields for High-Speed Fuel Injectors

NASA Technical Reports Server (NTRS)

Drozda, Tomasz G.; Cabell, Karen F.; Ziltz, Austin R.; Hass, Neal E.; Inman, Jennifer A.; Burns, Ross A.; Bathel, Brett F.; Danehy, Paul M.

2017-01-01

The current work compares experimentally and computationally obtained nitric oxide (NO) planar laser induced fluorescence (PLIF) images of the mixing flowfields for three types of high-speed fuel injectors: a strut, a ramp, and a rectangular flushwall. These injection devices, which exhibited promising mixing performance at lower flight Mach numbers, are currently being studied as a part of the Enhanced Injection and Mixing Project (EIMP) at the NASA Langley Research Center. The EIMP aims to investigate scramjet fuel injection and mixing physics, and improve the understanding of underlying physical processes relevant to flight Mach numbers greater than eight. In the experiments, conducted in the NASA Langley Arc-Heated Scramjet Test Facility (AHSTF), the injectors are placed downstream of a Mach 6 facility nozzle, which simulates the high Mach number air flow at the entrance of a scramjet combustor. Helium is used as an inert substitute for hydrogen fuel. Both schlieren and PLIF techniques are applied to obtain mixing flowfield flow visualizations. The experimental PLIF is obtained by using a UV laser sheet to interrogate a plane of the flow by exciting fluorescence from the NO molecules, which are present in the AHSTF air. Consequently, the absence of signal in the resulting PLIF images is an indication of pure helium (fuel). The computational PLIF is obtained by applying a fluorescence model for NO to the results of the Reynolds-averaged simulations (RAS) of the mixing flow field carried out using the VULCAN-CFD solver. This approach is required because the PLIF signal is a nonlinear function of not only NO concentration, but also pressure, temperature, and the flow velocity. This complexity allows additional flow features to be identified and compared with those obtained from the computational fluid dynamics (CFD) simulations, however, such comparisons are only semiquantitative. Three-dimensional image reconstruction, similar to that used in magnetic resonance

Relative phase shifts for metaplectic isotopies acting on mixed Gaussian states

NASA Astrophysics Data System (ADS)

de Gosson, Maurice A.; Nicacio, Fernando

2018-05-01

We address in this paper the notion of relative phase shift for mixed quantum systems. We study the Pancharatnam-Sjöqvist phase shift φ (t ) =ArgTr(U^ tρ ^ ) for metaplectic isotopies acting on Gaussian mixed states. We complete and generalize the previous results obtained by one of us, while giving rigorous proofs. The key actor in this study is the theory of the Conley-Zehnder index which is an intersection index related to the Maslov index.

Global Ocean Circulation in Thermohaline Coordinates and Small-scale and Mesoscale mixing: An Inverse Estimate.

NASA Astrophysics Data System (ADS)

Groeskamp, S.; Zika, J. D.; McDougall, T. J.; Sloyan, B.

2016-02-01

I will present results of a new inverse technique that infers small-scale turbulent diffusivities and mesoscale eddy diffusivities from an ocean climatology of Salinity (S) and Temperature (T) in combination with surface freshwater and heat fluxes.First, the ocean circulation is represented in (S,T) coordinates, by the diathermohaline streamfunction. Framing the ocean circulation in (S,T) coordinates, isolates the component of the circulation that is directly related to water-mass transformation.Because water-mass transformation is directly related to fluxes of salt and heat, this framework allows for the formulation of an inverse method in which the diathermohaline streamfunction is balanced with known air-sea forcing and unknown mixing. When applying this inverse method to observations, we obtain observationally based estimates for both the streamfunction and the mixing. The results reveal new information about the component of the global ocean circulation due to water-mass transformation and its relation to surface freshwater and heat fluxes and small-scale and mesoscale mixing. The results provide global constraints on spatially varying patterns of diffusivities, in order to obtain a realistic overturning circulation. We find that mesoscale isopycnal mixing is much smaller than expected. These results are important for our understanding of the relation between global ocean circulation and mixing and may lead to improved parameterisations in numerical ocean models.

Results of the NASP Ames Integrated Mixing Hypersonic Engine (AIMHYE) Scramjet Test Program

NASA Technical Reports Server (NTRS)

Cavolowsky, John A.; Loomis, Mark P.; Deiwert, George S.

1995-01-01

This paper describes the test techniques and results from the National Aerospace Plane Government Work Package 53, the Ames Integrated Mixing Hypersonic Engine (AIMHYE) Scramjet Test program conducted in the NASA Ames 16-Inch Combustion Driven Shock Tunnel. This was a series of near full-scale scramjet combustor tests with the objective to obtain high speed combustor and nozzle data from an engine with injector configurations similar to the NASP E21 and E22a designs. The experimental test approach was to use a large combustor model (80-100% throat height) designed and fabricated for testing in the semi-free jet mode. The conditions tested were similar to the "blue book" conditions at Mach 12, 14, and 16. GWP 53 validated use of large, long test time impulse facilities, specifically the Ames 16-Inch Shock Tunnel, for high Mach number scramjet propulsion testing an integrated test rig (inlet, combustor, and nozzle). Discussion of key features of the test program will include: effects of the 2-D combustor inlet pressure profile; performance of large injectors' fueling system that included nozzlettes, base injection, and film cooling; and heat transfer measurements to the combustor. Significant instrumentation development and application efforts include the following: combustor force balance application for measurement of combustor drag for comparison with integrated point measurements of skin friction; nozzle metric strip for measuring thrust with comparison to integrated pressure measurements; and nonintrusive optical fiber-based diode laser absorption measurements of combustion products for determination of combustor performance. Direct measurements will be reported for specific test article configurations and compared with CFD solutions.

Simulation of mixing in the quick quench region of a rich burn-quick quench mix-lean burn combustor

NASA Technical Reports Server (NTRS)

Shih, Tom I.-P.; Nguyen, H. Lee; Howe, Gregory W.; Li, Z.

1991-01-01

A computer program was developed to study the mixing process in the quick quench region of a rich burn-quick quench mix-lean burn combustor. The computer program developed was based on the density-weighted, ensemble-averaged conservation equations of mass, momentum (full compressible Navier-Stokes), total energy, and species, closed by a k-epsilon turbulence model with wall functions. The combustion process was modeled by a two-step global reaction mechanism, and NO(x) formation was modeled by the Zeldovich mechanism. The formulation employed in the computer program and the essence of the numerical method of solution are described. Some results obtained for nonreacting and reacting flows with different main-flow to dilution-jet momentum flux ratios are also presented.

Mixing times in a stirred vessel with a modified turbine.

PubMed

Bombač, Andrej; Beader, Dečan; Zun, Iztok

2012-12-01

We present a mixing-time analysis for a double-disk turbine (DDT, SI Pat.No. 22243) and the well-known Rushton turbine (RuT) based on liquid stirring in a baffled vessel. The mixing time was measured locally based on the pulse/response technique. A small quantity of hot water, poured into the liquid bulk, just above the measurement location, was used as the pulse, while the change in the liquid temperature represented the system response. The results were obtained in two ways: (i) from measurements on the set-up and (ii) based on a CFD analysis. The pouring of the hot water was numerically simulated through the initialization of the scalar field. The duration of the temperature-pulse initialization around the measuring location corresponded to the pouring time in the experiment. All the energy introduced was freely swept away by the flow. The CFD-analyzed mixing times were consistently higher than the measured ones across the whole testing range, from 150 to 460 min-1. When comparing our mixing-time results with those from the literature based on a dimensionless mixing time we found them to be in good agreement.

Contribution of Surface Thermal Forcing to Mixing in the Ocean

NASA Astrophysics Data System (ADS)

Wang, Fei; Huang, Shi-Di; Xia, Ke-Qing

2018-02-01

A critical ingredient of the meridional overturning circulation (MOC) is vertical mixing, which causes dense waters in the deep sea to rise throughout the stratified interior to the upper ocean. Here, we report a laboratory study aimed at understanding the contributions from surface thermal forcing (STF) to this mixing process. Our study reveals that the ratio of the thermocline thickness to the fluid depth largely determines the mixing rate and the mixing efficiency in an overturning flow driven by STF. By applying this finding to a hypothetical MOC driven purely by STF, we obtain a mixing rate of O(10-6 m2/s) and a corresponding meridional heat flux of O(10-2 petawatt, PW), which are far smaller than the values found for real oceans. These results provide quantitative support for the notion that STF alone is not sufficient to drive the MOC, which essentially acts as a heat conveyor belt powered by other energy sources.

Optimal Weights Mixed Filter for removing mixture of Gaussian and impulse noises

PubMed Central

Grama, Ion; Liu, Quansheng

2017-01-01

In this paper we consider the problem of restoration of a image contaminated by a mixture of Gaussian and impulse noises. We propose a new statistic called ROADGI which improves the well-known Rank-Ordered Absolute Differences (ROAD) statistic for detecting points contaminated with the impulse noise in this context. Combining ROADGI statistic with the method of weights optimization we obtain a new algorithm called Optimal Weights Mixed Filter (OWMF) to deal with the mixed noise. Our simulation results show that the proposed filter is effective for mixed noises, as well as for single impulse noise and for single Gaussian noise. PMID:28692667

Optimal Weights Mixed Filter for removing mixture of Gaussian and impulse noises.

PubMed

Jin, Qiyu; Grama, Ion; Liu, Quansheng

2017-01-01

In this paper we consider the problem of restoration of a image contaminated by a mixture of Gaussian and impulse noises. We propose a new statistic called ROADGI which improves the well-known Rank-Ordered Absolute Differences (ROAD) statistic for detecting points contaminated with the impulse noise in this context. Combining ROADGI statistic with the method of weights optimization we obtain a new algorithm called Optimal Weights Mixed Filter (OWMF) to deal with the mixed noise. Our simulation results show that the proposed filter is effective for mixed noises, as well as for single impulse noise and for single Gaussian noise.

The Value of Mixed Methods Research: A Mixed Methods Study

ERIC Educational Resources Information Center

McKim, Courtney A.

2017-01-01

The purpose of this explanatory mixed methods study was to examine the perceived value of mixed methods research for graduate students. The quantitative phase was an experiment examining the effect of a passage's methodology on students' perceived value. Results indicated students scored the mixed methods passage as more valuable than those who…

Theoretical study of mixing in liquid clouds – Part 1: Classical concepts

DOE PAGES

Korolev, Alexei; Khain, Alex; Pinsky, Mark; ...

2016-07-28

The present study considers final stages of in-cloud mixing in the framework of classical concept of homogeneous and extreme inhomogeneous mixing. Simple analytical relationships between basic microphysical parameters were obtained for homogeneous and extreme inhomogeneous mixing based on the adiabatic consideration. It was demonstrated that during homogeneous mixing the functional relationships between the moments of the droplets size distribution hold only during the primary stage of mixing. Subsequent random mixing between already mixed parcels and undiluted cloud parcels breaks these relationships. However, during extreme inhomogeneous mixing the functional relationships between the microphysical parameters hold both for primary and subsequent mixing.more » The obtained relationships can be used to identify the type of mixing from in situ observations. The effectiveness of the developed method was demonstrated using in situ data collected in convective clouds. It was found that for the specific set of in situ measurements the interaction between cloudy and entrained environments was dominated by extreme inhomogeneous mixing.« less

Development of a nonlocal convective mixing scheme with varying upward mixing rates for use in air quality and chemical transport models.

PubMed

Mihailović, Dragutin T; Alapaty, Kiran; Sakradzija, Mirjana

2008-06-01

Asymmetrical convective non-local scheme (CON) with varying upward mixing rates is developed for simulation of vertical turbulent mixing in the convective boundary layer in air quality and chemical transport models. The upward mixing rate form the surface layer is parameterized using the sensible heat flux and the friction and convective velocities. Upward mixing rates varying with height are scaled with an amount of turbulent kinetic energy in layer, while the downward mixing rates are derived from mass conservation. This scheme provides a less rapid mass transport out of surface layer into other layers than other asymmetrical convective mixing schemes. In this paper, we studied the performance of a nonlocal convective mixing scheme with varying upward mixing in the atmospheric boundary layer and its impact on the concentration of pollutants calculated with chemical and air-quality models. This scheme was additionally compared versus a local eddy-diffusivity scheme (KSC). Simulated concentrations of NO(2) and the nitrate wet deposition by the CON scheme are closer to the observations when compared to those obtained from using the KSC scheme. Concentrations calculated with the CON scheme are in general higher and closer to the observations than those obtained by the KSC scheme (of the order of 15-20%). Nitrate wet deposition calculated with the CON scheme are in general higher and closer to the observations than those obtained by the KSC scheme. To examine the performance of the scheme, simulated and measured concentrations of a pollutant (NO(2)) and nitrate wet deposition was compared for the year 2002. The comparison was made for the whole domain used in simulations performed by the chemical European Monitoring and Evaluation Programme Unified model (version UNI-ACID, rv2.0) where schemes were incorporated.

Why, and how, mixed methods research is undertaken in health services research in England: a mixed methods study

PubMed Central

O'Cathain, Alicia; Murphy, Elizabeth; Nicholl, Jon

2007-01-01

Background Recently, there has been a surge of international interest in combining qualitative and quantitative methods in a single study – often called mixed methods research. It is timely to consider why and how mixed methods research is used in health services research (HSR). Methods Documentary analysis of proposals and reports of 75 mixed methods studies funded by a research commissioner of HSR in England between 1994 and 2004. Face-to-face semi-structured interviews with 20 researchers sampled from these studies. Results 18% (119/647) of HSR studies were classified as mixed methods research. In the documentation, comprehensiveness was the main driver for using mixed methods research, with researchers wanting to address a wider range of questions than quantitative methods alone would allow. Interviewees elaborated on this, identifying the need for qualitative research to engage with the complexity of health, health care interventions, and the environment in which studies took place. Motivations for adopting a mixed methods approach were not always based on the intrinsic value of mixed methods research for addressing the research question; they could be strategic, for example, to obtain funding. Mixed methods research was used in the context of evaluation, including randomised and non-randomised designs; survey and fieldwork exploratory studies; and instrument development. Studies drew on a limited number of methods – particularly surveys and individual interviews – but used methods in a wide range of roles. Conclusion Mixed methods research is common in HSR in the UK. Its use is driven by pragmatism rather than principle, motivated by the perceived deficit of quantitative methods alone to address the complexity of research in health care, as well as other more strategic gains. Methods are combined in a range of contexts, yet the emerging methodological contributions from HSR to the field of mixed methods research are currently limited to the single

CFD simulation of local and global mixing time in an agitated tank

NASA Astrophysics Data System (ADS)

Li, Liangchao; Xu, Bin

2017-01-01

The Issue of mixing efficiency in agitated tanks has drawn serious concern in many industrial processes. The turbulence model is very critical to predicting mixing process in agitated tanks. On the basis of computational fluid dynamics(CFD) software package Fluent 6.2, the mixing characteristics in a tank agitated by dual six-blade-Rushton-turbines(6-DT) are predicted using the detached eddy simulation(DES) method. A sliding mesh(SM) approach is adopted to solve the rotation of the impeller. The simulated flow patterns and liquid velocities in the agitated tank are verified by experimental data in the literature. The simulation results indicate that the DES method can obtain more flow details than Reynolds-averaged Navier-Stokes(RANS) model. Local and global mixing time in the agitated tank is predicted by solving a tracer concentration scalar transport equation. The simulated results show that feeding points have great influence on mixing process and mixing time. Mixing efficiency is the highest for the feeding point at location of midway of the two impellers. Two methods are used to determine global mixing time and get close result. Dimensionless global mixing time remains unchanged with increasing of impeller speed. Parallel, merging and diverging flow pattern form in the agitated tank, respectively, by changing the impeller spacing and clearance of lower impeller from the bottom of the tank. The global mixing time is the shortest for the merging flow, followed by diverging flow, and the longest for parallel flow. The research presents helpful references for design, optimization and scale-up of agitated tanks with multi-impeller.

Investigation of mixed saliva by optoelectronic methods

NASA Astrophysics Data System (ADS)

Savchenko, Ekaterina; Nepomnyashchaya, Elina; Baranov, Maksim; Velichko, Elena; Aksenov, Evgenii; Bogomaz, Tatyana

2018-04-01

At present, saliva and its properties are being actively studied. Human saliva is a unique biological material that has potential in clinical practice. A detailed analysis of the characteristics and properties of saliva is relevant for diagnostic purposes. In this paper, the properties and characteristics of saliva are studied using optoelectronic methods: dynamic light scattering, electrophoretic light scattering and optical microscopy. Mixed saliva from a healthy patient and patient with diabetes mellitus type 2 was used as an object of the study. The dynamics of the behavior of a healthy and patient with diabetes mellitus type 2 is visible according to the results obtained. All three methods confirm hypothesis of structural changes in mixed saliva in the disease of diabetes mellitus type 2.

Illusory color mixing upon perceptual fading and filling-in does not result in 'forbidden colors'.

PubMed

Hsieh, P-J; Tse, P U

2006-07-01

A retinally stabilized object readily undergoes perceptual fading. It is commonly believed that the color of the apparently vanished object is filled in with the color of the background because the features of the filled-in area are determined by features located outside the stabilized boundary. Crane, H. D., & Piantanida, T. P. (1983) (On seeing reddish green and yellowish blue. Science, 221, 1078-1080) reported that the colors that are perceived upon full or partial perceptual fading can be 'forbidden' in the sense that they violate color opponency theory. For example, they claimed that their subjects could perceive "reddish greens" and "yellowish blues." Here we use visual stimuli composed of spatially alternating stripes of two different colors to investigate the characteristics of color mixing during perceptual filling-in, and to determine whether 'forbidden colors' really occur. Our results show that (1) the filled-in color is not solely determined by the background color, but can be the mixture of the background and the foreground color; (2) apparent color mixing can occur even when the two colors are presented to different eyes, implying that color mixing during filling-in is in part a cortical phenomenon; and (3) perceived colors are not 'forbidden colors' at all, but rather intermediate colors.

Molecular organization of a water-insoluble iridium(III) complex in mixed monolayers.

PubMed

Giner-Casares, Juan J; Pérez-Morales, Marta; Bolink, Henk J; Muñoz, Eulogia; de Miguel, Gustavo; Martín-Romero, María T; Camacho, Luis

2007-11-01

In this work, organized mixed monolayers containing a cationic water-insoluble iridium(III) complex, Ir-dye, [Ir(ppy)(2)(tmphen)]PF(6), (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline, and ppy = 2-phenylpyridine), and an anionic lipid matrix, DMPA, dimyristoyl-phosphatidic acid, with different molar proportions, were formed by the co-spreading method at the air-water interface. The presence of the dye at the interface, as well as the molecular organization of the mixed films, is deduced from surface techniques such as pi-A isotherms, Brewster angle microscopy (BAM) and reflection spectroscopy. The results obtained remark the formation of an equimolar mixed film, Ir-dye/DMPA = 1:1. BAM images reveal a whole homogeneous monolayer, with gradually increasing reflectivity along the compression process up to reaching the collapse of this equimolecular monolayer at pi approximately equal to 37 mNm(-1). Increasing the molar ratio of DMPA in the mixture, the excess of lipid molecules organizes themselves forming dark flower-like domains of pure DMPA at high surface pressures, coexisting with the mixed Ir-dye/DMPA = 1:1 monolayer. On the other hand, unstable mixed monolayers are obtained by using an initial dye surface concentration higher than the equimolecular one. These mixed Langmuir monolayers have been successfully transferred onto solid substrates by the LB (Langmuir-Blodgett) technique.

Laser wound: (two) mixed-beam (cw Nd:YAG-PW XeCl) lasing results in mixed injuries

NASA Astrophysics Data System (ADS)

Kull, Mart M.; Kruuv, H.; Zeltzer, Gregory L.; Nevorotin, Alexey J.

1992-08-01

The POLYCON system has been developed for simultaneous passage of different laser beams to a target. In this study, CW Nd:YAG (9 W/cm2) and XeCl excimer (30 mJ/pulse, 80 nsec, 10 Hz) laser beams were directed via individual fibers to a cone-shaped optical mixer continuously connected at the site of its outlet aperture with a common flexible cable destined for surgery. Contact mode cuts were made on rat liver and biopsy samples taken for electron microscopy. Injuries of mixed type have been found within the same cells, e.g., mitochondrial ballooning detected recently after Nd:YAG and vesiculation of the endoplasmic reticulum which is a feature characteristic of XeCl excimer laser. Taking into consideration satisfactory cutting properties, good hemostatic effect and favorable prognosis for recovery as evidenced by active phagocytosis along with proteolytic digestibility of debris in the wound, mixed beam lasing with the parameters tested can be approved as a perspective kind of surgery. In one study, a low potential for healing after CW mode Nd:YAG lasing has been revealed by specially devised tests. Contrary to that, the PW mode XeCl laser has been shown to provide better conditions for local recovery not incompatible with the impression of other workers. The excimers are also believed to be good cutters but they are mainly utilized in the experiments on tissues with low blood supply, due presumably to inherent poor hemostatic capacity of these tools. The lasers of that kind would undoubtedly be tried for tissues with high levels of blood supply provided hemostasis could be secured at the site of surgery by some means. In this paper, such a means is offered, and it is a mixed beam system in which XeCl excimer laser is used in the capacity of a cutter while Nd:YAG one is operating to stop bleeding with minimal side effects on healing in the post-operation period.

High-temperature apparatus for chaotic mixing of natural silicate melts

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

Morgavi, D.; Petrelli, M.; Vetere, F. P.

2015-10-15

A unique high-temperature apparatus was developed to trigger chaotic mixing at high-temperature (up to 1800 °C). This new apparatus, which we term Chaotic Magma Mixing Apparatus (COMMA), is designed to carry out experiments with high-temperature and high-viscosity (up to 10{sup 6} Pa s) natural silicate melts. This instrument allows us to follow in time and space the evolution of the mixing process and the associated modulation of chemical composition. This is essential to understand the dynamics of magma mixing and related chemical exchanges. The COMMA device is tested by mixing natural melts from Aeolian Islands (Italy). The experiment was performed atmore » 1180 °C using shoshonite and rhyolite melts, resulting in a viscosity ratio of more than three orders of magnitude. This viscosity ratio is close to the maximum possible ratio of viscosity between high-temperature natural silicate melts. Results indicate that the generated mixing structures are topologically identical to those observed in natural volcanic rocks highlighting the enormous potential of the COMMA to replicate, as a first approximation, the same mixing patterns observed in the natural environment. COMMA can be used to investigate in detail the space and time development of magma mixing providing information about this fundamental petrological and volcanological process that would be impossible to investigate by direct observations. Among the potentials of this new experimental device is the construction of empirical relationships relating the mixing time, obtained through experimental time series, and chemical exchanges between the melts to constrain the mixing-to-eruption time of volcanic systems, a fundamental topic in volcanic hazard assessment.« less

High-temperature apparatus for chaotic mixing of natural silicate melts.

PubMed

Morgavi, D; Petrelli, M; Vetere, F P; González-García, D; Perugini, D

2015-10-01

A unique high-temperature apparatus was developed to trigger chaotic mixing at high-temperature (up to 1800 °C). This new apparatus, which we term Chaotic Magma Mixing Apparatus (COMMA), is designed to carry out experiments with high-temperature and high-viscosity (up to 10(6) Pa s) natural silicate melts. This instrument allows us to follow in time and space the evolution of the mixing process and the associated modulation of chemical composition. This is essential to understand the dynamics of magma mixing and related chemical exchanges. The COMMA device is tested by mixing natural melts from Aeolian Islands (Italy). The experiment was performed at 1180 °C using shoshonite and rhyolite melts, resulting in a viscosity ratio of more than three orders of magnitude. This viscosity ratio is close to the maximum possible ratio of viscosity between high-temperature natural silicate melts. Results indicate that the generated mixing structures are topologically identical to those observed in natural volcanic rocks highlighting the enormous potential of the COMMA to replicate, as a first approximation, the same mixing patterns observed in the natural environment. COMMA can be used to investigate in detail the space and time development of magma mixing providing information about this fundamental petrological and volcanological process that would be impossible to investigate by direct observations. Among the potentials of this new experimental device is the construction of empirical relationships relating the mixing time, obtained through experimental time series, and chemical exchanges between the melts to constrain the mixing-to-eruption time of volcanic systems, a fundamental topic in volcanic hazard assessment.

Computation of turbulent high speed mixing layers using a two-equation turbulence model

NASA Technical Reports Server (NTRS)

Narayan, J. R.; Sekar, B.

1991-01-01

A two-equation turbulence model was extended to be applicable for compressible flows. A compressibility correction based on modelling the dilational terms in the Reynolds stress equations were included in the model. The model is used in conjunction with the SPARK code for the computation of high speed mixing layers. The observed trend of decreasing growth rate with increasing convective Mach number in compressible mixing layers is well predicted by the model. The predictions agree well with the experimental data and the results from a compressible Reynolds stress model. The present model appears to be well suited for the study of compressible free shear flows. Preliminary results obtained for the reacting mixing layers are included.

Numerical simulation of mechanical mixing in high solid anaerobic digester.

PubMed

Yu, Liang; Ma, Jingwei; Chen, Shulin

2011-01-01

Computational fluid dynamics (CFD) was employed to study mixing performance in high solid anaerobic digester (HSAD) with A-310 impeller and helical ribbon. A mathematical model was constructed to assess flow fields. Good agreement of the model results with experimental data was obtained for the A-310 impeller. A systematic comparison for the interrelationship of power number, flow number and Reynolds number was simulated in a digester with less than 5% TS and 10% TS (total solids). The simulation results suggested a great potential for using the helical ribbon mixer in the mixing of high solids digester. The results also provided quantitative confirmation for minimum power consumption in HSAD and the effect of share rate on bio-structure. Copyright © 2010 Elsevier Ltd. All rights reserved.

Breaking from binaries - using a sequential mixed methods design.

PubMed

Larkin, Patricia Mary; Begley, Cecily Marion; Devane, Declan

2014-03-01

To outline the traditional worldviews of healthcare research and discuss the benefits and challenges of using mixed methods approaches in contributing to the development of nursing and midwifery knowledge. There has been much debate about the contribution of mixed methods research to nursing and midwifery knowledge in recent years. A sequential exploratory design is used as an exemplar of a mixed methods approach. The study discussed used a combination of focus-group interviews and a quantitative instrument to obtain a fuller understanding of women's experiences of childbirth. In the mixed methods study example, qualitative data were analysed using thematic analysis and quantitative data using regression analysis. Polarised debates about the veracity, philosophical integrity and motivation for conducting mixed methods research have largely abated. A mixed methods approach can contribute to a deeper, more contextual understanding of a variety of subjects and experiences; as a result, it furthers knowledge that can be used in clinical practice. The purpose of the research study should be the main instigator when choosing from an array of mixed methods research designs. Mixed methods research offers a variety of models that can augment investigative capabilities and provide richer data than can a discrete method alone. This paper offers an example of an exploratory, sequential approach to investigating women's childbirth experiences. A clear framework for the conduct and integration of the different phases of the mixed methods research process is provided. This approach can be used by practitioners and policy makers to improve practice.

Mixed formulation for frictionless contact problems

NASA Technical Reports Server (NTRS)

Noor, Ahmed K.; Kim, Kyun O.

1989-01-01

Simple mixed finite element models and a computational precedure are presented for the solution of frictionless contact problems. The analytical formulation is based on a form of Reissner's large rotation theory of the structure with the effects of transverse shear deformation included. The contact conditions are incorporated into the formulation by using a perturbed Lagrangian approach with the fundamental unknowns consisting of the internal forces (stress resultants), the generalized displacements, and the Lagrange multipliers associated with the contact conditions. The element characteristic array are obtained by using a modified form of the two-field Hellinger-Reissner mixed variational principle. The internal forces and the Lagrange multipliers are allowed to be discontinuous at interelement boundaries. The Newton-Raphson iterative scheme is used for the solution of the nonlinear algebraic equations, and the determination of the contact area and the contact pressures.

Results of the 2013 UT modeling benchmark obtained with models implemented in CIVA

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

Toullelan, Gwénaël; Raillon, Raphaële; Chatillon, Sylvain

The 2013 Ultrasonic Testing (UT) modeling benchmark concerns direct echoes from side drilled holes (SDH), flat bottom holes (FBH) and corner echoes from backwall breaking artificial notches inspected with a matrix phased array probe. This communication presents the results obtained with the models implemented in the CIVA software: the pencilmodel is used to compute the field radiated by the probe, the Kirchhoff approximation is applied to predict the response of FBH and notches and the SOV (Separation Of Variables) model is used for the SDH responses. The comparison between simulated and experimental results are presented and discussed.

Comparison of results obtained with various sensors used to measure fluctuating quantities in jets.

NASA Technical Reports Server (NTRS)

Parthasarathy, S. P.; Massier, P. F.; Cuffel, R. F.

1973-01-01

An experimental investigation has been conducted to compare the results obtained with six different instruments that sense fluctuating quantities in free jets. These sensors are typical of those that have recently been used by various investigators who are engaged in experimental studies of jet noise. Intensity distributions and two-point correlations with space separation and time delay were obtained. The static pressure, density, and velocity fluctuations are well correlated over the entire cross section of the jet and the cross-correlations persist for several jet diameters along the flow direction. The eddies appear to be flattened in the flow direction by a ratio of 0.4.

An approach for accurate simulation of liquid mixing in a T-shaped micromixer.

PubMed

Matsunaga, Takuya; Lee, Ho-Joon; Nishino, Koichi

2013-04-21

In this paper, we propose a new computational method for efficient evaluation of the fluid mixing behaviour in a T-shaped micromixer with a rectangular cross section at high Schmidt number under steady state conditions. Our approach enables a low-cost high-quality simulation based on tracking of fluid particles for convective fluid mixing and posterior solving of a model of the species equation for molecular diffusion. The examined parameter range is Re = 1.33 × 10(-2) to 240 at Sc = 3600. The proposed method is shown to simulate well the mixing quality even in the engulfment regime, where the ordinary grid-based simulation is not able to obtain accurate solutions with affordable mesh sizes due to the numerical diffusion at high Sc. The obtained results agree well with a backward random-walk Monte Carlo simulation, by which the accuracy of the proposed method is verified. For further investigation of the characteristics of the proposed method, the Sc dependency is examined in a wide range of Sc from 10 to 3600 at Re = 200. The study reveals that the model discrepancy error emerges more significantly in the concentration distribution at lower Sc, while the resulting mixing quality is accurate over the entire range.

Analysis of Electrokinetic Mixing Using AC Electric Field and Patchwise Surface Heterogeneities

NASA Astrophysics Data System (ADS)

Luo, Win-Jet; Yarn, Kao-Feng; Hsu, Shou-Ping

2007-04-01

In this paper, the authors investigate the use of an applied AC electric field and microchannel surface heterogeneities to carry out the microfluidic mixing of two-dimensional, time-dependent electroosmotic flows. The time-dependent flow fields within the microchannel are simulated using the backwards-Euler time-stepping numerical method. The mixing efficiencies obtained in microchannels with two different patchwise surface heterogeneity patterns are investigated. In general, the results show that the application of an AC electric field significantly reduces the required mixing length compared with the use of a DC electric field. Furthermore, the presence of oppositely charged surface heterogeneities on the microchannel walls results in the formation of localized flow circulation regions within the bulk flow. These circulation regions grow and decay periodically in accordance with the periodic variation of the AC electric field intensity and provide an effective means of enhancing species mixing in the microchannel. Consequently, the use of an AC electric field together with patchwise surface heterogeneities permits a significant reduction in both the mixing channel length and the retention time required to attain a homogeneous solution.

FT-IR microspectroscopy in rapid identification of bacteria in pure and mixed culture

NASA Astrophysics Data System (ADS)

Fontoura, Inglid; Belo, Ricardo; Sakane, Kumiko; Cardoso, Maria Angélica Gargione; Khouri, Sônia; Uehara, Mituo; Raniero, Leandro; Martin, Airton A.

2010-02-01

In recent years FT-IR microspectroscopy has been developed for microbiology analysis and applied successfully in pure cultures of microorganisms to rapidly identify strains of bacteria, yeasts and fungi. The investigation and characterization of microorganism mixed cultures is also of growing importance, especially in hospitals where it is common to poly-microbial infections. In this work, the rapid identification of bacteria in pure and mixed cultures was studied. The bacteria were obtained from the Institute Oswaldo Cruz culture collection at Brazil. Escherichia coli ATCC 10799 and Staphylococcus aureus ATCC 14456 were analyzed, 3 inoculations were examined in triplicate: Escherichia coli, Staphylococcus aureus and a mixed culture of them. The inoculations were prepared according to McFarland 0.5, incubated at 37 ° C for 6 hours, diluted in saline, placed in the CaF2 window and store for one hour at 50°C to obtain thin film. The measurement was performed by Spectrum Spotlight 400 (Perkin-Elmer) equipment in the range of 4000-900 cm-1, with 32 scans using a transmittance technique with point and image modes. The data were processed (baseline, normalization, calculation of first derivate followed by smoothing with 9 point using a Savitzky-Golay algorithm) and a cluster analysis were done by Ward's algorithm and an excellent discrimination between pure and mixed culture was obtained. Our preliminary results indicate that the FT-IR microspectroscopy associated with cluster analysis can be used to discriminate between pure and mixed culture.

Balanced detection for self-mixing interferometry to improve signal-to-noise ratio

NASA Astrophysics Data System (ADS)

Zhao, Changming; Norgia, Michele; Li, Kun

2018-01-01

We apply balanced detection to self-mixing interferometry for displacement and vibration measurement, using two photodiodes for implementing a differential acquisition. The method is based on the phase opposition of the self-mixing signal measured between the two laser diode facet outputs. The balanced signal obtained by enlarging the self-mixing signal, also by canceling of the common-due noises mainly due to disturbances on laser supply and transimpedance amplifier. Experimental results demonstrate the signal-to-noise ratio significantly improves, with almost twice signals enhancement and more than half noise decreasing. This method allows for more robust, longer-distance measurement systems, especially using fringe-counting.

Modifications to JLab 12 GeV Refrigerator and Wide Range Mix Mode Performance Testing Results

NASA Astrophysics Data System (ADS)

Knudsen, P.; Ganni, V.; Hasan, N.; Dixon, K.; Norton, R.; Creel, J.

2017-02-01

Analysis of data obtained during the spring 2013 commissioning of the new 4.5 K refrigeration system at Jefferson Lab (JLab) for the 12 GeV upgrade indicated a wide capacity range with good efficiency and minimal operator interaction. Testing also showed that the refrigerator required higher liquid nitrogen (LN) consumption for its pre-cooler than anticipated by the design. This does not affect the capacity of the refrigerator, but it does result in an increased LN utility cost. During the summer of 2015 the modifications were implemented by the cold box manufacturer, according to a design similar to the JLab 12 GeV cold box specification. Subsequently, JLab recommissioned the cold box and performed extensive performance testing, ranging from 20% to 100% of the design maximum capacity, and in various modes of operation, ranging from pure refrigeration, pure liquefaction, half-and-half mix mode and at selected design modes using the Floating Pressure - Ganni Cycle. The testing demonstrated that the refrigerator system has a good and fairly constant performance over a wide capacity range and different modes of operation. It also demonstrated the modifications resulted in a LN consumption that met the design for the pure refrigeration mode (which is the most demanding) and was lower than the design for the nominal and maximum capacity modes. In addition, a pulsed-load test, similar to what is expected for cryogenic systems supporting fusion experiments, was conducted to observe the response using the Floating Pressure - Ganni Cycle, which was stable and robust. This paper will discuss the results and analysis of this testing pertaining to the LN consumption, the system efficiency over a wide range of capacity and different modes and the behaviour of the system to a pulsed load.

Δmix parameter in the overlap on domain-wall mixed action

NASA Astrophysics Data System (ADS)

Lujan, M.; Alexandru, A.; Chen, Y.; Draper, T.; Freeman, W.; Gong, M.; Lee, F. X.; Li, A.; Liu, K. F.; Mathur, N.

2012-07-01

A direct calculation of the mixed action parameter Δmix with valence overlap fermions on a domain-wall fermion sea is presented. The calculation is performed on four ensembles of the 2+1 flavor domain-wall gauge configurations: 243×64 (aml=0.005, a=0.114fm) and 323×64 (aml=0.004, 0.006, 0.008, a=0.085fm). For pion masses close to 300 MeV we find Δmix=0.030(6)GeV4 at a=0.114fm and Δmix=0.033(12)GeV4 at a=0.085fm. The results are quite independent of the lattice spacing and they are significantly smaller than the results for valence domain-wall fermions on asqtad sea or those of valence overlap fermions on clover sea. Combining the results extracted from these two ensembles, we get Δmix=0.030(6)(5)GeV4, where the first error is statistical and the second is the systematic error associated with the fitting method.

Mixed-methods evaluation of a novel online STI results service.

PubMed

Gibbs, Jo; Aicken, Catherine R H; Sutcliffe, Lorna J; Gkatzidou, Voula; Tickle, Laura J; Hone, Kate; Sadiq, S Tariq; Sonnenberg, Pam; Estcourt, Claudia S

2018-01-11

Evidence on optimal methods for providing STI test results is lacking. We evaluated an online results service, developed as part of an eSexual Health Clinic (eSHC). We evaluated the online results service using a mixed-methods approach within large exploratory studies of the eSHC. Participants were chlamydia- positive and negative users of online postal self-sampling services in six National Chlamydia Screening Programme (NCSP) areas and chlamydia-positive patients from two genitourinary medicine (GUM) clinics between 21 July 2014 and 13 March 2015. Participants received a discreetly worded National Health Service 'NHS no-reply' text message (SMS) informing them that their test results were ready and providing a weblink to a secure website. Participants logged in with their date of birth and mobile telephone or clinic number. Chlamydia-positive patients were offered online management. All interactions with the eSHC system were automatically logged and their timing recorded. Post-treatment, a service evaluation survey (n=152) and qualitative interviews (n=36) were conducted by telephone. Chlamydia-negative patients were offered a short online survey (n=274). Data were integrated. 92% (134/146) of NCSP chlamydia-positive patients, 82% (161/197) of GUM chlamydia-positive patients and 89% (1776/1997) of NCSP chlamydia-negative participants accessed test results within 7 days. 91% of chlamydia-positive patients were happy with the results service; 64% of those who had tested previously found the results service better or much better than previous experiences. 90% of chlamydia-negative survey participants agreed they would be happy to receive results this way in the future. Interviewees described accessing results with ease and appreciated the privacy and control the two-step process gave them. A discreet SMS to alert users/patients that results are available, followed by provision of results via a secure website, was highly acceptable, irrespective of test result and

Mixing, ergodicity and slow relaxation phenomena

NASA Astrophysics Data System (ADS)

Costa, I. V. L.; Vainstein, M. H.; Lapas, L. C.; Batista, A. A.; Oliveira, F. A.

2006-11-01

Investigations on diffusion in systems with memory [I.V.L. Costa, R. Morgado, M.V.B.T. Lima, F.A. Oliveira, Europhys. Lett. 63 (2003) 173] have established a hierarchical connection between mixing, ergodicity, and the fluctuation-dissipation theorem (FDT). This hierarchy means that ergodicity is a necessary condition for the validity of the FDT, and mixing is a necessary condition for ergodicity. In this work, we compare those results with recent investigations using the Lee recurrence relations method [M.H. Lee, Phys. Rev. B 26 (1982) 2547; M.H. Lee, Phys. Rev. Lett. 87 (2001) 250601; M.H. Lee, J. Phys. A: Math. Gen. 39 (2006) 4651]. Lee shows that ergodicity is violated in the dynamics of the electron gas [M.H. Lee, J. Phys. A: Math. Gen. 39 (2006) 4651]. This reinforces both works and implies that the results of [I.V.L. Costa, R. Morgado, M.V.B.T. Lima, F.A. Oliveira, Europhys. Lett. 63 (2003) 173] are more general than the framework in which they were obtained. Some applications to slow relaxation phenomena are discussed.

Heat transfer enhancement with mixing vane spacers using the field synergy principle

NASA Astrophysics Data System (ADS)

Yang, Lixin; Zhou, Mengjun; Tian, Zihao

2017-01-01

The single-phase heat transfer characteristics in a PWR fuel assembly are important. Many investigations attempt to obtain the heat transfer characteristics by studying the flow features in a 5 × 5 rod bundle with a spacer grid. The field synergy principle is used to discuss the mechanism of heat transfer enhancement using mixing vanes according to computational fluid dynamics results, including a spacer grid without mixing vanes, one with a split mixing vane, and one with a separate mixing vane. The results show that the field synergy principle is feasible to explain the mechanism of heat transfer enhancement in a fuel assembly. The enhancement in subchannels is more effective than on the rod's surface. If the pressure loss is ignored, the performance of the split mixing vane is superior to the separate mixing vane based on the enhanced heat transfer. Increasing the blending angle of the split mixing vane improves heat transfer enhancement, the maximum of which is 7.1%. Increasing the blending angle of the separate mixing vane did not significantly enhance heat transfer in the rod bundle, and even prevented heat transfer at a blending angle of 50°. This finding testifies to the feasibility of predicting heat transfer in a rod bundle with a spacer grid by field synergy, and upon comparison with analyzed flow features only, the field synergy method may provide more accurate guidance for optimizing the use of mixing vanes.

Developing a bone mineral density test result letter to send to patients: a mixed-methods study

PubMed Central

Edmonds, Stephanie W; Solimeo, Samantha L; Lu, Xin; Roblin, Douglas W; Saag, Kenneth G; Cram, Peter

2014-01-01

Purpose To use a mixed-methods approach to develop a letter that can be used to notify patients of their bone mineral density (BMD) results by mail that may activate patients in their bone-related health care. Patients and methods A multidisciplinary team developed three versions of a letter for reporting BMD results to patients. Trained interviewers presented these letters in a random order to a convenience sample of adults, aged 50 years and older, at two different health care systems. We conducted structured interviews to examine the respondents’ preferences and comprehension among the various letters. Results A total of 142 participants completed the interview. A majority of the participants were female (64.1%) and white (76.1%). A plurality of the participants identified a specific version of the three letters as both their preferred version (45.2%; P<0.001) and as the easiest to understand (44.6%; P<0.01). A majority of participants preferred that the letters include specific next steps for improving their bone health. Conclusion Using a mixed-methods approach, we were able to develop and optimize a printed letter for communicating a complex test result (BMD) to patients. Our results may offer guidance to clinicians, administrators, and researchers who are looking for guidance on how to communicate complex health information to patients in writing. PMID:24940049

Numerical analysis of mixing by sharp-edge-based acoustofluidic micromixer

NASA Astrophysics Data System (ADS)

Nama, Nitesh; Huang, Po-Hsun; Jun Huang, Tony; Costanzo, Francesco

2015-11-01

Recently, acoustically oscillated sharp-edges have been employed to realize rapid and homogeneous mixing at microscales (Huang, Lab on a Chip, 13, 2013). Here, we present a numerical model, qualitatively validated by experimental results, to analyze the acoustic mixing inside a sharp-edge-based micromixer. We extend our previous numerical model (Nama, Lab on a Chip, 14, 2014) to combine the Generalized Lagrangian Mean (GLM) theory with the convection-diffusion equation, while also allowing for the presence of a background flow as observed in a typical sharp-edge-based micromixer. We employ a perturbation approach to divide the flow variables into zeroth-, first- and second-order fields which are successively solved to obtain the Lagrangian mean velocity. The Langrangian mean velocity and the background flow velocity are further employed with the convection-diffusion equation to obtain the concentration profile. We characterize the effects of various operational and geometrical parameters to suggest potential design changes for improving the mixing performance of the sharp-edge-based micromixer. Lastly, we investigate the possibility of generation of a spatio-temporally controllable concentration gradient by placing sharp-edge structures inside the microchannel.

Some effects of swirl on turbulent mixing and combustion

NASA Technical Reports Server (NTRS)

Rubel, A.

1972-01-01

A general formulation of some effects of swirl on turbulent mixing is given. The basis for the analysis is that momentum transport is enhanced by turbulence resulting from rotational instability of the fluid field. An appropriate form for the turbulent eddy viscosity is obtained by mixing length type arguments. The result takes the form of a corrective factor that is a function of the swirl and acts to increase the eddy viscosity. The factor is based upon the initial mixing conditions implying that the rotational turbulence decays in a manner similar to that of free shear turbulence. Existing experimental data for free jet combustion are adequately matched by using the modifying factor to relate the effects of swirl on eddy viscosity. The model is extended and applied to the supersonic combustion of a ring jet of hydrogen injected into a constant area annular air stream. The computations demonstrate that swirling the flow could: (1) reduce the burning length by one half, (2) result in more uniform burning across the annulus width, and (3) open the possibility of optimization of the combustion characteristics by locating the fuel jet between the inner wall and center of the annulus width.

Using Riemannian geometry to obtain new results on Dikin and Karmarkar methods

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

Oliveira, P.; Joao, X.; Piaui, T.

1994-12-31

We are motivated by a 1990 Karmarkar paper on Riemannian geometry and Interior Point Methods. In this talk we show 3 results. (1) Karmarkar direction can be derived from the Dikin one. This is obtained by constructing a certain Z(x) representation of the null space of the unitary simplex (e, x) = 1; then the projective direction is the image under Z(x) of the affine-scaling one, when it is restricted to that simplex. (2) Second order information on Dikin and Karmarkar methods. We establish computable Hessians for each of the metrics corresponding to both directions, thus permitting the generation ofmore » {open_quotes}second order{close_quotes} methods. (3) Dikin and Karmarkar geodesic descent methods. For those directions, we make computable the theoretical Luenberger geodesic descent method, since we are able to explicit very accurate expressions of the corresponding geodesics. Convergence results are given.« less

Physical Interpretation of Mixing Diagrams

NASA Astrophysics Data System (ADS)

Khain, Alexander; Pinsky, Mark; Magaritz-Ronen, L.

2018-01-01

Type of mixing at cloud edges is often determined by means of mixing diagrams showing the dependence of normalized cube of the mean volume radius on the dilution level. The mixing diagrams correspond to the final equilibrium state of mixing between two air volumes. While interpreting in situ measurements, scattering diagrams are plotted in which normalized droplet concentration is used instead of dilution level. Utilization of such scattering diagrams for interpretation of in situ observations faces significant difficulties and often leads to misinterpretation of the mixing process and to uncertain conclusions concerning the mixing type. In this study we analyze the scattering diagrams obtained by means of a Lagrangian-Eulerian model of a stratocumulus cloud. The model consists of 2,000 interacting Largangian parcels which mix with their neighbors during their motion in the atmospheric boundary layer. In the diagram, each parcel is denoted by a point. Changes of microphysical parameters of the parcel are represented by movements of the point in the scattering diagram. The method of plotting the scattering diagrams using the model is in many aspects similar to that used in in situ measurements. It is shown that a scattering diagram shows snapshots of a transient mixing process. The location of points in the scattering diagrams reflects largely the history and the origin of air parcels. Location of points on scattering diagram characterizes intensity of entrainment, and different parameters of droplet size distributions (DSDs) like concentration, mean volume (or effective) radius, and DSD width.

Near-Infrared Scintillation of Liquid Argon: Recent Results Obtained with the NIR Facility at Fermilab

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

Escobar, C. O.; Rubinov, P.; Tilly, E.

After a short review of previous attempts to observe and measure the near-infrared scintillation in liquid argon, we present new results obtained with NIR, a dedicated cryostat at the Fermilab Proton Assembly Building (PAB). The new results give confidence that the near-infrared light can be used as the much needed light signal in large liquid argon time projection chambers.11 pages,

Experimental investigation of crossflow jet mixing in a rectangular duct

NASA Technical Reports Server (NTRS)

Liscinsky, D. S.; True, B.; Holdeman, J. D.

1993-01-01

An experimental investigation of the mixing of nonreacting opposed rows of jets injected normal to a confined rectangular crossflow has been conducted. Planar Mie-scattering was used to measure the time-average concentration distribution of the jet fluid in planes perpendicular to the duct axis. The mixing effectiveness of round orifice injectors was measured as a function of orifice spacing and orifice diameter. Mixing effectiveness was determined using a spatial unmixedness parameter based on the variance of mean jet concentration distributions. Optimum mixing was obtained when the spacing-to-duct height ratio was inversely proportional to the square root of the jet-to-mainstream momentum-flux ratio. For opposed rows of round holes with centerlines inline, mixing was similar for blockages up to 75 percent. Lower levels of unmixedness were obtained as a function of downstream location when axial injection length was minimized. Mixing may be enhanced if orifice centerlines of opposed rows are staggered, but note that blockage must be less than 50 percent for this configuration.

Simulation of uranium and plutonium oxides compounds obtained in plasma

NASA Astrophysics Data System (ADS)

Novoselov, Ivan Yu.; Karengin, Alexander G.; Babaev, Renat G.

2018-03-01

The aim of this paper is to carry out thermodynamic simulation of mixed plutonium and uranium oxides compounds obtained after plasma treatment of plutonium and uranium nitrates and to determine optimal water-salt-organic mixture composition as well as conditions for their plasma treatment (temperature, air mass fraction). Authors conclude that it needs to complete the treatment of nitric solutions in form of water-salt-organic mixtures to guarantee energy saving obtainment of oxide compounds for mixed-oxide fuel and explain the choice of chemical composition of water-salt-organic mixture. It has been confirmed that temperature of 1200 °C is optimal to practice the process. Authors have demonstrated that condensed products after plasma treatment of water-salt-organic mixture contains targeted products (uranium and plutonium oxides) and gaseous products are environmental friendly. In conclusion basic operational modes for practicing the process are showed.

Mixed or Complementary Messages: Making the Most of Unexpected Assessment Results

ERIC Educational Resources Information Center

Jones, Phil; Bauder, Julia; Engel, Kevin

2016-01-01

Grinnell College participated in ACRL's [Association of College and Research Libraries] first cohort of Assessment in Action (AiA), undertaking a mixed-methods action research project to assess the effectiveness of librarian-led research literacy sessions in improving students' research skills. The quantitative data showed that the quality of…

Direct simulations of chemically reacting turbulent mixing layers

NASA Technical Reports Server (NTRS)

Riley, J. J.; Metcalfe, R. W.

1984-01-01

The report presents the results of direct numerical simulations of chemically reacting turbulent mixing layers. The work consists of two parts: (1) the development and testing of a spectral numerical computer code that treats the diffusion reaction equations; and (2) the simulation of a series of cases of chemical reactions occurring on mixing layers. The reaction considered is a binary, irreversible reaction with no heat release. The reacting species are nonpremixed. The results of the numerical tests indicate that the high accuracy of the spectral methods observed for rigid body rotation are also obtained when diffusion, reaction, and more complex flows are considered. In the simulations, the effects of vortex rollup and smaller scale turbulence on the overall reaction rates are investigated. The simulation results are found to be in approximate agreement with similarity theory. Comparisons of simulation results with certain modeling hypotheses indicate limitations in these hypotheses. The nondimensional product thickness computed from the simulations is compared with laboratory values and is found to be in reasonable agreement, especially since there are no adjustable constants in the method.

Results of Investigative Tests of Gas Turbine Engine Compressor Blades Obtained by Electrochemical Machining

NASA Astrophysics Data System (ADS)

Kozhina, T. D.; Kurochkin, A. V.

2016-04-01

The paper highlights results of the investigative tests of GTE compressor Ti-alloy blades obtained by the method of electrochemical machining with oscillating tool-electrodes, carried out in order to define the optimal parameters of the ECM process providing attainment of specified blade quality parameters given in the design documentation, while providing maximal performance. The new technological methods suggested based on the results of the tests; in particular application of vibrating tool-electrodes and employment of locating elements made of high-strength materials, significantly extend the capabilities of this method.

Preliminary mixed-layer model results for FIRE marine stratocumulus IFO conditions

NASA Technical Reports Server (NTRS)

Barlow, R.; Nicholls, S.

1990-01-01

Some preliminary results from the Turton and Nicholls mixed layer model using typical FIRE boundary conditions are presented. The model includes entrainment and drizzle parametrizations as well as interactive long and shortwave radiation schemes. A constraint on the integrated turbulent kinetic energy balance ensures that the model remains energetically consistent at all times. The preliminary runs were used to identify the potentially important terms in the heat and moisture budgets of the cloud layer, and to assess the anticipated diurnal variability. These are compared with typical observations from the C130. Sensitivity studies also revealed the remarkable stability of these cloud sheets: a number of negative feedback mechanisms appear to operate to maintain the cloud over an extended time period. These are also discussed. The degree to which such a modelling approach can be used to explain observed features, the specification of boundary conditions and problems of interpretation in non-horizontally uniform conditions is also raised.

Search for neutral D meson mixing using semileptonic decays

NASA Astrophysics Data System (ADS)

Flood, Kevin T.

Based on a 87 fb-1 dataset, a search for D0-D¯0 mixing is made using the semileptonic decay modes D*+ → pi +D0, D0 → [K/K*]enu (+c.c.) at the B-Factory facility at the Stanford Linear Accelerator Center. These modes offer unambiguous initial and final-state charm flavor tags, and allow the combined use of the D0 lifetime and D*+- D0 mass difference (DeltaM) in a global likelihood fit. The high-statistics sample of reconstructed unmixed semileptonic D0 decays is used to model both the DeltaM distribution and the time-dependence of mixed events directly from the data. Neural networks are used both to select events and to fully reconstruct the D0. A result consistent with no charm mixing has been obtained, Rmix = 0.0023 +/- 0.0012(stat) +/- 0.0004(sys ). This corresponds to an upper limit of Rmix < 0.0047 (95% C.L.) and Rmix < 0.0043 (90% C.L.). The lowest current published limit on semileptonic charm mixing is 0.005 (90% C.L.) (E791, E.M. Aitala et al., Phys.Rev.Lett. 77 2384 (1996)). The current best published limit using any analysis technique on the total rate of charm mixing is 0.0016 (95% C.L.) (Babar Kpi mixing, B. Aubert et al., Phys.Rev.Lett. 91 171801 (2003)).

Geoelectrical signatures of reactive mixing

NASA Astrophysics Data System (ADS)

Ghosh, U.; Bandopadhyay, A.; Jougnot, D.; Le Borgne, T.; Meheust, Y.

2017-12-01

Characterizing the effects of fluid mixing on geochemical reactions in the subsurface is of paramount importance owing to their pivotal role in processes such as contaminant migration or aquifer remediation, to name a few [1]. Large velocity gradients in the porous media are expected to lead to enhanced diffusive mixing accompanied by augmented reaction rates [2]. Despite its importance, accurate monitoring of such processes still remains an open challenge, mainly due to the opacity of the medium and to the lack of access to it. However, in recent years, geophysical methods based on electrical conductivity and polarization have come up as a promising tool for mapping and monitoring such reactions in the subsurface. In this regard, one of the main challenges is to properly characterize the multiple sources of electrical signals and in particular isolate the influence of reactive mixing on the electrical conductivity from those of other sources [3]. In this work, we explore the coupling between fluid mixing, reaction and charge migration in porous media to evaluate the potential of obtaining a spatially-resolved measurement of local reaction rates in the subsurface from electrical measurements. To this end, we employ a lamellar description of the mixing interface [4] with novel semi-analytical upscaling techniques to quantify changes in electrical conductivity induced by chemical reactions across mixing fronts. The changes in electrical conductivity are strongly dependent on the concentration of ionic species as well as on the polarization of the pore (water) solution around the grains, which in turn are controlled by local reaction rates and, consequently, by the local velocity gradients. Hence, our results essentially suggest that local variations in the electrical conductivity may be quantitatively related to the mixing and reaction dynamics, and thus be used as a measurement tool to characterize these dynamics. References 1. M. Dentz, T. Le Borgne, A. Englert

Growth hormone and drug metabolism. Acute effects on microsomal mixed-function oxidase activities in rat liver.

PubMed Central

Wilson, J T; Spelsberg, T C

1976-01-01

Adult male rats were subjected either to sham operation or to hypophysectomy and adrenalectomy and maintained for a total of 10 days before treatment with growth hormone. Results of the early effects of growth hormone on the activities of the mixed-function oxidases in rat liver over a 96h period after growth-hormone treatment are presented. 2. Hypophysectomy and adrenalectomy result in decreased body and liver weight and decreased drug metabolism (mixed-function oxidases). Concentrations of electron-transport-system components are also decreased. 3. In the hypophysectomized/adrenalectomized rats, growth hormone decreases the activities of the liver mixed-function oxidases and the cytochrome P-450 and cytochrome c reductases, as well as decreasing the concentration of cytochrome P-450 compared with that of control rats. Similar but less dramatic results are obtained with sham-operated rats. 4. It is concluded that whereas growth hormone enhances liver growth, including induction of many enzyme activities, it results in a decrease in mixed-function oxidase activity. Apparently, mixed-function oxidase activity decreases in liver when growth (mitogenesis) increases. PMID:938458

Legionella in water samples: how can you interpret the results obtained by quantitative PCR?

PubMed

Ditommaso, Savina; Ricciardi, Elisa; Giacomuzzi, Monica; Arauco Rivera, Susan R; Zotti, Carla M

2015-02-01

Evaluation of the potential risk associated with Legionella has traditionally been determined from culture-based methods. Quantitative polymerase chain reaction (qPCR) is an alternative tool that offers rapid, sensitive and specific detection of Legionella in environmental water samples. In this study we compare the results obtained by conventional qPCR (iQ-Check™ Quanti Legionella spp.; Bio-Rad) and by culture method on artificial samples prepared in Page's saline by addiction of Legionella pneumophila serogroup 1 (ATCC 33152) and we analyse the selective quantification of viable Legionella cells by the qPCR-PMA method. The amount of Legionella DNA (GU) determined by qPCR was 28-fold higher than the load detected by culture (CFU). Applying the qPCR combined with PMA treatment we obtained a reduction of 98.5% of the qPCR signal from dead cells. We observed a dissimilarity in the ability of PMA to suppress the PCR signal in samples with different amounts of bacteria: the effective elimination of detection signals by PMA depended on the concentration of GU and increasing amounts of cells resulted in higher values of reduction. Using the results from this study we created an algorithm to facilitate the interpretation of viable cell level estimation with qPCR-PMA. Copyright © 2014 Elsevier Ltd. All rights reserved.

Are Bibliographic Management Software Search Interfaces Reliable?: A Comparison between Search Results Obtained Using Database Interfaces and the EndNote Online Search Function

ERIC Educational Resources Information Center

Fitzgibbons, Megan; Meert, Deborah

2010-01-01

The use of bibliographic management software and its internal search interfaces is now pervasive among researchers. This study compares the results between searches conducted in academic databases' search interfaces versus the EndNote search interface. The results show mixed search reliability, depending on the database and type of search…

When mixed methods produce mixed results: integrating disparate findings about miscarriage and women's wellbeing.

PubMed

Lee, Christina; Rowlands, Ingrid J

2015-02-01

To discuss an example of mixed methods in health psychology, involving separate quantitative and qualitative studies of women's mental health in relation to miscarriage, in which the two methods produced different but complementary results, and to consider ways in which the findings can be integrated. We describe two quantitative projects involving statistical analysis of data from 998 young women who had had miscarriages, and 8,083 who had not, across three waves of the Australian Longitudinal Study on Women's Health. We also describe a qualitative project involving thematic analysis of interviews with nine Australian women who had had miscarriages. The quantitative analyses indicate that the main differences between young women who do and do not experience miscarriage relate to social disadvantage (and thus likelihood of relatively early pregnancy) and to a lifestyle that makes pregnancy likely: Once these factors are accounted for, there are no differences in mental health. Further, longitudinal modelling demonstrates that women who have had miscarriages show a gradual increase in mental health over time, with the exception of women with prior diagnoses of anxiety, depression, or both. By contrast, qualitative analysis of the interviews indicates that women who have had miscarriages experience deep emotional responses and a long and difficult process of coming to terms with their loss. A contextual model of resilience provides a possible framework for understanding these apparently disparate results. Considering positive mental health as including the ability to deal constructively with negative life events, and consequent emotional distress, offers a model that distinguishes between poor mental health and the processes of coping with major life events. In the context of miscarriage, women's efforts to struggle with difficult emotions, and search for meaning, can be viewed as pathways to resilience rather than to psychological distress. Statement of contribution

Apparatus for mixing char-ash into coal stream

DOEpatents

Blaskowski, Henry J.

1982-03-16

Apparatus for obtaining complete mixing of char with coal prior to the introduction of the mixture into the combustor (30) of a coal gasifier (10). The coal is carried in one air stream (22), and the char in another air stream (54), to a riffle plate arrangement (26), where the streams of solid are intimately mixed or blended.

Comparisons Between NO PLIF Imaging and CFD Simulations of Mixing Flowfields for High-Speed Fuel Injectors

NASA Technical Reports Server (NTRS)

Drozda, Tomasz, G.; Cabell, Karen F.; Ziltz, Austin R.; Hass, Neil E.; Inman, Jennifer A.; Burns, Ross A.; Bathel, Brett F.; Danehy, Paul M.; Abul-Huda, Yasin M.; Gamba, Mirko

2017-01-01

The current work compares experimentally and computationally obtained nitric oxide (NO) planar laser-induced fluorescence (PLIF) images of the mixing flowfields for three types of high-speed fuel injectors: a strut, a ramp, and a rectangular flush-wall. These injection devices, which exhibited promising mixing performance at lower flight Mach numbers, are currently being studied as a part of the Enhanced Injection and Mixing Project (EIMP) at the NASA Langley Research Center. The EIMP aims to investigate scramjet fuel injection and mixing physics, and improve the understanding of underlying physical processes relevant to flight Mach numbers greater than eight. In the experiments, conducted in the NASA Langley Arc-Heated Scramjet Test Facility (AHSTF), the injectors are placed downstream of a Mach 6 facility nozzle, which simulates the high Mach number air flow at the entrance of a scramjet combustor. Helium is used as an inert substitute for hydrogen fuel. The PLIF is obtained by using a tunable laser to excite the NO, which is present in the AHSTF air as a direct result of arc-heating. Consequently, the absence of signal is an indication of pure helium (fuel). The PLIF images computed from the computational fluid dynamics (CFD) simulations are obtained by combining a fluorescence model for NO with the Reynolds-Averaged Simulation results carried out using the VULCAN-CFD solver to obtain a computational equivalent of the experimentally measured PLIF signal. The measured NO PLIF signal is mainly a function of NO concentration allowing for semi-quantitative comparisons between the CFD and the experiments. The PLIF signal intensity is also sensitive to pressure and temperature variations in the flow, allowing additional flow features to be identified and compared with the CFD. Good agreement between the PLIF and the CFD results provides increased confidence in the CFD simulations for investigations of injector performance.

To mix or not to mix venous blood samples collected in vacuum tubes?

PubMed

Parenmark, Anna; Landberg, Eva

2011-09-08

There are recommendations to mix venous blood samples by inverting the tubes immediately after venipuncture. Though mixing allows efficient anticoagulation in plasma tubes and fast initiation of coagulation in serum tubes, the effect on laboratory analyses and risk of haemolysis has not been thoroughly evaluated. Venous blood samples were collected by venipuncture in vacuum tubes from 50 patients (10 or 20 patients in each group). Four types of tubes and 18 parameters used in routine clinical chemistry were evaluated. For each patient and tube, three types of mixing strategies were used: instant mixing, no mixing and 5 min of rest followed by mixing. Most analyses did not differ significantly in samples admitted to different mixing strategies. Plasma lactate dehydrogenase and haemolysis index showed a small but significant increase in samples omitted to instant mixing compared to samples without mixing. However, in one out of twenty non-mixed samples, activated partial thromboplastin time was seriously affected. These results indicate that mixing blood samples after venipuncture is not mandatory for all types of tubes. Instant mixing may introduce interference for those analyses susceptible to haemolysis. However, tubes with liquid-based citrate buffer for coagulation testing should be mixed to avoid clotting.

Evaluation of a metering, mixing, and dispensing system for mixing polysulfide adhesive

NASA Technical Reports Server (NTRS)

Evans, Kurt B.

1989-01-01

Tests were performed to evaluate whether a metered mixing system can mix PR-1221 polysulfide adhesive as well as or better than batch-mixed adhesive; also, to evaluate the quality of meter-mixed PR-1860 and PS-875 polysulfide adhesives. These adhesives are candidate replacements for PR-1221 which will not be manufactured in the future. The following material properties were evaluated: peel strength, specific gravity and adhesive components of mixed adhesives, Shore A hardness, tensile adhesion strength, and flow rate. Finally, a visual test called the butterfly test was performed to observe for bubbles and unmixed adhesive. The results of these tests are reported and discussed.

Solving mixed integer nonlinear programming problems using spiral dynamics optimization algorithm

NASA Astrophysics Data System (ADS)

Kania, Adhe; Sidarto, Kuntjoro Adji

2016-02-01

Many engineering and practical problem can be modeled by mixed integer nonlinear programming. This paper proposes to solve the problem with modified spiral dynamics inspired optimization method of Tamura and Yasuda. Four test cases have been examined, including problem in engineering and sport. This method succeeds in obtaining the optimal result in all test cases.

A new unsteady mixing model to predict NO(x) production during rapid mixing in a dual-stage combustor

NASA Technical Reports Server (NTRS)

Menon, Suresh

1992-01-01

An advanced gas turbine engine to power supersonic transport aircraft is currently under study. In addition to high combustion efficiency requirements, environmental concerns have placed stringent restrictions on the pollutant emissions from these engines. A combustor design with the potential for minimizing pollutants such as NO(x) emissions is undergoing experimental evaluation. A major technical issue in the design of this combustor is how to rapidly mix the hot, fuel-rich primary zone product with the secondary diluent air to obtain a fuel-lean mixture for combustion in the second stage. Numerical predictions using steady-state methods cannot account for the unsteady phenomena in the mixing region. Therefore, to evaluate the effect of unsteady mixing and combustion processes, a novel unsteady mixing model is demonstrated here. This model has been used to study multispecies mixing as well as propane-air and hydrogen-air jet nonpremixed flames, and has been used to predict NO(x) production in the mixing region. Comparison with available experimental data show good agreement, thereby providing validation of the mixing model. With this demonstration, this mixing model is ready to be implemented in conjunction with steady-state prediction methods and provide an improved engineering design analysis tool.

An assessment of consistence of exhaust gas emission test results obtained under controlled NEDC conditions

NASA Astrophysics Data System (ADS)

Balawender, K.; Jaworski, A.; Kuszewski, H.; Lejda, K.; Ustrzycki, A.

2016-09-01

Measurements concerning emissions of pollutants contained in automobile combustion engine exhaust gases is of primary importance in view of their harmful impact on the natural environment. This paper presents results of tests aimed at determining exhaust gas pollutant emissions from a passenger car engine obtained under repeatable conditions on a chassis dynamometer. The test set-up was installed in a controlled climate chamber allowing to maintain the temperature conditions within the range from -20°C to +30°C. The analysis covered emissions of such components as CO, CO2, NOx, CH4, THC, and NMHC. The purpose of the study was to assess repeatability of results obtained in a number of tests performed as per NEDC test plan. The study is an introductory stage of a wider research project concerning the effect of climate conditions and fuel type on emission of pollutants contained in exhaust gases generated by automotive vehicles.

Helicity in supercritical temporal mixing layers

NASA Technical Reports Server (NTRS)

Bellan, J.; Okong'o, N.

2003-01-01

Databases of transitional states obtained from Direct Numerical Simulations (DNS) of temporal, supercritical mixing layers for two species systems, 02/H2 and C7Hle/N2, are analyzed to elucidate species-specific turbulence aspects.

Bioprocessing of a stored mixed liquid waste

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

Wolfram, J.H.; Rogers, R.D.; Finney, R.

1995-12-31

This paper describes the development and results of a demonstration for a continuous bioprocess for mixed waste treatment. A key element of the process is an unique microbial strain which tolerates high levels of aromatic solvents and surfactants. This microorganism is the biocatalysis of the continuous flow system designed for the processing of stored liquid scintillation wastes. During the past year a process demonstration has been conducted on commercial formulation of liquid scintillation cocktails (LSC). Based on data obtained from this demonstration, the Ohio EPA granted the Mound Applied Technologies Lab a treatability permit allowing the limited processing of actualmore » mixed waste. Since August 1994, the system has been successfully processing stored, {open_quotes}hot{close_quotes} LSC waste. The initial LSC waste fed into the system contained 11% pseudocumene and detectable quantities of plutonium. Another treated waste stream contained pseudocumene and tritium. Data from this initial work shows that the hazardous organic solvent, and pseudocumene have been removed due to processing, leaving the aqueous low level radioactive waste. Results to date have shown that living cells are not affected by the dissolved plutonium and that 95% of the plutonium was sorbed to the biomass. This paper discusses the bioprocess, rates of processing, effluent, and the implications of bioprocessing for mixed waste management.« less

Cooling of a magmatic system under thermal chaotic mixing

NASA Astrophysics Data System (ADS)

Petrelli, Maurizio; El Omari, Kamal; Le Guer, Yves; Perugini, Diego

2015-04-01

The cooling of a melt undergoing chaotic advection is studied numerically for a magma with a temperature-dependent viscosity in a 2D cavity with moving boundary. Different statistical mixing and energy indicators are used to characterize the efficiency of cooling by thermal chaotic mixing. We show that different cooling rates can be obtained during the thermal mixing even of a single basaltic magmatic batch undergoing chaotic advection. This process can induce complex temperature patterns inside the magma chamber. The emergence of chaotic dynamics strongly affects the temperature field during time and greatly increases the cooling rates. This mechanism has implications for the lifetime of a magmatic body and may favor the appearance of chemical heterogeneities in igneous systems as a result of different crystallization rates. Results from this study also highlight that even a single magma batch can develop, under chaotic thermal advection, complex thermal and therefore compositional patterns resulting from different cooling rates, which can account for some natural features that, to date, have received unsatisfactory explanations. Among them, the production of magmatic enclaves showing completely different cooling histories compared with the host magma, compositional zoning in mineral phases, and the generation of large-scale compositionally zoning observed in many plutons worldwide.

Cooling of a Magmatic System Under Thermal Chaotic Mixing

NASA Astrophysics Data System (ADS)

El Omari, Kamal; Le Guer, Yves; Perugini, Diego; Petrelli, Maurizio

2015-07-01

The cooling of a basaltic melt undergoing chaotic advection is studied numerically for a magma with a temperature-dependent viscosity in a two-dimensional (2D) cavity with moving boundary. Different statistical mixing and energy indicators are used to characterize the efficiency of cooling by thermal chaotic mixing. We show that different cooling rates can be obtained during the thermal mixing of a single basaltic magmatic batch undergoing chaotic advection. This process can induce complex temperature patterns inside the magma chamber. The emergence of chaotic dynamics strongly modulates the temperature fields over time and greatly increases the cooling rates. This mechanism has implications for the thermal lifetime of the magmatic body and may favor the appearance of chemical heterogeneities in the igneous system as a result of different crystallization rates. Results from this study also highlight that even a single magma batch can develop, under chaotic thermal advection, complex thermal and therefore compositional patterns resulting from different cooling rates, which can account for some natural features that, to date, have received unsatisfactory explanations, including the production of magmatic enclaves showing completely different cooling histories compared with the host magma, compositional zoning in mineral phases, and the generation of large-scale compositional zoning observed in many plutons worldwide.

Numerical investigation of power consumption and mixing time in a stirred vessel with regular and multiscale impellers

NASA Astrophysics Data System (ADS)

Basbug, Salur; Papadakis, George; Vassilicos, Christos

2015-11-01

The flow field inside a stirred tank is obtained by means of direct numerical simulation based on finite volume method at Re =500. Two different types of four-bladed radial impellers are considered: the first one is a regular type with rectangular blades and the second one is a modified version of the former with irregular blade edges, having the same thickness and the surface area. The shaft power is averaged over more than sixty revolutions and the comparison between the two cases shows that the impeller with irregular blades has lower energy consumption. Moreover, a passive scalar is injected into the vessel for a quarter period of revolution and the scalar transport equation is solved to investigate the mixing times. The coefficient of variation of the passive scalar is averaged over the whole volume in order to obtain a quantitative indicator of the mixing progress. The homogenization curves depend on the instantaneous flow conditions due to the transient nature of the mixing process, therefore multiple curves are averaged to obtain a representative result. There are indications that irregular blades can decrease mixing time with respect to regular ones.

Glucose Meters: A Review of Technical Challenges to Obtaining Accurate Results

PubMed Central

Tonyushkina, Ksenia; Nichols, James H.

2009-01-01

, anemia, hypotension, and other disease states. This article reviews the challenges involved in obtaining accurate glucose meter results. PMID:20144348

Time-dependent analysis of the mixed-field orientation of molecules without rotational symmetry

NASA Astrophysics Data System (ADS)

Thesing, Linda V.; Küpper, Jochen; González-Férez, Rosario

2017-06-01

We present a theoretical study of the mixed-field orientation of molecules without rotational symmetry. The time-dependent one-dimensional and three-dimensional orientation of a thermal ensemble of 6-chloropyridazine-3-carbonitrile molecules in combined linearly or elliptically polarized laser fields and tilted dc electric fields is computed. The results are in good agreement with recent experimental results of one-dimensional orientation for weak dc electric fields [J. L. Hansen, J. Chem. Phys. 139, 234313 (2013)]. Moreover, they predict that using elliptically polarized laser fields or strong dc fields, three-dimensional orientation is obtained. The field-dressed dynamics of excited rotational states is characterized by highly non-adiabatic effects. We analyze the sources of these non-adiabatic effects and investigate their impact on the mixed-field orientation for different field configurations in mixed-field-orientation experiments.

Enthalpy of mixing of liquid Co–Sn alloys

PubMed Central

Yakymovych, A.; Fürtauer, S.; Elmahfoudi, A.; Ipser, H.; Flandorfer, H.

2014-01-01

A literature overview of enthalpy of mixing data for liquid Co–Sn alloys shows large scattering but no clear temperature dependence. Therefore drop calorimetry was performed in the Co–Sn system at twelve different temperatures in 100 K steps in the temperature range (673 to 1773) K. The integral enthalpy of mixing was determined starting from 1173 K and fitted to a standard Redlich–Kister polynomial. In addition, the limiting partial molar enthalpy of Co in Sn was investigated by small additions of Co to liquid Sn at temperatures (673 to 1773) K. The integral and partial molar enthalpies of the Co–Sn system generally show an exothermic mixing behavior. Significant temperature dependence was detected for the enthalpies of mixing. The minimum integral enthalpy values vary with rising temperature from approx. −7820 J/mol at T = 1173 K to −1350 J/mol at T = 1773 K; the position of the minimum is between (59 and 61) at.% Co. The results are discussed and compared with literature data available for this system. X-ray studies and scanning electron microscopy of selected alloys obtained from the calorimetric measurements were carried out in order to check the completeness of the solution process. PMID:24994940

Towards understanding turbulent scalar mixing

NASA Technical Reports Server (NTRS)

Girimaji, Sharath S.

1992-01-01

In an effort towards understanding turbulent scalar mixing, we study the effect of molecular mixing, first in isolation and then by accounting for the effects of the velocity field. The chief motivation for this approach stems from the strong resemblance of the scalar probability density function (PDF) obtained from the scalar field evolving from the heat conduction equation that arises in a turbulent velocity field. However, the evolution of the scalar dissipation is different for the two cases. We attempt to account for these differences, which are due to the velocity field, using a Lagrangian frame analysis. After establishing the usefulness of this approach, we use the heat-conduction simulations (HCS), in lieu of the more expensive direct numerical simulations (DNS), to study many of the less understood aspects of turbulent mixing. Comparison between the HCS data and available models are made whenever possible. It is established that the beta PDF characterizes the evolution of the scalar PDF during mixing from all types of non-premixed initial conditions.

An apparatus for sequentially combining microvolumes of reagents by infrasonic mixing.

PubMed

Camien, M N; Warner, R C

1984-05-01

A method employing high-speed infrasonic mixing for obtaining timed samples for following the progress of a moderately rapid chemical reaction is described. Drops of 10 to 50 microliter each of two reagents are mixed to initiate the reaction, followed, after a measured time interval, by mixing with a drop of a third reagent to quench the reaction. The method was developed for measuring the rate of denaturation of covalently closed, circular DNA in NaOH at several temperatures. For this purpose the timed samples were analyzed by analytical ultracentrifugation. The apparatus was tested by determination of the rate of hydrolysis of 2,4-dinitrophenyl acetate in an alkaline buffer. The important characteristics of the method are (i) it requires very small volumes of sample and reagents; (ii) the components of the reaction mixture are pre-equilibrated and mixed with no transfer outside the prescribed constant temperature environment; (iii) the mixing is very rapid; and (iv) satisfactorily precise measurements of relatively short time intervals (approximately 2 sec minimum) between sequential mixings of the components are readily obtainable.

Flame spread behavior over combustible thick solid of paper, bagasse and mixed paper/bagasse

NASA Astrophysics Data System (ADS)

Azahari Razali, Mohd; Mohd, Sofian; Sapit, Azwan; Nizam Mohammed, Akmal; Husaini Ismail, Ahmad; Faisal Hushim, Mohd; Jaat, Norrizam; Khalid, Amir

2017-09-01

Flame spread behavior on combustible solid is one of important research related to Fire Safety Engineering. Now, there are a lot of combustible solid composed from mixed materials. In this study, experiments have been conducted to investigate flame spread behavior over combustible solid composed by paper, bagasse and mixed paper/bagasse. Experimental data is captured by using video recording and examined flame spread shape and rate. From the results obtained, shows that the different materials produce different flame spread shape and rate. Different flame shape is seen between all types of samples. Flame spread rate of 100% paper is faster than the one of 100% bagasse. Based on the result, it is also inferred that the material composition can be influenced on the flame spread shape and flame spread rate of mixed paper/bagasse.

Statistical independence of the initial conditions in chaotic mixing.

PubMed

García de la Cruz, J M; Vassilicos, J C; Rossi, L

2017-11-01

Experimental evidence of the scalar convergence towards a global strange eigenmode independent of the scalar initial condition in chaotic mixing is provided. This convergence, underpinning the independent nature of chaotic mixing in any passive scalar, is presented by scalar fields with different initial conditions casting statistically similar shapes when advected by periodic unsteady flows. As the scalar patterns converge towards a global strange eigenmode, the scalar filaments, locally aligned with the direction of maximum stretching, as described by the Lagrangian stretching theory, stack together in an inhomogeneous pattern at distances smaller than their asymptotic minimum widths. The scalar variance decay becomes then exponential and independent of the scalar diffusivity or initial condition. In this work, mixing is achieved by advecting the scalar using a set of laminar flows with unsteady periodic topology. These flows, that resemble the tendril-whorl map, are obtained by morphing the forcing geometry in an electromagnetic free surface 2D mixing experiment. This forcing generates a velocity field which periodically switches between two concentric hyperbolic and elliptic stagnation points. In agreement with previous literature, the velocity fields obtained produce a chaotic mixer with two regions: a central mixing and an external extensional area. These two regions are interconnected through two pairs of fluid conduits which transfer clean and dyed fluid from the extensional area towards the mixing region and a homogenized mixture from the mixing area towards the extensional region.

An Investigation of Generalized Differential Evolution Metaheuristic for Multiobjective Optimal Crop-Mix Planning Decision

PubMed Central

Olugbara, Oludayo

2014-01-01

This paper presents an annual multiobjective crop-mix planning as a problem of concurrent maximization of net profit and maximization of crop production to determine an optimal cropping pattern. The optimal crop production in a particular planting season is a crucial decision making task from the perspectives of economic management and sustainable agriculture. A multiobjective optimal crop-mix problem is formulated and solved using the generalized differential evolution 3 (GDE3) metaheuristic to generate a globally optimal solution. The performance of the GDE3 metaheuristic is investigated by comparing its results with the results obtained using epsilon constrained and nondominated sorting genetic algorithms—being two representatives of state-of-the-art in evolutionary optimization. The performance metrics of additive epsilon, generational distance, inverted generational distance, and spacing are considered to establish the comparability. In addition, a graphical comparison with respect to the true Pareto front for the multiobjective optimal crop-mix planning problem is presented. Empirical results generally show GDE3 to be a viable alternative tool for solving a multiobjective optimal crop-mix planning problem. PMID:24883369

An investigation of generalized differential evolution metaheuristic for multiobjective optimal crop-mix planning decision.

PubMed

Adekanmbi, Oluwole; Olugbara, Oludayo; Adeyemo, Josiah

2014-01-01

This paper presents an annual multiobjective crop-mix planning as a problem of concurrent maximization of net profit and maximization of crop production to determine an optimal cropping pattern. The optimal crop production in a particular planting season is a crucial decision making task from the perspectives of economic management and sustainable agriculture. A multiobjective optimal crop-mix problem is formulated and solved using the generalized differential evolution 3 (GDE3) metaheuristic to generate a globally optimal solution. The performance of the GDE3 metaheuristic is investigated by comparing its results with the results obtained using epsilon constrained and nondominated sorting genetic algorithms-being two representatives of state-of-the-art in evolutionary optimization. The performance metrics of additive epsilon, generational distance, inverted generational distance, and spacing are considered to establish the comparability. In addition, a graphical comparison with respect to the true Pareto front for the multiobjective optimal crop-mix planning problem is presented. Empirical results generally show GDE3 to be a viable alternative tool for solving a multiobjective optimal crop-mix planning problem.

Preconditioned Mixed Spectral Element Methods for Elasticity and Stokes Problems

NASA Technical Reports Server (NTRS)

Pavarino, Luca F.

1996-01-01

Preconditioned iterative methods for the indefinite systems obtained by discretizing the linear elasticity and Stokes problems with mixed spectral elements in three dimensions are introduced and analyzed. The resulting stiffness matrices have the structure of saddle point problems with a penalty term, which is associated with the Poisson ratio for elasticity problems or with stabilization techniques for Stokes problems. The main results of this paper show that the convergence rate of the resulting algorithms is independent of the penalty parameter, the number of spectral elements Nu and mildly dependent on the spectral degree eta via the inf-sup constant. The preconditioners proposed for the whole indefinite system are block-diagonal and block-triangular. Numerical experiments presented in the final section show that these algorithms are a practical and efficient strategy for the iterative solution of the indefinite problems arising from mixed spectral element discretizations of elliptic systems.

The effect of misclassification errors on case mix measurement.

PubMed

Sutherland, Jason M; Botz, Chas K

2006-12-01

Case mix systems have been implemented for hospital reimbursement and performance measurement across Europe and North America. Case mix categorizes patients into discrete groups based on clinical information obtained from patient charts in an attempt to identify clinical or cost difference amongst these groups. The diagnosis related group (DRG) case mix system is the most common methodology, with variants adopted in many countries. External validation studies of coding quality have confirmed that widespread variability exists between originally recorded diagnoses and re-abstracted clinical information. DRG assignment errors in hospitals that share patient level cost data for the purpose of establishing cost weights affects cost weight accuracy. The purpose of this study is to estimate bias in cost weights due to measurement error of reported clinical information. DRG assignment error rates are simulated based on recent clinical re-abstraction study results. Our simulation study estimates that 47% of cost weights representing the least severe cases are over weight by 10%, while 32% of cost weights representing the most severe cases are under weight by 10%. Applying the simulated weights to a cross-section of hospitals, we find that teaching hospitals tend to be under weight. Since inaccurate cost weights challenges the ability of case mix systems to accurately reflect patient mix and may lead to potential distortions in hospital funding, bias in hospital case mix measurement highlights the role clinical data quality plays in hospital funding in countries that use DRG-type case mix systems. Quality of clinical information should be carefully considered from hospitals that contribute financial data for establishing cost weights.

Computational fluid dynamics study on mixing mode and power consumption in anaerobic mono- and co-digestion.

PubMed

Zhang, Yuan; Yu, Guangren; Yu, Liang; Siddhu, Muhammad Abdul Hanan; Gao, Mengjiao; Abdeltawab, Ahmed A; Al-Deyab, Salem S; Chen, Xiaochun

2016-03-01

Computational fluid dynamics (CFD) was applied to investigate mixing mode and power consumption in anaerobic mono- and co-digestion. Cattle manure (CM) and corn stover (CS) were used as feedstock and stirred tank reactor (STR) was used as digester. Power numbers obtained by the CFD simulation were compared with those from the experimental correlation. Results showed that the standard k-ε model was more appropriate than other turbulence models. A new index, net power production instead of gas production, was proposed to optimize feedstock ratio for anaerobic co-digestion. Results showed that flow field and power consumption were significantly changed in co-digestion of CM and CS compared with those in mono-digestion of either CM or CS. For different mixing modes, the optimum feedstock ratio for co-digestion changed with net power production. The best option of CM/CS ratio for continuous mixing, intermittent mixing I, and intermittent mixing II were 1:1, 1:1 and 1:3, respectively. Copyright © 2016. Published by Elsevier Ltd.

Analytical solution for reactive solute transport considering incomplete mixing within a reference elementary volume

NASA Astrophysics Data System (ADS)

Chiogna, Gabriele; Bellin, Alberto

2013-05-01

The laboratory experiments of Gramling et al. (2002) showed that incomplete mixing at the pore scale exerts a significant impact on transport of reactive solutes and that assuming complete mixing leads to overestimation of product concentration in bimolecular reactions. Successively, several attempts have been made to model this experiment, either considering spatial segregation of the reactants, non-Fickian transport applying a Continuous Time Random Walk (CTRW) or an effective upscaled time-dependent kinetic reaction term. Previous analyses of these experimental results showed that, at the Darcy scale, conservative solute transport is well described by a standard advection dispersion equation, which assumes complete mixing at the pore scale. However, reactive transport is significantly affected by incomplete mixing at smaller scales, i.e., within a reference elementary volume (REV). We consider here the family of equilibrium reactions for which the concentration of the reactants and the product can be expressed as a function of the mixing ratio, the concentration of a fictitious non reactive solute. For this type of reactions we propose, in agreement with previous studies, to model the effect of incomplete mixing at scales smaller than the Darcy scale assuming that the mixing ratio is distributed within an REV according to a Beta distribution. We compute the parameters of the Beta model by imposing that the mean concentration is equal to the value that the concentration assumes at the continuum Darcy scale, while the variance decays with time as a power law. We show that our model reproduces the concentration profiles of the reaction product measured in the Gramling et al. (2002) experiments using the transport parameters obtained from conservative experiments and an instantaneous reaction kinetic. The results are obtained applying analytical solutions both for conservative and for reactive solute transport, thereby providing a method to handle the effect of

Conservative mixing, competitive mixing and their applications

NASA Astrophysics Data System (ADS)

Klimenko, A. Y.

2010-12-01

In many of the models applied to simulations of turbulent transport and turbulent combustion, the mixing between particles is used to reflect the influence of the continuous diffusion terms in the transport equations. Stochastic particles with properties and mixing can be used not only for simulating turbulent combustion, but also for modeling a large spectrum of physical phenomena. Traditional mixing, which is commonly used in the modeling of turbulent reacting flows, is conservative: the total amount of scalar is (or should be) preserved during a mixing event. It is worthwhile, however, to consider a more general mixing that does not possess these conservative properties; hence, our consideration lies beyond traditional mixing. In non-conservative mixing, the particle post-mixing average becomes biased towards one of the particles participating in mixing. The extreme form of non-conservative mixing can be called competitive mixing or competition: after a mixing event, the loser particle simply receives the properties of the winner particle. Particles with non-conservative mixing can be used to emulate various phenomena involving competition. In particular, we investigate cyclic behavior that can be attributed to complex competing systems. We show that the localness and intransitivity of competitive mixing are linked to the cyclic behavior.

The use of "mixing" procedure of mixed methods in health services research.

PubMed

Zhang, Wanqing; Creswell, John

2013-08-01

Mixed methods research has emerged alongside qualitative and quantitative approaches as an important tool for health services researchers. Despite growing interest, among health services researchers, in using mixed methods designs, little has been done to identify the procedural aspects of doing so. To describe how mixed methods researchers mix the qualitative and quantitative aspects of their studies in health services research. We searched the PubMed for articles, using mixed methods in health services research, published between January 1, 2006 and December 30, 2010. We identified and reviewed 30 published health services research articles on studies in which mixed methods had been used. We selected 3 articles as illustrations to help health services researcher conceptualize the type of mixing procedures that they were using. Three main "mixing" procedures have been applied within these studies: (1) the researchers analyzed the 2 types of data at the same time but separately and integrated the results during interpretation; (2) the researchers connected the qualitative and quantitative portions in phases in such a way that 1 approach was built upon the findings of the other approach; and (3) the researchers mixed the 2 data types by embedding the analysis of 1 data type within the other. "Mixing" in mixed methods is more than just the combination of 2 independent components of the quantitative and qualitative data. The use of "mixing" procedure in health services research involves the integration, connection, and embedding of these 2 data components.

Mixed-venous oxygen tension by nitrogen rebreathing - A critical, theoretical analysis.

NASA Technical Reports Server (NTRS)

Kelman, G. R.

1972-01-01

There is dispute about the validity of the nitrogen rebreathing technique for determination of mixed-venous oxygen tension. This theoretical analysis examines the circumstances under which the technique is likely to be applicable. When the plateau method is used the probable error in mixed-venous oxygen tension is plus or minus 2.5 mm Hg at rest, and of the order of plus or minus 1 mm Hg during exercise. Provided, that the rebreathing bag size is reasonably chosen, Denison's (1967) extrapolation technique gives results at least as accurate as those obtained by the plateau method. At rest, however, extrapolation should be to 30 rather than to 20 sec.

Evaluation of a hybrid kinetics/mixing-controlled combustion model for turbulent premixed and diffusion combustion using KIVA-II

NASA Technical Reports Server (NTRS)

Nguyen, H. Lee; Wey, Ming-Jyh

1990-01-01

Two-dimensional calculations were made of spark ignited premixed-charge combustion and direct injection stratified-charge combustion in gasoline fueled piston engines. Results are obtained using kinetic-controlled combustion submodel governed by a four-step global chemical reaction or a hybrid laminar kinetics/mixing-controlled combustion submodel that accounts for laminar kinetics and turbulent mixing effects. The numerical solutions are obtained by using KIVA-2 computer code which uses a kinetic-controlled combustion submodel governed by a four-step global chemical reaction (i.e., it assumes that the mixing time is smaller than the chemistry). A hybrid laminar/mixing-controlled combustion submodel was implemented into KIVA-2. In this model, chemical species approach their thermodynamics equilibrium with a rate that is a combination of the turbulent-mixing time and the chemical-kinetics time. The combination is formed in such a way that the longer of the two times has more influence on the conversion rate and the energy release. An additional element of the model is that the laminar-flame kinetics strongly influence the early flame development following ignition.

Evaluation of a hybrid kinetics/mixing-controlled combustion model for turbulent premixed and diffusion combustion using KIVA-2

NASA Technical Reports Server (NTRS)

Nguyen, H. Lee; Wey, Ming-Jyh

1990-01-01

Two dimensional calculations were made of spark ignited premixed-charge combustion and direct injection stratified-charge combustion in gasoline fueled piston engines. Results are obtained using kinetic-controlled combustion submodel governed by a four-step global chemical reaction or a hybrid laminar kinetics/mixing-controlled combustion submodel that accounts for laminar kinetics and turbulent mixing effects. The numerical solutions are obtained by using KIVA-2 computer code which uses a kinetic-controlled combustion submodel governed by a four-step global chemical reaction (i.e., it assumes that the mixing time is smaller than the chemistry). A hybrid laminar/mixing-controlled combustion submodel was implemented into KIVA-2. In this model, chemical species approach their thermodynamics equilibrium with a rate that is a combination of the turbulent-mixing time and the chemical-kinetics time. The combination is formed in such a way that the longer of the two times has more influence on the conversion rate and the energy release. An additional element of the model is that the laminar-flame kinetics strongly influence the early flame development following ignition.

Incomplete Mixing and Reactions - A Lagrangian Approach in a Pure Shear Flow

NASA Astrophysics Data System (ADS)

Paster, A.; Aquino, T.; Bolster, D.

2014-12-01

Incomplete mixing of reactive solutes is well known to slow down reaction rates relative to what would be expected from assuming perfect mixing. As reactions progress in a system and deplete reactant concentrations, initial fluctuations in the concentrations of reactions can be amplified relative to mean background concentrations and lead to spatial segregation of reactants. As the system evolves, in the absence of sufficient mixing, this segregation will increase, leading to a persistence of incomplete mixing that fundamentally changes the effective rate at which overall reactions will progress. On the other hand, non-uniform fluid flows are known to affect mixing between interacting solutes. Thus a natural question arises: Can non-uniform flows sufficiently enhance mixing to suppress incomplete mixing effects, and if so, under what conditions? In this work we address this question by considering one of the simplest possible flows, a laminar pure shear flow, which is known to significantly enhance mixing relative to diffusion alone. To study this system we adapt a novel Lagrangian particle-based random walk method, originally designed to simulate reactions in purely diffusive systems, to the case of advection and diffusion in a shear flow. To interpret the results we develop a semi-analytical solution, by proposing a closure approximation that aims to capture the effect of incomplete mixing. The results obtained via the Lagrangian model and the semi-analytical solutions consistently highlight that if shear effects in the system are not sufficiently strong, incomplete mixing effects initially similar to purely diffusive systems will occur, slowing down the overall reaction rate. Then, at some later time, dependent on the strength of the shear, the system will return to behaving as if it were well-mixed, but represented by a reduced effective reaction rate. If shear effects are sufficiently strong, the incomplete mixing regime never emerges and the system can behave

Incomplete Mixing and Reactions - A Lagrangian Approach in a Pure Shear Flow

NASA Astrophysics Data System (ADS)

Paster, Amir; Bolster, Diogo; Aquino, Tomas

2015-04-01

Incomplete mixing of reactive solutes is well known to slow down reaction rates relative to what would be expected from assuming perfect mixing. As reactions progress in a system and deplete reactant concentrations, initial fluctuations in the concentrations of reactions can be amplified relative to mean background concentrations and lead to spatial segregation of reactants. As the system evolves, in the absence of sufficient mixing, this segregation will increase, leading to a persistence of incomplete mixing that fundamentally changes the effective rate at which overall reactions will progress. On the other hand, nonuniform fluid flows are known to affect mixing between interacting solutes. Thus a natural question arises: Can non-uniform flows sufficiently enhance mixing to suppress incomplete mixing effects, and if so, under what conditions? In this work we address this question by considering one of the simplest possible flows, a laminar pure shear flow, which is known to significantly enhance mixing relative to diffusion alone. To study this system we adapt a novel Lagrangian particle-based random walk method, originally designed to simulate reactions in purely diffusive systems, to the case of advection and diffusion in a shear flow. To interpret the results we develop a semi-analytical solution, by proposing a closure approximation that aims to capture the effect of incomplete mixing. The results obtained via the Lagrangian model and the semi-analytical solutions consistently highlight that if shear effects in the system are not sufficiently strong, incomplete mixing effects initially similar to purely diffusive systems will occur, slowing down the overall reaction rate. Then, at some later time, dependent on the strength of the shear, the system will return to behaving as if it were well-mixed, but represented by a reduced effective reaction rate. If shear effects are sufficiently strong, the incomplete mixing regime never emerges and the system can behave

Seasonal variability of the diapycnal mixing in the Canary Islands channels

NASA Astrophysics Data System (ADS)

Rodríguez-Santana, Angel; Marrero-Díaz, Angeles; Machín, Francisco Jose; García-Weil, Luis; Sangrà, Pablo; Vélez-Belchí, Pedro; Fraile-Nuez, Eugenio; Estrada-Allis, Sheila

2014-05-01

Trimonthly surveys of XBT and XCTD (Expandable Bathytermograph and Conductivity-Temperature-Depth) crossing the whole Canary Islands channels were carried out (projects TRAMIC and PROMECA) from November 2012 until September 2013 using opportunity ships (Naviera Armas Ferries). With this data set and using salinity analytical relationships (Machín et al, 2010), vertical sections of temperature and potential density were obtained for each channel and season. In order to estimate the intensity of the diapycnal mixing in the first 500 m of the pycnocline, vertical sections of Thorpe length scale, Turner angle and gradient Richardson number (from the geostrophic vertical shear) were calculated for all the cases. The first results show how the diapycnal mixing due to the vertical shear instabilities is more intense close to the islands and in summer when the seasonal pycnocline is present. Mixing due to double diffusion processes (salt fingers) was found without sizable changes in the permanent pycnocline. Net turbulence diffusivities and diapycnal diffusive fluxes with their variability spatial and temporal will be estimate for each channel taking into account that processes of double diffusion and turbulence induced by vertical shear are present at the same time. Additionally the results obtained from hydrographic data from the cruise RAPROCAN-2013 (IEO) (October 2013) around Canary Islands will be used to compare them with the channels results. This work was co-funded by Canary Government (TRAMIC project: PROID20100092), European Union (FEDER) and Spanish Government (PROMECA: CTM2008-04057/MAR and CTM2009-06993-E/MAR)

Mixing efficiency inside micro-droplets coalesced by two components in cross-structure

NASA Astrophysics Data System (ADS)

Ren, Yanlin; Liu, Zhaomiao; Pang, Yan

2017-11-01

The mixing of micro-droplets is used in analytical chemistry, medicine production and material synthesis owing to its advantages including the encapsulation and narrow time residence distribution. In this work, droplets are coalesced by two dispersed phase with different flow rates, generated in cross-structure and mixed in planar serpentine structure. The mixing efficiency of micro-droplets under control characters including the width of entrance and the flow rate of dispersed phases have been investigated by experiments and numerical simulations. The UDS (user-defined scalar) as dimensionless concentration of the solution is adopted in simulation, and is used to calculate the concentration and the mixing effect. By changing the flow rates and the entrances` width, the changing rules of the mixing characters have been obtained. The asymmetry distributions of components make rapid mixing process in half part of each droplet when travel through a straight channel. Increasing of the ratio of entrance width result into larger droplet and weaken the chaotic mixing effect. Meanwhile, the coalesced mechanism can be performed by ranging the ratio of flow rates, the ranges are also determined by the widths of entrances. The authors gratefully acknowledge the support of National Natural Science Foundation of China (Grant No. 11572013).

Airglow during ionospheric modifications by the sura facility radiation. experimental results obtained in 2010

NASA Astrophysics Data System (ADS)

Grach, S. M.; Klimenko, V. V.; Shindin, A. V.; Nasyrov, I. A.; Sergeev, E. N.; A. Yashnov, V.; A. Pogorelko, N.

2012-06-01

We present the results of studying the structure and dynamics of the HF-heated volume above the Sura facility obtained in 2010 by measurements of ionospheric airglow in the red (λ = 630 nm) and green (λ = 557.7 nm) lines of atomic oxygen. Vertical sounding of the ionosphere (followed by modeling of the pump-wave propagation) and measurements of stimulated electromagnetic emission were used for additional diagnostics of ionospheric parameters and the processes occurring in the heated volume.

Effect of gas mixing on physical properties of warm collisional helicon plasmas

NASA Astrophysics Data System (ADS)

Kabir, M.; Niknam, A. R.

2017-10-01

The effect of inert gas mixing on the physical properties of a helicon plasma source with a Nagoya type III antenna is analytically investigated by taking into account the thermal and collisional effects. The dielectric permittivity tensor of this mixed gas plasma is obtained by using the Bhatnagar-Gross- Krook kinetic theory. Considering the dielectric tensor of mixed gas plasma and solving the electromagnetic field equations, the profiles of electromagnetic fields and plasma resistance are plotted and discussed. The results show that the plasma resistance peaks decrease with increasing Xe fraction in Ar-Xe plasma, and increase with the He fraction in Ar-He plasma. It is also shown that by increasing the xenon filling fraction, the electromagnetic field amplitudes are lowered, and by increasing the helium filling fraction, they are increased.

Addressing Research Design Problem in Mixed Methods Research

NASA Astrophysics Data System (ADS)

Alavi, Hamed; Hąbek, Patrycja

2016-03-01

Alongside other disciplines in social sciences, management researchers use mixed methods research more and more in conduct of their scientific investigations. Mixed methods approach can also be used in the field of production engineering. In comparison with traditional quantitative and qualitative research methods, reasons behind increasing popularity of mixed research method in management science can be traced in different factors. First of all, any particular discipline in management can be theoretically related to it. Second is that concurrent approach of mixed research method to inductive and deductive research logic provides researchers with opportunity to generate theory and test hypothesis in one study simultaneously. In addition, it provides a better justification for chosen method of investigation and higher validity for obtained answers to research questions. Despite increasing popularity of mixed research methods among management scholars, there is still need for a comprehensive approach to research design typology and process in mixed research method from the perspective of management science. The authors in this paper try to explain fundamental principles of mixed research method, its typology and different steps in its design process.

Microgravity acoustic mixing for particle cloud combustors

NASA Technical Reports Server (NTRS)

Pla, Frederic; Rubinstein, Robert I.

1990-01-01

Experimental and theoretical investigations of acoustic mixing procedures designed to uniformly distribute fuel particles in a combustion tube for application in the proposed Particle Cloud Combustion Experiment (PCCE) are described. Two acoustic mixing methods are investigated: mixing in a cylindrical tube using high frequency spinning modes generated by suitably phased, or quadrature speakers, and acoustic premixing in a sphere. Quadrature mixing leads to rapid circumferential circulation of the powder around the tube. Good mixing is observed in the circulating regions. However, because axial inhomogeneities are necessarily present in the acoustic field, this circulation does not extend throughout the tube. Simultaneous operation of the quadrature-speaker set and the axial-speaker was observed to produce considerably enhanced mixing compared to operation of the quadrature-speaker set alone. Mixing experiments using both types of speakers were free of the longitudinal powder drift observed using axial-speakers alone. Vigorous powder mixing was obtained in the sphere for many normal modes: however, in no case was the powder observed to fill the sphere entirely. Theoretical analysis indicated that mixing under steady conditions cannot fill more than a hemisphere except under very unusual conditions. Premixing in a hemisphere may be satisfactory; otherwise, complete mixing in microgravity might be possible by operating the speaker in short bursts. A general conclusion is that acoustic transients are more likely to produce good mixing than steady state conditions. The reason is that in steady conditions, flow structures like nodal planes are possible and often even unavoidable. These tend to separate the mixing region into cells across which powder cannot be transferred. In contrast, transients not only are free of such structures, they also have the characteristics, desirable for mixing, of randomness and disorder. This conclusion is corroborated by mixing

MIXING STUDY FOR JT-71/72 TANKS

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

Lee, S.

2013-11-26

All modeling calculations for the mixing operations of miscible fluids contained in HBLine tanks, JT-71/72, were performed by taking a three-dimensional Computational Fluid Dynamics (CFD) approach. The CFD modeling results were benchmarked against the literature results and the previous SRNL test results to validate the model. Final performance calculations were performed by using the validated model to quantify the mixing time for the HB-Line tanks. The mixing study results for the JT-71/72 tanks show that, for the cases modeled, the mixing time required for blending of the tank contents is no more than 35 minutes, which is well below 2.5more » hours of recirculation pump operation. Therefore, the results demonstrate the adequacy of 2.5 hours’ mixing time of the tank contents by one recirculation pump to get well mixed.« less

The Oporto mixed-longitudinal growth, health and performance study. Design, methods and baseline results.

PubMed

Souza, Michele Caroline de; Chaves, Raquel Nichele de; Dos Santos, Fernanda Karina; Gomes, Thayse Natacha Queiroz Ferreira; Santos, Daniel Vilhena E; Borges, Alessandra Silva; Pereira, Sara Isabel Sampaio; Forjaz, Cláudia Lúcia de Moraes; Eisenmann, Joey; Maia, José António Ribeiro

2017-02-01

Studies concerning child and adolescent growth, development, performance and health aimed at the multiple interactions amongst this complex set of variables are not common in the Portuguese speaking countries. The aim of this paper is to address the key ideas, methodology and design of the Oporto Growth, Health and Performance Study (OGHPS). The OGHPS is a multidisciplinary mixed-longitudinal study whose main purpose is to examine the multiple interactions among biological, environmental and lifestyle indicators that affect growth, development, health and performance of Portuguese adolescents aged 10-18 years old. This study briefly presents baseline results for growth, physical fitness and lifestyle behaviours for those participating in the cross-sectional sample (n ≈ 8000). Approximately 30% were over-fat or obese. On average, boys were more physically fit and active than girls. Few adolescents meet the guidelines for sleep duration (≈10%) and eating habits (16.2-24.8%), while 76-85% meet the recommended levels of moderate-to-vigorous physical activity. The OGHPS has an innovative approach due to its mixed-longitudinal design and the broad array of variables. Furthermore, subsequent analyses of the longitudinal data will enable a detailed exploration of important factors affecting the growth trajectories of health and performance variables and will also help to identify some of the most opportune times for interventions in terms of health behaviours.

Method for stabilizing low-level mixed wastes at room temperature

DOEpatents

Wagh, A.S.; Singh, D.

1997-07-08

A method to stabilize solid and liquid waste at room temperature is provided comprising combining solid waste with a starter oxide to obtain a powder, contacting the powder with an acid solution to create a slurry, said acid solution containing the liquid waste, shaping the now-mixed slurry into a predetermined form, and allowing the now-formed slurry to set. The invention also provides for a method to encapsulate and stabilize waste containing cesium comprising combining the waste with Zr(OH){sub 4} to create a solid-phase mixture, mixing phosphoric acid with the solid-phase mixture to create a slurry, subjecting the slurry to pressure; and allowing the now pressurized slurry to set. Lastly, the invention provides for a method to stabilize liquid waste, comprising supplying a powder containing magnesium, sodium and phosphate in predetermined proportions, mixing said powder with the liquid waste, such as tritium, and allowing the resulting slurry to set. 4 figs.

Method for stabilizing low-level mixed wastes at room temperature

DOEpatents

Wagh, Arun S.; Singh, Dileep

1997-01-01

A method to stabilize solid and liquid waste at room temperature is provided comprising combining solid waste with a starter oxide to obtain a powder, contacting the powder with an acid solution to create a slurry, said acid solution containing the liquid waste, shaping the now-mixed slurry into a predetermined form, and allowing the now-formed slurry to set. The invention also provides for a method to encapsulate and stabilize waste containing cesium comprising combining the waste with Zr(OH).sub.4 to create a solid-phase mixture, mixing phosphoric acid with the solid-phase mixture to create a slurry, subjecting the slurry to pressure; and allowing the now pressurized slurry to set. Lastly, the invention provides for a method to stabilize liquid waste, comprising supplying a powder containing magnesium, sodium and phosphate in predetermined proportions, mixing said powder with the liquid waste, such as tritium, and allowing the resulting slurry to set.

Patient perceptions of receiving test results via online portals: a mixed-methods study.

PubMed

Giardina, Traber D; Baldwin, Jessica; Nystrom, Daniel T; Sittig, Dean F; Singh, Hardeep

2018-04-01

Online portals provide patients with access to their test results, but it is unknown how patients use these tools to manage results and what information is available to promote understanding. We conducted a mixed-methods study to explore patients' experiences and preferences when accessing their test results via portals. We conducted 95 interviews (13 semistructured and 82 structured) with adults who viewed a test result in their portal between April 2015 and September 2016 at 4 large outpatient clinics in Houston, Texas. Semistructured interviews were coded using content analysis and transformed into quantitative data and integrated with the structured interview data. Descriptive statistics were used to summarize the structured data. Nearly two-thirds (63%) did not receive any explanatory information or test result interpretation at the time they received the result, and 46% conducted online searches for further information about their result. Patients who received an abnormal result were more likely to experience negative emotions (56% vs 21%; P = .003) and more likely to call their physician (44% vs 15%; P = .002) compared with those who received normal results. Study findings suggest that online portals are not currently designed to present test results to patients in a meaningful way. Patients experienced negative emotions often with abnormal results, but sometimes even with normal results. Simply providing access via portals is insufficient; additional strategies are needed to help patients interpret and manage their online test results. Given the absence of national guidance, our findings could help strengthen policy and practice in this area and inform innovations that promote patient understanding of test results.

Obtaining of caffeine from Turkish tea fiber and stalk wastes.

PubMed

Gürü, M; Içen, H

2004-08-01

The aim of this study was to find a cheap method to obtain caffeine. Experiments were performed on fiber and stalk wastes of Turkish tea plants that had no economical value other than being used merely as low grade fuel and fodder. Tea stalks and fiber were obtained from tea factories. Parameters affecting caffeine extraction from tea wastes were determined to be, mixing rate, water/tea ratio, temperature, time and particle size. The maximum yields by dried mass from the tea fibers and stalks were 1.16% and 0.92%, respectively.

Denitrification by the mix-culturing of fungi and bacteria with shell.

PubMed

Liu, Deli; Zhang, Shan; Zheng, Yongliang; Shoun, Hirofumi

2006-01-01

Denitrification by pure and mixed culture of Fusarium oxysporum and Pseudomonas stutzeri in different mineral medium and in synthetic wastewater were examined. The results obtained revealed that a rapid N2 evolution by F. oxysporum and P. stutzeri in mineral medium and synthetic wastewater was observed. In co-cultures of F. oxysporum and P. stutzeri, N2O produced by F. oxysporum was rapidly consumed by P. stutzeri. This indicated that mixed culture of F. oxysporum and P. stutzeri could be used for efficient nitrate and nitrite removal. Using synthetic wastewater, about 87% of nitrate was reduced by co-denitrification of F. oxysporum and P. stutzeri after incubation for 6 days. In the further denitrification tests, the interaction of shell and mixed culture of F. oxysporum and P. stutzeri was investigated. The dinitrogen was rapidly evolved (442.48 micromol N2 produced from 1.0 mmol of NO3(-) in 36 h). These results clearly showed that shell provide a suitable microenvironment for P. stutzeri, which is beneficial to the denitrification.

Quantum Groups, Property (T), and Weak Mixing

NASA Astrophysics Data System (ADS)

Brannan, Michael; Kerr, David

2018-06-01

For second countable discrete quantum groups, and more generally second countable locally compact quantum groups with trivial scaling group, we show that property (T) is equivalent to every weakly mixing unitary representation not having almost invariant vectors. This is a generalization of a theorem of Bekka and Valette from the group setting and was previously established in the case of low dual by Daws, Skalski, and Viselter. Our approach uses spectral techniques and is completely different from those of Bekka-Valette and Daws-Skalski-Viselter. By a separate argument we furthermore extend the result to second countable nonunimodular locally compact quantum groups, which are shown in particular not to have property (T), generalizing a theorem of Fima from the discrete setting. We also obtain quantum group versions of characterizations of property (T) of Kerr and Pichot in terms of the Baire category theory of weak mixing representations and of Connes and Weiss in terms of the prevalence of strongly ergodic actions.

Electroosmotic flow mixing in zigzag microchannels.

PubMed

Chen, Jia-Kun; Yang, Ruey-Jen

2007-03-01

In this study we performed numerical and experimental investigations into the mixing of EOFs in zigzag microchannels with two different corner geometries, namely sharp corners and flat corners. In the zigzag microchannel with sharp corners, the flow travels more rapidly near the inner wall of the corner than near the outer wall as a result of the higher electric potential drop. The resulting velocity gradient induces a racetrack effect, which enhances diffusion within the fluid and hence improves the mixing performance. The simulation results reveal that the mixing index is approximately 88.83%. However, the sharp-corner geometry causes residual liquid or bubbles to become trapped in the channel at the point where the flow is almost stationary, when the channel is in the process of cleaning. Accordingly, a zigzag microchannel with flat-corner geometry is developed. The flat-corner geometry forms a convergent-divergent type nozzle which not only enhances the mixing performance in the channel, but also prevents the accumulation of residual liquid or bubbles. Scaling analysis reveals that this corner geometry leads to an effective increase in the mixing length. The experimental results reveal that the mixing index is increased to 94.30% in the flat-corner zigzag channel. Hence, the results demonstrate that the mixing index of the flat-corner zigzag channel is better than that of the conventional sharp-corner microchannel. Finally, the results of Taguchi analysis indicate that the attainable mixing index is determined primarily by the number of corners in the microchannel and by the flow passing height at each corner.

Beta-decay strength and isospin mixing studies in the sd and fp-shells

NASA Astrophysics Data System (ADS)

Jokinen, A.; ńystö, J.; Dendooven, P.; Honkanen, A.; Lipas, P.; Peräjärvi, K.; Oinonen, M.; Siiskonen, T.

1998-12-01

We have studied beta decays of MT<0 nuclei in sd and fp shells. The decay of 41Ti shows a large, 10(8) %, isospin mixing of IAS and the Gamow-Teller strength is observed to be quenched by a factor of q2=0.64. These results can be reproduced qualitatively in our shell model calculations. We have observed for the first time proton and gamma decay of the isobaric analogue state in 23Mg. Our results on the isospin mixing of the isobaric analogue state agrees well with the shell model calculations. The obtained proton branch of the IAS is used to extract the transition strength for the reaction 22Na(p,γ)23Mg.

Discrimination of Mixed Taste Solutions using Ultrasonic Wave and Soft Computing

NASA Astrophysics Data System (ADS)

Kojima, Yohichiro; Kimura, Futoshi; Mikami, Tsuyoshi; Kitama, Masataka

In this study, ultrasonic wave acoustic properties of mixed taste solutions were investigated, and the possibility of taste sensing based on the acoustical properties obtained was examined. In previous studies, properties of solutions were discriminated based on sound velocity, amplitude and frequency characteristics of ultrasonic waves propagating through the five basic taste solutions and marketed beverages. However, to make this method applicable to beverages that contain many taste substances, further studies are required. In this paper, the waveform of an ultrasonic wave with frequency of approximately 5 MHz propagating through mixed solutions composed of sweet and salty substance was measured. As a result, differences among solutions were clearly observed as differences in their properties. Furthermore, these mixed solutions were discriminated by a self-organizing neural network. The ratio of volume in their mixed solutions was estimated by a distance-type fuzzy reasoning method. Therefore, the possibility of taste sensing was shown by using ultrasonic wave acoustic properties and the soft computing, such as the self-organizing neural network and the distance-type fuzzy reasoning method.

Mixed models and reduced/selective integration displacement models for nonlinear analysis of curved beams

NASA Technical Reports Server (NTRS)

Noor, A. K.; Peters, J. M.

1981-01-01

Simple mixed models are developed for use in the geometrically nonlinear analysis of deep arches. A total Lagrangian description of the arch deformation is used, the analytical formulation being based on a form of the nonlinear deep arch theory with the effects of transverse shear deformation included. The fundamental unknowns comprise the six internal forces and generalized displacements of the arch, and the element characteristic arrays are obtained by using Hellinger-Reissner mixed variational principle. The polynomial interpolation functions employed in approximating the forces are one degree lower than those used in approximating the displacements, and the forces are discontinuous at the interelement boundaries. Attention is given to the equivalence between the mixed models developed herein and displacement models based on reduced integration of both the transverse shear and extensional energy terms. The advantages of mixed models over equivalent displacement models are summarized. Numerical results are presented to demonstrate the high accuracy and effectiveness of the mixed models developed and to permit a comparison of their performance with that of other mixed models reported in the literature.

The southpaw advantage? Lateral preference in mixed martial arts.

PubMed

Baker, Joseph; Schorer, Jörg

2013-01-01

Performers with a left-orientation have a greater likelihood of obtaining elite levels of performance in many interactive sports. This study examined whether combat stance orientation was related to skill and success in Mixed Martial Arts fighters. Data were extracted for 1468 mixed martial artists from a reliable and valid online data source. Measures included fighting stance, win percentage and an ordinal measure of skill based on number of fights. The overall analysis revealed that the fraction of fighters using a southpaw stance was greater than the fraction of left-handers in the general population, but the relationship between stance and hand-preference is not well-understood. Furthermore, t-tests found no statistically significant relationship between laterality and winning percentage, although there was a significant difference between stances for number of fights. Southpaw fighters had a greater number of fights than those using an orthodox stance. These results contribute to an expanding database on the influence of laterality on sport performance and a relatively limited database on variables associated with success in mixed martial arts.

Nonlinear Errors Resulting from Ghost Reflection and Its Coupling with Optical Mixing in Heterodyne Laser Interferometers

PubMed Central

Fu, Haijin; Wang, Yue; Tan, Jiubin; Fan, Zhigang

2018-01-01

Even after the Heydemann correction, residual nonlinear errors, ranging from hundreds of picometers to several nanometers, are still found in heterodyne laser interferometers. This is a crucial factor impeding the realization of picometer level metrology, but its source and mechanism have barely been investigated. To study this problem, a novel nonlinear model based on optical mixing and coupling with ghost reflection is proposed and then verified by experiments. After intense investigation of this new model’s influence, results indicate that new additional high-order and negative-order nonlinear harmonics, arising from ghost reflection and its coupling with optical mixing, have only a negligible contribution to the overall nonlinear error. In real applications, any effect on the Lissajous trajectory might be invisible due to the small ghost reflectance. However, even a tiny ghost reflection can significantly worsen the effectiveness of the Heydemann correction, or even make this correction completely ineffective, i.e., compensation makes the error larger rather than smaller. Moreover, the residual nonlinear error after correction is dominated only by ghost reflectance. PMID:29498685

Comparing Alternative Slashing Techniques on a Mixed Hardwood Forest: 2-Year Results

Treesearch

Donald G. Hodges; Richard M. Evans; Wayne K. Clatterbuck

2002-01-01

Regenerating commercially important species following the harvest of an existing mixed hardwood stand requires adequate advance regeneration of the desired species and control of competing vegetation. These objectives can be achieved by removing the noncommercial stems before or after harvesting. This study was designed to evaluate the efficacy of pre- and post...

Structural difference rule for amorphous alloy formation by ion mixing

NASA Technical Reports Server (NTRS)

Liu, B.-X.; Johnson, W. L.; Nicolet, M.A.; Lau, S. S.

1983-01-01

A rule is formulated which establishes a sufficient condition that an amorphous binary alloy will be formed by ion mixing of multilayered samples when the two constituent metals are of different crystalline structure, regardless of their atomic sizes and electronegativities. The rule is supported by the experimental results obtained on six selected binary metal systems, as well as by the previous data reported in the literature. The amorphization mechanism is discussed in terms of the competition between two different structures resulting in frustration of the crystallization process.

Compressibility effects on turbulent mixing

NASA Astrophysics Data System (ADS)

Panickacheril John, John; Donzis, Diego

2016-11-01

We investigate the effect of compressibility on passive scalar mixing in isotropic turbulence with a focus on the fundamental mechanisms that are responsible for such effects using a large Direct Numerical Simulation (DNS) database. The database includes simulations with Taylor Reynolds number (Rλ) up to 100, turbulent Mach number (Mt) between 0.1 and 0.6 and Schmidt number (Sc) from 0.5 to 1.0. We present several measures of mixing efficiency on different canonical flows to robustly identify compressibility effects. We found that, like shear layers, mixing is reduced as Mach number increases. However, data also reveal a non-monotonic trend with Mt. To assess directly the effect of dilatational motions we also present results with both dilatational and soleniodal forcing. Analysis suggests that a small fraction of dilatational forcing decreases mixing time at higher Mt. Scalar spectra collapse when normalized by Batchelor variables which suggests that a compressive mechanism similar to Batchelor mixing in incompressible flows might be responsible for better mixing at high Mt and with dilatational forcing compared to pure solenoidal mixing. We also present results on scalar budgets, in particular on production and dissipation. Support from NSF is gratefully acknowledged.

Mixing enhancement of low-Reynolds electro-osmotic flows in microchannels with temperature-patterned walls.

PubMed

Alizadeh, A; Zhang, L; Wang, M

2014-10-01

Mixing becomes challenging in microchannels because of the low Reynolds number. This study aims to present a mixing enhancement method for electro-osmotic flows in microchannels using vortices caused by temperature-patterned walls. Since the fluid is non-isothermal, the conventional form of Nernst-Planck equation is modified by adding a new migration term which is dependent on both temperature and internal electric potential gradient. This term results in the so-called thermo-electrochemical migration phenomenon. The coupled Navier-Stokes, Poisson, modified Nernst-Planck, energy and advection-diffusion equations are iteratively solved by multiple lattice Boltzmann methods to obtain the velocity, internal electric potential, ion distribution, temperature and species concentration fields, respectively. To enhance the mixing, three schemes of temperature-patterned walls have been considered with symmetrical or asymmetrical arrangements of blocks with surface charge and temperature. Modeling results show that the asymmetric arrangement scheme is the most efficient scheme and enhances the mixing of species by 39% when the Reynolds number is on the order of 10(-3). Current results may help improve the design of micro-mixers at low Reynolds number. Copyright © 2014 Elsevier Inc. All rights reserved.

Patient perceptions of receiving test results via online portals: a mixed-methods study

PubMed Central

Giardina, Traber D; Baldwin, Jessica; Nystrom, Daniel T; Sittig, Dean F; Singh, Hardeep

2018-01-01

Abstract Objective Online portals provide patients with access to their test results, but it is unknown how patients use these tools to manage results and what information is available to promote understanding. We conducted a mixed-methods study to explore patients’ experiences and preferences when accessing their test results via portals. Materials and Methods We conducted 95 interviews (13 semistructured and 82 structured) with adults who viewed a test result in their portal between April 2015 and September 2016 at 4 large outpatient clinics in Houston, Texas. Semistructured interviews were coded using content analysis and transformed into quantitative data and integrated with the structured interview data. Descriptive statistics were used to summarize the structured data. Results Nearly two-thirds (63%) did not receive any explanatory information or test result interpretation at the time they received the result, and 46% conducted online searches for further information about their result. Patients who received an abnormal result were more likely to experience negative emotions (56% vs 21%; P = .003) and more likely to call their physician (44% vs 15%; P = .002) compared with those who received normal results. Discussion Study findings suggest that online portals are not currently designed to present test results to patients in a meaningful way. Patients experienced negative emotions often with abnormal results, but sometimes even with normal results. Simply providing access via portals is insufficient; additional strategies are needed to help patients interpret and manage their online test results. Conclusion Given the absence of national guidance, our findings could help strengthen policy and practice in this area and inform innovations that promote patient understanding of test results. PMID:29240899

Mixing in a T-shaped micromixer at moderate Reynolds numbers

NASA Astrophysics Data System (ADS)

Minakov, A. V.; Rudyak, V. Ya.; Gavrilov, A. A.; Dekterev, A. A.

2012-09-01

In the present work, the regimes of the flow and mixing of fluids in a T-shaped micromixer in the range of the Reynolds numbers from 1 to 1000 are investigated systematically with the aid of numerical modeling. The flow and mixing regimes are shown to alter substantially with increasing Reynolds numbers. Five different flow regimes have been identified in the total. The dependencies of the friction coefficient and mixing efficiency on the Reynolds number are obtained. A sharp increase in the mixing efficiency at a flow transition from the symmetric to asymmetric steady regime is shown. On the other hand, the mixing efficiency slightly drops in the laminar-turbulent transition region. A substantial influence of the slip presence on walls on flow structure in the channel and mixing efficiency has been revealed.

The Effect of Diet Mixing on a Nonselective Herbivore

PubMed Central

2016-01-01

The balanced-diet hypothesis states that a diverse prey community is beneficial to consumers due to resource complementarity among the prey species. Nonselective consumer species cannot differentiate between prey items and are therefore not able to actively regulate their diet intake. We thus wanted to test whether the balanced-diet hypothesis is applicable to nonselective consumers. We conducted a laboratory experiment in which a nonselective model grazer, the freshwater gastropod Lymnaea stagnalis, was fed benthic green algae as single species or as a multi-species mixture and quantified the snails’ somatic growth rates and shell lengths over a seven-week period. Gastropods fed the mixed diet were found to exhibit a higher somatic growth rate than the average of the snails fed single prey species. However, growth on the multi-species mixture did not exceed the growth rate obtained on the best single prey species. Similar results were obtained regarding the animals’ shell height increase over time. The mixed diet did not provide the highest growth rate, which confirms our hypothesis. We thus suggest that the balanced-diet hypothesis is less relevant for non-selective generalist consumers, which needs to be considered in estimates of secondary production. PMID:27391787

Adolescent (Mis)Perceptions about Nicotine Addiction: Results from a Mixed-Methods Study

ERIC Educational Resources Information Center

Roditis, Maria; Lee, Joann; Halpern-Felsher, Bonnie L.

2016-01-01

Purpose: Despite evidence that adolescents become addicted to nicotine even after limited use, adolescents believe they can experiment with or smoke cigarettes for a few years and easily quit. The goal of this study was to examine adolescents' understanding of the definition and process of nicotine addiction using a mixed-methods approach. Method:…

Current patch test results in consecutive patients with, and chemical analysis of, disperse blue (DB) 106, DB 124, and the mix of DB 106 and 124.

PubMed

Uter, Wolfgang; Hildebrandt, Stephan; Geier, Johannes; Schnuch, Axel; Lessmann, Holger

2007-10-01

Disperse blue (DB) 106 and 124 are important textile dye allergens. However, the dye raw material is impure, leading to uncertainty regarding the actual patch test (PT) concentration. To examine, (i) the allergen content of previously and currently used DB 106 and 124 and a respective mix, and (ii) the frequency of positive PT reactions to the DB 106/124 mix and to the single compounds in consecutive PT patients. High performance liquid chromatography (HPLC) analysis and purification of DB 106 and 124, respectively. Descriptive analysis of PT data from the Information network of departments of dermatology obtained between January 2003 and December 2005. Retrospectively, 2 batches of the DB 106/124 mix proved to contain an amount of allergen different to the 1 declared (based on information of suppliers of raw material). However, since February 2005, DB 106 and 124, respectively, are available at a reliable concentration of 0.3% petrolatum. In 2005, the prevalence of positive PT reactions to both the mix (0.89%) and the single constituents combined (0.56%) did not qualify them for inclusion in the standard series. Quality control, providing accurate test concentrations of allergens based on technical grade purity raw materials is necessary for valid diagnosis of contact allergy and comparable epidemiological data.

Recrystallization Behavior in Mixed Solder Joints of BGA Components during Thermal Shock

NASA Astrophysics Data System (ADS)

Tan, Shihai; Han, Jing; Guo, Fu

2018-03-01

Sn-37Pb and Sn-3.0Ag-0.5Cu solder pastes printed onto a board were attached to ball grid array (BGA) samples using Sn-3.0Ag-0.5Cu solder balls. Before thermal shock, the initial grain orientations on the cross-section were obtained by scanning electron microscopy equipped with an electron backscattered diffraction system. Three mixed solder joints (two from the corner and another from the middle of the BGA component) and three lead-free solder joints (at the same positions) were selected to investigate the recrystallization behavior under thermal shock (TS) cycling conditions. All of the mixed and lead-free solder joints were initially single crystal. The results showed that recrystallization occurred in both the mixed and lead-free solder joints after 200 TS. For the mixed solder joints, more recrystallization was observed and the location of samples had a significant influence on their recrystallization behavior, while location was not as important for the lead-free samples after 200 TS in this study. Both the mixed and lead-free solder joints at the corner of BGA components showed the poorest reliability. According to misorientation distribution maps and subgrain rotation behaviors, the reliability of mixed solder joints was much poorer than that of lead-free solder joints.

Control of mixing hotspots over the vertical turbulent flux in the Southern Ocean

NASA Astrophysics Data System (ADS)

Mashayek, Ali; Ferrari, Raffaele; Ledwell, Jim; Merrifield, Sophia; St. Laurent, Louis

2015-11-01

Vertical turbulent mixing in the Southern Ocean is believed to play a role in setting the rate of the ocean Meridional Overturning Circulation (MOC), one of the key regulators of the climate system. The extent to which mixing influences the MOC, however, depends on its strength and is still under debate. To address this, a passive tracer was released upstream of the Drake Passage in 2009 as a part of the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES). Vertical dispersion of the tracer was measured in subsequent years to estimate vertical mixing. The inferred effective turbulent diffusivity values have proven larger than those obtained from localized measurements of shear made at various locations along the path of the tracer. While the values inferred from tracer imply a key role played by mixing in setting the MOC, those based on localized measurements suggest otherwise. In this work we employ the tracer data and localized turbulence measurements from DIMES in combination with a high resolution numerical ocean model to investigate whether these discrepancies are the result of different sampling strategies: the microstructure profiles sampled mixing only in a few regions, while the tracer sampled mixing over a much wider area as it spread spatially.

Investigation of mixed-host organic light emitting diodes

NASA Astrophysics Data System (ADS)

Yeh Yee, Kee

One of the limiting factors to the OLED stability or lifetime is the charge buildup at the bilayer heterojunction (HJ) between the hole transport layer (HTL) and electron transport layer (ETL). In recent years, this abrupt interface has been moderated by mixing HTL and ETL to form a single mixed-host, light emitting layer. For uniformly mixed-host (UM) OLED, the device lifetime and also the efficiency were improved due to the spatial broadening of the recombination zone. Similar device architectures, such as the step-wise graded mixed-host (SGM-OLED) and the continuously graded mixed-host (CGM-OLED) have also been implemented by a number of researchers. In this work, a premix of hole transport material (HTM) and electron transport material (ETM), namely TPD and Alq, is prepared for one-step thermal evaporation of the mixed-host light emitting layer (EML). Depending on the evaporation rate, the CGM-OLEDs with different concentration profiles of HTM and ETM in the EML are obtained, which are inversely proportional to each other.

Microbubble cloud characterization by nonlinear frequency mixing.

PubMed

Cavaro, M; Payan, C; Moysan, J; Baqué, F

2011-05-01

In the frame of the fourth generation forum, France decided to develop sodium fast nuclear reactors. French Safety Authority requests the associated monitoring of argon gas into sodium. This implies to estimate the void fraction, and a histogram indicating the bubble population. In this context, the present letter studies the possibility of achieving an accurate determination of the histogram with acoustic methods. A nonlinear, two-frequency mixing technique has been implemented, and a specific optical device has been developed in order to validate the experimental results. The acoustically reconstructed histograms are in excellent agreement with those obtained using optical methods.

Study on effect of mixing mechanism by the transverse gaseous injection flow in scramjet engine with variable parameters

NASA Astrophysics Data System (ADS)

Yadav, Siddhita; Pandey, K. M.

2018-04-01

In scramjet engine the mixing mechanism of fuel and atmospheric air is very complicated, because the fuel have time in milliseconds for mixing with atmospheric air in combustion chamber having supersonic speed. Mixing efficiency of fuel and atmospheric air depends on mainly these parameters: Aspect ratio of injector, vibration amplitude, shock type, number of injector, jet to transverse flow momentum flux ratio, injector geometry, injection angle, molecular weight, incoming air stream angle, jet to transverse flow pressure ratio, spacing variation, mass flow rate of fuel etc. here is a very brief study of these parameters from previously done research on these parameters for the improvement of mixing efficiency. The mixing process have the significant role for the working of engine, and mixing between the atmospheric air and the jet fuel is significant factor for improving the overall thrust of the engine. The results obtained by study of papers are obtained by the 3D-Reynolds Average-Nervier-Stokes(RANS) equations along with the 2-equation k-ω shear-stress-transport (SST) turbulence model. Engine having multi air jets have 60% more mixing efficiency than single air jet, thus if the jets are increased, the mixing efficiency of engine can also be increased up to 150% by changing jet from 1 to 16. When using delta shape of injector the mixing efficiency is inversely proportional to the pressure ratio. When the fuel is injected inside the combustor from the top and bottom walls of the engine efficiency of mixing in reacting zone is higher than the single wall injection and in comparison to parallel flow, the transverse type flow is better as the atmospheric air jet can penetrate smoothly in the fuel jets and mixes well in less time. Hence this study of parameters and their effects on mixing can enhance the efficiency of mixing in engine.

Turbulent mixing induced by Richtmyer-Meshkov instability

NASA Astrophysics Data System (ADS)

Krivets, V. V.; Ferguson, K. J.; Jacobs, J. W.

2017-01-01

Richtmyer-Meshkov instability is studied in shock tube experiments with an Atwood number of 0.7. The interface is formed in a vertical shock tube using opposed gas flows, and three-dimensional random initial interface perturbations are generated by the vertical oscillation of gas column producing Faraday waves. Planar Laser Mie scattering is used for flow visualization and for measurements of the mixing process. Experimental image sequences are recorded at 6 kHz frequency and processed to obtain the time dependent variation of the integral mixing layer width. Measurements of the mixing layer width are compared with Mikaelian's [1] model in order to extract the growth exponent θ where a fairly wide range of values is found varying from θ ≈ 0.2 to 0.6.

Cacodylic acid for precommercial thinning in mixed-conifer stands shows erratic results.

Treesearch

William W. Oliver

1970-01-01

In a small-scale test, a silvicide consisting of cacodylic acid was injected during the growing season at dosages recommended by the manufacturer. The treatment did not thin adequately two of three mixed-conifer stands. Ponderosa pine and lower crown classes seemed more susceptible to the silvicide than Douglas-fir and upper crown classes. No flashback was recognized....

Solid-state reaction synthesis for mixed-phase Eu3+-doped bismuth molybdate and its luminescence properties

NASA Astrophysics Data System (ADS)

Liang, Danyang; Ding, Yu; Wang, Nan; Cai, Xiaomeng; Li, Jia; Han, Linyu; Wang, Shiqi; Han, Yuanyuan; Jia, Guang; Wang, Liyong

2017-09-01

A method for mixed-phase bismuth molybdate doped with Eu3+ ions was developed by solid-state reaction assisting with polyvinyl alcohol (PVA). The results of powder X-ray diffraction showed a mixed-phase structure and the microscopical characterization technology revealed the formation process with the addition of PVA. As a structure inducer, the PVA molecules played a vital role in the formation of phase structure. The as-obtained Eu3+-doped bismuth molybdates were also characterized by using different spectroscopic techniques including FTIR and photoluminescence (PL). The results show that doping concentration, PVA addition and calcination temperature affect photoluminescence properties remarkably.

Transport and mixing of a volume of fluid in a complex geometry

NASA Astrophysics Data System (ADS)

Gavelli, Filippo

This work presents the results of the experimental investigation of an entire sequence of events, leading to an unwanted injection of boron-depleted water into the core of a PWR. The study is subdivided into three tasks: the generation of a dilute volume in the primary system, its transport to the core, and the mixing encountered along the path. Experiments conducted at the University of Maryland (UM) facility show that, during a Small-Break LOCA transient, volumes of dilute coolant are segregated in the system, by means of phase-separating energy transport from the core to the steam generators (Boiler Condenser Mode). Two motion-initiating mechanisms are considered: the resumption of natural circulation during the recovery of the primary liquid inventory, and the reactor coolant pump startup under BCM conditions. During the inventory recovery, various phenomena are observed, that contribute to the mixing of the dilute volumes prior to the resumption of flow. The pump activation, instead, occurs in a stagnant system, therefore, no mixing of the unborated liquid has occurred. Since an unmixed slug has the potential for a larger reactivity excursion than a partially mixed one, the pump-initiated flow resumption represents the worst-case scenario. The impulse - response method is applied, for the first time, to the problem of mixing in the downcomer. This allows to express the mixing in terms of two parameters, the dispersion number and the residence time, characteristics of the flow distribution in the complex annular geometry. Other important results are obtained from the analysis of the experimental data with this procedure. It is shown that the turbulence generated by the pump impeller has a significant impact on the overall mixing. Also, the geometric discontinuities in the downcomer (in particular, the gap enlargement below the cold leg elevation) are shown to be the cause of vortex structures that highly enhance the mixing process.

Innovative Formulation Combining Al, Zr and Si Precursors to Obtain Anticorrosion Hybrid Sol-Gel Coating.

PubMed

Genet, Clément; Menu, Marie-Joëlle; Gavard, Olivier; Ansart, Florence; Gressier, Marie; Montpellaz, Robin

2018-05-10

The aim of our study is to improve the aluminium alloy corrosion resistance with Organic-Inorganic Hybrid (OIH) sol-gel coating. Coatings are obtained from unusual formulation with precursors mixing: glycidoxypropyltrimethoxysilane (GPTMS), zirconium (IV) propoxide (TPOZ) and aluminium tri-sec-butoxide (ASB). This formulation was characterized and compared with sol formulations GPTMS/TPOZ and GPTMS/ASB. In each formulation, a corrosion inhibitor, cerium (III) nitrate hexahydrate, is employed to improve the corrosion performance. Coatings obtained from sol based on GPTMS/TPOZ/ASB have good anti-corrosion performances with Natural Salt Spray (NSS) resistance of 500 h for a thickness lower than 4 µm. Contact angle measurement showed a coating hydrophobic behaviour. To understand these performances, nuclear magnetic resonance (NMR) analyses were performed, results make sol-gel coating condensation evident and are in very good agreement with previous results.

New stability conditions for mixed linear Levin-Nohel integro-differential equations

NASA Astrophysics Data System (ADS)

Dung, Nguyen Tien

2013-08-01

For the mixed Levin-Nohel integro-differential equation, we obtain new necessary and sufficient conditions of asymptotic stability. These results improve those obtained by Becker and Burton ["Stability, fixed points and inverse of delays," Proc. - R. Soc. Edinburgh, Sect. A 136, 245-275 (2006)], 10.1017/S0308210500004546 and Jin and Luo ["Stability of an integro-differential equation," Comput. Math. Appl. 57(7), 1080-1088 (2009)], 10.1016/j.camwa.2009.01.006 when b(t) = 0 and supplement the 3/2-stability theorem when a(t, s) = 0. In addition, the case of the equations with several delays is discussed as well.

Environmental and international tariffs in a mixed duopoly

NASA Astrophysics Data System (ADS)

Ferreira, Fernanda A.; Ferreira, Flávio

2013-10-01

In this paper, we study the effects of environmental and trade policies in an international mixed duopoly serving two markets, in which the public firm maximizes the sum of consumer surplus and its profit. We also analyse the effects of privatization. The model has two stages. In the first stage, governments choose environmental taxes and import tariffs, simultaneously. Then, the firms engage in a Cournot competition, choosing output levels for the domestic market and to export. We compare the results obtained in the three different ways of moving on the decision make of the firms.

COMPUTATIONAL FLUID DYNAMICS MODELING OF SCALED HANFORD DOUBLE SHELL TANK MIXING - CFD MODELING SENSITIVITY STUDY RESULTS

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

JACKSON VL

2011-08-31

The primary purpose of the tank mixing and sampling demonstration program is to mitigate the technical risks associated with the ability of the Hanford tank farm delivery and celtification systems to measure and deliver a uniformly mixed high-level waste (HLW) feed to the Waste Treatment and Immobilization Plant (WTP) Uniform feed to the WTP is a requirement of 24590-WTP-ICD-MG-01-019, ICD-19 - Interface Control Document for Waste Feed, although the exact definition of uniform is evolving in this context. Computational Fluid Dynamics (CFD) modeling has been used to assist in evaluating scaleup issues, study operational parameters, and predict mixing performance atmore » full-scale.« less

Effect of the 6PBT stirrer eccentricity and off-bottom clearance on mixing of pseudoplastic fluid in a stirred tank

NASA Astrophysics Data System (ADS)

Luan, Deyu; Zhang, Shengfeng; Wei, Xing; Duan, Zhenya

The aim of this work is to investigate the effect of the shaft eccentricity on the flow field and mixing characteristics in a stirred tank with the novel stirrer composed of perturbed six-bent-bladed turbine (6PBT). The difference between coaxial and eccentric agitations is studied using computational fluid dynamics (CFD) simulations combined with standard k-ε turbulent equations, that offer a complete image of the three-dimensional flow field. In order to determine the capability of CFD to forecast the mixing process, particle image velocimetry (PIV), which provide an accurate representation of the time-averaged velocity, was used to measure fluid velocity. The test liquid used was 1.25% (wt) xanthan gum solution, a pseudoplastic fluid with a yield stress. The comparison of the experimental and simulated mean flow fields has demonstrated that calculations based on Reynolds-averaged Navier-Stokes equations are suitable for obtaining accurate results. The effects of the shaft eccentricity and the stirrer off-bottom distance on the flow model, mixing time and mixing efficiency were extensively analyzed. It is observed that the microstructure of the flow field has a significant effect on the tracer mixing process. The eccentric agitation can lead to the flow model change and the non-symmetric flow structure, which would possess an obvious superiority of mixing behavior. Moreover, the mixing rate and mixing efficiency are dependent on the shaft eccentricity and the stirrer off-bottom distance, showing the corresponding increase of the eccentricity with the off-bottom distance. The efficient mixing process of pseudoplastic fluid stirred by 6PBT impeller is obtained with the considerably low mixing energy per unit volume when the stirrer off-bottom distance, C, is T/3 and the eccentricity, e, is 0.2. The research results provide valuable references for the improvement of pseudoplastic fluid agitation technology.

Jet mixing into a heated cross flow in a cylindrical duct: Influence of geometry and flow variations

NASA Technical Reports Server (NTRS)

Hatch, M. S.; Sowa, W. A.; Samuelsen, G. S.; Holdeman, J. D.

1992-01-01

To examine the mixing characteristics of jets in an axi-symmetric can geometry, temperature measurements were obtained downstream of a row of cold jets injected into a heated cross stream. Parametric, non-reacting experiments were conducted to determine the influence of geometry and flow variations on mixing patterns in a cylindrical configuration. Results show that jet to mainstream momentum flux ratio and orifice geometry significantly impact the mixing characteristics of jets in a can geometry. For a fixed number of orifices, the coupling between momentum flux ratio and injector determines (1) the degree of jet penetration at the injection plane, and (2) the extent of circumferential mixing downstream of the injection plane. The results also show that, at a fixed momentum flux ratio, jet penetration decreases with (1) an increase in slanted slot aspect ratio, and (2) an increase in the angle of the slots with respect to the mainstream direction.

Mixing and combustion enhancement of Turbocharged Solid Propellant Ramjet

NASA Astrophysics Data System (ADS)

Liu, Shichang; Li, Jiang; Zhu, Gen; Wang, Wei; Liu, Yang

2018-02-01

Turbocharged Solid Propellant Ramjet is a new concept engine that combines the advantages of both solid rocket ramjet and Air Turbo Rocket, with a wide operation envelope and high performance. There are three streams of the air, turbine-driving gas and augment gas to mix and combust in the afterburner, and the coaxial intake mode of the afterburner is disadvantageous to the mixing and combustion. Therefore, it is necessary to carry out mixing and combustion enhancement research. In this study, the numerical model of Turbocharged Solid Propellant Ramjet three-dimensional combustion flow field is established, and the numerical simulation of the mixing and combustion enhancement scheme is conducted from the aspects of head region intake mode to injection method in afterburner. The results show that by driving the compressed air to deflect inward and the turbine-driving gas to maintain strong rotation, radial and tangential momentum exchange of the two streams can be enhanced, thereby improving the efficiency of mixing and combustion in the afterburner. The method of injecting augment gas in the transverse direction and making sure the injection location is as close as possible to the head region is beneficial to improve the combustion efficiency. The outer combustion flow field of the afterburner is an oxidizer-rich environment, while the inner is a fuel-rich environment. To improve the efficiency of mixing and combustion, it is necessary to control the injection velocity of the augment gas to keep it in the oxygen-rich zone of the outer region. The numerical simulation for different flight conditions shows that the optimal mixing and combustion enhancement scheme can obtain high combustion efficiency and have excellent applicability in a wide working range.

Liquid–liquid mixing studies in annular centrifugal contactors comparing stationary mixing vane options

DOE PAGES

Wardle, Kent E.

2015-09-11

Comparative studies of multiphase operation of an annular centrifugal contactor show the impact of housing stationary mixing vane configuration. A number of experimental results for several different mixing vane options are reported for operation of a 12.5 cm engineering-scale contactor unit. Fewer straight vanes give greater mixing-zone hold-up compared to curved vanes. Quantitative comparison of droplet size distribution also showed a significant decrease in mean diameter for four straight vanes versus eight curved vanes. This set of measurements gives a compelling case for careful consideration of mixing vane geometry when evaluating hydraulic operation and extraction process efficiency of annular centrifugalmore » contactors.« less

Improving the mixing performances of rice straw anaerobic digestion for higher biogas production by computational fluid dynamics (CFD) simulation.

PubMed

Shen, Fei; Tian, Libin; Yuan, Hairong; Pang, Yunzhi; Chen, Shulin; Zou, Dexun; Zhu, Baoning; Liu, Yanping; Li, Xiujin

2013-10-01

As a lignocellulose-based substrate for anaerobic digestion, rice straw is characterized by low density, high water absorbability, and poor fluidity. Its mixing performances in digestion are completely different from traditional substrates such as animal manures. Computational fluid dynamics (CFD) simulation was employed to investigate mixing performances and determine suitable stirring parameters for efficient biogas production from rice straw. The results from CFD simulation were applied in the anaerobic digestion tests to further investigate their reliability. The results indicated that the mixing performances could be improved by triple impellers with pitched blade, and complete mixing was easily achieved at the stirring rate of 80 rpm, as compared to 20-60 rpm. However, mixing could not be significantly improved when the stirring rate was further increased from 80 to 160 rpm. The simulation results agreed well with the experimental results. The determined mixing parameters could achieve the highest biogas yield of 370 mL (g TS)(-1) (729 mL (g TS(digested))(-1)) and 431 mL (g TS)(-1) (632 mL (g TS(digested))(-1)) with the shortest technical digestion time (T 80) of 46 days. The results obtained in this work could provide useful guides for the design and operation of biogas plants using rice straw as substrates.

MixHMM: Inferring Copy Number Variation and Allelic Imbalance Using SNP Arrays and Tumor Samples Mixed with Stromal Cells

PubMed Central

Schulz, Vincent; Chen, Min; Tuck, David

2010-01-01

Background Genotyping platforms such as single nucleotide polymorphism (SNP) arrays are powerful tools to study genomic aberrations in cancer samples. Allele specific information from SNP arrays provides valuable information for interpreting copy number variation (CNV) and allelic imbalance including loss-of-heterozygosity (LOH) beyond that obtained from the total DNA signal available from array comparative genomic hybridization (aCGH) platforms. Several algorithms based on hidden Markov models (HMMs) have been designed to detect copy number changes and copy-neutral LOH making use of the allele information on SNP arrays. However heterogeneity in clinical samples, due to stromal contamination and somatic alterations, complicates analysis and interpretation of these data. Methods We have developed MixHMM, a novel hidden Markov model using hidden states based on chromosomal structural aberrations. MixHMM allows CNV detection for copy numbers up to 7 and allows more complete and accurate description of other forms of allelic imbalance, such as increased copy number LOH or imbalanced amplifications. MixHMM also incorporates a novel sample mixing model that allows detection of tumor CNV events in heterogeneous tumor samples, where cancer cells are mixed with a proportion of stromal cells. Conclusions We validate MixHMM and demonstrate its advantages with simulated samples, clinical tumor samples and a dilution series of mixed samples. We have shown that the CNVs of cancer cells in a tumor sample contaminated with up to 80% of stromal cells can be detected accurately using Illumina BeadChip and MixHMM. Availability The MixHMM is available as a Python package provided with some other useful tools at http://genecube.med.yale.edu:8080/MixHMM. PMID:20532221

Quantifying uncertainty in stable isotope mixing models

DOE PAGES

Davis, Paul; Syme, James; Heikoop, Jeffrey; ...

2015-05-19

Mixing models are powerful tools for identifying biogeochemical sources and determining mixing fractions in a sample. However, identification of actual source contributors is often not simple, and source compositions typically vary or even overlap, significantly increasing model uncertainty in calculated mixing fractions. This study compares three probabilistic methods, SIAR [ Parnell et al., 2010] a pure Monte Carlo technique (PMC), and Stable Isotope Reference Source (SIRS) mixing model, a new technique that estimates mixing in systems with more than three sources and/or uncertain source compositions. In this paper, we use nitrate stable isotope examples (δ 15N and δ 18O) butmore » all methods tested are applicable to other tracers. In Phase I of a three-phase blind test, we compared methods for a set of six-source nitrate problems. PMC was unable to find solutions for two of the target water samples. The Bayesian method, SIAR, experienced anchoring problems, and SIRS calculated mixing fractions that most closely approximated the known mixing fractions. For that reason, SIRS was the only approach used in the next phase of testing. In Phase II, the problem was broadened where any subset of the six sources could be a possible solution to the mixing problem. Results showed a high rate of Type I errors where solutions included sources that were not contributing to the sample. In Phase III some sources were eliminated based on assumed site knowledge and assumed nitrate concentrations, substantially reduced mixing fraction uncertainties and lowered the Type I error rate. These results demonstrate that valuable insights into stable isotope mixing problems result from probabilistic mixing model approaches like SIRS. The results also emphasize the importance of identifying a minimal set of potential sources and quantifying uncertainties in source isotopic composition as well as demonstrating the value of additional information in reducing the uncertainty in calculated

Cornell Mixing Zone Expert System

EPA Pesticide Factsheets

This page provides an overview Cornell Mixing Zone Expert System water quality modeling and decision support system designed for environmental impact assessment of mixing zones resulting from wastewater discharge from point sources

Mixing of nanosize particles by magnetically assisted impaction techniques

NASA Astrophysics Data System (ADS)

Scicolone, James V.

Nanoparticles and nanocomposites offer unique properties that arise from their small size, large surface area, and the interactions of phases at their interfaces, and are attractive for their potential to improve performance of drugs, biomaterials, catalysts and other high-value-added materials. However, a major problem in utilizing nanoparticles is that they often lose their high surface area due to grain growth. Creating nanostructured composites where two or more nanosized constituents are intimately mixed can prevent this loss in surface area, but in order to obtain homogeneous mixing, de-agglomeration of the individual nanoparticle constituents is necessary. Due to high surface area, nano-particles form very large, fractal agglomerates. The structure of these agglomerates can have a large agglomerate composed of sub-agglomerates (SA), which itself consists of primary agglomerates (PA), that contain chain or net like nano-particle structures; typically sub-micron size. Thus the final agglomerate has a hierarchical, fractal structure, and depending upon the forces applied, it could break down to a certain size scale. The agglomerates can be fairly porous and fragile or they could be quite dense, based on primary particle size and its surface energy. Thus depending upon the agglomerate strength at different length scales, one could achieve deagglomeration and subsequent mixing at varying length scale. A better understanding of this can have a major impact on the field of nano-structured materials; thus the long term objective of this project is to gain fundamental understanding of deagglomeration and mixing of nano-agglomerates. Dry mixing is in general not effective in achieving desired mixing at nanoscale, whereas wet mixing suffers from different disadvantages like nanomaterial of interest should be insoluble, has to wet the liquid, and involves additional steps of filtration and drying. This research examines the use of environmentally friendly a novel

Multiple jet study data correlations. [data correlation for jet mixing flow of air jets

NASA Technical Reports Server (NTRS)

Walker, R. E.; Eberhardt, R. G.

1975-01-01

Correlations are presented which allow determination of penetration and mixing of multiple cold air jets injected normal to a ducted subsonic heated primary air stream. Correlations were obtained over jet-to-primary stream momentum flux ratios of 6 to 60 for locations from 1 to 30 jet diameters downstream of the injection plane. The range of geometric and operating variables makes the correlations relevant to gas turbine combustors. Correlations were obtained for the mixing efficiency between jets and primary stream using an energy exchange parameter. Also jet centerplane velocity and temperature trajectories were correlated and centerplane dimensionless temperature distributions defined. An assumption of a Gaussian vertical temperature distribution at all stations is shown to result in a reasonable temperature field model. Data are presented which allow comparison of predicted and measured values over the range of conditions specified above.

Attractiveness of own-race, other-race, and mixed-race faces.

PubMed

Rhodes, Gillian; Lee, Kieran; Palermo, Romina; Weiss, Mahi; Yoshikawa, Sakiko; Clissa, Peter; Williams, Tamsyn; Peters, Marianne; Winkler, Chris; Jeffery, Linda

2005-01-01

Averaged face composites, which represent the central tendency of a familiar population of faces, are attractive. If this prototypicality contributes to their appeal, then averaged composites should be more attractive when their component faces come from a familiar, own-race population than when they come from a less familiar, other-race population. We compared the attractiveness of own-race composites, other-race composites, and mixed-race composites (where the component faces were from both races). In experiment 1, Caucasian participants rated own-race composites as more attractive than other-race composites, but only for male faces. However, mixed-race (Caucasian/Japanese) composites were significantly more attractive than own-race composites, particularly for the opposite sex. In experiment 2, Caucasian and Japanese participants living in Australia and Japan, respectively, selected the most attractive face from a continuum with exaggerated Caucasian characteristics at one end and exaggerated Japanese characteristics at the other, with intervening images including a Caucasian averaged composite, a mixed-race averaged composite, and a Japanese averaged composite. The most attractive face was, again, a mixed-race composite, for both Caucasian and Japanese participants. In experiment 3, Caucasian participants rated individual Eurasian faces as significantly more attractive than either Caucasian or Asian faces. Similar results were obtained with composites. Eurasian faces and composites were also rated as healthier than Caucasian or Asian faces and composites, respectively. These results suggest that signs of health may be more important than prototypicality in making average faces attractive.

Optimization of the parameters for obtaining zirconia-alumina coatings, made by flame spraying from results of numerical simulation

NASA Astrophysics Data System (ADS)

Ferrer, M.; Vargas, F.; Peña, G.

2017-12-01

The K-Sommerfeld values (K) and the melting percentage (% F) obtained by numerical simulation using the Jets et Poudres software were used to find the projection parameters of zirconia-alumina coatings by thermal spraying flame, in order to obtain coatings with good morphological and structural properties to be used as thermal insulation. The experimental results show the relationship between the Sommerfeld parameter and the porosity of the zirconia-alumina coatings. It is found that the lowest porosity is obtained when the K-Sommerfeld value is close to 45 with an oxidant flame, on the contrary, when superoxidant flames are used K values are close 52, which improve wear resistance.

Building America Residential System Research Results: Achieving 30% Whole House Energy Savings Level in Mixed-Humid Climates; January 2006 - December 2006

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

Anderson, R.; Hendron, R.; Eastment, M.

2006-12-01

This report summarizes research results for the 30% energy savings level and demonstrates that lead builders can successfully provide 30% homes in the Mixed-Humid Climate Region on a cost-neutral basis.

Catalytic oxidation of toluene: comparative study over powder and monolithic manganese-nickel mixed oxide catalysts.

PubMed

Duplančić, Marina; Tomašić, Vesna; Gomzi, Zoran

2017-07-05

This paper is focused on development of the metal monolithic structure for total oxidation of toluene at low temperature. The well-adhered catalyst, based on the mixed oxides of manganese and nickel, is washcoated on the Al/Al 2 O 3 plates as metallic support. For the comparison purposes, results observed for the manganese-nickel mixed oxide supported on the metallic monolith are compared with those obtained using powder type of the same catalyst. Prepared manganese-nickel mixed oxides in both configurations show remarkable low-temperature activity for the toluene oxidation. The reaction temperature T 50 corresponding to 50% of the toluene conversion is observed at temperatures of ca. 400-430 K for the powder catalyst and at ca. 450-490 K for the monolith configuration. The appropriate mathematical models, such as one-dimensional (1D) pseudo-homogeneous model of the fixed bed reactor and the 1D heterogeneous model of the metal monolith reactor, are applied to describe and compare catalytic performances of both reactors. Validation of the applied models is performed by comparing experimental data with theoretical predictions. The obtained results confirmed that the reaction over the monolithic structure is kinetically controlled, while in the case of the powder catalyst the reaction rate is influenced by the intraphase diffusion.

Mixing method and apparatus

DOEpatents

Green, Norman W.

1982-06-15

Method of mixing particulate materials comprising contacting a primary source and a secondary source thereof whereby resulting mixture ensues; preferably at least one of the two sources has enough motion to insure good mixing and the particulate materials may be heat treated if desired. Apparatus for such mixing comprising an inlet for a primary source, a reactor communicating therewith, a feeding means for supplying a secondary source to the reactor, and an inlet for the secondary source. Feeding means is preferably adapted to supply fluidized materials.

Can mixed star-plus-wormhole systems mimic black holes?

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

Dzhunushaliev, Vladimir; Folomeev, Vladimir; Kleihaus, Burkhard

We consider mixed strongly gravitating configurations consisting of a wormhole threaded by two types of ordinary matter. For such systems, the possibility of obtaining static spherically symmetric solutions describing compact massive central objects enclosed by high-redshift surfaces (black-hole-like configurations) is studied. Using the standard thin accretion disk model, we exhibit potentially observable differences allowing to distinguish the mixed systems from ordinary black holes with the same masses.

Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing

NASA Astrophysics Data System (ADS)

Watanabe, T.; Nagata, K.

2016-08-01

We report on the numerical study of the mixing volume model (MVM) for molecular diffusion in Lagrangian simulations of turbulent mixing problems. The MVM is based on the multi-particle interaction in a finite volume (mixing volume). A priori test of the MVM, based on the direct numerical simulations of planar jets, is conducted in the turbulent region and the interfacial layer between the turbulent and non-turbulent fluids. The results show that the MVM predicts well the mean effects of the molecular diffusion under various numerical and flow parameters. The number of the mixing particles should be large for predicting a value of the molecular diffusion term positively correlated to the exact value. The size of the mixing volume relative to the Kolmogorov scale η is important in the performance of the MVM. The scalar transfer across the turbulent/non-turbulent interface is well captured by the MVM especially with the small mixing volume. Furthermore, the MVM with multiple mixing particles is tested in the hybrid implicit large-eddy-simulation/Lagrangian-particle-simulation (LES-LPS) of the planar jet with the characteristic length of the mixing volume of O(100η). Despite the large mixing volume, the MVM works well and decays the scalar variance in a rate close to the reference LES. The statistics in the LPS are very robust to the number of the particles used in the simulations and the computational grid size of the LES. Both in the turbulent core region and the intermittent region, the LPS predicts a scalar field well correlated to the LES.

Mixing modes in a population-based interview survey: comparison of a sequential and a concurrent mixed-mode design for public health research.

PubMed

Mauz, Elvira; von der Lippe, Elena; Allen, Jennifer; Schilling, Ralph; Müters, Stephan; Hoebel, Jens; Schmich, Patrick; Wetzstein, Matthias; Kamtsiuris, Panagiotis; Lange, Cornelia

2018-01-01

Population-based surveys currently face the problem of decreasing response rates. Mixed-mode designs are now being implemented more often to account for this, to improve sample composition and to reduce overall costs. This study examines whether a concurrent or sequential mixed-mode design achieves better results on a number of indicators of survey quality. Data were obtained from a population-based health interview survey of adults in Germany that was conducted as a methodological pilot study as part of the German Health Update (GEDA). Participants were randomly allocated to one of two surveys; each of the surveys had a different design. In the concurrent mixed-mode design ( n  = 617) two types of self-administered questionnaires (SAQ-Web and SAQ-Paper) and computer-assisted telephone interviewing were offered simultaneously to the respondents along with the invitation to participate. In the sequential mixed-mode design ( n  = 561), SAQ-Web was initially provided, followed by SAQ-Paper, with an option for a telephone interview being sent out together with the reminders at a later date. Finally, this study compared the response rates, sample composition, health indicators, item non-response, the scope of fieldwork and the costs of both designs. No systematic differences were identified between the two mixed-mode designs in terms of response rates, the socio-demographic characteristics of the achieved samples, or the prevalence rates of the health indicators under study. The sequential design gained a higher rate of online respondents. Very few telephone interviews were conducted for either design. With regard to data quality, the sequential design (which had more online respondents) showed less item non-response. There were minor differences between the designs in terms of their costs. Postage and printing costs were lower in the concurrent design, but labour costs were lower in the sequential design. No differences in health indicators were found between

Controllability of switched singular mix-valued logical control networks with constraints

NASA Astrophysics Data System (ADS)

Deng, Lei; Gong, Mengmeng; Zhu, Peiyong

2018-03-01

The present paper investigates the controllability problem of switched singular mix-valued logical control networks (SSMLCNs) with constraints on states and controls. First, using the semi-tenser product (STP) of matrices, the SSMLCN is expressed in an algebraic form, based on which a necessary and sufficient condition is given for the uniqueness of solution of SSMLCNs. Second, a necessary and sufficient criteria is derived for the controllability of constrained SSMLCNs, by converting a constrained SSMLCN into a parallel constrained switched mix-valued logical control network. Third, an algorithm is presented to design a proper switching sequence and a control scheme which force a state to a reachable state. Finally, a numerical example is given to demonstrate the efficiency of the results obtained in this paper.

The ultrasound-enhanced bioscouring performance of four polygalacturonase enzymes obtained from rhizopus oryzae

USDA-ARS?s Scientific Manuscript database

An analytical and statistical method has been developed to measure the ultrasound-enhanced bioscouring performance of milligram quantities of endo- and exo-polygalacturonase enzymes obtained from Rhizopus oryzae fungi. UV-Vis spectrophotometric data and a general linear mixed models procedure indic...

Determination and characterization by numerical simulations of flow mixing due to electrokinetic instabilities in cross-shaped microchannels

NASA Astrophysics Data System (ADS)

Guerrero, Esteban; Chen, Daming; Hageman, Logan; Guzman, Amador

2017-11-01

This article describes a computational study of flow mixing in microchannels due to electrokinetic instabilities that are compared to experimental results obtained in a cross- microchannel with an ionic solution of potassium chloride with two different ionic concentrations, with the purpose of determining the parameter combinations to produce the onset of flow mixing and its characteristics. For the numerical simulation process carried out using a finite element method-based commercial code, we applied a typical zeta potential used in other articles as a boundary condition for the microchannel walls. For the experiments, we used a commercial silicon glass (Caliper NS95) microchannel. For determining a flow mixing regime, we use the concept of ``mixing index'' established by (Fu et al., 2005) for an electrical conductivity ratio range of 18 to 52 with an electric field range of 1100 to 1900 V/cm. From our numerical simulation results we have found a threshold for the electrical Rayleigh number for starting a flow mixing regime, and a minimum microchannel characteristic length for achieving a 90% of flow mixing that will allow us to significantly reduce the mixing time. Vicerrectoria de Investigacion y Departamento de Ingeniera Mecánica y Metalúrgica Pontificia Universidad Catolica de Chile.

A Comparative Evaluation of Mixed Dentition Analysis on Reliability of Cone Beam Computed Tomography Image Compared to Plaster Model

PubMed Central

Gowd, Snigdha; Shankar, T; Dash, Samarendra; Sahoo, Nivedita; Chatterjee, Suravi; Mohanty, Pritam

2017-01-01

Aims and Objective: The aim of the study was to evaluate the reliability of cone beam computed tomography (CBCT) obtained image over plaster model for the assessment of mixed dentition analysis. Materials and Methods: Thirty CBCT-derived images and thirty plaster models were derived from the dental archives, and Moyer's and Tanaka-Johnston analyses were performed. The data obtained were interpreted and analyzed statistically using SPSS 10.0/PC (SPSS Inc., Chicago, IL, USA). Descriptive and analytical analysis along with Student's t-test was performed to qualitatively evaluate the data and P < 0.05 was considered statistically significant. Results: Statistically, significant results were obtained on data comparison between CBCT-derived images and plaster model; the mean for Moyer's analysis in the left and right lower arch for CBCT and plaster model was 21.2 mm, 21.1 mm and 22.5 mm, 22.5 mm, respectively. Conclusion: CBCT-derived images were less reliable as compared to data obtained directly from plaster model for mixed dentition analysis. PMID:28852639

Quark mixing and exponential form of the Cabibbo-Kobayashi-Maskawa matrix

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

Zhukovsky, K. V., E-mail: zhukovsk@phys.msu.ru; Dattoli, D., E-mail: dattoli@frascati.enea.i

2008-10-15

Various forms of representation of the mixing matrix are discussed. An exponential parametrization e{sup A} of the Cabibbo-Kobayashi-Maskawa matrix is considered in the context of the unitarity requirement, this parametrization being the most general form of the mixing matrix. An explicit representation for the exponential mixing matrix in terms of the first and second degrees of the matrix A exclusively is obtained. This representation makes it possible to calculate this exponential mixing matrix readily in any order of the expansion in the small parameter {lambda}. The generation of new unitary parametric representations of the mixing matrix with the aid ofmore » the exponential matrix is demonstrated.« less

Turbulent mixing& combustion in TNT explosions

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

Kuhl, A L; Ferguson, R E; Oppenheim, A K

2000-12-12

Effects of turbulent mixing induced by explosion of a 1-g spherical TNT charge in air are investigated. The detonation wave in the charge transforms the solid explosive (C{sub 7}H{sub 5}N{sub 3}O{sub 6}) to gaseous products, rich in C{sub (S)}, and CO. The detonation pressure ({approx}210 kb) causes the products to expand rapidly, driving a blast wave into the surrounding air (Brode, 1959). The interface between the products and air is unstable (Richtmyer, 1960; Meshkov, 1960; Anisimov & Zel'dovich, 1977). As shown in Collage Ia-c, this region rapidly transitions into a turbulent mixing layer (Kuhl, 1996). As the embedded shock, I,more » implodes, it draws the mixing structures (Taylor cavities) into the origin (Collage Id-e). In this way air becomes distributed throughout the hot detonation products gases. This process is enhanced by shock reflections from confining walls. In either case (confined or unconfined), rapid combustion takes place where the expanded detonation products play the role of fuel. This leads to a dramatic increase in chamber pressure (Fig. 1)-in contrast to a corresponding TNT explosion in nitrogen. The problem was modeled as turbulent combustion in an unmixed system at large Reynolds, Peclet and Damkohler numbers (Kuhl et al, 1997). The numerical solution was obtained by a high-order Godunov scheme (Colella & Glaz, 1985). Adaptive Mesh Refinement (Berger & Colella, 1989) was used to follow the turbulent mixing on the computational grid in as much detail as possible. The results reveal all the dynamic features (Fig. 2) of the exothermic process of combustion controlled by fluid-mechanic transport in a highly turbulent field (Kuhl & Oppenheim, 1997), in contrast to the conventional reaction-diffusion mechanism of Zel'dovich & Frank-Kamenetskii (1938).« less

Mixed heavy–light matching in the Universal One-Loop Effective Action

DOE PAGES

Ellis, Sebastian A. R.; Quevillon, Jérémie; You, Tevong; ...

2016-11-10

Recently, a general result for evaluating the path integral at one loop was obtained in the form of the Universal One-Loop Effective Action. It may be used to derive effective field theory operators of dimensions up to six, by evaluating the traces of matrices in this expression, with the mass dependence encapsulated in the universal coefficients. In this study we show that it can account for loops of mixed heavy–light particles in the matching procedure. Our prescription for computing these mixed contributions to the Wilson coefficients is conceptually simple. Moreover it has the advantage of maintaining the universal structure ofmore » the effective action, which we illustrate using the example of integrating out a heavy electroweak triplet scalar coupling to a light Higgs doublet. Finally we also identify new structures that were previously neglected in the universal results.« less

New high-definition thickness data obtained at tropical glaciers: preliminary results from Antisana volcano (Ecuador) using GPR prospection

NASA Astrophysics Data System (ADS)

Zapata, Camilo; Andrade, Daniel; Córdova, Jorge; Maisincho, Luis; Carvajal, Juan; Calispa, Marlon; Villacís, Marcos

2014-05-01

The study of tropical glaciers has been a significant contribution to the understanding of glacier dynamics and climate change. Much of the data and results have been obtained by analyzing plan-view images obtained by air- and space-borne sensors, as well as depth data obtained by diverse methodologies at selected points on the glacier surface. However, the measurement of glacier thicknesses has remained an elusive task in tropical glaciers, often located in rough terrains where the application of geophysical surveys (i.e. seismic surveys) requires logistics sometimes hardly justified by the amount of obtained data. In the case of Ecuador, however, where most glaciers have developed on active volcanoes and represent sources/reservoirs of fresh water, the precise knowledge of such information is fundamental for scientific research but also in order to better assess key aspects for the society. The relatively recent but fast development of the GPR technology has helped to obtain new highdefinition thickness data at Antisana volcano that will be used to: 1) better understand the dynamics and fate of tropical glaciers; 2) better estimate the amount of fresh water stored in the glaciers; 3) better assess the hazards associated with the sudden widespread melting of glaciers during volcanic eruptions. The measurements have been obtained at glaciers 12 and 15 of Antisana volcano, with the help of a commercial GPR equipped with a 25 MHz antenna. A total of 30 transects have been obtained, covering a distance of more than 3 km, from the glacier ablation zone, located at ~ 4600 masl, up to the level of 5200 masl. The preliminary results show a positive correlation between altitude and glacier thickness, with maximum and minimum calculated values reaching up to 80 m, and down to 15 m, respectively. The experience gained at Antisana volcano will be used to prepare a more widespread GPR survey in the glaciers of Cotopaxi volcano, whose implications in terms of volcanic hazards

[The mixed gonadal dysgenesis. Diagnostic criteria and surgical treatment].

PubMed

Blanco, J A; Martínez-Mora, J; Granada, M; Toran, N; Isnard, R M; Castellví, A; Casasa, J M

1997-01-01

The Mixed Gonadal Dysgenesis represents the 7.6% of all our patients with intersexual states. We report 14 patients who present Mixed Gonadal Dysgenesis. We have studied: diagnosis age; external genitalia description; sex assigned in birth and if has changed; the karyotype; sex chromatine; hormonal study; genitography; internal genitalia and internal Mullerians ducts structures; gonadal histologycal study; surgical treatment and hormonal treatment. The results show that 50% of the cases presents a 46XY karyotype and the other 50% mosaicisme 45XO/46XY. The histological study is very distinctive. A vulvovagynoplasty and clitoroplasty was made in all the cases. Four patients must follow an hormonal treatment after reaching puberal age. Summing up, with patients having ambiguous genitalia we can suspect it consists of a Mixed Gonadal Dysgenesis. The diagnosis must be precocious. And this diagnosis will be based in an ambiguous genitalia, with a karyotype 46XY or 45XO/46XY, the persistence of the internal Müllerian duct structures, and the histological study with a dysgenetic testis. These patients should be raised as females because they can obtain a good morphological and functional development like a normal female.

Why, and how, mixed methods research is undertaken in health services research in England: a mixed methods study.

PubMed

O'Cathain, Alicia; Murphy, Elizabeth; Nicholl, Jon

2007-06-14

Recently, there has been a surge of international interest in combining qualitative and quantitative methods in a single study--often called mixed methods research. It is timely to consider why and how mixed methods research is used in health services research (HSR). Documentary analysis of proposals and reports of 75 mixed methods studies funded by a research commissioner of HSR in England between 1994 and 2004. Face-to-face semi-structured interviews with 20 researchers sampled from these studies. 18% (119/647) of HSR studies were classified as mixed methods research. In the documentation, comprehensiveness was the main driver for using mixed methods research, with researchers wanting to address a wider range of questions than quantitative methods alone would allow. Interviewees elaborated on this, identifying the need for qualitative research to engage with the complexity of health, health care interventions, and the environment in which studies took place. Motivations for adopting a mixed methods approach were not always based on the intrinsic value of mixed methods research for addressing the research question; they could be strategic, for example, to obtain funding. Mixed methods research was used in the context of evaluation, including randomised and non-randomised designs; survey and fieldwork exploratory studies; and instrument development. Studies drew on a limited number of methods--particularly surveys and individual interviews--but used methods in a wide range of roles. Mixed methods research is common in HSR in the UK. Its use is driven by pragmatism rather than principle, motivated by the perceived deficit of quantitative methods alone to address the complexity of research in health care, as well as other more strategic gains. Methods are combined in a range of contexts, yet the emerging methodological contributions from HSR to the field of mixed methods research are currently limited to the single context of combining qualitative methods and

Different mixing techniques in experimental mesocosms—does mixing affect plankton biomass and community composition?

PubMed Central

Striebel, Maren; Kirchmaier, Leo; Hingsamer, Peter

2014-01-01

Over the past four decades, mesocosm studies have been successfully used for a wide range of applications and have provided a lot of information on trophic interactions and biogeochemical cycling of aquatic ecosystem. However, the setup of such mesocosms (e.g., dimensions and duration of experiments) needs to be adapted to the relevant biological processes being investigated. Mixing of the water column is an important factor to be considered in mesocosm experiments because enclosing water in an artificial chamber always alters the mixing regime. Various approaches have been applied to generate mixing in experimental ecosystems, including pure mechanical mixing (e.g., using a disc), airlifts, bubbling with compressed air, and pumping. In this study, we tested different mixing techniques for outdoor mesocosms and their impact on plankton biomass and community composition. We compared mesocosms mixed with a disc, an airlift-system, and bubbling, and used a nonactively mixed mesocosm as a control. We investigated phytoplankton, ciliate, and zooplankton communities during a 19-d mesocosm experiment. Based on our results, we concluded that mechanical mixing with a disc was the most effective technique due to the undertow produced by lowering and lifting the disc. While no mixing technique affected seston biomass, zooplankton biomass was highest in the treatments mixed with the disc. The airlift treatments had the lowest relative share of small flagellates. However, no further differences in phytoplankton community composition occurred and no differences in zooplankton community composition existed between all actively mixed treatments. PMID:25729335

Ill-posedness in modeling mixed sediment river morphodynamics

NASA Astrophysics Data System (ADS)

Chavarrías, Víctor; Stecca, Guglielmo; Blom, Astrid

2018-04-01

In this paper we analyze the Hirano active layer model used in mixed sediment river morphodynamics concerning its ill-posedness. Ill-posedness causes the solution to be unstable to short-wave perturbations. This implies that the solution presents spurious oscillations, the amplitude of which depends on the domain discretization. Ill-posedness not only produces physically unrealistic results but may also cause failure of numerical simulations. By considering a two-fraction sediment mixture we obtain analytical expressions for the mathematical characterization of the model. Using these we show that the ill-posed domain is larger than what was found in previous analyses, not only comprising cases of bed degradation into a substrate finer than the active layer but also in aggradational cases. Furthermore, by analyzing a three-fraction model we observe ill-posedness under conditions of bed degradation into a coarse substrate. We observe that oscillations in the numerical solution of ill-posed simulations grow until the model becomes well-posed, as the spurious mixing of the active layer sediment and substrate sediment acts as a regularization mechanism. Finally we conduct an eigenstructure analysis of a simplified vertically continuous model for mixed sediment for which we show that ill-posedness occurs in a wider range of conditions than the active layer model.

Amperometric Enzyme Sensor to Check the Total Antioxidant Capacity of Several Mixed Berries. Comparison with Two Other Spectrophotometric and Fluorimetric Methods

PubMed Central

Tomassetti, Mauro; Serone, Maruschka; Angeloni, Riccardo; Campanella, Luigi; Mazzone, Elisa

2015-01-01

The aim of this research was to test the correctness of response of a superoxide dismutase amperometric biosensor used for the purpose of measuring and ranking the total antioxidant capacity of several systematically analysed mixed berries. Several methods are described in the literature for determining antioxidant capacity, each culminating in the construction of an antioxidant capacity scale and each using its own unit of measurement. It was therefore endeavoured to correlate and compare the results obtained using the present amperometric biosensor method with those resulting from two other different methods for determining the total antioxidant capacity selected from among those more frequently cited in the literature. The purpose was to establish a methodological approach consisting in the simultaneous application of different methods that it would be possible to use to obtain an accurate estimation of the total antioxidant capacity of different mixed berries and the food products containing them. Testing was therefore extended to also cover jams, yoghurts and juices containing mixed berries. PMID:25654720

Surface immunoglobulins on blood lymphocytes of normal and immunodeficient persons studied by the mixed antiglobulin method

PubMed Central

Litwin, S. D.; Ochs, H.; Pollara, B.

1973-01-01

Surface immunoglobulins on human peripheral blood lymphocytes were investigated by the mixed antiglobulin technique—using the single layer mixed antiglobulin method as originally described (SLMA), and a modification employing a double layer of antibody (DLMA). Lymphocytes isolated from the blood of normal individuals had a mean of 7.8 and 18.4 per cent Ig + cells by the SLMA and DLMA techniques respectively. The DLMA data are similar to results obtained by other methods of detecting membrane Igs indicating that the mixed antiglobulin method is comparable in sensitivity. When the total numbers of Ig + cells, obtained by separate κ and λ testing, were compared with results obtained using single anti-light chain antisera, there was no significant difference, suggesting that most positive lymphocytes carry a single variety of light chain. Lymphocytes from the blood of seventeen patients with primary immunodeficiency were analysed. Four patients with variable immunodeficiency and four others with absent serum IgA all had normal surface Igs including α chains. All members of a family having an X-linked immunodeficiency had normal surface Igs including the affected members and a presumed carrier. Four cases of immunodeficiency associated with thymoma proved to have disparate findings. One patient exhibited a selective absence of μ antigens on the membranes of blood lymphocytes of over 2800 tested cells. Two other cases had normal surface Igs while a fourth patient, previously reported, lacked all surface Igs. PMID:4796276

Measuring cognitive load: mixed results from a handover simulation for medical students.

PubMed

Young, John Q; Irby, David M; Barilla-LaBarca, Maria-Louise; Ten Cate, Olle; O'Sullivan, Patricia S

2016-02-01

The application of cognitive load theory to workplace-based activities such as patient handovers is hindered by the absence of a measure of the different load types. This exploratory study tests a method for measuring cognitive load during handovers. The authors developed the Cognitive Load Inventory for Handoffs (CLI4H) with items for intrinsic, extraneous, and germane load. Medical students completed the measure after participating in a simulated handover. Exploratory factor and correlation analyses were performed to collect evidence for validity. Results yielded a two-factor solution for intrinsic and germane load that explained 50 % of the variance. The extraneous load items performed poorly and were removed from the model. The score for intrinsic load correlated with the Paas Cognitive Load scale (r = 0.31, p = 0.004) and was lower for students with more prior handover training (p = 0.036). Intrinsic load did not, however, correlate with performance. Germane load did not correlate with the Paas Cognitive Load scale but did correlate as expected with performance (r = 0.30, p = 0.005) and was lower for those students with more prior handover training (p = 0.03). The CLI4H yielded mixed results with some evidence for validity of the score from the intrinsic load items. The extraneous load items performed poorly and the use of only a single item for germane load limits conclusions. The instrument requires further development and testing. Study results and limitations provide guidance to future efforts to measure cognitive load during workplace-based activities, such as handovers.

Germinated wheat: Phytochemical composition and mixing characteristics

USDA-ARS?s Scientific Manuscript database

Germinated grain recently attracts interest due to its beneficial effect on human health. In this research, whole wheat flour samples obtained after three days and five days of germination were analyzed for biochemical components, mixing quality, and effects on human breast cancer cells. Germinati...

Interannual control of plankton communities by deep winter mixing and prey/predator interactions in the NW Mediterranean: Results from a 30-year 3D modeling study

NASA Astrophysics Data System (ADS)

Auger, P. A.; Ulses, C.; Estournel, C.; Stemmann, L.; Somot, S.; Diaz, F.

2014-05-01

A realistic modeling approach is designed to address the role of winter mixing on the interannual variability of plankton dynamics in the north-western (NW) Mediterranean basin. For the first time, a high-resolution coupled hydrodynamic-biogeochemical model (Eco3m-S) covering a 30-year period (1976-2005) is validated on available in situ and satellite data for the NW Mediterranean. In this region, cold, dry winds in winter often lead to deep convection and strong upwelling of nutrients into the euphotic layer. High nutrient contents at the end of winter then support the development of a strong spring bloom of phytoplankton. Model results indicate that annual primary production is not affected by winter mixing due to seasonal balance (minimum in winter and maximum in spring). However, the total annual water column-integrated phytoplankton biomass appears to be favored by winter mixing because zooplankton grazing activity is low in winter and early spring. This reduced grazing is explained here by the rarefaction of prey due to both light limitation and the effect of mixing-induced dilution on prey/predator interactions. A negative impact of winter mixing on winter zooplankton biomass is generally simulated except for mesozooplankton. This difference is assumed to stem from the lower parameterized mortality, top trophic position and detritivorous diet of mesozooplankton in the model. Moreover, model suggests that the variability of annual mesozooplankton biomass is principally modulated by the effects of winter mixing on winter biomass. Thus, interannual variability of winter nutrient contents in the euphotic layer, resulting from winter mixing, would control spring primary production and thus annual mesozooplankton biomass. Our results show a bottom-up control of mesozooplankton communities, as observed at a coastal location of the Ligurian Sea.

A flavor symmetry model for bilarge leptonic mixing and the lepton masses

NASA Astrophysics Data System (ADS)

Ohlsson, Tommy; Seidl, Gerhart

2002-11-01

We present a model for leptonic mixing and the lepton masses based on flavor symmetries and higher-dimensional mass operators. The model predicts bilarge leptonic mixing (i.e., the mixing angles θ12 and θ23 are large and the mixing angle θ13 is small) and an inverted hierarchical neutrino mass spectrum. Furthermore, it approximately yields the experimental hierarchical mass spectrum of the charged leptons. The obtained values for the leptonic mixing parameters and the neutrino mass squared differences are all in agreement with atmospheric neutrino data, the Mikheyev-Smirnov-Wolfenstein large mixing angle solution of the solar neutrino problem, and consistent with the upper bound on the reactor mixing angle. Thus, we have a large, but not close to maximal, solar mixing angle θ12, a nearly maximal atmospheric mixing angle θ23, and a small reactor mixing angle θ13. In addition, the model predicts θ 12≃ {π}/{4}-θ 13.

Effects of mixing system and pilot fuel quality on diesel-biogas dual fuel engine performance.

PubMed

Bedoya, Iván Darío; Arrieta, Andrés Amell; Cadavid, Francisco Javier

2009-12-01

This paper describes results obtained from CI engine performance running on dual fuel mode at fixed engine speed and four loads, varying the mixing system and pilot fuel quality, associated with fuel composition and cetane number. The experiments were carried out on a power generation diesel engine at 1500 m above sea level, with simulated biogas (60% CH(4)-40% CO(2)) as primary fuel, and diesel and palm oil biodiesel as pilot fuels. Dual fuel engine performance using a naturally aspirated mixing system and diesel as pilot fuel was compared with engine performance attained with a supercharged mixing system and biodiesel as pilot fuel. For all loads evaluated, was possible to achieve full diesel substitution using biogas and biodiesel as power sources. Using the supercharged mixing system combined with biodiesel as pilot fuel, thermal efficiency and substitution of pilot fuel were increased, whereas methane and carbon monoxide emissions were reduced.

Are mixed explicit/implicit solvation models reliable for studying phosphate hydrolysis? A comparative study of continuum, explicit and mixed solvation models.

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

Kamerlin, Shina C. L.; Haranczyk, Maciej; Warshel, Arieh

2009-05-01

Phosphate hydrolysis is ubiquitous in biology. However, despite intensive research on this class of reactions, the precise nature of the reaction mechanism remains controversial. In this work, we have examined the hydrolysis of three homologous phosphate diesters. The solvation free energy was simulated by means of either an implicit solvation model (COSMO), hybrid quantum mechanical / molecular mechanical free energy perturbation (QM/MM-FEP) or a mixed solvation model in which N water molecules were explicitly included in the ab initio description of the reacting system (where N=1-3), with the remainder of the solvent being implicitly modelled as a continuum. Here, bothmore » COSMO and QM/MM-FEP reproduce Delta Gobs within an error of about 2kcal/mol. However, we demonstrate that in order to obtain any form of reliable results from a mixed model, it is essential to carefully select the explicit water molecules from short QM/MM runs that act as a model for the true infinite system. Additionally, the mixed models tend to be increasingly inaccurate the more explicit water molecules are placed into the system. Thus, our analysis indicates that this approach provides an unreliable way for modelling phosphate hydrolysis in solution.« less

Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing

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

Watanabe, T., E-mail: watanabe.tomoaki@c.nagoya-u.jp; Nagata, K.

We report on the numerical study of the mixing volume model (MVM) for molecular diffusion in Lagrangian simulations of turbulent mixing problems. The MVM is based on the multi-particle interaction in a finite volume (mixing volume). A priori test of the MVM, based on the direct numerical simulations of planar jets, is conducted in the turbulent region and the interfacial layer between the turbulent and non-turbulent fluids. The results show that the MVM predicts well the mean effects of the molecular diffusion under various numerical and flow parameters. The number of the mixing particles should be large for predicting amore » value of the molecular diffusion term positively correlated to the exact value. The size of the mixing volume relative to the Kolmogorov scale η is important in the performance of the MVM. The scalar transfer across the turbulent/non-turbulent interface is well captured by the MVM especially with the small mixing volume. Furthermore, the MVM with multiple mixing particles is tested in the hybrid implicit large-eddy-simulation/Lagrangian-particle-simulation (LES–LPS) of the planar jet with the characteristic length of the mixing volume of O(100η). Despite the large mixing volume, the MVM works well and decays the scalar variance in a rate close to the reference LES. The statistics in the LPS are very robust to the number of the particles used in the simulations and the computational grid size of the LES. Both in the turbulent core region and the intermittent region, the LPS predicts a scalar field well correlated to the LES.« less

Stability of nonuniform rotor blades in hover using a mixed formulation

NASA Technical Reports Server (NTRS)

Stephens, W. B.; Hodges, D. H.; Avila, J. H.; Kung, R. M.

1980-01-01

A mixed formulation for calculating static equilibrium and stability eigenvalues of nonuniform rotor blades in hover is presented. The static equilibrium equations are nonlinear and are solved by an accurate and efficient collocation method. The linearized perturbation equations are solved by a one step, second order integration scheme. The numerical results correlate very well with published results from a nearly identical stability analysis based on a displacement formulation. Slight differences in the results are traced to terms in the equations that relate moments to derivatives of rotations. With the present ordering scheme, in which terms of the order of squares of rotations are neglected with respect to unity, it is not possible to achieve completely equivalent models based on mixed and displacement formulations. The one step methods reveal that a second order Taylor expansion is necessary to achieve good convergence for nonuniform rotating blades. Numerical results for a hypothetical nonuniform blade, including the nonlinear static equilibrium solution, were obtained with no more effort or computer time than that required for a uniform blade.

Defect-induced mix experiment for NIF

NASA Astrophysics Data System (ADS)

Schmitt, M. J.; Bradley, P. A.; Cobble, J. A.; Hsu, S. C.; Krasheninnikova, N. S.; Kyrala, G. A.; Magelssen, G. R.; Murphy, T. J.; Obrey, K. A.; Tregillis, I. L.; Wysocki, F. J.; Finnegan, S. M.

2013-11-01

The Defect Induced Mix Experiment (DIME-II) will measure the implosion and mix characteristics of CH capsules filled with 5 atmospheres of DT by incorporating mid-Z dopant layers of Ge and Ga. This polar direct drive (PDD) experiment also will demonstrate the filling of a CH capsule at target chamber center using a fill tube. Diagnostics for these experiments include areal x-ray backlighting to obtain early time images of the implosion trajectory and a multiple-monochromatic imager (MMI) to collect spectrally-resolved images of the capsule dopant line emission near bangtime. The inclusion of two (or more) thin dopant layers at separate depths within the capsule shell facilitates spatial correlation of mix between the layers and the hot gas core on a single shot. The dopant layers are typically 2 μm thick and contain dopant concentrations of 1.5%. Three dimensional Hydra simulations have been performed to assess the effects of PDD asymmetry on capsule performance.

Response of TLD-100 in mixed fields of photons and electrons.

PubMed

Lawless, Michael J; Junell, Stephanie; Hammer, Cliff; DeWerd, Larry A

2013-01-01

Thermoluminescent dosimeters (TLDs) are routinely used for dosimetric measurements of high energy photon and electron fields. However, TLD response in combined fields of photon and electron beam qualities has not been characterized. This work investigates the response of TLD-100 (LiF:Mg,Ti) to sequential irradiation by high-energy photon and electron beam qualities. TLDs were irradiated to a known dose by a linear accelerator with a 6 MV photon beam, a 6 MeV electron beam, and a NIST-traceable (60)Co beam. TLDs were also irradiated in a mixed field of the 6 MeV electron beam and the 6 MV photon beam. The average TLD response per unit dose of the TLDs for each linac beam quality was normalized to the average response per unit dose of the TLDs irradiated by the (60)Co beam. Irradiations were performed in water and in a Virtual Water™ phantom. The 6 MV photon beam and 6 MeV electron beam were used to create dose calibration curves relating TLD response to absorbed dose to water, which were applied to the TLDs irradiated in the mixed field. TLD relative response per unit dose in the mixed field was less sensitive than the relative response in the photon field and more sensitive than the relative response in the electron field. Application of the photon dose calibration curve to the TLDs irradiated in a mixed field resulted in an underestimation of the delivered dose, while application of the electron dose calibration curve resulted in an overestimation of the dose. The relative response of TLD-100 in mixed fields fell between the relative response in the photon-only and electron-only fields. TLD-100 dosimetry of mixed fields must account for this intermediate response to minimize the estimation errors associated with calibration factors obtained from a single beam quality.

Torulaspora delbrueckii contribution in mixed brewing fermentations with different Saccharomyces cerevisiae strains.

PubMed

Canonico, Laura; Comitini, Francesca; Ciani, Maurizio

2017-10-16

In recent years, there has been growing demand for distinctive high quality beer. Fermentation management has a fundamental role in beer quality and the levels of aroma compounds. Use of non-conventional yeast has been proposed to enhance beer bioflavor. In the present work we investigated mixed fermentations using three commercial Saccharomyces cerevisiae strains, without and with addition of a selected Torulaspora delbrueckii strain evaluating their interactions, as well as the aroma profiles. At the S. cerevisiae/T. delbrueckii co-inoculation ratio of 1:20, viable cell counts indicated that T. delbrueckii dominated all of the three combinations. In the mixed fermentations, T. delbrueckii provided higher levels of higher alcohols (excepting of β-phenyl ethanol), in contrast to data obtained in winemaking, where higher alcohols had lower levels. Moreover, mixed fermentations showed significantly higher ethyl acetate (from 5 to 16mg/L) and isoamyl acetate (from 0.019 to 0.128mg/L), and were generally lower in ethyl hexanoate and ethyl octanoate. Therefore, irrespective of S. cerevisiae strain, T. delbrueckii influenced on all mixed fermentations. On the other hand, the mixed fermentations were also affected by each of the three S. cerevisiae strains, which resulted in beers with distinctive flavors. Copyright © 2017 Elsevier B.V. All rights reserved.

Internal Mixing Studied for GE/ARL Ejector Nozzle

NASA Technical Reports Server (NTRS)

Zaman, Khairul

2005-01-01

To achieve jet noise reduction goals for the High Speed Civil Transport aircraft, researchers have been investigating the mixer-ejector nozzle concept. For this concept, a primary nozzle with multiple chutes is surrounded by an ejector. The ejector mixes low-momentum ambient air with the hot engine exhaust to reduce the jet velocity and, hence, the jet noise. It is desirable to mix the two streams as fast as possible in order to minimize the length and weight of the ejector. An earlier model of the mixer-ejector nozzle was tested extensively in the Aerodynamic Research Laboratory (ARL) of GE Aircraft Engines at Cincinnati, Ohio. While testing was continuing with later generations of the nozzle, the earlier model was brought to the NASA Lewis Research Center for relatively fundamental measurements. Goals of the Lewis study were to obtain details of the flow field to aid computational fluid dynamics (CFD) efforts and obtain a better understanding of the flow mechanisms, as well as to experiment with mixing enhancement devices, such as tabs. The measurements were made in an open jet facility for cold (unheated) flow without a surrounding coflowing stream.

Finite time synchronization of memristor-based Cohen-Grossberg neural networks with mixed delays.

PubMed

Chen, Chuan; Li, Lixiang; Peng, Haipeng; Yang, Yixian

2017-01-01

Finite time synchronization, which means synchronization can be achieved in a settling time, is desirable in some practical applications. However, most of the published results on finite time synchronization don't include delays or only include discrete delays. In view of the fact that distributed delays inevitably exist in neural networks, this paper aims to investigate the finite time synchronization of memristor-based Cohen-Grossberg neural networks (MCGNNs) with both discrete delay and distributed delay (mixed delays). By means of a simple feedback controller and novel finite time synchronization analysis methods, several new criteria are derived to ensure the finite time synchronization of MCGNNs with mixed delays. The obtained criteria are very concise and easy to verify. Numerical simulations are presented to demonstrate the effectiveness of our theoretical results.

Nationwide review of mixed and non-mixed components from different manufacturers in total hip arthroplasty

PubMed Central

Peters, Rinne M; van Steenbergen, Liza N; Bulstra, Sjoerd K; Zeegers, Adelgunde V C M; Stewart, Roy E; Poolman, Rudolf W; Hosman, Anton H

2016-01-01

Background and purpose Combining components from different manufacturers in total hip arthroplasty (THA) is common practice worldwide. We determined the proportion of THAs used in the Netherlands that consist of components from different manufacturers, and compared the revision rates of these mixed THAs with those of non-mixed THAs. Patients and methods Data on primary and revision hip arthroplasty are recorded in the LROI, the nationwide population-based arthroplasty register in the Netherlands. We selected all 163,360 primary THAs that were performed in the period 2007–2014. Based on the manufacturers of the components, 4 groups were discerned: non-mixed THAs with components from the same manufacturer (n = 142,964); mixed stem-head THAs with different manufacturers for the femoral stem and head (n = 3,663); mixed head-cup THAs with different head and cup manufacturers (n = 12,960), and mixed stem-head-cup THAs with different femoral stem, head, and cup manufacturers (n = 1,773). Mixed prostheses were defined as THAs (stem, head, and cup) composed of components made by different manufacturers. Results 11% of THAs had mixed components (n = 18,396). The 6-year revision rates were similar for mixed and non-mixed THAs: 3.4% (95% CI: 3.1w–3.7) for mixed THAs and 3.5% (95% CI: 3.4–3.7) for non-mixed THAs. Revision of primary THAs due to loosening of the acetabulum was more common in mixed THAs (16% vs. 12%). Interpretation Over an 8-year period in the Netherlands, 11% of THAs had mixed components—with similar medium-term revision rates to those of non-mixed THAs. PMID:27348544

Study of abrasive resistance of foundries models obtained with use of additive technology

NASA Astrophysics Data System (ADS)

Ol'khovik, Evgeniy

2017-10-01

A problem of determination of resistance of the foundry models and patterns from ABS (PLA) plastic, obtained by the method of 3D printing with using FDM additive technology, to abrasive wear and resistance in the environment of foundry sand mould is considered in the present study. The description of a technique and equipment for tests of castings models and patterns for wear is provided in the article. The manufacturing techniques of models with the use of the 3D printer (additive technology) are described. The scheme with vibration load was applied to samples tests. For the most qualitative research of influence of sandy mix on plastic, models in real conditions of abrasive wear have been organized. The results also examined the application of acrylic paintwork to the plastic model and a two-component coating. The practical offers and recommendation on production of master models with the use of FDM technology allowing one to reach indicators of durability, exceeding 2000 cycles of moulding in foundry sand mix, are described.

A novel algorithm for laser self-mixing sensors used with the Kalman filter to measure displacement

NASA Astrophysics Data System (ADS)

Sun, Hui; Liu, Ji-Gou

2018-07-01

This paper proposes a simple and effective method for estimating the feedback level factor C in a self-mixing interferometric sensor. It is used with a Kalman filter to retrieve the displacement. Without the complicated and onerous calculation process of the general C estimation method, a final equation is obtained. Thus, the estimation of C only involves a few simple calculations. It successfully retrieves the sinusoidal and aleatory displacement by means of simulated self-mixing signals in both weak and moderate feedback regimes. To deal with the errors resulting from noise and estimate bias of C and to further improve the retrieval precision, a Kalman filter is employed following the general phase unwrapping method. The simulation and experiment results show that the retrieved displacement using the C obtained with the proposed method is comparable to the joint estimation of C and α. Besides, the Kalman filter can significantly decrease measurement errors, especially the error caused by incorrectly locating the peak and valley positions of the signal.

Response of TLD-100 in mixed fields of photons and electrons

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

Lawless, Michael J.; Junell, Stephanie; Hammer, Cliff

Purpose: Thermoluminescent dosimeters (TLDs) are routinely used for dosimetric measurements of high energy photon and electron fields. However, TLD response in combined fields of photon and electron beam qualities has not been characterized. This work investigates the response of TLD-100 (LiF:Mg,Ti) to sequential irradiation by high-energy photon and electron beam qualities. Methods: TLDs were irradiated to a known dose by a linear accelerator with a 6 MV photon beam, a 6 MeV electron beam, and a NIST-traceable {sup 60}Co beam. TLDs were also irradiated in a mixed field of the 6 MeV electron beam and the 6 MV photon beam.more » The average TLD response per unit dose of the TLDs for each linac beam quality was normalized to the average response per unit dose of the TLDs irradiated by the {sup 60}Co beam. Irradiations were performed in water and in a Virtual Water Trade-Mark-Sign phantom. The 6 MV photon beam and 6 MeV electron beam were used to create dose calibration curves relating TLD response to absorbed dose to water, which were applied to the TLDs irradiated in the mixed field. Results: TLD relative response per unit dose in the mixed field was less sensitive than the relative response in the photon field and more sensitive than the relative response in the electron field. Application of the photon dose calibration curve to the TLDs irradiated in a mixed field resulted in an underestimation of the delivered dose, while application of the electron dose calibration curve resulted in an overestimation of the dose. Conclusions: The relative response of TLD-100 in mixed fields fell between the relative response in the photon-only and electron-only fields. TLD-100 dosimetry of mixed fields must account for this intermediate response to minimize the estimation errors associated with calibration factors obtained from a single beam quality.« less

The difference between two random mixed quantum states: exact and asymptotic spectral analysis

NASA Astrophysics Data System (ADS)

Mejía, José; Zapata, Camilo; Botero, Alonso

2017-01-01

We investigate the spectral statistics of the difference of two density matrices, each of which is independently obtained by partially tracing a random bipartite pure quantum state. We first show how a closed-form expression for the exact joint eigenvalue probability density function for arbitrary dimensions can be obtained from the joint probability density function of the diagonal elements of the difference matrix, which is straightforward to compute. Subsequently, we use standard results from free probability theory to derive a relatively simple analytic expression for the asymptotic eigenvalue density (AED) of the difference matrix ensemble, and using Carlson’s theorem, we obtain an expression for its absolute moments. These results allow us to quantify the typical asymptotic distance between the two random mixed states using various distance measures; in particular, we obtain the almost sure asymptotic behavior of the operator norm distance and the trace distance.

Geodetic results from ISAGEX data. [for obtaining center of mass coordinates for geodetic camera sites

NASA Technical Reports Server (NTRS)

Marsh, J. G.; Douglas, B. C.; Walls, D. M.

1974-01-01

Laser and camera data taken during the International Satellite Geodesy Experiment (ISAGEX) were used in dynamical solutions to obtain center-of-mass coordinates for the Astro-Soviet camera sites at Helwan, Egypt, and Oulan Bator, Mongolia, as well as the East European camera sites at Potsdam, German Democratic Republic, and Ondrejov, Czechoslovakia. The results are accurate to about 20m in each coordinate. The orbit of PEOLE (i=15) was also determined from ISAGEX data. Mean Kepler elements suitable for geodynamic investigations are presented.

Lipid production by pure and mixed cultures of Chlorella pyrenoidosa and Rhodotorula mucilaginosa isolated in Nuevo Leon, Mexico.

PubMed

Reyna-Martínez, Raúl; Gomez-Flores, Ricardo; López-Chuken, Ulrico J; González-González, Rosario; Fernández-Delgadillo, Sergio; Balderas-Rentería, Isaias

2015-01-01

Given the well-known environmental drawbacks of using fossil fuels, advances in the field of alternative energy have become a worldwide technological priority. Special interest has been focused on the production of biodiesel obtained from oleaginous microorganisms. In the present research, lipid production by two species, microalgae Chlorella pyrenoidosa and yeast Rhodotorula mucilaginosa was assessed, independently and in mixed culture to evaluate a possible synergy. Fatty acid analysis was performed by gas chromatography. Among pure and mixed cultures of both strains and several culturing conditions, the highest biomass and lipid productivity was obtained by C. pyrenoidosa (8.05 and 1.62 g/L, respectively). The results of this study showed that both strains used are in fact oleaginous strains as they were found to reach up to 20 % of lipids, in addition, lipids in both pure and mixed cultures were mainly of triglycerides (>90 %), composed of fatty acid chains between 16 and 18 carbons.

Comparative Studies on Dyeability with Direct, Acid and Reactive Dyes after Chemical Modification of Jute with Mixed Amino Acids Obtained from Extract of Waste Soya Bean Seeds

NASA Astrophysics Data System (ADS)

Bhaumik, Nilendu Sekhar; Konar, Adwaita; Roy, Alok Nath; Samanta, Ashis Kumar

2017-12-01

Jute fabric was treated with mixed natural amino acids obtained from waste soya bean seed extract for chemical modification of jute for its cataionization and to enhance its dyeability with anionic dyes (like direct, reactive and acid dye) as well enabling soya modified jute for salt free dyeing with anionic reactive dyes maintaining its eco-friendliness. Colour interaction parameters including surface colour strength were assessed and compared for both bleached and soya-modified jute fabric for reactive dyeing and compared with direct and acid dye. Improvement in K/S value (surface colour strength) was observed for soya-modified jute even in absence of salt applied in dye bath for reactive dyes as well as for direct and acid dyes. In addition, reactive dye also shows good dyeability even in acid bath in salt free conditions. Colour fastness to wash was evaluated for bleached and soya-modified jute fabric after dyeing with direct, acid and reactive dyes are reported. Treatment of jute with soya-extracted mixed natural amino acids showed anchoring of some amino/aldemine groups on jute cellulosic polymer evidenced from Fourier Transform Infra-Red (FTIR) Spectroscopy. This amino or aldemine group incorporation in bleached jute causes its cationization and hence when dyed in acid bath for reactive dye (instead of conventional alkali bath) showed dye uptake for reactive dyes. Study of surface morphology by Scanning Electron Microscopy (SEM) of said soya-modified jute as compared to bleached jute was studied and reported.

Investigation on flow and mixing characteristics of supersonic mixing layer induced by forced vibration of cantilever

NASA Astrophysics Data System (ADS)

Zhang, Dongdong; Tan, Jianguo; Lv, Liang

2015-12-01

The mixing process has been an important issue for the design of supersonic combustion ramjet engine, and the mixing efficiency plays a crucial role in the improvement of the combustion efficiency. In the present study, nanoparticle-based planar laser scattering (NPLS), particle image velocimetry (PIV) and large eddy simulation (LES) are employed to investigate the flow and mixing characteristics of supersonic mixing layer under different forced vibration conditions. The indexes of fractal dimension, mixing layer thickness, momentum thickness and scalar mixing level are applied to describe the mixing process. Results show that different from the development and evolution of supersonic mixing layer without vibration, the flow under forced vibration is more likely to present the characteristics of three-dimensionality. The laminar flow region of mixing layer under forced vibration is greatly shortened and the scales of rolled up Kelvin-Helmholtz vortices become larger, which promote the mixing process remarkably. The fractal dimension distribution reveals that comparing with the flow without vibration, the turbulent fluctuation of supersonic mixing layer under forced vibration is more intense. Besides, the distribution of mixing layer thickness, momentum thickness and scalar mixing level are strongly influenced by forced vibration. Especially, when the forcing frequency is 4000 Hz, the mixing layer thickness and momentum thickness are 0.0391 m and 0.0222 m at the far field of 0.16 m, 83% and 131% higher than that without vibration at the same position, respectively.

Development of a new continuous process for mixing of complex non-Newtonian fluids

NASA Astrophysics Data System (ADS)

Migliozzi, Simona; Mazzei, Luca; Sochon, Bob; Angeli, Panagiota; Thames Multiphase Team; Coral Project Collaboration

2017-11-01

Design of new continuous mixing operations poses many challenges, especially when dealing with highly viscous non-Newtonian fluids. Knowledge of complex rheological behaviour of the working mixture is crucial for development of an efficient process. In this work, we investigate the mixing performance of two different static mixers and the effects of the mixture rheology on the manufacturing of novel non-aqueous-based oral care products using experimental and computational fluid dynamic methods. The two liquid phases employed, i.e. a carbomer suspension in polyethylene glycol and glycerol, start to form a gel when they mix. We studied the structure evolution of the liquid mixture using time-resolved rheometry and we obtained viscosity rheograms at different phase ratios from pressure drop measurements in a customized mini-channel. The numerical results and rheological model were validated with experimental measurements carried out in a specifically designed setup. EPSRS-CORAL.

Finishing bacterial genome assemblies with Mix.

PubMed

Soueidan, Hayssam; Maurier, Florence; Groppi, Alexis; Sirand-Pugnet, Pascal; Tardy, Florence; Citti, Christine; Dupuy, Virginie; Nikolski, Macha

2013-01-01

Among challenges that hamper reaping the benefits of genome assembly are both unfinished assemblies and the ensuing experimental costs. First, numerous software solutions for genome de novo assembly are available, each having its advantages and drawbacks, without clear guidelines as to how to choose among them. Second, these solutions produce draft assemblies that often require a resource intensive finishing phase. In this paper we address these two aspects by developing Mix , a tool that mixes two or more draft assemblies, without relying on a reference genome and having the goal to reduce contig fragmentation and thus speed-up genome finishing. The proposed algorithm builds an extension graph where vertices represent extremities of contigs and edges represent existing alignments between these extremities. These alignment edges are used for contig extension. The resulting output assembly corresponds to a set of paths in the extension graph that maximizes the cumulative contig length. We evaluate the performance of Mix on bacterial NGS data from the GAGE-B study and apply it to newly sequenced Mycoplasma genomes. Resulting final assemblies demonstrate a significant improvement in the overall assembly quality. In particular, Mix is consistent by providing better overall quality results even when the choice is guided solely by standard assembly statistics, as is the case for de novo projects. Mix is implemented in Python and is available at https://github.com/cbib/MIX, novel data for our Mycoplasma study is available at http://services.cbib.u-bordeaux2.fr/mix/.

Proteolysis in tempeh-type products obtained with Rhizopus and Aspergillus strains from grass pea (Lathyrus sativus) seeds.

PubMed

Starzyńska-Janiszewska, Anna; Stodolak, Bożena; Wikiera, Agnieszka

2015-01-01

Tempeh is a food product obtained from legumes by means of solid-state fermentation with Rhizopus sp. Our previous research proved that mixed-culture inoculum may also be successfully applied. The objective of present research was to study the proteolytic activity of R. microsporus var. chinensis and A. oryzae during tempeh-type fermentation of grass pea seeds, and the effect of inoculum composition on the protein level and in vitro protein bioavailability in products. Fermentation substrate were soaked and cooked grass pea seeds. Material was mixed with single- or mixed-culture inoculum, and incubated in perforated plastic bags at 30°C for 32 hrs. In the products, the proteolytic activity (pH 3, 5 and 7), glucosamine, total protein and free amino acids levels, as well as protein in vitro bioavailability and degree of protein hydrolysis were obtained. The significant correlation was found between glucosamine content and proteolytic activity in grass pea seeds fermented with Rhizopus or Aspergillus. The activities of Rhizopus proteases were higher than Aspergillus ones, which corresponded with the degree of seed protein hydrolysis. Both strains showed the highest activity of protease at pH 3. Tempeh made with pure culture of Rhizopus had 37% protein of 69% in-vitro bioavailability. Mixed-culture fermentation improved nutritional parameters of products only when the dose of Aspergillus spores in the inoculum was equal and lower than that of Rhizopus. This process resulted in higher in-vitro bioavailability of protein, slightly more efficient protein hydrolysis and higher level of free amino acids, as compared to standard tempeh. The activity of A. oryzae in tempeh-type fermentation is beneficial as long as it does not dominate the activity and/or growth of Rhizopus strain.

Perfect mixing of immiscible macromolecules at fluid interfaces

NASA Astrophysics Data System (ADS)

Sheiko, Sergei; Matyjaszewski, Krzysztof; Tsukruk, Vladimir; Carrillo, Jan-Michael; Rubinstein, Michael; Dobrynin, Andrey; Zhou, Jing

2014-03-01

Macromolecules typically phase separate unless their shapes and chemical compositions are tailored to explicitly drive mixing. But now our research has shown that physical constraints can drive spontaneous mixing of chemically different species. We have obtained long-range 2D arrays of perfectly mixed macromolecules having a variety of molecular architectures and chemistries, including linear chains, block-copolymer stars, and bottlebrush copolymers with hydrophobic, hydrophilic, and lipophobic chemical compositions. This is achieved by entropy-driven enhancement of steric repulsion between macromolecules anchored on a substrate. By monitoring the kinetics of mixing, we have proved that molecular intercalation is an equilibrium state. The array spacing is controlled by the length of the brush side chains. This entropic templating strategy opens new ways for generating patterns on sub-100 nm length scales with potential application in lithography, directed self-assembly, and biomedical assays. Financial support from the National Science Foundation DMR-0906985, DMR-1004576, DMR-1122483, and DMR-0907515.

An experimental study of secondary vortex structure in mixing layers

NASA Technical Reports Server (NTRS)

Bell, J. H.; Mehta, Rabindra D.

1990-01-01

This report covers the first eight months of an experimental research project on the secondary vortex structure in plane mixing layers. The aim of the project is to obtain quantitative data on the behavior of the secondary structure in a turbulent mixing layer at reasonable reynolds numbers (Re(sub delta(sub w)) approx. 50,000). In particular, we hope to resolve the questions of how the scale of the secondary vortex structure changes with the scale of the mixing layer, and whether the structures are fixed in space, or whether they 'meander' in the spanwise direction.

In-line mixing states monitoring of suspensions using ultrasonic reflection technique.

PubMed

Zhan, Xiaobin; Yang, Yili; Liang, Jian; Zou, Dajun; Zhang, Jiaqi; Feng, Luyi; Shi, Tielin; Li, Xiwen

2016-02-01

Based on the measurement of echo signal changes caused by different concentration distributions in the mixing process, a simple ultrasonic reflection technique is proposed for in-line monitoring of the mixing states of suspensions in an agitated tank in this study. The relation between the echo signals and the concentration of suspensions is studied, and the mixing process of suspensions is tracked by in-line measurement of ultrasonic echo signals using two ultrasonic sensors. Through the analysis of echo signals over time, the mixing states of suspensions are obtained, and the homogeneity of suspensions is quantified. With the proposed technique, the effects of impeller diameter and agitation speed on the mixing process are studied, and the optimal agitation speed and the minimum mixing time to achieve the maximum homogeneity are acquired under different operating conditions and design parameters. The proposed technique is stable and feasible and shows great potential for in-line monitoring of mixing states of suspensions. Copyright © 2015 Elsevier B.V. All rights reserved.

Structural Color Tuning: Mixing Melanin-Like Particles with Different Diameters to Create Neutral Colors.

PubMed

Kawamura, Ayaka; Kohri, Michinari; Yoshioka, Shinya; Taniguchi, Tatsuo; Kishikawa, Keiki

2017-04-18

We present the ability to tune structural colors by mixing colloidal particles. To produce high-visibility structural colors, melanin-like core-shell particles composed of a polystyrene (PSt) core and a polydopamine (PDA) shell, were used as components. The results indicated that neutral structural colors could be successfully obtained by simply mixing two differently sized melanin-like PSt@PDA core-shell particles. In addition, the arrangements of the particles, which were important factors when forming structural colors, were investigated by mathematical processing using a 2D Fourier transform technique and Voronoi diagrams. These findings provide new insights for the development of structural color-based ink applications.

Disease Risk Mitigation: The Equivalence of Two Selective Mixing Strategies on Aggregate Contact Patterns & Resulting Epidemic Spread☆

PubMed Central

Morin, Benjamin R; Perrings, Charles; Levin, Simon; Kinzig, Ann

2014-01-01

The personal choices affecting the transmission of infectious diseases include the number of contacts an individual makes, and the risk-characteristics of those contacts. We consider whether these different choices have distinct implications for the course of an epidemic. We also consider whether choosing contact mitigation (how much to mix) and affinity mitigation (with whom to mix) strategies together has different epidemiological effects than choosing each separately. We use a set of differential equation compartmental models of the spread of disease, coupled with a model of selective mixing. We assess the consequences of varying contact or affinity mitigation as a response to disease risk. We do this by comparing disease incidence and dynamics under varying contact volume, contact type, and both combined across several different disease models. Specifically, we construct a change of variables that allows one to transition from contact mitigation to affinity mitigation, and vice versa. In the absence of asymptomatic infection we find no difference in the epidemiological impacts of the two forms of disease risk mitigation. Furthermore, since models that include both mitigation strategies are under-determined, varying both results in no outcome that could not be reached by choosing either separately. Which strategy is actually chosen then depends not on their epidemiological consequences, but on the relative cost of reducing contact volume versus altering contact type. Although there is no fundamental epidemiological difference between the two forms of mitigation, the social cost of alternative strategies can be very different. From a social perspective, therefore, whether one strategy should be promoted over another depends on economic not epidemiological factors. PMID:25150459

Separating and recycling metals from mixed metallic particles of crushed electronic wastes by vacuum metallurgy.

PubMed

Zhan, Lu; Xu, Zhenming

2009-09-15

During the treatment of electronic wastes, a crushing process is usually used to strip metals from various base plates. Several methods have been applied to separate metals from nonmetals. However, mixed metallic particles obtained from these processes are still a mixture of various metals, including some toxic heavy metals such as lead and cadmium. With emphasis on recovering copper and other precious metals, there have hitherto been no satisfactory methods to recover these toxic metals. In this paper, the criterion of separating metals from mixed metallic particles by vacuum metallurgy is built. The results show that the metals with high vapor pressure have been almost recovered completely, leading to a considerable reduction of environmental pollution. In addition, the purity of copper in mixed particles has been improved from about 80 wt % to over 98 wt %.

Main results and experience obtained on Mir space station and experiment program for Russian segment of ISS.

PubMed

Utkin, V F; Lukjashchenko, V I; Borisov, V V; Suvorov, V V; Tsymbalyuk, M M

2003-07-01

This article presents main scientific and practical results obtained in course of scientific and applied research and experiments on Mir space station. Based on Mir experience, processes of research program formation for the Russian Segment of the ISS are briefly described. The major trends of activities planned in the frames of these programs as well as preliminary results of increment research programs implementation in the ISS' first missions are also presented. c2003 Elsevier Science Ltd. All rights reserved.

Extrusion-mixing compared with hand-mixing of polyether impression materials?

PubMed

McMahon, Caroline; Kinsella, Daniel; Fleming, Garry J P

2010-12-01

The hypotheses tested were two-fold (a) whether altering the base:catalyst ratio influences working time, elastic recovery and strain in compression properties of a hand-mixed polyether impression material and (b) whether an extrusion-mixed polyether impression material would have a significant advantage over a hand-mixed polyether impression material mixed to the optimum base:catalyst ratio. The polyether was hand-mixed at the optimum (manufacturers recommended) base:catalyst ratios (7:1) and further groups were made by increasing or decreasing the catalyst length by 25%. Additionally specimens were also made from an extrusion-mixed polyether impression material and compared with the optimum hand-mixed base:catalyst ratio. A penetrometer assembly was used to measure the working time (n=5). Five cylindrical specimens for each hand-mixed and extrusion mixed group investigated were employed for elastic recovery and strain in compression testing. Hand-mixing polyether impression materials with 25% more catalyst than that recommended significantly decreased the working time while hand-mixing with 25% less catalyst than that recommended significantly increased the strain in compression. The extrusion-mixed polyether impression material provided similar working time, elastic recovery and strain in compression to the hand-mixed polyether mixed at the optimum base:catalyst ratio.

The Effect of a Dissipative Ladle Shroud on Mixing in Tundish: Mathematical and Experimental Modelling

NASA Astrophysics Data System (ADS)

Zhang, Jiangshan; Yang, Shufeng; Li, Jingshe; Tang, Haiyan; Jiang, Zhengyi

2018-01-01

The effect of a dissipative ladle shroud (DLS) on mixing in tundish was investigated, compared with that of a conventional ladle shroud (CLS) using mathematical and physical modelling. The tracer profiles of mathematical results, achieved using large eddy simulation, were validated by physical observations employing high-speed cinephotography. The design of a DLS dramatically changed the flow patterns and contributed the intermixing of fluid elements inside the ladle shroud. The vortex flow encouraged the turbulent mixing and was verified by tracking of physical tracer dispersion inside the DLS. Residence Time Distribution (RTD) curves were obtained in two different sized tundishes to examine the mixing behaviours. The findings indicated that the DLS benefited the tundish mixing in terms of increasing active volume. The effect seemed to be more remarkable in the smaller tundish. The DLS gave rise to a more plug-like flow pattern inside the tundish, showing potential to shorten the transition length during grade change.

New classes of solutions in the coupled PT symmetric nonlocal nonlinear Schrödinger equations with four wave mixing

NASA Astrophysics Data System (ADS)

Vinayagam, P. S.; Radha, R.; Al Khawaja, U.; Ling, Liming

2018-06-01

We investigate generalized nonlocal coupled nonlinear Schorödinger equation containing Self-Phase Modulation, Cross-Phase Modulation and four wave mixing involving nonlocal interaction. By means of Darboux transformation we obtained a family of exact breathers and solitons including the Peregrine soliton, Kuznetsov-Ma breather, Akhmediev breather along with all kinds of soliton-soliton and breather-soltion interactions. We analyze and emphasize the impact of the four-wave mixing on the nature and interaction of the solutions. We found that the presence of four wave mixing converts a two-soliton solution into an Akhmediev breather. In particular, the inclusion of four wave mixing results in the generation of a new solutions which is spatially and temporally periodic called "Soliton (Breather) lattice".

Study of effects of injector geometry on fuel-air mixing and combustion

NASA Technical Reports Server (NTRS)

Bangert, L. H.; Roach, R. L.

1977-01-01

An implicit finite-difference method has been developed for computing the flow in the near field of a fuel injector as part of a broader study of the effects of fuel injector geometry on fuel-air mixing and combustion. Detailed numerical results have been obtained for cases of laminar and turbulent flow without base injection, corresponding to the supersonic base flow problem. These numerical results indicated that the method is stable and convergent, and that significant savings in computer time can be achieved, compared with explicit methods.

A Comparative Evaluation of Mixed Dentition Analysis on Reliability of Cone Beam Computed Tomography Image Compared to Plaster Model.

PubMed

Gowd, Snigdha; Shankar, T; Dash, Samarendra; Sahoo, Nivedita; Chatterjee, Suravi; Mohanty, Pritam

2017-01-01

The aim of the study was to evaluate the reliability of cone beam computed tomography (CBCT) obtained image over plaster model for the assessment of mixed dentition analysis. Thirty CBCT-derived images and thirty plaster models were derived from the dental archives, and Moyer's and Tanaka-Johnston analyses were performed. The data obtained were interpreted and analyzed statistically using SPSS 10.0/PC (SPSS Inc., Chicago, IL, USA). Descriptive and analytical analysis along with Student's t -test was performed to qualitatively evaluate the data and P < 0.05 was considered statistically significant. Statistically, significant results were obtained on data comparison between CBCT-derived images and plaster model; the mean for Moyer's analysis in the left and right lower arch for CBCT and plaster model was 21.2 mm, 21.1 mm and 22.5 mm, 22.5 mm, respectively. CBCT-derived images were less reliable as compared to data obtained directly from plaster model for mixed dentition analysis.

[Characteristics of electroosmotic flow in open-tubular capillary electrochromatography with magnetic nanoparticle coating as mixed-mode stationary phase].

PubMed

Qin, Sasa; Zhou, Chaoran; Zhu, Yaxian; Ren, Zhiyu; Zhang, Lingyi; Fu, Honggang; Zhang, Weibing

2011-09-01

A novel open-tubular capillary electrochromatography (OT-CEC) column with magnetic nanoparticle coating as mixed-mode stationary phase was prepared. The mixed-mode stationary phases were obtained by mixing C18 and amino modified magnetic nanoparticles with different ratios. The mixed modified magnetic nanoparticles as stationary phase were introduced into the capillary by using external magnetic force. The magnetic nanoparticle coating can be easily regenerated by removing the external magnetic field, and applied to other separation modes. The characteristics of electroosmotic flow (EOF) were theoretically investigated through the effect of physicochemical properties of different stationary phases on EOF. The experiment was conducted under different ratios of mixed-mode stationary phases and coating lengths, and it was verified that the theoretical conclusions accorded with the experimental results. It was shown that the EOF can be easily adjusted by changing the ratio of stationary phases or the number of permanent magnets.

Composites in small and simple devices to increase mixing on detector surfaces

NASA Astrophysics Data System (ADS)

Hernandez, L. F.; Lima, R. R.; Leite, A. R.; Fachini, E. R.; Silva, M. L. P.

2013-03-01

This work aims at three different applications for the betterment of plasma generated-composite thin films: pre-mixing, spray formation in miniaturized structures and an increase in the performance of detector surfaces. Miniaturized structures were projected, simulated with FEMLAB® 3.2 software and then constructed. Clustered films made from tetraethoxysilane (TEOS) and nonafluoro(iso)butyl ether (HFE®) precursors were deposited on silicon, acrylic and quartz substrates for different kinds of film characterization/or in the projected structures. Physical and chemical characterization guided the selection of best films previous to/after UVC exposure. The active surfaces (plasma-deposited films) in structures were modified by UVC exposure and then tested. The applications include pre-mixing of liquids and/or spray formation, best results being obtained with surface covered by derivative-HFE films, which acted as passivation layers. Preliminary results show good humidity sensing for TEOS-derivative films.

SOURCE ASSESSMENT: ASPHALT HOT MIX

EPA Science Inventory

This report summarizes data on air emissions from the asphalt hot mix industry. A representative asphalt hot mix plant was defined, based on the results of an industrial survey, to assess the severity of emissions from this industry. Source severity was defined as the ratio of th...

25 CFR 162.539 - Must I obtain a WEEL before obtaining a WSR lease?

Code of Federal Regulations, 2014 CFR

2014-04-01

... AND PERMITS Wind and Solar Resource Leases Wsr Leases § 162.539 Must I obtain a WEEL before obtaining... direct result of energy resource information gathered from a WEEL activity, obtaining a WEEL is not a...

25 CFR 162.539 - Must I obtain a WEEL before obtaining a WSR lease?

Code of Federal Regulations, 2013 CFR

2013-04-01

... AND PERMITS Wind and Solar Resource Leases Wsr Leases § 162.539 Must I obtain a WEEL before obtaining... direct result of energy resource information gathered from a WEEL activity, obtaining a WEEL is not a...

Growth parameters of Penicillium expansum calculated from mixed inocula as an alternative to account for intraspecies variability.

PubMed

Garcia, Daiana; Ramos, Antonio J; Sanchis, Vicente; Marín, Sonia

2014-09-01

The aim of this work was to compare the radial growth rate (μ) and the lag time (λ) for growth of 25 isolates of Penicillium expansum at 1 and 20 ºC with those of the mixed inoculum of the 25 isolates. Moreover, the evolution of probability of growth through time was also compared for the single strains and mixed inoculum. Working with a mixed inoculum would require less work, time and consumables than if a range of single strains has to be used in order to represent a given species. Suitable predictive models developed for a given species should represent as much as possible the behavior of all strains belonging to this species. The results suggested, on one hand, that the predictions based on growth parameters calculated on the basis of mixed inocula may not accurately predict the behavior of all possible strains but may represent a percentage of them, and the median/mean values of μ and λ obtained by the 25 strains may be substituted by the value obtained with the mixed inoculum. Moreover, the predictions may be biased, in particular, the predictions of λ which may be underestimated (fail-safe). Moreover, the prediction of time for a given probability of growth through a mixed inoculum may not be accurate for all single inocula, but it may represent 92% and 60% of them at 20 and 1 ºC, respectively, and also their overall mean and median values. In conclusion, mixed inoculum could be a good alternative to estimate the mean or median values of high number of isolates, but not to account for those strains with marginal behavior. In particular, estimation of radial growth rate, and time for 0.10 and 0.50 probability of growth using a cocktail inoculum accounted for the estimates of most single isolates tested. For the particular case of probability models, this is an interesting result as for practical applications in the food industry the estimation of t10 or lower probability may be required. Copyright © 2014 Elsevier B.V. All rights reserved.

Who Moves to Mixed-Income Neighborhoods?*

PubMed Central

McKinnish, Terra; White, T. Kirk

2011-01-01

This paper uses confidential Census data, specifically the 1990 and 2000 Census Long Form data, to study the income dispersion of recent cohorts of migrants to mixed-income neighborhoods. We investigate whether neighborhoods with high levels of income dispersion attract economically diverse in-migrants. If recent in-migrants to mixed-income neighborhoods exhibit high levels of income dispersion, this is consistent with stable mixed-income neighborhoods. If, however, mixed-income neighborhoods are comprised of homogenous low-income (high-income) cohorts of long-term residents combined with homogenous high-income (low-income) cohorts of recent arrivals, this is consistent with neighborhood transition. Our results indicate that neighborhoods with high levels of income dispersion do in fact attract a much more heterogeneous set of in-migrants, particularly from the tails of the income distribution. Our results also suggest that the residents of mixed-income neighborhoods may be less heterogeneous with respect to lifetime income. PMID:21479114

Southern Ocean Mixed-Layer Seasonal and Interannual Variations From Combined Satellite and In Situ Data

NASA Astrophysics Data System (ADS)

Buongiorno Nardelli, B.; Guinehut, S.; Verbrugge, N.; Cotroneo, Y.; Zambianchi, E.; Iudicone, D.

2017-12-01

The depth of the upper ocean mixed layer provides fundamental information on the amount of seawater that directly interacts with the atmosphere. Its space-time variability modulates water mass formation and carbon sequestration processes related to both the physical and biological pumps. These processes are particularly relevant in the Southern Ocean, where surface mixed-layer depth estimates are generally obtained either as climatological fields derived from in situ observations or through numerical simulations. Here we demonstrate that weekly observation-based reconstructions can be used to describe the variations of the mixed-layer depth in the upper ocean over a range of space and time scales. We compare and validate four different products obtained by combining satellite measurements of the sea surface temperature, salinity, and dynamic topography and in situ Argo profiles. We also compute an ensemble mean and use the corresponding spread to estimate mixed-layer depth uncertainties and to identify the more reliable products. The analysis points out the advantage of synergistic approaches that include in input the sea surface salinity observations obtained through a multivariate optimal interpolation. Corresponding data allow to assess mixed-layer depth seasonal and interannual variability. Specifically, the maximum correlations between mixed-layer anomalies and the Southern Annular Mode are found at different time lags, related to distinct summer/winter responses in the Antarctic Intermediate Water and Sub-Antarctic Mode Waters main formation areas.

Lp-mixed affine surface area

NASA Astrophysics Data System (ADS)

Wang, Weidong; Leng, Gangsong

2007-11-01

According to the three notions of mixed affine surface area, Lp-affine surface area and Lp-mixed affine surface area proposed by Lutwak, in this article, we give the concept of ith Lp-mixed affine surface area such that the first and second notions of Lutwak are its special cases. Further, some Lutwak's results are extended associated with this concept. Besides, applying this concept, we establish an inequality for the volumes and dual quermassintegrals of a class of star bodies.

Dielectric relaxation of selenium-tellurium mixed former glasses

NASA Astrophysics Data System (ADS)

Palui, A.; Ghosh, A.

2017-05-01

We report the study of dielectric properties of mixed network former glasses of composition 0.3Ag2O-0.7(xSeO2-(1-x)TeO2); x=0, 0.1, 0.3, 0.4, 0.5 and 0.6 in a wide frequency 10 Hz - 2 MHz and temperature range 223 K - 403 K. The experimental data have been analyzed in the framework of complex dielectric permittivity. The dielectric permittivity data have been analyzed using the Cole-Cole function. The inverse temperature dependence of relaxation time obtained from real part of dielectric permittivity data follows the Arrhenius relation. The activation energy shows mixed glass former effect with variation of mixed former ratio. A non-zero value of shape parameters is observed and it is almost independent of temperature and composition.

Dielectric properties and microstructure of sintered BaTiO3 fabricated by using mixed 150-nm and 80-nm powders with various additives

NASA Astrophysics Data System (ADS)

Oh, Min Wook; Kang, Jae Won; Yeo, Dong Hun; Shin, Hyo Soon; Jeong, Dae Yong

2015-04-01

Recently, the use of small-sized BaTiO3 particles for ultra-thin MLCC research has increased as a method for minimizing the dielectric layer's thickness in thick film process. However, when particles smaller than 100 nm are used, the reduced particle size leads to a reduced dielectric constant. The use of nanoparticles, therefore, requires an increase in the amount of additive used due to the increase in the specific surface area, thus increasing the production cost. In this study, a novel method of coating 150-nm and 80-nm BaTiO3 powders with additives and mixing them together was employed, taking advantage of the effect obtained through the use of BaTiO3 particles smaller than 100 nm, to conveniently obtain the desired dielectric constant and thermal characteristics. Also, the microstructure and the dielectric properties were evaluated. The additives Dy, Mn, Mg, Si, and Cr were coated on a 150-nm powder, and the additives Dy, Mn, Mg, and Si were coated on 80-nm powder, followed by mixing at a ratio of 1:1. As a result, the microstructure revealed grain formation according to the liquid-phase additive Si; additionally, densification was well realized. However, non-reducibility was not obtained, and the material became a semiconductor. When the amount of added Mn in the 150-nm powder was increased to 0.2 and 0.3 mol%, insignificant changes in the microstructure were observed, and the bulk density after mixing was found to have increased drastically in comparison to that before mixing. Also, non-reducibility was obtained for certain conditions. The dielectric property was found to be consistent with the densification and the grain size. The mixed composition #1-0.3 had a dielectric constant over 2000, and the result somewhat satisfied the dielectric constant temperature dependency for X6S.

Housing Mix, School Mix: Barriers to Success

ERIC Educational Resources Information Center

Camina, M. M.; Iannone, P.

2014-01-01

Recent UK policy has emphasised both the development of socially mixed communities and the creation of balanced school intakes. In this paper, we use a case study of an area of mixed tenure in eastern England to explore policy in practice and the extent to which mechanisms of segregation impact on both the creation of socially mixed neighbourhoods…

A global renewable mix with proven technologies and common materials

NASA Astrophysics Data System (ADS)

Ballabrera, J.; Garcia-Olivares, A.; Garcia-Ladona, E.; Turiel, A.

2012-04-01

A global alternative mix to fossil fuels is proposed, based on proven renewable energy technologies that do not use scarce materials. Taking into account the availability of materials, the resulting mix consists of a combination of onshore and offshore wind turbines, concentrating solar power stations, hydroelectricity and wave power devices attached to the offshore turbines. Solar photovoltaic power could contribute to the mix if its dependence on scarce materials is solved. Material requirements are studied for the generation, power transport and for some future transport systems. The order of magnitude of copper, aluminium, neodymium, lithium, nickel, zinc and platinum that might be required for the proposed solution is obtained and compared with available reserves. While the proposed global alternative to fossil fuels seems technically feasible, lithium, nickel and platinum could become limiting materials for future vehicles fleet if no global recycling system were implemented and rechargeable zinc-air batteries could not be developed. As much as 60% of the current copper reserves would have to be employed in the implementation of the proposed solution. Altogether, the availability of materials may become a long-term physical constraint, preventing the continuation of the usual exponential growth of energy consumption.

Blood Mixing Upregulates Platelet Membrane-Bound CD40 Ligand Expression in vitro Independent of Abo Compatibility.

PubMed

Huang, Go-Shine; Hu, Mei-Hua; Lin, Tso-Chou; Lin, Yi-Chang; Tsai, Yi-Ting; Lin, Chih-Yuan; Ke, Hung-Yen; Zheng, Xu-Zhi; Tsai, Chien-Sung

2017-11-30

Platelets play a central role in the inflammation response via CD40 ligand (CD40L) expression, which may lead to transfusion reactions. The precise role of platelet CD40L-mediated inflammation in transfusion reactions is unclear. Therefore, we assessed the effects of in vitro blood mixing on platelet CD40L expression. In addition, we examined the effect of ABO compatibility on CD40L expression. Donor packed red blood cells were acquired from a blood bank, and recipient blood was obtained from patients undergoing cardiac surgery and prepared as washed platelets. Donor blood was mixed with suspended, washed recipient platelets to obtain a final mixing ratio of 1%, 5%, or 10% (vol/vol). The blood mixtures were divided into three groups: Group M, cross-matched blood-type mixing (n = 20); Group S, ABO type-specific uncross-matched blood (n = 20); and Group I, ABO incompatibility (not ABO type-specific blood and not process cross-matched) mixing (n = 20). The blood mixtures were used to detect platelet membrane-bound CD40L expression by flow cytometry. Blood mixing resulted in an increase in CD40L expression in Group M (P < 0.001), Group S (P < 0.001), and Group I (P < 0.001). CD40L expression following blood mixing potentially led to a transfusion reaction in each of the groups. There were no differences in CD40L expression among the three groups (P = 0.988) correlated with ABO compatibility or incompatibility. This indicates that the reactions between red blood cell surface antigens and plasma antibodies do not play a role in the induction of CD40L expression.

Optimal minimal measurements of mixed states

NASA Astrophysics Data System (ADS)

Vidal, G.; Latorre, J. I.; Pascual, P.; Tarrach, R.

1999-07-01

The optimal and minimal measuring strategy is obtained for a two-state system prepared in a mixed state with a probability given by any isotropic a priori distribution. We explicitly construct the specific optimal and minimal generalized measurements, which turn out to be independent of the a priori probability distribution, obtaining the best guesses for the unknown state as well as a closed expression for the maximal mean-average fidelity. We do this for up to three copies of the unknown state in a way that leads to the generalization to any number of copies, which we then present and prove.

Modelling Viscoelastic Behaviour of Polymer by A Mixed Velocity, Displacement Formulation - Numerical and Experimental Results

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

Pham, VT.; Silva, L.; Digonnet, H.

2011-05-04

The objective of this work is to model the viscoelastic behaviour of polymer from the solid state to the liquid state. With this objective, we perform experimental tensile tests and compare with simulation results. The chosen polymer is a PMMA whose behaviour depends on its temperature. The computation simulation is based on Navier-Stokes equations where we propose a mixed finite element method with an interpolation P1+/P1 using displacement (or velocity) and pressure as principal variables. The implemented technique uses a mesh composed of triangles (2D) or tetrahedra (3D). The goal of this approach is to model the viscoelastic behaviour ofmore » polymers through a fluid-structure coupling technique with a multiphase approach.« less

VMT Mix Modeling for Mobile Source Emissions Forecasting: Formulation and Empirical Application

DOT National Transportation Integrated Search

2000-05-01

The purpose of the current report is to propose and implement a methodology for obtaining improved link-specific vehicle miles of travel (VMT) mix values compared to those obtained from existent methods. Specifically, the research is developing a fra...

Purists need not apply: the case for pragmatism in mixed methods research.

PubMed

Florczak, Kristine L

2014-10-01

The purpose of this column is to describe several different ways of conducting mixed method research. The paradigms that underpin both qualitative and quantitative research are also considered along with a cursory review of classical pragmatism as it relates conducting mixed methods studies. Finally, the idea of loosely coupled systems as a means to support mixed methods studies is proposed along with several caveats to researchers who desire to use this new way of obtaining knowledge. © The Author(s) 2014.

Prototype Mixed Finite Element Hydrodynamics Capability in ARES

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

Rieben, R N

This document describes work on a prototype Mixed Finite Element Method (MFEM) hydrodynamics algorithm in the ARES code, and its application to a set of standard test problems. This work is motivated by the need for improvements to the algorithms used in the Lagrange hydrodynamics step to make them more robust. We begin by identifying the outstanding issues with traditional numerical hydrodynamics algorithms followed by a description of the proposed method and how it may address several of these longstanding issues. We give a theoretical overview of the proposed MFEM algorithm as well as a summary of the coding additionsmore » and modifications that were made to add this capability to the ARES code. We present results obtained with the new method on a set of canonical hydrodynamics test problems and demonstrate significant improvement in comparison to results obtained with traditional methods. We conclude with a summary of the issues still at hand and motivate the need for continued research to develop the proposed method into maturity.« less

Examining Sexual Dysfunction in Non-Muscle-Invasive Bladder Cancer: Results of Cross-Sectional Mixed-Methods Research

PubMed Central

Kowalkowski, Marc A; Chandrashekar, Aravind; Amiel, Gilad E; Lerner, Seth P; Wittmann, Daniela A; Latini, David M; Goltz, Heather Honoré

2014-01-01

Introduction More than 70,000 new cases of bladder cancer are diagnosed in the United States annually; with 75% being non-muscle-invasive (NMIBC). Research examining sexual dysfunction in bladder cancer survivors is limited, and previous studies have focused on cystectomy patients. Aims To evaluate the impact of sexual dysfunction on NMIBC survivors. Methods Mixed-methods data collection integrated a quantitative survey (Study 1; n = 117) and semi-structured qualitative interviews (Study 2; n = 26) from a non-overlapping sample of NMIBC survivors. We performed descriptive and classification and regression tree (CART) analyses of survey data and qualitative analysis of interviews. Main Outcome Measures Self-reported sexual activity, interest in sex, and physiologic symptoms (e.g., male erectile/ejaculatory difficulties, female vaginal dryness) over the previous 4 weeks; partner communication about sexuality; contamination concerns; illness intrusiveness. Results Participants in these studies averaged 65 years of age (mean and median) and were male (77%), white (91%), and married (75%). Survey (Study 1) results linked NMIBC treatment to sexual symptoms and relationship issues. Many participants reported sexual inactivity (38.8%). Sexually active participants reported erectile difficulties (60.0%), vaginal dryness (62.5%), and worry about contaminating partner with treatment agents (23.2%). While almost one-half reported the usefulness of talking with partners about sexual function, only one-fifth of participants reported sharing all concerns with their partners. CART analysis supported the importance of communication. One-half of interviewees (Study 2) reported sexual dysfunction. Two-thirds reported negative impacts on their relationships, including perceived loss of intimacy and divorce; over one-third were sexually inactive for fear of contaminating their partner or spreading NMIBC. Conclusions Survivors' sexual symptoms may result from NMIBC, comorbidities, or

Turning Ocean Mixing Upside Down

NASA Astrophysics Data System (ADS)

Ferrari, Raffaele; Mashayek, Ali; Campin, Jean-Michael; McDougall, Trevor; Nikurashin, Maxim

2015-11-01

It is generally understood that small-scale mixing, such as is caused by breaking internal waves, drives upwelling of the densest ocean waters that sink to the ocean bottom at high latitudes. However the observational evidence that small-scale mixing is more vigorous close to the ocean bottom than above implies that small-scale mixing converts light waters into denser ones, thus driving a net sinking of abyssal water. It is shown that abyssal waters return to the surface along weakly stratified boundary layers, where the small-scale mixing of density decays to zero. The net ocean meridional overturning circulation is thus the small residual of a large sinking of waters, driven by small-scale mixing in the stratified interior, and an equally large upwelling, driven by the reduced small-scale mixing along the ocean boundaries. Thus whether abyssal waters upwell or sink in the net cannot be inferred simply from the vertical profile of mixing intensity, but depends also on the ocean hypsometry, i.e. the shape of the bottom topography. The implications of this result for our understanding of the abyssal ocean circulation will be presented with a combination of numerical models and observations.

Enhanced kefiran production by mixed culture of Lactobacillus kefiranofaciens and Saccharomyces cerevisiae.

PubMed

Cheirsilp, Benjamas; Shimizu, Hiroshi; Shioya, Suteaki

2003-01-09

In a batch mixed culture of Lactobacillus kefiranofaciens and Saccharomyces cerevisiae, which could assimilate lactic acid, cell growth and kefiran production rates of L. kefiranofaciens significantly increased, compared with those in pure cultures. The kefiran production rate was 36 mg l(-1) h(-1) in the mixed culture under the anaerobic condition, which was greater than that in the pure culture (24 mg l(-1) h(-1)). Under the aerobic condition, a more intensive interaction between these two strains was observed and higher kefiran production rate (44 mg l(-1) h(-1)) was obtained compared with that under the anaerobic condition. Kefiran production was further enhanced by an addition of fresh medium in the fed-batch mixed culture. In the fed-batch mixed culture, a final kefiran concentration of 5.41 g l(-1) was achieved at 87 h, thereby attaining the highest productivity at 62 mg l(-1) h(-1). Simulation study considered the reduction of lactic acid in pure culture was performed to estimate the additional effect of coculture with S. cerevisiae. Slightly higher cell growth and kefiran production rates in the mixed culture than those expected from pure culture by simulation were observed. These results suggest that coculture of L. kefiranofaciens and S. cerevisiae not only reduces the lactic acid concentration by consumption but also stimulates cell growth and kefiran production of L. kefiranofaciens.

Development of Impregnated Agglomerate Pelletization (IAP) process for fabrication of (Th,U)O 2 mixed oxide pellets

NASA Astrophysics Data System (ADS)

Khot, P. M.; Nehete, Y. G.; Fulzele, A. K.; Baghra, Chetan; Mishra, A. K.; Afzal, Mohd.; Panakkal, J. P.; Kamath, H. S.

2012-01-01

Impregnated Agglomerate Pelletization (IAP) technique has been developed at Advanced Fuel Fabrication Facility (AFFF), BARC, Tarapur, for manufacturing (Th, 233U)O 2 mixed oxide fuel pellets, which are remotely fabricated in hot cell or shielded glove box facilities to reduce man-rem problem associated with 232U daughter radionuclides. This technique is being investigated to fabricate the fuel for Indian Advanced Heavy Water Reactor (AHWR). In the IAP process, ThO 2 is converted to free flowing spheroids by powder extrusion route in an unshielded facility which are then coated with uranyl nitrate solution in a shielded facility. The dried coated agglomerate is finally compacted and then sintered in oxidizing/reducing atmosphere to obtain high density (Th,U)O 2 pellets. In this study, fabrication of (Th,U)O 2 mixed oxide pellets containing 3-5 wt.% UO 2 was carried out by IAP process. The pellets obtained were characterized using optical microscopy, XRD and alpha autoradiography. The results obtained were compared with the results for the pellets fabricated by other routes such as Coated Agglomerate Pelletization (CAP) and Powder Oxide Pelletization (POP) route.

Groundwater-derived nutrient and trace element transport to a nearshore Kona coral ecosystem: Experimental mixing model results

USGS Publications Warehouse

Prouty, Nancy G.; Swarzenski, Peter W.; Fackrell, Joseph; Johannesson, Karen H.; Palmore, C. Diane

2017-01-01

Study regionThe groundwater influenced coastal waters along the arid Kona coast of the Big Island, Hawai’i.Study focusA salinity-and phase partitioning-based mixing experiment was constructed using contrasting groundwater endmembers along the arid Konacoast of the Big Island, Hawai’i and local open seawater to better understand biogeochemical and physicochemical processes that influence the fate of submarine groundwater discharge (SGD)-derived nutrients and trace elements.New Hydrological Insights for the RegionTreated wastewater effluent was the main source for nutrient enrichment downstream at the Honokōhau Harbor site. Conservative mixing for some constituents, such as nitrate + nitrite, illustrate the effectiveness of physical mixing to maintain oceanic concentrations in the colloid (0.02–0.45 μm) and truly dissolved (

Electrochemical variational study of donor/acceptor orbital mixing and electronic coupling in cyanide-bridged mixed-valence complexes

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

Dong, Yuhuua; Hupp, J.T.

1992-07-08

Cyanide-bridged mixed-valence complexes are interesting examples of strongly covalently linked redox systems which, nevertheless, exist in valence-localized form. As mixed-valence species, they display fairly intense intervalence (or metal-to-metal) charge-transfer transitions ([epsilon] [approx] 3000 M[sup [minus]1] cm[sup [minus]1]), which tend to be shifted toward the visible region from the near-infrared on account of substantial redox asymmetry. The authors have recently succeeded in obtaining (by femtosecond transient absorbance spectroscopy) a direct measure of the thermal kinetics (k[sub ET]) of the highly exothermic back-electron-transfer reaction which follows intervalence excitation in one of these complexes, (H[sub 3]N)[sub 5]Ru-NC-Fe(CN)[sub 5][sup [minus

Estimated SAGE II ozone mixing ratios in early 1993 and comparisons with Stratospheric Photochemistry, Aerosols and Dynamic Expedition measurements

NASA Technical Reports Server (NTRS)

Yue, G. K.; Veiga, R. E.; Poole, L. R.; Zawodny, J. M.; Proffitt, M. H.

1994-01-01

An empirical time-series model for estimating ozone mixing ratios based on Stratospheric Aerosols and Gas Experiment II (SAGE II) monthly mean ozone data for the period October 1984 through June 1991 has been developed. The modeling results for ozone mixing ratios in the 10- to 30- km region in early months of 1993 are presented. In situ ozone profiles obtained by a dual-beam UV-absorption ozone photometer during the Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE) campaign, May 1-14, 1993, are compared with the model results. With the exception of two profiles at altitudes below 16 km, ozone mixing ratios derived by the model and measured by the ozone photometer are in relatively good agreement within their individual uncertainties. The identified discrepancies in the two profiles are discussed.

Lagrangian turbulence: Structures and mixing in admissible model flows

NASA Astrophysics Data System (ADS)

Ottino, Julio M.

1991-12-01

The goal of our research was to bridge the gap between modern ideas from dynamical systems and chaos and more traditional approaches to turbulence. In order to reach this objective we conducted theoretical and computational work on two systems: (1) a perturbed-Kelvin cat eyes flow, and (2) prototype solutions of the Navier-Stokes equations near solid walls. The main results obtained are two-fold: we have been able to produce flows capable of producing complex distributions of vorticity, and we have been able to construct flowfields, based on solutions of the Navier-Stokes equations, which are capable of displaying both Eulerian and Lagrangian turbulence. These results exemplify typical mechanisms of mixing enhancement in transitional flows.

Mixed and Complex Mixed Migration during Armed Conflict: Multidimensional Empirical Evidence from Nepal

PubMed Central

Williams, Nathalie E.

2015-01-01

Historically, legal, policy, and academic communities largely ascribed to a dichotomy between forced and voluntary migration, creating a black and white vision that was convenient for legal and policy purposes. More recently, discussions have begun addressing the possibility of mixed migration, acknowledging that there is likely a wide continuum between forced and voluntary, and most migrants likely move with some amount of compulsion and some volition, even during armed conflict. While the mixed migration hypothesis is well-received, empirical evidence is disparate and somewhat blunt at this point. In this article, I contribute a direct theoretical and causal pathway discussion of mixed migration. I also propose the complex mixed migration hypothesis, which argues that not only do non-conflict related factors influence migration during conflict, but they do so differently than during periods of relative peace. I empirically test both hypotheses in the context of the recent armed conflict in Nepal. Using detailed survey data and event history models, results provide strong evidence for both mixed migration and complex mixed migration during conflict hypotheses. These hypotheses and evidence suggest that armed conflict might have substantial impacts on long-term population growth and change, with significant relevance in both academic and policy spheres. PMID:26366007

Features of neutrino mixing

NASA Astrophysics Data System (ADS)

Chiu, S. H.; Kuo, T. K.

2018-03-01

The elements (squared) of the neutrino mixing matrix are found to satisfy, as functions of the induced mass, a set of differential equations. They show clearly the dominance of pole terms when the neutrino masses "cross." Using the known vacuum mixing parameters as initial conditions, it is found that these equations have very good approximate solutions, for all values of the induced mass. The results are applicable to long baseline experiments.

Mixed problems for the Korteweg-de Vries equation

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

Faminskii, A V

1999-06-30

Results are established concerning the non-local solubility and wellposedness in various function spaces of the mixed problem for the Korteweg-de Vries equation u{sub t}+u{sub xxx}+au{sub x}+uu{sub x}=f(t,x) in the half-strip (0,T)x(-{infinity},0). Some a priori estimates of the solutions are obtained using a special solution J(t,x) of the linearized KdV equation of boundary potential type. Properties of J are studied which differ essentially as x{yields}+{infinity} or x{yields}-{infinity}. Application of this boundary potential enables us in particular to prove the existence of generalized solutions with non-regular boundary values.

A variable mixing-length ratio for convection theory

NASA Technical Reports Server (NTRS)

Chan, K. L.; Wolff, C. L.; Sofia, S.

1981-01-01

It is argued that a natural choice for the local mixing length in the mixing-length theory of convection has a value proportional to the local density scale height of the convective bubbles. The resultant variable mixing-length ratio (the ratio between the mixing length and the pressure scale height) of this theory is enhanced in the superadiabatic region and approaches a constant in deeper layers. Numerical tests comparing the new mixing length successfully eliminate most of the density inversion that typically plagues conventional results. The new approach also seems to indicate the existence of granular motion at the top of the convection zone.

Rates and mechanisms of turbulent dissipation and mixing in the Southern Ocean: Results from the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES)

NASA Astrophysics Data System (ADS)

Sheen, K. L.; Brearley, J. A.; Naveira Garabato, A. C.; Smeed, D. A.; Waterman, S.; Ledwell, J. R.; Meredith, M. P.; St. Laurent, L.; Thurnherr, A. M.; Toole, J. M.; Watson, A. J.

2013-06-01

The spatial distribution of turbulent dissipation rates and internal wavefield characteristics is analyzed across two contrasting regimes of the Antarctic Circumpolar Current (ACC), using microstructure and finestructure data collected as part of the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES). Mid-depth turbulent dissipation rates are found to increase from O>(1×10-10Wkg -1>) in the Southeast Pacific to O>(1×10-9Wkg -1>) in the Scotia Sea, typically reaching 3×10-9Wkg -1 within a kilometer of the seabed. Enhanced levels of turbulent mixing are associated with strong near-bottom flows, rough topography, and regions where the internal wavefield is found to have enhanced energy, a less-inertial frequency content and a dominance of upward propagating energy. These results strongly suggest that bottom-generated internal waves play a major role in determining the spatial distribution of turbulent dissipation in the ACC. The energy flux associated with the bottom internal wave generation process is calculated using wave radiation theory, and found to vary between 0.8 mW m-2 in the Southeast Pacific and 14 mW m-2 in the Scotia Sea. Typically, 10%-30% of this energy is found to dissipate within 1 km of the seabed. Comparison between turbulent dissipation rates inferred from finestructure parameterizations and microstructure-derived estimates suggests a significant departure from wave-wave interaction physics in the near-field of wave generation sites.

Microfluidic mixing through oscillatory transverse perturbations

NASA Astrophysics Data System (ADS)

Wu, J. W.; Xia, H. M.; Zhang, Y. Y.; Zhu, P.

2018-05-01

Fluid mixing in miniaturized fluidic devices is a challenging task. In this work, the mixing enhancement through oscillatory transverse perturbations coupling with divergent circular chambers is studied. To simplify the design, an autonomous microfluidic oscillator is used to produce the oscillatory flow. It is then applied to four side-channels that intersect with a central channel of constant flow. The mixing performance is tested at high fluid viscosities of up to 16 cP. Results show that the oscillatory flow can cause strong transverse perturbations which effectively enhance the mixing. The influence of a fluidic capacitor in the central channel is also examined, which at low viscosities can intensify the perturbations and further improve the mixing.

Does Para-chloroaniline Really Form after Mixing Sodium Hypochlorite and Chlorhexidine?

PubMed

Orhan, Ekim Onur; Irmak, Özgür; Hür, Deniz; Yaman, Batu Can; Karabucak, Bekir

2016-03-01

Mixing sodium hypochlorite (NaOCl) with chlorhexidine (CHX) forms a brown-colored precipitate. Previous studies are not in agreement whether this precipitate contains para-chloroaniline (PCA). Tests used for analysis may demonstrate different outcomes. Purpose of this study was to determine whether PCA is formed through the reaction of mixing NaOCl and CHX by using high performance liquid chromatography, proton nuclear magnetic resonance spectroscopy, gas chromatography, thin layer chromatography, infrared spectroscopy, and gas chromatography/mass spectrometry. To obtain a brown precipitate, 4.99% NaOCl was mixed with 2.0% CHX. This brown precipitate was analyzed and compared with signals obtained from commercially available 4.99% NaOCl, 2% solutions, and 98% PCA in powder form. Chromatographic and spectroscopic analyses showed that brown precipitate does not contain free PCA. This study will be a cutoff proof for the argument on PCA formation from reaction of CHX and NaOCl. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Conversion of Syngas-Derived C2+ Mixed Oxygenates to C3-C5 Olefins over ZnxZryOz Mixed Oxides Catalysts

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

Smith, Colin D.; Lebarbier, Vanessa M.; Flake, Matthew D.

2016-04-01

In this study we report on a ZnxZryOz mixed oxide type catalyst capable of converting a syngas-derived C2+ mixed oxygenate feedstock to isobutene-rich olefins. Aqueous model feed comprising of ethanol, acetaldehyde, acetic acid, ethyl acetate, methanol, and propanol was used as representative liquid product derived from a Rh-based mixed oxygenate synthesis catalyst. Greater than 50% carbon yield to C3-C5 mixed olefins was demonstrated when operating at 400-450oC and 1 atm. In order to rationalize formation of the products observed feed components were individually evaluated. Major constituents of the feed mixture (ethanol, acetaldehyde, acetic acid, and ethyl acetate) were found tomore » produce isobutene-rich olefins. C-C coupling was also demonstrated for propanol feedstock - a minor constituent of the mixed oxygenate feed - producing branched C6 olefins, revealing scalability to alcohols higher than ethanol following an analogous reaction pathway. Using ethanol and propanol feed mixtures, cross-coupling reactions produced mixtures of C4, C5, and C6 branched olefins. The presence of H2 in the feed was found to facilitate hydrogenation of the ketone intermediates, thus producing straight chain olefins as byproducts. While activity loss from coking is observed complete catalyst regeneration is achieved by employing mild oxidation. For conversion of the mixed oxygenate feed a Zr/Zn ratio of 2.5 and a reaction temperature of 450oC provides the best balance of stability, activity, and selectivity. X-ray diffraction and scanning transmission electron microscopy analysis reveals the presence of primarily cubic phase ZrO2 and a minor amount of the monoclinic phase, with ZnO being highly dispersed in the lattice. The presence of ZnO appears to stabilize the cubic phase resulting in less monoclinic phase as the ZnO concentration increases. Infrared spectroscopy shows the mixed oxide acid sites are characterized as primarily Lewis type acidity. The direct relationship

LatMix 2011 and 2012 Dispersion Analysis

DTIC Science & Technology

2017-05-15

was to complete the analysis and write -up of additional manuscripts relating to LatMix, and to further strengthen the results for multiple manuscripts...versus a propagation of energy upwards from small mixing events (e.g., via generation of vo rtices). A key technical goal of our work was to develop...raw waveforms co llected during the LatMix 20 l I airborne lidar surveys, and completion of the analysis and write -up of major results stemming from

Gritty Surface Sample Holder Invented To Obtain Correct X-ray Absorption Fine Structure Spectra for Concentrated Materials by Fluorescence Yield.

PubMed

Abe, Hitoshi; Niwa, Yasuhiro; Kimura, Masao; Murakami, Youichi; Yokoyama, Toshiharu; Hosono, Hideo

2016-04-05

A gritty surface sample holder has been invented to obtain correct XAFS spectra for concentrated samples by fluorescence yield (FY). Materials are usually mixed with boron nitride (BN) to prepare proper concentrations to measure XAFS spectra. Some materials, however, could not be mixed with BN and would be measured in too concentrated conditions to obtain correct XAFS spectra. Consequently, XAFS spectra will be incorrect typically with decreased intensities of the peaks. We have invented the gritty surface sample holders to obtain correct XAFS spectra even for concentrated materials for FY measurements. Pure Cu and CuO powders were measured mounted on the sample holders, and the same spectra were obtained as transmission spectra of properly prepared samples. This sample holder is useful to measure XAFS for any concentrated materials.

Hot-flow tests of a series of 10-percent-scale turbofan forced mixing nozzles

NASA Technical Reports Server (NTRS)

Head, V. L.; Povinelli, L. A.; Gerstenmaier, W. H.

1984-01-01

An approximately 1/10-scale model of a mixed-flow exhaust system was tested in a static facility with fully simulated hot-flow cruise and takeoff conditions. Nine mixer geometries with 12 to 24 lobes were tested. The areas of the core and fan stream were held constant to maintain a bypass ratio of approximately 5. The research results presented in this report were obtained as part of a program directed toward developing an improved mixer design methodology by using a combined analytical and experimental approach. The effects of lobe spacing, lobe penetration, lobe-to-centerbody gap, lobe contour, and scalloping of the radial side walls were investigated. Test measurements included total pressure and temperature surveys, flow angularity surveys, and wall and centerbody surface static pressure measurements. Contour plots at various stations in the mixing region are presented to show the mixing effectiveness for the various lobe geometries.

Identifying geochemical processes using End Member Mixing Analysis to decouple chemical components for mixing ratio calculations

NASA Astrophysics Data System (ADS)

Pelizardi, Flavia; Bea, Sergio A.; Carrera, Jesús; Vives, Luis

2017-07-01

Mixing calculations (i.e., the calculation of the proportions in which end-members are mixed in a sample) are essential for hydrological research and water management. However, they typically require the use of conservative species, a condition that may be difficult to meet due to chemical reactions. Mixing calculation also require identifying end-member waters, which is usually achieved through End Member Mixing Analysis (EMMA). We present a methodology to help in the identification of both end-members and such reactions, so as to improve mixing ratio calculations. The proposed approach consists of: (1) identifying the potential chemical reactions with the help of EMMA; (2) defining decoupled conservative chemical components consistent with those reactions; (3) repeat EMMA with the decoupled (i.e., conservative) components, so as to identify end-members waters; and (4) computing mixing ratios using the new set of components and end-members. The approach is illustrated by application to two synthetic mixing examples involving mineral dissolution and cation exchange reactions. Results confirm that the methodology can be successfully used to identify geochemical processes affecting the mixtures, thus improving the accuracy of mixing ratios calculations and relaxing the need for conservative species.

Neutral B-meson Mixing and CP Violation at LHCb

NASA Astrophysics Data System (ADS)

Oblakowska-Mucha, A.; LHCb Collaboration

2016-11-01

The LHCb detector is a single-arm forward spectrometer that collects data at the LHC, designed for studies of flavour physics with high precision. We present a selection of recent measurements of mixing and CP-violating parameters, including sin 2β and weak phase ϕ s, using several decays. A good understanding of the pollution from sub-leading penguin to pologies in these measurements can be achieved by measuring CP violation and polarization in the decay Bs 0→Jψ⁄K 0* and B 0→Jψ⁄ ρ 0. All results here presented are obtained using the full Run I dataset.

Analysis of mixed traffic flow with human-driving and autonomous cars based on car-following model

NASA Astrophysics Data System (ADS)

Zhu, Wen-Xing; Zhang, H. M.

2018-04-01

We investigated the mixed traffic flow with human-driving and autonomous cars. A new mathematical model with adjustable sensitivity and smooth factor was proposed to describe the autonomous car's moving behavior in which smooth factor is used to balance the front and back headway in a flow. A lemma and a theorem were proved to support the stability criteria in traffic flow. A series of simulations were carried out to analyze the mixed traffic flow. The fundamental diagrams were obtained from the numerical simulation results. The varying sensitivity and smooth factor of autonomous cars affect traffic flux, which exhibits opposite varying tendency with increasing parameters before and after the critical density. Moreover, the sensitivity of sensors and smooth factors play an important role in stabilizing the mixed traffic flow and suppressing the traffic jam.

Evaluation of the degree of mixing of combinations of dry syrup, powder, and fine granule products in consideration of particle size distribution using near infrared spectrometry.

PubMed

Yamamoto, Yoshihisa; Suzuki, Toyofumi; Matsumoto, Mika; Ohtani, Michiteru; Hayano, Shuichi; Fukami, Toshiro; Tomono, Kazuo

2012-01-01

We used near infrared (NIR) spectroscopy to evaluate the degree of mixing of blended dry syrup (DS) products whose particle sizes are not specified in the Revised 16th Edition of the Japanese Pharmacopoeia, and also evaluated the degree of mixing when powder products or fine granule products were added to DS products. The data obtained were used to investigate the relationship between the particle size distributions of the products studied and the degree of mixing. We found that the particle size distribution characteristics of the 15 DS products studied can be broadly classified into 5 types. Combinations of frequently prescribed products were selected to represent 4 of the 5 particle size distribution types and were blended with a mortar and pestle. The coefficient of variation (CV) decreased as the percent mass of Asverin® Dry Syrup 2% (Asverin-DS) increased in blends of Periactin® Powder 1% (Periactin) and Asverin-DS, indicating an improved degree of mixing (uniformity). In contrast, in blends of Periactin and Mucodyne® DS 33.3%, mixing a combination at a 1:1 mass ratio 40 times resulted in a CV of 20%. Other mixing frequencies and mass ratios resulted in a CV by 50% to 70%, indicating a very poor degree of mixing (poor uniformity). These results suggest that when combining different DSs, or a DS with a powder or fine granule product, the blending obtained with a mortar and pestle improves as the particle size distributions of the components approach each other and as the ranges of the distributions narrow.

Unruh effect for mixing neutrinos

NASA Astrophysics Data System (ADS)

Cozzella, Gabriel; Fulling, Stephen A.; Landulfo, André G. S.; Matsas, George E. A.; Vanzella, Daniel A. T.

2018-05-01

Recently, the inverse β -decay rate calculated with respect to uniformly accelerated observers (experiencing the Unruh thermal bath) was revisited. Concerns have been raised regarding the compatibility of inertial and accelerated observers' results when neutrino mixing is taken into account. Here, we show that these concerns are unfounded by discussing the properties of the Unruh thermal bath with mixing neutrinos and explicitly calculating the decay rates according to both sets of observers, confirming thus that they are in agreement. The Unruh effect is perfectly valid for mixing neutrinos.

Effect of windowing on lithosphere elastic thickness estimates obtained via the coherence method: Results from northern South America

NASA Astrophysics Data System (ADS)

Ojeda, GermáN. Y.; Whitman, Dean

2002-11-01

The effective elastic thickness (Te) of the lithosphere is a parameter that describes the flexural strength of a plate. A method routinely used to quantify this parameter is to calculate the coherence between the two-dimensional gravity and topography spectra. Prior to spectra calculation, data grids must be "windowed" in order to avoid edge effects. We investigated the sensitivity of Te estimates obtained via the coherence method to mirroring, Hanning and multitaper windowing techniques on synthetic data as well as on data from northern South America. These analyses suggest that the choice of windowing technique plays an important role in Te estimates and may result in discrepancies of several kilometers depending on the selected windowing method. Te results from mirrored grids tend to be greater than those from Hanning smoothed or multitapered grids. Results obtained from mirrored grids are likely to be over-estimates. This effect may be due to artificial long wavelengths introduced into the data at the time of mirroring. Coherence estimates obtained from three subareas in northern South America indicate that the average effective elastic thickness is in the range of 29-30 km, according to Hanning and multitaper windowed data. Lateral variations across the study area could not be unequivocally determined from this study. We suggest that the resolution of the coherence method does not permit evaluation of small (i.e., ˜5 km), local Te variations. However, the efficiency and robustness of the coherence method in rendering continent-scale estimates of elastic thickness has been confirmed.

Methods of testing parameterizations: Vertical ocean mixing

NASA Technical Reports Server (NTRS)

Tziperman, Eli

1992-01-01

The ocean's velocity field is characterized by an exceptional variety of scales. While the small-scale oceanic turbulence responsible for the vertical mixing in the ocean is of scales a few centimeters and smaller, the oceanic general circulation is characterized by horizontal scales of thousands of kilometers. In oceanic general circulation models that are typically run today, the vertical structure of the ocean is represented by a few tens of discrete grid points. Such models cannot explicitly model the small-scale mixing processes, and must, therefore, find ways to parameterize them in terms of the larger-scale fields. Finding a parameterization that is both reliable and plausible to use in ocean models is not a simple task. Vertical mixing in the ocean is the combined result of many complex processes, and, in fact, mixing is one of the less known and less understood aspects of the oceanic circulation. In present models of the oceanic circulation, the many complex processes responsible for vertical mixing are often parameterized in an oversimplified manner. Yet, finding an adequate parameterization of vertical ocean mixing is crucial to the successful application of ocean models to climate studies. The results of general circulation models for quantities that are of particular interest to climate studies, such as the meridional heat flux carried by the ocean, are quite sensitive to the strength of the vertical mixing. We try to examine the difficulties in choosing an appropriate vertical mixing parameterization, and the methods that are available for validating different parameterizations by comparing model results to oceanographic data. First, some of the physical processes responsible for vertically mixing the ocean are briefly mentioned, and some possible approaches to the parameterization of these processes in oceanographic general circulation models are described in the following section. We then discuss the role of the vertical mixing in the physics of the

Estimating the effective rate of fast chemical reactions with turbulent mixing of reactants

NASA Astrophysics Data System (ADS)

Vorotilin, V. P.; Yanovskii, Yu. G.

2015-07-01

On the basis of representation of a turbulent fluid as an aggregation of independent turbulent particles (vortexes), we derive relations for the effective rate of chemical reactions and obtain a closed system of equations describing reactions with turbulent mixing of reactants. A variant of instantaneous reactions is considered that explains the proposed approach simply. In particular, the turbulent mixing events according to this approach are uniquely related to the acts of chemical interaction, which makes it possible to exclude from consideration the mixing of inert impurities-the most difficult point of the theory formulated using classical notions. The obtained system of equations is closed without introducing arbitrarily adopted correlations, by naturally introducing the concept of effective reaction and writing the equations of conservation for both the concentrations of reactants and their volumes.

Statistical classification of drug incidents due to look-alike sound-alike mix-ups.

PubMed

Wong, Zoie Shui Yee

2016-06-01

It has been recognised that medication names that look or sound similar are a cause of medication errors. This study builds statistical classifiers for identifying medication incidents due to look-alike sound-alike mix-ups. A total of 227 patient safety incident advisories related to medication were obtained from the Canadian Patient Safety Institute's Global Patient Safety Alerts system. Eight feature selection strategies based on frequent terms, frequent drug terms and constituent terms were performed. Statistical text classifiers based on logistic regression, support vector machines with linear, polynomial, radial-basis and sigmoid kernels and decision tree were trained and tested. The models developed achieved an average accuracy of above 0.8 across all the model settings. The receiver operating characteristic curves indicated the classifiers performed reasonably well. The results obtained in this study suggest that statistical text classification can be a feasible method for identifying medication incidents due to look-alike sound-alike mix-ups based on a database of advisories from Global Patient Safety Alerts. © The Author(s) 2014.

Do Mixed-Flora Preoperative Urine Cultures Matter?

PubMed

Polin, Michael R; Kawasaki, Amie; Amundsen, Cindy L; Weidner, Alison C; Siddiqui, Nazema Y

2017-06-01

To determine whether mixed-flora preoperative urine cultures, as compared with no-growth preoperative urine cultures, are associated with a higher prevalence of postoperative urinary tract infections (UTIs). This was a retrospective cohort study. Women who underwent urogynecologic surgery were included if their preoperative clean-catch urine culture result was mixed flora or no growth. Women were excluded if they received postoperative antibiotics for reasons other than treatment of a UTI. Women were divided into two cohorts based on preoperative urine culture results-mixed flora or no growth; the prevalence of postoperative UTI was compared between cohorts. Baseline characteristics were compared using χ 2 or Student t tests. A logistic regression analysis then was performed. We included 282 women who were predominantly postmenopausal, white, and overweight. There were many concomitant procedures; 46% underwent a midurethral sling procedure and 68% underwent pelvic organ prolapse surgery. Preoperative urine cultures resulted as mixed flora in 192 (68%) and no growth in 90 (32%) patients. Overall, 14% were treated for a UTI postoperatively. There was no difference in the proportion of patients treated for a postoperative UTI between the two cohorts (25 mixed flora vs 13 no growth, P = 0.77). These results remained when controlling for potentially confounding variables in a logistic regression model (adjusted odds ratio 0.92, 95% confidence interval 0.43-1.96). In women with mixed-flora compared with no-growth preoperative urine cultures, there were no differences in the prevalence of postoperative UTI. The clinical practice of interpreting mixed-flora cultures as negative is appropriate.

Scaling of Convective Mixing in Porous Media

NASA Astrophysics Data System (ADS)

Hidalgo, Juan J.; Fe, Jaime; Cueto-Felgueroso, Luis; Juanes, Ruben

2012-12-01

Convective mixing in porous media is triggered by a Rayleigh-Bénard-type hydrodynamic instability as a result of an unstable density stratification of fluids. While convective mixing has been studied extensively, the fundamental behavior of the dissolution flux and its dependence on the system parameters are not yet well understood. Here, we show that the dissolution flux and the rate of fluid mixing are determined by the mean scalar dissipation rate. We use this theoretical result to provide computational evidence that the classical model of convective mixing in porous media exhibits, in the regime of high Rayleigh number, a dissolution flux that is constant and independent of the Rayleigh number. Our findings support the universal character of convective mixing and point to the need for alternative explanations for nonlinear scalings of the dissolution flux with the Rayleigh number, recently observed experimentally.

An Update on Phased Array Results Obtained on the GE Counter-Rotating Open Rotor Model

NASA Technical Reports Server (NTRS)

Podboy, Gary; Horvath, Csaba; Envia, Edmane

2013-01-01

Beamform maps have been generated from 1) simulated data generated by the LINPROP code and 2) actual experimental phased array data obtained on the GE Counter-rotating open rotor model. The beamform maps show that many of the tones in the experimental data come from their corresponding Mach radius. If the phased array points to the Mach radius associated with a tone then it is likely that the tone is a result of the loading and thickness noise on the blades. In this case, the phased array correctly points to where the noise is coming from and indicates the axial location of the loudest source in the image but not necessarily the correct vertical location. If the phased array does not point to the Mach radius associated with a tone then some mechanism other than loading and thickness noise may control the amplitude of the tone. In this case, the phased array may or may not point to the actual source. If the source is not rotating it is likely that the phased array points to the source. If the source is rotating it is likely that the phased array indicates the axial location of the loudest source but not necessarily the correct vertical location. These results indicate that you have to be careful in how you interpret phased array data obtained on an open rotor since they may show the tones coming from a location other than the source location. With a subsonic tip speed open rotor the tones can come form locations outboard of the blade tips. This has implications regarding noise shielding.

Quantifying Diapycnal Mixing in an Energetic Ocean

NASA Astrophysics Data System (ADS)

Ivey, Gregory N.; Bluteau, Cynthia E.; Jones, Nicole L.

2018-01-01

Turbulent diapycnal mixing controls global circulation and the distribution of tracers in the ocean. For turbulence in stratified shear flows, we introduce a new turbulent length scale Lρ dependent on χ. We show the flux Richardson number Rif is determined by the dimensionless ratio of three length scales: the Ozmidov scale LO, the Corrsin shear scale LS, and Lρ. This new model predicts that Rif varies from 0 to 0.5, which we test primarily against energetic field observations collected in 100 m of water on the Australian North West Shelf (NWS), in addition to laboratory observations. The field observations consisted of turbulence microstructure vertical profiles taken near moored temperature and velocity turbulence time series. Irrespective of the value of the gradient Richardson number Ri, both instruments yielded a median Rif=0.17, while the observed Rif ranged from 0.01 to 0.50, in agreement with the predicted range of Rif. Using a Prandtl mixing length model, we show that diapycnal mixing Kρ can be predicted from Lρ and the background vertical shear S. Using field and laboratory observations, we show that Lρ=0.3LE where LE is the Ellison length scale. The diapycnal diffusivity can thus be calculated from Kρ=0.09LES2. This prediction agrees very well with the diapycnal mixing estimates obtained from our moored turbulence instruments for observed diffusivities as large as 10-1 m2s-1. Moorings with relatively low sampling rates can thus provide long time series estimates of diapycnal mixing rates, significantly increasing the number of diapycnal mixing estimates in the ocean.

An investigation of the effects of elevated mixing temperatures on the properties of asphalt cement.

DOT National Transportation Integrated Search

1972-01-01

This laboratory investigation was instituted to determine the feasibility of increasing the design mixing temperature for hot-mix asphaltic concrete. Based on data obtained from modified thin film oven tests, it appears that the upper design limit co...

Investigation with an Interferometer of the Turbulent Mixing of a Free Supersonic Jet

NASA Technical Reports Server (NTRS)

Gooderum, Paul B; Wood, George P; Brevoort, Maurice J

1950-01-01

The free turbulent mixing of a supersonic jet of Mach number 1.6 has been experimentally investigated. An interferometer, of which a description is given, was used for the investigation. Density and velocity distributions through the mixing zone have been obtained. It was found that there was similarity in distribution at the cross sections investigated and that, in the subsonic portion of the mixing zone, the velocity distribution fitted the theoretical distribution for incompressible flow. It was found that the rates of spread of the mixing zone both into the jet and into the ambient air were less than those of subsonic jets.

Convection Enhances Mixing in the Southern Ocean

NASA Astrophysics Data System (ADS)

Sohail, Taimoor; Gayen, Bishakhdatta; Hogg, Andrew McC.

2018-05-01

Mixing efficiency is a measure of the energy lost to mixing compared to that lost to viscous dissipation. In a turbulent stratified fluid the mixing efficiency is often assumed constant at η = 0.2, whereas with convection it takes values closer to 1. The value of mixing efficiency when both stratified shear flow and buoyancy-driven convection are active remains uncertain. We use a series of numerical simulations to determine the mixing efficiency in an idealized Southern Ocean model. The model is energetically closed and fully resolves convection and turbulence such that mixing efficiency can be diagnosed. Mixing efficiency decreases with increasing wind stress but is enhanced by turbulent convection and by large thermal gradients in regions with a strongly stratified thermocline. Using scaling theory and the model results, we predict an overall mixing efficiency for the Southern Ocean that is significantly greater than 0.2 while emphasizing that mixing efficiency is not constant.

Influence of the vertical mixing parameterization on the modeling results of the Arctic Ocean hydrology

NASA Astrophysics Data System (ADS)

Iakshina, D. F.; Golubeva, E. N.

2017-11-01

The vertical distribution of the hydrological characteristics in the upper ocean layer is mostly formed under the influence of turbulent and convective mixing, which are not resolved in the system of equations for large-scale ocean. Therefore it is necessary to include additional parameterizations of these processes into the numerical models. In this paper we carry out a comparative analysis of the different vertical mixing parameterizations in simulations of climatic variability of the Arctic water and sea ice circulation. The 3D regional numerical model for the Arctic and North Atlantic developed in the ICMMG SB RAS (Institute of Computational Mathematics and Mathematical Geophysics of the Siberian Branch of the Russian Academy of Science) and package GOTM (General Ocean Turbulence Model1,2, http://www.gotm.net/) were used as the numerical instruments . NCEP/NCAR reanalysis data were used for determination of the surface fluxes related to ice and ocean. The next turbulence closure schemes were used for the vertical mixing parameterizations: 1) Integration scheme based on the Richardson criteria (RI); 2) Second-order scheme TKE with coefficients Canuto-A3 (CANUTO); 3) First-order scheme TKE with coefficients Schumann and Gerz4 (TKE-1); 4) Scheme KPP5 (KPP). In addition we investigated some important characteristics of the Arctic Ocean state including the intensity of Atlantic water inflow, ice cover state and fresh water content in Beaufort Sea.

A comparison of pure mode I and mixed mode I-III cracking of an adhesive containing an open knit cloth carrier

NASA Technical Reports Server (NTRS)

Ripling, E. J.; Crosley, P. B.; Johnson, W. S.

1988-01-01

Static and fatigue tests were carried out on two commercial modified epoxy film adhesives with a wide open knit polyester carrier in order to compare crack resistance in mode I and mixed mode I-III loading. The carrier cloth is found to have a significant influence on the cracking behavior of the adhesives. The open air net carrier used in this study separates from the adhesive in mode I cracking but shreds during mixed-mode crack extension. This decreases the opening mode toughness but increases the mixed-mode toughness as compared with results obtained earlier using a heavier knit carrier. The results suggest that the type of carrier may have a far larger influence on crack resistance than is generally recognized.

Phase behavior of stratum corneum lipids in mixed Langmuir-Blodgett monolayers.

PubMed Central

ten Grotenhuis, E; Demel, R A; Ponec, M; Boer, D R; van Miltenburg, J C; Bouwstra, J A

1996-01-01

The lipids found in the bilayers of the stratum corneum fulfill the vital barrier role of mammalian bodies. The main classes of lipids found in stratum corneum are ceramides, cholesterol, and free fatty acids. For an investigation of their phase behavior, mixed Langmuir-Blodgett monolayers of these lipids were prepared. Atomic force microscopy was used to investigate the structure of the monolayers as a function of the monolayer composition. Three different types of ceramide were used: ceramide extracted from pigskin, a commercially available ceramide with several fatty acid chain lengths, and two synthetic ceramides that have only one fatty acid chain length. In pigskin ceramide-cholesterol mixed monolayers phase separation was observed. This phase separation was also found for the commercially available type III Sigma ceramide-cholesterol mixed monolayers with molar ratios ranging from 1:0.1 to 1:1. These monolayers separated into two phases, one composed of the long fatty acid chain fraction of Sigma ceramide III and the other of the short fatty acid chain fraction of Sigma ceramide III mixed with cholesterol. Mixtures with a higher cholesterol content consisted of only one phase. These observations were confirmed by the results obtained with synthetic ceramides, which have only one fatty acid chain length. The synthetic ceramide with a palmitic acid (16:0) chain mixed with cholesterol, and the synthetic ceramide with a lignoceric acid (24:0) chain did not. Free fatty acids showed a preference to mix with one of these phases, depending on their fatty acid chain lengths. The results of this investigation suggest that the model system used in this study is in good agreement with those of other studies concerning the phase behavior of the stratum corneum lipids. By varying the composition of the monolayers one can study the role of each lipid class in detail. Images FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 PMID:8874014

Liquid–Liquid Mixing Studies in Annular Centrifugal Contactors Comparing Stationary Mixing Vane Options

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

Wardle, Kent E.

2015-11-10

Comparative studies of multiphase operation of annular centrifugal contactors showing the impact of housing stationary mixing vane configuration. A number of experimental results for several different mixing vane options are reported with selected measurements in a lab-scale 5 cm contactor and 12.5 cm engineering-scale unit. Fewer straight vanes give greater mixingzone hold-up compared to curved vanes. Quantitative comparison of droplet size distribution also showed a significant decrease in mean diameter for four straight vanes versus eight curved vanes. This set of measurements gives a compelling case for careful consideration of mixing vane geometry when evaluating hydraulic operation and extraction processmore » efficiency of annular centrifugal contactors.« less

Production of high-quality polydisperse construction mixes for additive 3D technologies.

NASA Astrophysics Data System (ADS)

Gerasimov, M. D.; Brazhnik, Yu V.; Gorshkov, P. S.; Latyshev, S. S.

2018-03-01

The paper describes a new design of a mixer allowing production of high quality polydisperse powders, used in additive 3D technologies. A new principle of dry powder particle mixing is considered, implementing a possibility of a close-to-ideal distribution of such particles in common space. A mathematical model of the mixer is presented, allowing evaluating quality indicators of the produced mixture. Experimental results are shown and rational values of process parameters of the mixer are obtained.

A novel mixed phospholipid functionalized monolithic column for early screening of drug induced phospholipidosis risk.

PubMed

Zhao, XiangLong; Chen, WeiJia; Liu, ZhengHua; Guo, JiaLiang; Zhou, ZhengYin; Crommen, Jacques; Moaddel, Ruin; Jiang, ZhengJin

2014-11-07

Drug-induced phospholipidosis (PLD) is characterized by the excessive accumulation of phospholipids, resulting in multilamellar vesicle structure within lysosomes. In the present study, a novel mixed phospholipid functionalized monolithic column was developed for the first time through a facile one-step co-polymerization approach. The phospholipid composition of the monolith can be adjusted quantitatively and accurately to mimic the mixed phospholipid environment of different biomembranes on a solid matrix. The mixed phospholipid functionalized monolith as a promising immobilized artificial membrane technique was used to study drug-phospholipid interaction. Scanning electron microscopy, elemental analysis, FT-IR spectra, ζ-potential analysis and micro-HPLC were carried out to characterize the physicochemical properties and separation performance of the monolith. Mechanism studies revealed that both hydrophobic and electrostatic interactions play an important role in the retention of analytes. The ratio of their contributions to retention can be easily manipulated by adjusting the composition of the mixed phospholipids, in order to better mimic the interaction between drugs and cell membrane. The obtained mixed phospholipid functionalized monolithic columns were applied to the screening of drug-induced PLD potency. Data from 79 drugs on the market demonstrated that the chromatographic hydrophobicity index referring to the mixed phospholipid functionalized monolith at pH 7.4 (CHI IAM7.4) for the selected drugs were highly correlated with the drug-induced PLD potency data obtained from other in vivo or in vitro assays. Moreover, the effect of the acidic phospholipid phosphatidylserine proportion on prediction accuracy was also investigated. The monolith containing 20% phosphatidylserine and 80% phosphatidylcholine exhibited the best prediction ability for the drug-induced PLD potency of the tested compounds. This research has led to the successful development of a

Determining the impact of cell mixing on signaling during development.

PubMed

Uriu, Koichiro; Morelli, Luis G

2017-06-01

Cell movement and intercellular signaling occur simultaneously to organize morphogenesis during embryonic development. Cell movement can cause relative positional changes between neighboring cells. When intercellular signals are local such cell mixing may affect signaling, changing the flow of information in developing tissues. Little is known about the effect of cell mixing on intercellular signaling in collective cellular behaviors and methods to quantify its impact are lacking. Here we discuss how to determine the impact of cell mixing on cell signaling drawing an example from vertebrate embryogenesis: the segmentation clock, a collective rhythm of interacting genetic oscillators. We argue that comparing cell mixing and signaling timescales is key to determining the influence of mixing. A signaling timescale can be estimated by combining theoretical models with cell signaling perturbation experiments. A mixing timescale can be obtained by analysis of cell trajectories from live imaging. After comparing cell movement analyses in different experimental settings, we highlight challenges in quantifying cell mixing from embryonic timelapse experiments, especially a reference frame problem due to embryonic motions and shape changes. We propose statistical observables characterizing cell mixing that do not depend on the choice of reference frames. Finally, we consider situations in which both cell mixing and signaling involve multiple timescales, precluding a direct comparison between single characteristic timescales. In such situations, physical models based on observables of cell mixing and signaling can simulate the flow of information in tissues and reveal the impact of observed cell mixing on signaling. © 2017 Japanese Society of Developmental Biologists.

Mixing {Xi}--{Xi}' Effects and Static Properties of Heavy {Xi}'s

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

Aliev, T. M.; Ozpineci, A.; Zamiralov, V. S.

It is shown the importance of mixing of heavy baryons {Xi}--{Xi}' with the new quantum numbers for analysis of its characteristics. The quark model of Ono is used as an example. Masses of new baryons as well as mixing angles of the states {Xi}--{Xi}' are obtained. The same reasoning is shown to be valid for the interpolating currents of these baryons in the framework of the QCD sum rules.

Preparation and performance study of a novel liquid scintillator with mixed solvent as the matrix

NASA Astrophysics Data System (ADS)

Zheng, Zhanlong; Zhu, Jiayi; Luo, Xuan; Xu, Yewei; Zhang, Qianfeng; Zhang, Xing; Bi, Yutie; Zhang, Lin

2017-04-01

A novel liquid scintillator with the mixed solvent as the matrix was prepared for obtaining a good comprehensive performance. In this ternary liquid scintillator, the combination of 20% pseudocumene (PC) and 80% linear-alkyl benzene (LAB) by volume was chosen as the mixed solvent, and 2,5-diphenyloxazole (PPO) and 1,4-bis(2-Methylstyryl) benzene (bis-MSB) were as the primary fluor and wavelength shifter, respectively. The optimum prescription was obtained with regard to the light yield. Some characterizations based on the optimal formulation were conducted. The fluorescence emission spectra and wavelength-dependent optical attenuation length of the sample were measured by the fluorescence spectrophotometer and an UV-Vis spectrometer, respectively. The light yield was characterized by adopting the home-made optical platform device. The decay time was tested by adopting the time-correlated single photon counting (TCSPC) technique featured in high dynamic range of several orders of magnitude in light intensity. The experimental test results showed that the sample had a fairly good comprehensive performance.

Characterization of Ferroplasma acidiphilum growing in pure and mixed culture with Leptospirillum ferriphilum.

PubMed

Merino, M P; Andrews, B A; Parada, P; Asenjo, J A

2016-11-01

Biomining is defined as biotechnology for metal recovery from minerals, and is promoted by the concerted effort of a consortium of acidophile prokaryotes, comprised of members of the Bacteria and Archaea domains. Ferroplasma acidiphilum and Leptospirillum ferriphilum are the dominant species in extremely acid environments and have great use in bioleaching applications; however, the role of each species in this consortia is still a subject of research. The hypothesis of this work is that F. acidiphilum uses the organic matter secreted by L. ferriphilum for growth, maintaining low levels of organic compounds in the culture medium, preventing their toxic effects on L. ferriphilum. To test this hypothesis, a characterization of Ferroplasma acidiphilum strain BRL-115 was made with the objective of determining its optimal growth conditions. Subsequently, under the optimal conditions, L. ferriphilum and F. acidiphilum were tested growing in each other's supernatant, in order to define if there was exchange of metabolites between the species. With these results, a mixed culture in batch cyclic operation was performed to obtain main specific growth rates, which were used to evaluate a mixed metabolic model previously developed by our group. It was observed that F. acidiphilum, strain BRL-115 is a chemomixotrophic organism, and its growth is maximized with yeast extract at a concentration of 0.04% wt/vol. From the experiments of L. ferriphilum growing on F. acidiphilum supernatant and vice versa, it was observed that in both cases cell growth is favorably affected by the presence of the filtered medium of the other microorganism, proving a synergistic interaction between these species. Specific growth rates were obtained in cyclic batch operation of the mixed culture and were used as input data for a Flux Balance Analysis of the mixed metabolic model, obtaining a reasonable behavior of the metabolic fluxes and the system as a whole, therefore consolidating the model

Mixing it but not mixed-up: mixed methods research in medical education (a critical narrative review).

PubMed

Maudsley, Gillian

2011-01-01

Some important research questions in medical education and health services research need 'mixed methods research' (particularly synthesizing quantitative and qualitative findings). The approach is not new, but should be more explicitly reported. The broad search question here, of a disjointed literature, was thus: What is mixed methods research - how should it relate to medical education research?, focused on explicit acknowledgement of 'mixing'. Literature searching focused on Web of Knowledge supplemented by other databases across disciplines. Five main messages emerged: - Thinking quantitative and qualitative, not quantitative versus qualitative - Appreciating that mixed methods research blends different knowledge claims, enquiry strategies, and methods - Using a 'horses for courses' [whatever works] approach to the question, and clarifying the mix - Appreciating how medical education research competes with the 'evidence-based' movement, health services research, and the 'RCT' - Being more explicit about the role of mixed methods in medical education research, and the required expertise Mixed methods research is valuable, yet the literature relevant to medical education is fragmented and poorly indexed. The required time, effort, expertise, and techniques deserve better recognition. More write-ups should explicitly discuss the 'mixing' (particularly of findings), rather than report separate components.

Obtaining Crack-free WC-Co Alloys by Selective Laser Melting

NASA Astrophysics Data System (ADS)

Khmyrov, R. S.; Safronov, V. A.; Gusarov, A. V.

Standard hardmetals of WC-Co system are brittle and often crack at selective laser melting (SLM). The objective of this study is to estimate the range of WC/Co ratio where cracking can be avoided. Micron-sized Co powder was mixed with WC nanopowder in a ball mill to obtain uniform distribution of WC over the surface of Co particles. Continuous layers of remelted material on the surface of a hardmetal plate were obtained from this composite powder by SLM at 1.07μm wavelength. The layers have satisfactory porosity and are well bound to the substrate. The chemical composition of the layers matches the composition of the initial powder mixtures. The powder mixture with 25wt.%WC can be used for SLM to obtain materials without cracks. The powder mixture with 50wt.%WC cracks because of formation of brittle W3Co3C phase. Cracking can considerably reduce the mechanical strength, so that the use of this composition is not advised.

Installation of warm mix asphalt projects in Virginia.

DOT National Transportation Integrated Search

2007-01-01

Several processes have been developed to reduce the mixing and compaction temperatures of hot mix asphalt (HMA) without sacrificing the quality of the resulting pavement. The purpose of this study was to evaluate the installation of warm mix asphalt ...

Fuel-rich, catalytic reaction experimental results

NASA Technical Reports Server (NTRS)

Rollbuhler, R. James

1991-01-01

Future aeropropulsion gas turbine combustion requirements call for operating at very high inlet temperatures, pressures, and large temperature rises. At the same time, the combustion process is to have minimum pollution effects on the environment. Aircraft gas turbine engines utilize liquid hydrocarbon fuels which are difficult to uniformly atomize and mix with combustion air. An approach for minimizing fuel related problems is to transform the liquid fuel into gaseous form prior to the completion of the combustion process. Experimentally obtained results are presented for vaporizing and partially oxidizing a liquid hydrocarbon fuel into burnable gaseous components. The presented experimental data show that 1200 to 1300 K reaction product gas, rich in hydrogen, carbon monoxide, and light-end hydrocarbons, is formed when flowing 0.3 to 0.6 fuel to air mixes through a catalyst reactor. The reaction temperatures are kept low enough that nitrogen oxides and carbon particles (soot) do not form. Results are reported for tests using different catalyst types and configurations, mass flowrates, input temperatures, and fuel to air ratios.

Rock Fracture Toughness Study Under Mixed Mode I/III Loading

NASA Astrophysics Data System (ADS)

Aliha, M. R. M.; Bahmani, A.

2017-07-01

Fracture growth in underground rock structures occurs under complex stress states, which typically include the in- and out-of-plane sliding deformation of jointed rock masses before catastrophic failure. However, the lack of a comprehensive theoretical and experimental fracture toughness study for rocks under contributions of out-of plane deformations (i.e. mode III) is one of the shortcomings of this field. Therefore, in this research the mixed mode I/III fracture toughness of a typical rock material is investigated experimentally by means of a novel cracked disc specimen subjected to bend loading. It was shown that the specimen can provide full combinations of modes I and III and consequently a complete set of mixed mode I/III fracture toughness data were determined for the tested marble rock. By moving from pure mode I towards pure mode III, fracture load was increased; however, the corresponding fracture toughness value became smaller. The obtained experimental fracture toughness results were finally predicted using theoretical and empirical fracture models.

Development of characterization protocol for mixed liquid radioactive waste classification

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

Zakaria, Norasalwa, E-mail: norasalwa@nuclearmalaysia.gov.my; Wafa, Syed Asraf; Wo, Yii Mei

2015-04-29

Mixed liquid organic waste generated from health-care and research activities containing tritium, carbon-14, and other radionuclides posed specific challenges in its management. Often, these wastes become legacy waste in many nuclear facilities and being considered as ‘problematic’ waste. One of the most important recommendations made by IAEA is to perform multistage processes aiming at declassification of the waste. At this moment, approximately 3000 bottles of mixed liquid waste, with estimated volume of 6000 litres are currently stored at the National Radioactive Waste Management Centre, Malaysia and some have been stored for more than 25 years. The aim of this studymore » is to develop a characterization protocol towards reclassification of these wastes. The characterization protocol entails waste identification, waste screening and segregation, and analytical radionuclides profiling using various analytical procedures including gross alpha/ gross beta, gamma spectrometry, and LSC method. The results obtained from the characterization protocol are used to establish criteria for speedy classification of the waste.« less

Disease risk mitigation: the equivalence of two selective mixing strategies on aggregate contact patterns and resulting epidemic spread.

PubMed

Morin, Benjamin R; Perrings, Charles; Levin, Simon; Kinzig, Ann

2014-12-21

The personal choices affecting the transmission of infectious diseases include the number of contacts an individual makes, and the risk-characteristics of those contacts. We consider whether these different choices have distinct implications for the course of an epidemic. We also consider whether choosing contact mitigation (how much to mix) and affinity mitigation (with whom to mix) strategies together has different epidemiological effects than choosing each separately. We use a set of differential equation compartmental models of the spread of disease, coupled with a model of selective mixing. We assess the consequences of varying contact or affinity mitigation as a response to disease risk. We do this by comparing disease incidence and dynamics under varying contact volume, contact type, and both combined across several different disease models. Specifically, we construct a change of variables that allows one to transition from contact mitigation to affinity mitigation, and vice versa. In the absence of asymptomatic infection we find no difference in the epidemiological impacts of the two forms of disease risk mitigation. Furthermore, since models that include both mitigation strategies are underdetermined, varying both results in no outcome that could not be reached by choosing either separately. Which strategy is actually chosen then depends not on their epidemiological consequences, but on the relative cost of reducing contact volume versus altering contact type. Although there is no fundamental epidemiological difference between the two forms of mitigation, the social cost of alternative strategies can be very different. From a social perspective, therefore, whether one strategy should be promoted over another depends on economic not epidemiological factors. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mixed handedness and achievement test scores of middle school boys.

PubMed

Sarma, P S B

2008-10-01

The purpose of the study was to replicate findings of an earlier study of fourth grade boys manifesting mixed handedness with a sample. Among 32 mixed-handed boys in Grades 6 to 8, the right-handed writer, left-handed thrower group obtained low spelling scores (Normal Curve Equivalent Scores) on the California Achievement Test significantly more frequently than the left-handed writer, right-handed thrower group. These findings are consistent with data for Grade 4 boys in the earlier study. Findings strengthen the hypotheses that mixed handedness is not a unitary neuropsychological entity and that boys who write with the right hand and throw with the left hand might be at risk for certain academic deficits.

Laboratory evaluation of warm mix asphalt.

DOT National Transportation Integrated Search

2011-09-14

"Hot Mix Asphalt (HMA) has been traditionally produced at a discharge temperature of between : 280F (138C) and 320 F (160C), resulting in high energy (fuel) costs and generation of greenhouse : gases. The goal for Warm Mix Asphalt (WMA) is to...

Development of pulsating twin jets mechanism for mixing flow heat transfer analysis.

PubMed

Gitan, Ali Ahmed; Zulkifli, Rozli; Abdullah, Shahrir; Sopian, Kamaruzzaman

2014-01-01

Pulsating twin jets mechanism (PTJM) was developed in the present work to study the effect of pulsating twin jets mixing region on the enhancement of heat transfer. Controllable characteristics twin pulsed jets were the main objective of our design. The variable nozzle-nozzle distance was considered to study the effect of two jets interaction at the mixing region. Also, the phase change between the frequencies of twin jets was taken into account to develop PTJM. All of these factors in addition to the ability of producing high velocity pulsed jet led to more appropriate design for a comprehensive study of multijet impingement heat transfer problems. The performance of PTJM was verified by measuring the pulse profile at frequency of 20 Hz, where equal velocity peak of around 64 m/s for both jets was obtained. Moreover, the jet velocity profile at different pulsation frequencies was tested to verify system performance, so the results revealed reasonable velocity profile configuration. Furthermore, the effect of pulsation frequency on surface temperature of flat hot plate in the midpoint between twin jets was studied experimentally. Noticeable enhancement in heat transfer was obtained with the increasing of pulsation frequency.

Development of Pulsating Twin Jets Mechanism for Mixing Flow Heat Transfer Analysis

PubMed Central

Abdullah, Shahrir

2014-01-01

Pulsating twin jets mechanism (PTJM) was developed in the present work to study the effect of pulsating twin jets mixing region on the enhancement of heat transfer. Controllable characteristics twin pulsed jets were the main objective of our design. The variable nozzle-nozzle distance was considered to study the effect of two jets interaction at the mixing region. Also, the phase change between the frequencies of twin jets was taken into account to develop PTJM. All of these factors in addition to the ability of producing high velocity pulsed jet led to more appropriate design for a comprehensive study of multijet impingement heat transfer problems. The performance of PTJM was verified by measuring the pulse profile at frequency of 20 Hz, where equal velocity peak of around 64 m/s for both jets was obtained. Moreover, the jet velocity profile at different pulsation frequencies was tested to verify system performance, so the results revealed reasonable velocity profile configuration. Furthermore, the effect of pulsation frequency on surface temperature of flat hot plate in the midpoint between twin jets was studied experimentally. Noticeable enhancement in heat transfer was obtained with the increasing of pulsation frequency. PMID:24672370

Small signal analysis of four-wave mixing in InAs/GaAs quantum-dot semiconductor optical amplifiers

NASA Astrophysics Data System (ADS)

Ma, Shaozhen; Chen, Zhe; Dutta, Niloy K.

2009-02-01

A model to study four-wave mixing (FWM) wavelength conversion in InAs-GaAs quantum-dot semiconductor optical amplifier is proposed. Rate equations involving two QD states are solved to simulate the carrier density modulation in the system, results show that the existence of QD excited state contributes to the ultra fast recover time for single pulse response by serving as a carrier reservoir for the QD ground state, its speed limitations are also studied. Nondegenerate four-wave mixing process with small intensity modulation probe signal injected is simulated using this model, a set of coupled wave equations describing the evolution of all frequency components in the active region of QD-SOA are derived and solved numerically. Results show that better FWM conversion efficiency can be obtained compared with the regular bulk SOA, and the four-wave mixing bandwidth can exceed 1.5 THz when the detuning between pump and probe lights is 0.5 nm.

Kinetic Plasma and Turbulent Mix Studies using DT Plastic-shell Implosions with Shell-thickness and Pressure Variations

NASA Astrophysics Data System (ADS)

Kim, Y.; Herrmann, H. W.; Hoffman, N. M.; Schmitt, M. J.; Bradley, P. A.; Kagan, G.; Gales, S.; Horsfield, C. J.; Rubery, M.; Leatherland, A.; Gatu Johnson, M.; Glebov, V.; Seka, W.; Marshall, F.; Stoeckl, C.; Church, J.

2014-10-01

Kinetic plasma and turbulent mix effects on inertial confinement fusion have been studied using a series of DT-filled plastic-shell implosions at the OMEGA laser facility. Plastic capsules of 4 different shell thicknesses (7.4, 15, 20, 29 micron) were shot at 2 different fill pressures in order to vary the ion mean free path compared to the size of fuel region (i.e., Knudsen number). We varied the empirical Knudsen number by a factor of 25. Measurements were obtained from the burn-averaged ion temperature and fuel areal density. Preliminary results indicate that as the empirical Knudsen number increases, fusion performances (e.g., neutron yield) increasingly deviate from hydrodynamic simulations unless turbulent mix and ion kinetic terms (e.g., enhanced ion diffusion, viscosity, thermal conduction, as well as Knudsen-layer fusion reactivity reduction) are considered. We are developing two separate simulations: one is a reduced-ion-kinetics model and the other is turbulent mix model. Two simulation results will be compared with the experimental observables.

Optimal mixing rate in linear solvent strength gradient liquid chromatography. Balanced mixing program.

PubMed

Blumberg, Leonid M; Desmet, Gert

2016-12-09

The mixing rate (R ϕ ) is the temporal rate of increase in the solvent strength in gradient LC. The optimal R ϕ (R ϕ ,Opt ) is the one at which a required peak capacity of gradient LC analysis is obtained in the shortest time. The balanced mixing program is a one where, for better separation of early eluting solutes, the mixing ramp is preceded by a balanced isocratic hold of the duration depending on R ϕ . The improvement in the separation of the earlier eluites due to the balanced programming has been evaluated. The value of R ϕ ,Opt depends on the solvent composition range covered by the mixing ramp and on the column pressure conditions. The R ϕ ,Opt for a column operating at maximum instrumental pressure is different from R ϕ ,Opt for a column operating below the instrumental pressure limit. On the other hand, it has been shown that the difference in the R ϕ ,Opt values under different conditions is not very large so that a single default R ϕ previously recommended for gradient analyses without the isocratic hold also yields a good approximation to the shortest analysis time for all conditions in the balanced analyses. With or without the initial balance isocratic hold, the recommended default R ϕ is about 5%/t 0 (5% increase in the solvent strength per each t 0 -long increment in time) for small-molecule samples, and about an order of magnitude slower (0.5%/t 0 ) for protein samples. A discussion illustrating the use of the optimization criteria employed here for the techniques other than LSS gradient LC is included. Copyright © 2016 Elsevier B.V. All rights reserved.

Xenon-ion-induced and thermal mixing of Co/Si bilayers and their interplay

NASA Astrophysics Data System (ADS)

Novaković, M.; Zhang, K.; Popović, M.; Bibić, N.; Hofsäss, H.; Lieb, K. P.

2011-05-01

Studies on ion-irradiated transition-metal/silicon bilayers demonstrate that interface mixing and silicide phase formation depend sensitively on the ion and film parameters, including the structure of the metal/Si interface. Thin Co layers e-gun evaporated to a thickness of 50 nm on Si(1 0 0) wafers were bombarded at room temperature with 400-keV Xe + ions at fluences of up to 3 × 10 16 cm -2. We used either crystalline or pre-amorphized Si wafers the latter ones prepared by 1.0-keV Ar-ion implantation. The as-deposited or Xe-ion-irradiated samples were then isochronally annealed at temperatures up to 700 °C. Changes of the bilayer structures induced by ion irradiation and/or annealing were investigated with RBS, XRD and HRTEM. The mixing rate for the Co/c-Si couples, Δ σ2/ Φ = 3.0(4) nm 4, is higher than the value expected for ballistic mixing and about half the value typical for spike mixing. Mixing of pre-amorphized Si is much weaker relative to crystalline Si wafers, contrary to previous results obtained for Fe/Si bilayers. Annealing of irradiated samples produces very similar interdiffusion and phase formation patterns above 400 °C as in the non-irradiated Co/Si bilayers: the phase evolution follows the sequence Co 2Si → CoSi → CoSi 2.

Experiments and High-resolution Simulations of Density and Viscosity Feedbacks on Convective Mixing

NASA Astrophysics Data System (ADS)

Hidalgo, Juan J.; Fe, Jaime; MacMinn, Christopher W.; Cueto-Felgueroso, Luis; Juanes, Ruben

2011-11-01

Dissolution by convective mixing is one of the main trapping mechanisms during CO2 sequestration in saline aquifers. Initially, the buoyant CO2 dissolves into the underlying brine by diffusion. The CO2-brine mixture is denser than the two initial fluids, leading to a Rayleigh-Bénard-type instability known as convective mixing, which greatly accelerates CO2 dissolution. Although this is a well-known process, it remains unclear how convective mixing scales with the governing parameters of the system and its impact on the actual mixing of CO2 and brine. We explore the dependence of the CO2 dissolution flux on the nonlinearity of the density and viscosity of the fluid mixture by means of high-resolution numerical simulations and laboratory experiments with an analogue fluid system (water and propylene glycol). We find that the value of the concentration for which the density of the mixture is maximum, and the viscosity contrast between the fluids, both exert a powerful control on the convective flux. From the experimental and simulation results, we obtain the scaling behavior of convective mixing, and clarify the role of nonlinear density and viscosity feedbacks. JJH acknowledges the support from the FP7 Marie Curie Actions of the European Commission, via the CO2-MATE project (PIOF-GA-2009-253678).

A scoring system for appraising mixed methods research, and concomitantly appraising qualitative, quantitative and mixed methods primary studies in Mixed Studies Reviews.

PubMed

Pluye, Pierre; Gagnon, Marie-Pierre; Griffiths, Frances; Johnson-Lafleur, Janique

2009-04-01

A new form of literature review has emerged, Mixed Studies Review (MSR). These reviews include qualitative, quantitative and mixed methods studies. In the present paper, we examine MSRs in health sciences, and provide guidance on processes that should be included and reported. However, there are no valid and usable criteria for concomitantly appraising the methodological quality of the qualitative, quantitative and mixed methods studies. To propose criteria for concomitantly appraising the methodological quality of qualitative, quantitative and mixed methods studies or study components. A three-step critical review was conducted. 2322 references were identified in MEDLINE, and their titles and abstracts were screened; 149 potentially relevant references were selected and the full-text papers were examined; 59 MSRs were retained and scrutinized using a deductive-inductive qualitative thematic data analysis. This revealed three types of MSR: convenience, reproducible, and systematic. Guided by a proposal, we conducted a qualitative thematic data analysis of the quality appraisal procedures used in the 17 systematic MSRs (SMSRs). Of 17 SMSRs, 12 showed clear quality appraisal procedures with explicit criteria but no SMSR used valid checklists to concomitantly appraise qualitative, quantitative and mixed methods studies. In two SMSRs, criteria were developed following a specific procedure. Checklists usually contained more criteria than needed. In four SMSRs, a reliability assessment was described or mentioned. While criteria for quality appraisal were usually based on descriptors that require specific methodological expertise (e.g., appropriateness), no SMSR described the fit between reviewers' expertise and appraised studies. Quality appraisal usually resulted in studies being ranked by methodological quality. A scoring system is proposed for concomitantly appraising the methodological quality of qualitative, quantitative and mixed methods studies for SMSRs. This

Neutrino mixing and big bang nucleosynthesis

NASA Astrophysics Data System (ADS)

Bell, Nicole

2003-04-01

We analyse active-active neutrino mixing in the early universe and show that transformation of neutrino-antineutrino asymmetries between flavours is unavoidable when neutrino mixing angles are large. This process is a standard Mikheyev-Smirnov-Wolfenstein flavour transformation, modified by the synchronisation of momentum states which results from neutrino-neutrino forward scattering. The new constraints placed on neutrino asymmetries eliminate the possibility of degenerate big bang nucleosynthesis.Implications of active-sterile neutrino mixing will also be reviewed.

Tidal Energy Available for Deep Ocean Mixing: Bounds from Altimetry Data

NASA Technical Reports Server (NTRS)

Egbert, Gary D.; Ray, Richard D.

1999-01-01

Maintenance of the large-scale thermohaline circulation has long presented a problem to oceanographers. Observed mixing rates in the pelagic ocean are an order of magnitude too small to balance the rate at which dense bottom water is created at high latitudes. Recent observational and theoretical work suggests that much of this mixing may occur in hot spots near areas of rough topography (e.g., mid-ocean ridges and island arcs). Barotropic tidal currents provide a very plausible source of energy to maintain these mixing processes. Topex/Poseidon (T/P) satellite altimetry data have made precise mapping of open ocean tidal elevations possible for the first time. We can thus obtain empirical, spatially localized, estimates of barotropic tidal dissipation. These provide an upper bound on the amount of tidal energy that is dissipated in the deep ocean, and hence is available for deep mixing. We will present and compare maps of open ocean tidal energy flux divergence, and estimates of tidal energy flux into shallow seas, derived from T/P altimetry data using both formal data assimilation methods and empirical approaches. With the data assimilation methods we can place formal error bars on the fluxes. Our results show that 20-25% of tidal energy dissipation occurs outside of the shallow seas, the traditional sink for tidal energy. This suggests that up to 1 TW of energy may be available from the tides (lunar and solar) for mixing the deep ocean. The dissipation indeed appears to be concentrated over areas of rough topography.

Tidal Energy Available for Deep Ocean Mixing: Bounds From Altimetry Data

NASA Technical Reports Server (NTRS)

Egbert, Gary D.; Ray, Richard D.

1999-01-01

Maintenance of the large-scale thermohaline circulation has long presented a problem to oceanographers. Observed mixing rates in the pelagic ocean are an order of magnitude too small to balance the rate at which dense bottom water is created at high latitudes. Recent observational and theoretical work suggests that much of this mixing may occur in hot spots near areas of rough topography (e.g., mid-ocean ridges and island arcs). Barotropic tidal currents provide a very plausible source of energy to maintain these mixing processes. Topex/Poseidon satellite altimetry data have made precise mapping of open ocean tidal elevations possible for the first time. We can thus obtain empirical, spatially localized, estimates of barotropic tidal dissipation. These provide an upper bound on the amount of tidal energy that is dissipated in the deep ocean, and hence is available for deep mixing. We will present and compare maps of open ocean tidal energy flux divergence, and estimates of tidal energy flux into shallow seas, derived from T/P altimetry data using both formal data assimilation methods and empirical approaches. With the data assimilation methods we can place formal error bars on the fluxes. Our results show that 20-25% of tidal energy dissipation occurs outside of the shallow seas, the traditional sink for tidal energy. This suggests that up to 1 TW of energy may be available from the tides (lunar and solar) for mixing the deep ocean. The dissipation indeed appears to be concentrated over areas of rough topography.

Tidal Energy Available for Deep Ocean Mixing: Bounds from Altimetry Data

NASA Technical Reports Server (NTRS)

Ray, Richard D.; Egbert, Gary D.

1999-01-01

Maintenance of the large-scale thermohaline circulation has long presented an interesting problem. Observed mixing rates in the pelagic ocean are an order of magnitude too small to balance the rate at which dense bottom water is created at high latitudes. Recent observational and theoretical work suggests that much of this mixing may occur in hot spots near areas of rough topography (e.g., mid-ocean ridges and island arcs). Barotropic tidal currents provide a very plausible source of energy to maintain these mixing processes. Topex/Poseidon satellite altimetry data have made precise mapping of open ocean tidal elevations possible for the first time. We can thus obtain empirical, spatially localized, estimates of barotropic tidal dissipation. These provide an upper bound on the amount of tidal energy that is dissipated in the deep ocean, and hence is available for deep mixing. We will present and compare maps of open ocean tidal energy flux divergence, and estimates of tidal energy flux into shallow seas, derived from T/P altimetry data using both formal data assimilation methods and empirical approaches. With the data assimilation methods we can place formal error bars on the fluxes. Our results show that 20-25% of tidal energy dissipation occurs outside of the shallow seas, the traditional sink for tidal energy. This suggests that up to 1 TW of energy may be available from the tides (lunar and solar) for mixing the deep ocean. The dissipation indeed appears to be concentrated over areas of rough topography.

Analysis of mixed model in gear transmission based on ADAMS

NASA Astrophysics Data System (ADS)

Li, Xiufeng; Wang, Yabin

2012-09-01

The traditional method of mechanical gear driving simulation includes gear pair method and solid to solid contact method. The former has higher solving efficiency but lower results accuracy; the latter usually obtains higher precision of results while the calculation process is complex, also it is not easy to converge. Currently, most of the researches are focused on the description of geometric models and the definition of boundary conditions. However, none of them can solve the problems fundamentally. To improve the simulation efficiency while ensure the results with high accuracy, a mixed model method which uses gear tooth profiles to take the place of the solid gear to simulate gear movement is presented under these circumstances. In the process of modeling, build the solid models of the mechanism in the SolidWorks firstly; Then collect the point coordinates of outline curves of the gear using SolidWorks API and create fit curves in Adams based on the point coordinates; Next, adjust the position of those fitting curves according to the position of the contact area; Finally, define the loading conditions, boundary conditions and simulation parameters. The method provides gear shape information by tooth profile curves; simulates the mesh process through tooth profile curve to curve contact and offer mass as well as inertia data via solid gear models. This simulation process combines the two models to complete the gear driving analysis. In order to verify the validity of the method presented, both theoretical derivation and numerical simulation on a runaway escapement are conducted. The results show that the computational efficiency of the mixed model method is 1.4 times over the traditional method which contains solid to solid contact. Meanwhile, the simulation results are more closely to theoretical calculations. Consequently, mixed model method has a high application value regarding to the study of the dynamics of gear mechanism.

Comparison of Theoretical Stresses and Deflections of Multicell Wings with Experimental Results Obtained from Plastic Models

NASA Technical Reports Server (NTRS)

Zender, George W

1956-01-01

The experimental deflections and stresses of six plastic multicell-wing models of unswept, delta, and swept plan form are presented and compared with previously published theoretical results obtained by the electrical analog method. The comparisons indicate that the theory is reliable except for the evaluation of stresses in the vicinity of the leading edge of delta wings and the leading and trailing edges of swept wings. The stresses in these regions are questionable, apparently because of simplifications employed in idealizing the actual structure for theoretical purposes and because of local effects of concentrated loads.

MixSIAR: advanced stable isotope mixing models in R

EPA Science Inventory

Background/Question/Methods The development of stable isotope mixing models has coincided with modeling products (e.g. IsoSource, MixSIR, SIAR), where methodological advances are published in parity with software packages. However, while mixing model theory has recently been ex...

Water Droplet Impingement on Simulated Glaze, Mixed, and Rime Ice Accretions

NASA Technical Reports Server (NTRS)

Papadakis, Michael; Rachman, Arief; Wong, See-Cheuk; Yeong, Hsiung-Wei; Hung, Kuohsing E.; Vu, Giao T.; Bidwell, Colin S.

2007-01-01

Water droplet impingement data were obtained at the NASA Glenn Icing Research Tunnel (IRT) for a 36-in. chord NACA 23012 airfoil with and without simulated ice using a dye-tracer method. The simulated ice shapes were defined with the NASA Glenn LEWICE 2.2 ice accretion program and including one rime, four mixed and five glaze ice shapes. The impingement experiments were performed with spray clouds having median volumetric diameters of 20, 52, 111, 154, and 236 micron. Comparisons to the experimental data were generated which showed good agreement for the rime and mixed shapes at lower drop sizes. For larger drops sizes LEWICE 2.2 over predicted the collection efficiencies due to droplet splashing effects which were not modeled in the program. Also for the more complex glaze ice shapes interpolation errors resulted in the over prediction of collection efficiencies in cove or shadow regions of ice shapes.

Enhanced copper micro/nano-particle mixed paste sintered at low temperature for 3D interconnects

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

Dai, Y. Y.; Anantha, P.; Tan, C. S., E-mail: tancs@ntu.edu.sg

2016-06-27

An enhanced copper paste, formulated by copper micro- and nano-particles mixture, is reported to prevent paste cracking and obtain an improved packing density. The particle mixture of two different sizes enables reduction in porosity of the micro-paste and resolves the cracking issue in the nano-paste. In-situ temperature and resistance measurements indicate that the mixed paste has a lower densification temperature. Electrical study also shows a ∼12× lower sheet resistance of 0.27 Ω/sq. In addition, scanning electron microscope image analysis confirms a ∼50% lower porosity, which is consistent with the thermal and electrical results. The 3:1 (micro:nano, wt. %) mixed pastemore » is found to have the strongest synergistic effect. This phenomenon is discussed further. Consequently, the mixed paste is a promising material for potential low temperature 3D interconnects fabrication.« less

Mixing of Supersonic Streams

NASA Technical Reports Server (NTRS)

Hawk, C. W.; Landrum, D. B.; Muller, S.; Turner, M.; Parkinson, D.

1998-01-01

The Strutjet approach to Rocket Based Combined Cycle (RBCC) propulsion depends upon fuel-rich flows from the rocket nozzles and turbine exhaust products mixing with the ingested air for successful operation in the ramjet and scramjet modes. It is desirable to delay this mixing process in the air-augmented mode of operation present during low speed flight. A model of the Strutjet device has been built and is undergoing test to investigate the mixing of the streams as a function of distance from the Strutjet exit plane during simulated low speed flight conditions. Cold flow testing of a 1/6 scale Strutjet model is underway and nearing completion. Planar Laser Induced Fluorescence (PLIF) diagnostic methods are being employed to observe the mixing of the turbine exhaust gas with the gases from both the primary rockets and the ingested air simulating low speed, air augmented operation of the RBCC. The ratio of the pressure in the turbine exhaust duct to that in the rocket nozzle wall at the point of their intersection is the independent variable in these experiments. Tests were accomplished at values of 1.0, 1.5 and 2.0 for this parameter. Qualitative results illustrate the development of the mixing zone from the exit plane of the model to a distance of about 19 equivalent rocket nozzle exit diameters downstream. These data show the mixing to be confined in the vertical plane for all cases, The lateral expansion is more pronounced at a pressure ratio of 1.0 and suggests that mixing with the ingested flow would be likely beginning at a distance of 7 nozzle exit diameters downstream of the nozzle exit plane.

Mixing of Supersonic Streams

NASA Technical Reports Server (NTRS)

Hawk, C. W.; Landrum, D. B.; Muller, S.; Turner, M.; Parkinson, D.

1998-01-01

The Strutjet approach to Rocket Based Combined Cycle (RBCC) propulsion depends upon fuel-rich flows from the rocket nozzles and turbine exhaust products mixing with the ingested air for successful operation in the ramjet and scramjet modes. It is desirable to delay this mixing process in the air-augmented mode of operation present during low speed flight. A model of the Strutjet device has been built and is undergoing test to investigate the mixing of the streams as a function of distance from the Strutjet exit plane during simulated low speed flight conditions. Cold flow testing of a 1/6 scale Strutjet model is underway and nearing completion. Planar Laser Induced Fluorescence (PLIF) diagnostic methods are being employed to observe the mixing of the turbine exhaust gas with the gases from both the primary rockets and the ingested air simulating low speed, air augmented operation of the RBCC. The ratio of the pressure in the turbine exhaust duct to that in the rocket nozzle wall at the point of their intersection is the independent variable in these experiments. Tests were accomplished at values of 1.0, 1.5 and 2.0 for this parameter. Qualitative results illustrate the development of the mixing zone from the exit plane of the model to a distance of about 10 rocket nozzle exit diameters downstream. These data show the mixing to be confined in the vertical plane for all cases, The lateral expansion is more pronounced at a pressure ratio of 1.0 and suggests that mixing with the ingested flow would be likely beginning at a distance of 7 nozzle exit diameters downstream of the nozzle exit plane.

Mixed Convection Flow in Horizontal CVD Reactors

NASA Astrophysics Data System (ADS)

Chiu, Wilson K. S.; Richards, Cristy J.; Jaluria, Yogesh

1998-11-01

Increasing demands for high quality films and production rates are challenging current Chemical Vapor Deposition (CVD) technology. Since film quality and deposition rates are strongly dependent on gas flow and heat transfer (W.K.S. Chiu and Y. Jaluria, ASME HTD-Vol. 347, pp. 293-311, 1997.), process improvement is obtained through the study of mixed convection flow and temperature distribution in a CVD reactor. Experimental results are presented for a CVD chamber with a horizontal or inclined resistance heated susceptor. Vaporized glycol solution illuminated by a light sheet is used for flow visualization. Temperature measurements are obtained by inserting thermocouple probes into the gas stream or embedding probes into the reactor walls. Flow visualization and temperature measurements show predominantly two dimensional flow and temperature distributions along the streamwise direction under forced convection conditions. Natural convection dominates under large heating rates and low flow rates. Over the range of parameters studied, several distinct flow regimes, characterized by instability, separation, and turbulence, are evident. Different flow regimes alter the flow pattern and temperature distribution, and in consequence, significantly modify deposition rates and uniformity.

Sequential anaerobic/aerobic digestion for enhanced sludge stabilization: comparison of the process performance for mixed and waste sludge [corrected].

PubMed

Tomei, M Concetta; Carozza, Nicola Antonello

2015-05-01

Sequential anaerobic-aerobic digestion has been demonstrated as a promising alternative for enhanced sludge stabilization. In this paper, a feasibility study of the sequential digestion applied to real waste activated sludge (WAS) and mixed sludge is presented. Process performance is evaluated in terms of total solid (TS) and volatile solid (VS) removal, biogas production, and dewaterability trend in the anaerobic and double-stage digested sludge. In the proposed digestion lay out, the aerobic stage was operated with intermittent aeration to reduce the nitrogen load recycled to the wastewater treatment plant (WWTP). Experimental results showed a very good performance of the sequential digestion process for both waste and mixed sludge, even if, given its better digestibility, higher efficiencies are observed for mixed sludge. VS removal efficiencies in the anaerobic stage were 48 and 50% for waste and mixed sludge, respectively, while a significant additional improvement of the VS removal of 25% for WAS and 45% for mixed sludge has been obtained in the aerobic stage. The post-aerobic stage, operated with intermittent aeration, was also efficient in nitrogen removal, providing a significant decrease of the nitrogen content in the supernatant: nitrification efficiencies of 90 and 97% and denitrification efficiencies of 62 and 70% have been obtained for secondary and mixed sludges, respectively. A positive effect due to the aerobic stage was also observed on the sludge dewaterability in both cases. Biogas production, expressed as Nm(3)/(kgVSdestroyed), was 0.54 for waste and 0.82 for mixed sludge and is in the range of values reported in the literature in spite of the low anaerobic sludge retention time of 15 days.

A complementary marriage of perspectives: understanding organizational social context using mixed methods.

PubMed

Beidas, Rinad S; Wolk, Courtney L Benjamin; Walsh, Lucia M; Evans, Arthur C; Hurford, Matthew O; Barg, Frances K

2014-11-23

Organizational factors impact the delivery of mental health services in community settings. Mixed-methods analytic approaches have been recommended, though little research within implementation science has explicitly compared inductive and deductive perspectives to understand their relative value in understanding the same constructs. The purpose of our study is to use two different paradigmatic approaches to deepen our understanding of organizational social context. We accomplish this by using a mixed-methods approach in an investigation of organizational social context in community mental health clinics. Nineteen agencies, representing 23 sites, participated. Enrolled participants included 130 therapists, 36 supervisors, and 22 executive administrators. Quantitative data was obtained via the Organizational Social Context (OSC) measure. Qualitative data, comprised of direct observation with spot sampling generated from agency visits, was coded using content analysis and grounded theory. The present study examined elements of organizational social context that would have been missed if only quantitative data had been obtained and utilized mixed methods to investigate if stratifying observations based on quantitative ratings from the OSC resulted in the emergence of differential themes. Four of the six OSC constructs were commonly observed in field observations (i.e., proficiency, rigidity, functionality, stress), while the remaining two constructs were not frequently observed (i.e., resistance, engagement). Constructs emerged related to organizational social context that may have been missed if only quantitative measurement was employed, including those around the physical environment, commentary about evidence-based practice initiatives, leadership, cultural diversity, distrust, and affect. Stratifying agencies by "best," "average," and "worst" organizational social context impacted interpretation for three constructs (affect, stress, and leadership). Results

Large-eddy simulation of a turbulent mixing layer

NASA Technical Reports Server (NTRS)

Mansour, N. N.; Ferziger, J. H.; Reynolds, W. C.

1978-01-01

The three dimensional, time dependent (incompressible) vorticity equations were used to simulate numerically the decay of isotropic box turbulence and time developing mixing layers. The vorticity equations were spatially filtered to define the large scale turbulence field, and the subgrid scale turbulence was modeled. A general method was developed to show numerical conservation of momentum, vorticity, and energy. The terms that arise from filtering the equations were treated (for both periodic boundary conditions and no stress boundary conditions) in a fast and accurate way by using fast Fourier transforms. Use of vorticity as the principal variable is shown to produce results equivalent to those obtained by use of the primitive variable equations.

Maximum likelihood estimates, from censored data, for mixed-Weibull distributions

NASA Astrophysics Data System (ADS)

Jiang, Siyuan; Kececioglu, Dimitri

1992-06-01

A new algorithm for estimating the parameters of mixed-Weibull distributions from censored data is presented. The algorithm follows the principle of maximum likelihood estimate (MLE) through the expectation and maximization (EM) algorithm, and it is derived for both postmortem and nonpostmortem time-to-failure data. It is concluded that the concept of the EM algorithm is easy to understand and apply (only elementary statistics and calculus are required). The log-likelihood function cannot decrease after an EM sequence; this important feature was observed in all of the numerical calculations. The MLEs of the nonpostmortem data were obtained successfully for mixed-Weibull distributions with up to 14 parameters in a 5-subpopulation, mixed-Weibull distribution. Numerical examples indicate that some of the log-likelihood functions of the mixed-Weibull distributions have multiple local maxima; therefore, the algorithm should start at several initial guesses of the parameter set.

Mixing Layer Formation near the Tropopause Due to Gravity Wave Critical Level Interactions in a Cloud-Resolving Model.

NASA Astrophysics Data System (ADS)

Moustaoui, Mohamed; Joseph, Binson; Teitelbaum, Hector

2004-12-01

A plausible mechanism for the formation of mixing layers in the lower stratosphere above regions of tropical convection is demonstrated numerically using high-resolution, two-dimensional (2D), anelastic, nonlinear, cloud-resolving simulations. One noteworthy point is that the mixing layer simulated in this study is free of anvil clouds and well above the cloud anvil top located in the upper troposphere. Hence, the present mechanism is complementary to the well-known process by which overshooting cloud turrets causes mixing within stratospheric anvil clouds. The paper is organized as a case study verifying the proposed mechanism using atmospheric soundings obtained during the Central Equatorial Pacific Experiment (CEPEX), when several such mixing layers, devoid of anvil clouds, had been observed. The basic dynamical ingredient of the present mechanism is (quasi stationary) gravity wave critical level interactions, occurring in association with a reversal of stratospheric westerlies to easterlies below the tropopause region. The robustness of the results is shown through simulations at different resolutions. The insensitivity of the qualitative results to the details of the subgrid scheme is also evinced through further simulations with and without subgrid mixing terms. From Lagrangian reconstruction of (passive) ozone fields, it is shown that the mixing layer is formed kinematically through advection by the resolved-scale (nonlinear) velocity field.

LIF measurements of scalar mixing in turbulent shear layers

NASA Technical Reports Server (NTRS)

Karasso, Paris S.; Mungal, M. G.

1993-01-01

The structure of shear layer flows at high Reynolds numbers remains a very interesting problem. Straight mixing layers have been studied and yielded information on the probability density function (pdf) of a passive scalar across the layer. Konrad and Koochesfahani & Dimotakis measured the pdf of the mixture fraction for mixing layers of moderate Reynolds numbers, each about 25,000 (Re based on velocity difference and visual thickness). Their measurements showed a 'non-marching' pdf (central hump which is invariant from edge to edge across the layer), a result which is linked to the visualizations of the spanwise Kelvin-Helmholtz (K-H) instability mode, which is the primary instability for plane shear layer flows. A secondary instability mode, the Taylor-Gortler (T-G) instability, which is associated with streamwise vortical structures, has also been observed in shear layers. Image reconstruction by Jimenez et al. and volume renderings by Karasso & Mungal at low Re numbers have demonstrated that the K-H and the T-G instability modes occur simultaneously in a non-mutually destructive way, evidence that supports the quasi two-dimensional aspect of these flows and the non-marching character of the pdf at low Reynolds numbers. At higher Re numbers though, the interaction of these two instability modes is still unclear and may affect the mixing process. In this study, we perform measurements of the concentration pdf of plane mixing layers for different operating conditions. At a speed ratio of r = U(sub 1)/U(sub 2) = 4:1, we examine three Reynolds number cases: Re = 14,000, Re = 31,000, and Re = 62,000. Some other Re number cases' results, not presented in detail, are invoked to explain the behavior of the pdf of the concentration field. A case of r = 2.6:1 at Re = 20,000 is also considered. The planar laser-induced fluorescence technique is used to yield quantitative measurements. The different Re are obtained by changing the velocity magnitudes of the two streams. The

Impact of chemical reaction in fully developed radiated mixed convective flow between two rotating disk

NASA Astrophysics Data System (ADS)

Hayat, T.; Khan, M. Waleed Ahmed; Khan, M. Ijaz; Waqas, M.; Alsaedi, A.

2018-06-01

Flow of magnetohydrodynamic (MHD) viscous fluid between two rotating disks is modeled. Angular velocities of two disks are different. Flow is investigated for nonlinear mixed convection. Heat transfer is analyzed for nonlinear thermal radiation and heat generation/absorption. Chemical reaction is also implemented. Convective conditions of heat and mass transfer are studied. Transformations used lead to reduction of PDEs into the ODEs. The impacts of important physical variables like Prandtl number, Reynold number, Hartman number, mixed convection parameter, chemical reaction and Schmidt number on velocities, temperature and concentration are elaborated. In addition velocity and temperature gradients are physically interpreted. Our obtained results indicate that radial, axial and tangential velocities decrease for higher estimation of Hartman number.

Cumulus cloud venting of mixed layer ozone

NASA Technical Reports Server (NTRS)

Ching, J. K. S.; Shipley, S. T.; Browell, E. V.; Brewer, D. A.

1985-01-01

Observations are presented which substantiate the hypothesis that significant vertical exchange of ozone and aerosols occurs between the mixed layer and the free troposphere during cumulus cloud convective activity. The experiments utilized the airborne Ultra-Violet Differential Absorption Lidar (UV-DIAL) system. This system provides simultaneous range resolved ozone concentration and aerosol backscatter profiles with high spatial resolution. Evening transects were obtained in the downwind area where the air mass had been advected. Space-height analyses for the evening flight show the cloud debris as patterns of ozone typically in excess of the ambient free tropospheric background. This ozone excess was approximately the value of the concentration difference between the mixed layer and free troposphere determined from independent vertical soundings made by another aircraft in the afternoon.

Mix-and-diffuse serial synchrotron crystallography

DOE PAGES

Beyerlein, Kenneth R.; Dierksmeyer, Dennis; Mariani, Valerio; ...

2017-10-09

Unravelling the interaction of biological macromolecules with ligands and substrates at high spatial and temporal resolution remains a major challenge in structural biology. The development of serial crystallography methods at X-ray free-electron lasers and subsequently at synchrotron light sources allows new approaches to tackle this challenge. Here, a new polyimide tape drive designed for mix-and-diffuse serial crystallography experiments is reported. The structure of lysozyme bound by the competitive inhibitor chitotriose was determined using this device in combination with microfluidic mixers. The electron densities obtained from mixing times of 2 and 50 s show clear binding of chitotriose to the enzymemore » at a high level of detail. Here, the success of this approach shows the potential for high-throughput drug screening and even structural enzymology on short timescales at bright synchrotron light sources.« less

Mix-and-diffuse serial synchrotron crystallography

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

Beyerlein, Kenneth R.; Dierksmeyer, Dennis; Mariani, Valerio

Unravelling the interaction of biological macromolecules with ligands and substrates at high spatial and temporal resolution remains a major challenge in structural biology. The development of serial crystallography methods at X-ray free-electron lasers and subsequently at synchrotron light sources allows new approaches to tackle this challenge. Here, a new polyimide tape drive designed for mix-and-diffuse serial crystallography experiments is reported. The structure of lysozyme bound by the competitive inhibitor chitotriose was determined using this device in combination with microfluidic mixers. The electron densities obtained from mixing times of 2 and 50 s show clear binding of chitotriose to the enzymemore » at a high level of detail. Here, the success of this approach shows the potential for high-throughput drug screening and even structural enzymology on short timescales at bright synchrotron light sources.« less

Barium Stars and Thermohaline Mixing

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

Husti, Laura

2008-01-24

Barium stars are formed in binary systems through mass transfer from the carbon and s-element rich primary in the AGB phase, to the secondary star which is in a less evolved evolutionary stage. The mixing of the accreted material from the AGB donor with the envelope of the secondary results in a dilution of the s-element abundances. Dilution in red giants is explained by the occurence of the first dredge up, while in case of dwarfs thermohaline mixing would determine it. A comparison between the theoretical predictions of the AGB stellar models and the spectroscopical observations of a large samplemore » of barium stars has been made. Dilution due to thermohaline mixing was taken into account when searching for best fits of the observational data. The importance of thermohaline mixing in barium dwarfs is discussed.« less

Application of whole-body personal TL dosemeters in mixed field beta-gamma radiation.

PubMed

Ciupek, K; Aksamit, D; Wołoszczuk, K

2014-11-01

Application of whole-body personal TL dosemeters based on a high-sensitivity LiF:Mg,Cu,P (MCP-N) in mixed field beta-gamma radiation has been characterised. The measurements were carried out with (90)Sr/(90)Y, (85)Kr and (137)Cs point sources to calculate the energy response and linearity of the TLD response in a dose range of 0.1-30 mSv. From the result, calibration curves were obtained, enabling the readout of individual dose equivalent Hp(10) from gamma radiation and Hp(0.07) from beta radiation in mixed field beta-gamma. Limitation of the methodology and its application are presented and discussed. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Two-state semiconductor laser self-mixing velocimetry exploiting coupled quantum-dot emission-states: experiment, simulation and theory

PubMed Central

Gioannini, Mariangela; Dommermuth, Marius; Drzewietzki, Lukas; Krestnikov, Igor; Livshits, Daniil; Krakowski, Michel; Breuer, Stefan

2014-01-01

We exploit the coupled emission-states of a single-chip semiconductor InAs/GaAs quantum-dot laser emitting simultaneously on ground-state (λGS = 1245 nm) and excited-state (λES = 1175 nm) to demonstrate coupled-two-state self-mixing velocimetry for a moving diffuse reflector. A 13 Hz-narrow Doppler beat frequency signal at 317 Hz is obtained for a reflector velocity of 3 mm/s, which exemplifies a 66-fold improvement in width as compared to single-wavelength self-mixing velocimetry. Simulation results reveal the physical origin of this signal, the coupling of excited-state and ground-state photons via the carriers, which is unique for quantum-dot lasers and reproduce the experimental results with excellent agreement. PMID:25321809

Prediction of free turbulent mixing using a turbulent kinetic energy method

NASA Technical Reports Server (NTRS)

Harsha, P. T.

1973-01-01

Free turbulent mixing of two-dimensional and axisymmetric one- and two-stream flows is analyzed by a relatively simple turbulent kinetic energy method. This method incorporates a linear relationship between the turbulent shear and the turbulent kinetic energy and an algebraic relationship for the length scale appearing in the turbulent kinetic energy equation. Good results are obtained for a wide variety of flows. The technique is shown to be especially applicable to flows with heat and mass transfer, for which nonunity Prandtl and Schmidt numbers may be assumed.

Experiments on the rise and mixing in neutral crossflow of plumes from two identical sources for different wind directions

NASA Astrophysics Data System (ADS)

Contini, Daniele; Robins, Alan

A study of the mixing phase of two identical buoyant plumes emitted from adjacent sources into a neutral cross-flow is presented. Results were obtained in a water towing-tank by using both quantitative plume visualisations and point concentration detection with a colorimeter system. Plume trajectories and cross-sectional distributions of concentration were obtained for different flow directions, φ, with respect to the source axis and for two stack separations. Particular attention has been given to the influence of φ on plume trajectories during the mixing phase and to the changes in the shape of the plume cores, induced during the mixing, that influence the rate of entrainment of ambient fluid. The results show that the additional rise, E, of the combined plume decreases almost linearly with sin( φ) when φ is increased, and vanishes when φ is around 20-30°; thereafter, E becomes negative, due to the presence of a form of "induced downwash" effect. The rise reduction is a consequence of the complex and protracted mixing of two vortices of opposite vorticity that creates strong asymmetry in the concentration distribution within the plume core, resulting in an accumulation of plume material at the bottom of the combined plume and a consequent decrease of the height of the centre of mass of the combined plume. There is clear evidence that the asymmetry slowly diminishes during plume development, so that at large distance from the mixing zone the concentration distribution becomes similar to that of a single plume with a characteristic double-vortex structure, though this develops with a deficit in plume rise. Results also show that the average dilution over a cross-section of the plume increases with φ and, when φ reaches 90°, becomes approximately equal to that in a single plume, even though the actual tracer distribution is quite different, particularly at short distances from the sources.

Controls on the time-scales of mantle mixing

NASA Astrophysics Data System (ADS)

Crameri, F.; Cagney, N.; Lithgow-Bertelloni, C. R.; Whitehead, J. A.

2016-12-01

Understanding the processes controlling the mantle mixing is crucial to our geochemical interpretation of basalts, and our understanding of the mantle heterogeneity. We investigate the influence of various mantle conditions on the time scales of mixing using numerical simulations. We examine the effects of Rayleigh number (Ra), depth- and temperature-dependent rheology and internal heating, as well as the role of Prandtl number (Pr), in order to assess how mixing in the early magma ocean and experiments (where Pr tends to be 103) differs from that in the present-day mantle (Pr 1025). We use the "coarse grained density" method to quantify the mixing state and determine the mixing time. The mixing time is found to be strongly affected by the Rayleigh number, scaling with Ra-0.65, in agreement with previous studies. In contrast, when Ra is held constant, the temperature-dependent rheology has a weak effect. The depth-dependent rheology also has a negligible effect on the mixing time, as material that is initially viscous is transported to the low viscosity near the surface where it undergoes fast mixing. The internal heating rate does not affect the mixing time, provided that it does not increase the fluid temperature above that of the boundary condition. In this case, the decrease in mixing time is shown to be a result of an increase in the effective Ra. Finally, we show that for moderate and low Pr, the mixing time increases with Pr0.45. However, for all Pr greater than about 100, the mixing time is the same at the infinite-Pr value. Our results have several implications for the mantle: (1) Ra is the controlling factor on mantle mixing. (2) The non-Newtonian rheology of the mantle has a very weak effect on mantle mixing and can be neglected. (3) A dramatic increase in viscosity in the deep mantle has been proposed at a cause of regions of unmixed `primitive' mantle. Our results show that this hypothesis is unlikely, as depth dependent rheology does not increase in

Evaluation of a statistics-based Ames mutagenicity QSAR model and interpretation of the results obtained.

PubMed

Barber, Chris; Cayley, Alex; Hanser, Thierry; Harding, Alex; Heghes, Crina; Vessey, Jonathan D; Werner, Stephane; Weiner, Sandy K; Wichard, Joerg; Giddings, Amanda; Glowienke, Susanne; Parenty, Alexis; Brigo, Alessandro; Spirkl, Hans-Peter; Amberg, Alexander; Kemper, Ray; Greene, Nigel

2016-04-01

The relative wealth of bacterial mutagenicity data available in the public literature means that in silico quantitative/qualitative structure activity relationship (QSAR) systems can readily be built for this endpoint. A good means of evaluating the performance of such systems is to use private unpublished data sets, which generally represent a more distinct chemical space than publicly available test sets and, as a result, provide a greater challenge to the model. However, raw performance metrics should not be the only factor considered when judging this type of software since expert interpretation of the results obtained may allow for further improvements in predictivity. Enough information should be provided by a QSAR to allow the user to make general, scientifically-based arguments in order to assess and overrule predictions when necessary. With all this in mind, we sought to validate the performance of the statistics-based in vitro bacterial mutagenicity prediction system Sarah Nexus (version 1.1) against private test data sets supplied by nine different pharmaceutical companies. The results of these evaluations were then analysed in order to identify findings presented by the model which would be useful for the user to take into consideration when interpreting the results and making their final decision about the mutagenic potential of a given compound. Copyright © 2015 Elsevier Inc. All rights reserved.

Efficient resource recycling from liquid digestate by microalgae-yeast mixed culture and the assessment of key gene transcription related to nitrogen assimilation in microalgae.

PubMed

Qin, Lei; Liu, Lu; Wang, Zhongming; Chen, Weining; Wei, Dong

2018-05-18

To determine the feasibility of microalgae-yeast mixed culture using the liquid digestate of dairy wastewater (LDDW) for biofuels and single cell protein (SCP) production, the cell growth, nutrient removal and outputs evaluation of the mono and mixed culture of Chlorella vulgaris and Yarrowia lipolytica in LDDW were investigated by adding glycerol as carbon source. The results showed that the mixed culture could enhance the biological utilization efficiency of nitrogen and phosphorus, and obtain higher yield of biomass (1.62 g/L), lipid (0.31 g/L), protein (0.51 g/L), and higher heating value (34.06 KJ/L). Compared with the mono culture of C. vulgaris, a decline of the transcription level in nitrate reductase and glutamine synthetase II genes in C. vulgaris was observed in the mixed culture when ammonia was sufficient. The results suggest the possibility of using the mixed culture for the efficient treatment of LDDW and resources recycling. Copyright © 2018. Published by Elsevier Ltd.

Conductivity detection for monitoring mixing reactions in microfluidic devices.

PubMed

Liu, Y; Wipf, D O; Henry, C S

2001-08-01

A conductivity detector was coupled to poly(dimethylsiloxane)-glass capillary electrophoresis microchips to monitor microfluidic flow. Electroosmotic flow was investigated with both conductivity detection (CD) and the current monitoring method. No significant variation was observed between these methods, but CD showed a lower relative standard deviation. Gradient mixing experiments were employed to investigate the relationship between the electrolyte conductivity and the electrolyte concentration. A good linear response of conductivity to concentration was obtained for solutions whose difference in concentrations were less than 27 mM. The new system holds great promise for precision mixing in microfluidic devices using electrically driven flows.

Complete genome sequence of Thioalkalivibrio sp. K90mix

PubMed Central

Muyzer, Gerard; Sorokin, Dimitry Y.; Mavromatis, Konstantinos; Lapidus, Alla; Foster, Brian; Sun, Hui; Ivanova, Natalia; Pati, Amrita; D'haeseleer, Patrik; Woyke, Tanja; Kyrpides, Nikos C.

2011-01-01

Thioalkalivibrio sp. K90mix is an obligately chemolithoautotrophic, natronophilic sulfur-oxidizing bacterium (SOxB) belonging to the family Ectothiorhodospiraceae within the Gammaproteobacteria. The strain was isolated from a mixture of sediment samples obtained from different soda lakes located in the Kulunda Steppe (Altai, Russia) based on its extreme potassium carbonate tolerance as an enrichment method. Here we report the complete genome sequence of strain K90mix and its annotation. The genome was sequenced within the Joint Genome Institute Community Sequencing Program, because of its relevance to the sustainable removal of sulfide from wastewater and gas streams. PMID:22675584

Experiments in dilution jet mixing effects of multiple rows and non-circular orifices

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Srinivasan, R.; Coleman, E. B.; Meyers, G. D.; White, C. D.

1985-01-01

Experimental and empirical model results are presented that extend previous studies of the mixing of single-sided and opposed rows of jets in a confined duct flow to include effects of non-circular orifices and double rows of jets. Analysis of the mean temperature data obtained in this investigation showed that the effects of orifice shape and double rows are significant only in the region close to the injection plane, provided that the orifices are symmetric with respect to the main flow direction. The penetration and mixing of jets from 45-degree slanted slots is slightly less than that from equivalent-area symmetric orifices. The penetration from 2-dimensional slots is similar to that from equivalent-area closely-spaced rows of holes, but the mixing is slower for the 2-D slots. Calculated mean temperature profiles downstream of jets from non-circular and double rows of orifices, made using an extension developed for a previous empirical model, are shown to be in good agreement with the measured distributions.

Experiments in dilution jet mixing - Effects of multiple rows and non-circular orifices

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Srinivasan, R.; Coleman, E. B.; Meyers, G. D.; White, C. D.

1985-01-01

Experimental and empirical model results are presented that extend previous studies of the mixing of single-sided and opposed rows of jets in a confined duct flow to include effects of non-circular orifices and double rows of jets. Analysis of the mean temperature data obtained in this investigation showed that the effects of orifice shape and double rows are significant only in the region close to the injection plane, provided that the orifices are symmetric with respect to the main flow direction. The penetration and mixing of jets from 45-degree slanted slots is slightly less than that from equivalent-area symmetric orifices. The penetration from two-dimensional slots is similar to that from equivalent-area closely-spaced rows of holes, but the mixing is slower for the 2-D slots. Calculated mean temperature profiles downstream of jets from non-circular and double rows of orifices, made using an extension developed for a previous empirical model, are shown to be in good agreement with the measured distributions.

Valid statistical approaches for analyzing sholl data: Mixed effects versus simple linear models.

PubMed

Wilson, Machelle D; Sethi, Sunjay; Lein, Pamela J; Keil, Kimberly P

2017-03-01

The Sholl technique is widely used to quantify dendritic morphology. Data from such studies, which typically sample multiple neurons per animal, are often analyzed using simple linear models. However, simple linear models fail to account for intra-class correlation that occurs with clustered data, which can lead to faulty inferences. Mixed effects models account for intra-class correlation that occurs with clustered data; thus, these models more accurately estimate the standard deviation of the parameter estimate, which produces more accurate p-values. While mixed models are not new, their use in neuroscience has lagged behind their use in other disciplines. A review of the published literature illustrates common mistakes in analyses of Sholl data. Analysis of Sholl data collected from Golgi-stained pyramidal neurons in the hippocampus of male and female mice using both simple linear and mixed effects models demonstrates that the p-values and standard deviations obtained using the simple linear models are biased downwards and lead to erroneous rejection of the null hypothesis in some analyses. The mixed effects approach more accurately models the true variability in the data set, which leads to correct inference. Mixed effects models avoid faulty inference in Sholl analysis of data sampled from multiple neurons per animal by accounting for intra-class correlation. Given the widespread practice in neuroscience of obtaining multiple measurements per subject, there is a critical need to apply mixed effects models more widely. Copyright © 2017 Elsevier B.V. All rights reserved.

Use of a mixed culture strategy to isolate halophilic bacteria with antibacterial and cytotoxic activity from the Manaure solar saltern in Colombia.

PubMed

Conde-Martínez, Natalia; Acosta-González, Alejandro; Díaz, Luis E; Tello, Edisson

2017-12-08

Water evaporation in solar salterns creates salinity gradients that promote the adaptation of microbial species to different salinities. This competitive habitat challenges the metabolic capabilities of microorganisms and promotes alterations in their production of secondary metabolites. Thus, solar salterns are a potentially important source of new natural products. In Colombia, the most important and representative solar saltern is located in Manaure (La Guajira) in the north of Colombia. The aim of this study was to develop an alternative screening strategy to select halophilic bacteria as producers of bioactive compounds from mixed microbial cultures rather than individual environmental isolates. Brine and sediment samples from different ponds (across a salinity gradient) were inoculated in seven different culture media to grow bacteria and archaea, allowing for a total of 40 different mixed cultures. An organic extract from each mixed culture was obtained and tested against multidrug resistant pathogens, including Klebsiella pneumoniae, vancomycin-resistant Enterococcus faecium, methicillin-resistant Staphylococcus aureus and Bacillus subtilis. In addition, the extracts were tested against two human cancer cell lines, cervical adenocarcinoma (SiHa) and lung carcinoma (A-549). Twenty-four of the forty extracts from mixed cultures obtained from brine and sediment samples from the Manaure solar saltern showed antibacterial activity against Bacillus subtilis. Two extracts, referred to as A1SM3-29 and A1SM3-36, were also active against a methicillin-resistant Staphylococcus aureus, with the latter extract also showing slight cytotoxic activity against the assayed human lung cancer cell line. From this mixed culture, nine isolates were cultivated, and their extracts were tested against the same pathogens, resulting in the identification of a Vibrio sp. strain (A1SM3-36-8) with antimicrobial activity that was similar to that observed for the mixed culture extract