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Background Mycoplasma genitalium (MG) is on the CDC Watch List of Antimicrobial Resistance Threats, yet there is no systematic surveillance to monitor change. Methods We initiated surveillance in sexual health clinics in 6 cities, selecting a quota sample of urogenital specimens tested for gonorrhea and/or chlamydia. We abstracted patient data from medical records and detected MG and macrolide-resistance mutations (MRMs) by nucleic acid amplification testing. We used Poisson regression to estimate adjusted prevalence ratios (aPRs) and 95% CIs, adjusting for sampling criteria (site, birth sex, symptom status). Results From October–December 2020 we tested 1743 urogenital specimens: 57.0% from males, 46.1% from non-Hispanic Black persons, and 43.8% from symptomatic patients. MG prevalence was 16.6% (95% CI: 14.9–18.5%; site-specific range: 9.9–23.5%) and higher in St Louis (aPR: 1.9; 1.27–2.85), Greensboro (aPR: 1.8; 1.18–2.79), and Denver (aPR: 1.7; 1.12–2.44) than Seattle. Prevalence was highest in persons <18 years (30.4%) and declined 3% per each additional year of age (aPR:.97;.955–.982). MG was detected in 26.8%, 21.1%, 11.8%, and 15.4% of urethritis, vaginitis, cervicitis, and pelvic inflammatory disease (PID), respectively. It was present in 9% of asymptomatic males and 15.4% of asymptomatic females, and associated with male urethritis (aPR: 1.7; 1.22–2.50) and chlamydia (aPR: 1.7; 1.13–2.53). MRM prevalence was 59.1% (95% CI: 53.1–64.8%; site-specific range: 51.3–70.6%). MRMs were associated with vaginitis (aPR: 1.8; 1.14–2.85), cervicitis (aPR: 3.5; 1.69–7.30), and PID cervicitis (aPR: 1.8; 1.09–3.08). Conclusions MG infection is common in persons at high risk of sexually transmitted infections; testing symptomatic patients would facilitate appropriate therapy. Macrolide resistance is high and azithromycin should not be used without resistance testing. [ABSTRACT FROM AUTHOR]

The primary objectives of this study were to analyze economic feasibility of incorporating black soldier fly products in broiler feed and to compare the viability of alive (alive grown larvae (AGL)) or processed (defatted larvae meal (DLM) and insect oil) insect inclusion into the two Dutch broiler welfare systems: conventional and better life one star (BLS). An existing simulation model for insect production was adapted to build an economic model for the insect-fed broiler breast meat supply chain. Amounts, full costs, and breakeven prices of different production setups were compared and the impacts of specific input parameters were tested by sensitivity and breakeven analyses. Results indicated a hypothetical demand of 2.15 million tons wet matter of raw substrate to meet the total Dutch breast meat production (BLS broilers and 10% AGL inclusion). In case of 10% processed insect inclusion, the conventional broiler breast meat price increased from 3,947 to 6,069 €/t (53.7%) and the BLS breast meat price from 6,493 to 9,662 €/t (48.8%). Alive insect inclusion resulted in a smaller cost increase (42.2%) by skipping the costly processing step. To become price competitive, DLM or AGL must cost 618 or 801 €/ton dry matter (tDM), respectively, requiring a raw substrate mix price of −109 €/tDM. High input amounts and costs currently hinder the widespread adoption of insect products in Dutch mass poultry feed. However, in the long run, using negative value substrates or targeting niche markets for broiler welfare with low AGL inclusion levels could become viable business models. Research is needed on the impact of negative value substrates on insect production performance and contamination risks. Furthermore, the impact of varying AGL composition requires special attention. [ABSTRACT FROM AUTHOR]

Abstract: Intermolecular interactions in mixtures of room-temperature ionic liquids (RTILs) and co-solvents define the properties of the solution. In this work, we study the mixing behavior in the binary systems [EMIM][EtSO4]/water, [EMIM][EtSO4]/methanol and [EMIM][EtSO4]/ethanol, which is governed by a change in the balance of molecular interactions present in neat [EMIM][EtSO4]. The mixing behavior and interactions are investigated at molecular level by means of Raman spectroscopy, and at macroscopic level utilizing excess data taken from the literature. The discussion of the results aims at a distinct interpretation of the spectroscopic data and at identifying the relationships between molecular phenomena and macroscopic behavior. The Raman spectra of the binary systems indicate that the balance of intermolecular interactions in the neat RTIL is dominantly distorted by solute–solvent interactions involving hydrogen atoms (IIHAs). In concert with former studies, the spectroscopic and macroscopic data suggest, that the IIHA include a combination of conventional (red-shifting) and unconventional (blue-shifting) hydrogen bonds. With increasing co-solvent concentration, the interionic bonds become successively weaker and eventually ion-co-solvent interactions even replace those between the RTIL counter ions leading to ion pair dissociation. [Copyright &y& Elsevier]

Abstract: Stable dropwise condensation of steam was achieved by ion beam implantation of N+ on titanium surfaces stabilized by a preoxidation procedure. It is pointed out that dropwise condensation can be adjusted by ion implantation in spite of increased wettability indicated by contact angle and surface free energy measurements. Our results suggest a nucleation mechanism possibly caused by interactions of nano-scale surface roughness and surface chemistry effects connected with precipitation of nitrides. Measured heat transfer coefficients for dropwise condensation were up to 5.5 times larger than values calculated by Nußelt film theory. No significant influence of the applied ion implantation parameters was found. [Copyright &y& Elsevier]

Condensation processes are of importance for many heat transfer applications where a large amount of energy has to be transferred by a working fluid using the latent heat available during the phase transition. Whether ideal dropwise or filmwise condensation or a mixed condensation form can be realized depends on the properties of the heat transfer surface. The quantities that mainly influence the condensation form are the surface tension of the condensing fluid, the surface roughness or structure, and the surface energy of the condenser surface. During the past two decades at LTT-Erlangen, experimental and theoretical work has been carried out to reduce the surface energy of common heat transfer surfaces in such a way that stable dropwise condensation can be reached and maintained for extended time periods. In this situation, heat transfer is superior to filmwise condensation for at least one order of magnitude. The methods that have been developed and extensively tested for a selective adjustment of dropwise condensation of water at metallic surfaces are surface coating by diamond-like carbon films (DLC) and ion implantation. For both methods, the principles and fundamental experimental investigations are explained, and for ion implantation, a technical utilization is presented in the form of its application to sea water desalination plants based on mechanical vapor compression. [ABSTRACT FROM AUTHOR]

Abstract: The existence of good experimental data for turbulent premixed flames is of interest for the development and validation of numerical models. In this paper special focus is laid on the systematic variation of either the fuel–air ratio with fixed flow rate or varied flow and turbulence with fixed composition. In total, 15 different turbulent Bunsen flames are investigated. With the planar conditioned particle image velocimetry (CPIV) technique, simultaneous access is given to the flow, turbulence, and flame position data, using PIV for flow and turbulence and the density jump at the instantaneous flame front for reaction progress variable and density. This allows the fast determination of a large amount of statistical data such as Reynolds- and Favre-averaged mean reaction progress and velocities, which are needed for the density-weighted sets of equations used in the numerical codes. Additionally, conditioned and unconditioned mean velocities and velocity fluctuations can be determined and the turbulent flux terms of the reaction progress variable can be measured directly. Thus, a comprehensive data set is presented, which can be used for validation studies. The measured turbulent flux is compared with two models, the gradient diffusion assumption and a relation proposed by Veynante et al. that accounts for the competition between gas-dynamic expansion and turbulent mixing. While the former approach fails, the latter shows reasonable agreement for the radial flux and also accounts for the trend observed for the varied flow or flame conditions. The axial turbulent flux near the tip of the flame is not fully resolved. [Copyright &y& Elsevier]

Surface light scattering (SLS) has been used for the measurement of the viscosity of diisodecyl phthalate (DIDP), a potential candidate for an industrial reference material in the moderate- to high-viscosity region from (0.01 to 1) Pa·s. The investigations reported here were stimulated by recent research activities of the International Association for Transport Properties (IATP), which aim at evaluating a recommendation concerning standard reference values for DIDP at moderately high viscosity at room temperature. For this purpose, the measurement of the viscosity of DIDP using viscometers of different types and operating principles was encouraged. Even though in the case of high-viscosity fluids reference data for the interfacial tension are needed for data evaluation, the integration of the SLS method within this project is particularly interesting. In contrast to conventional viscometers, SLS allows the determination of viscosity in macroscopic thermodynamic equilibrium. Furthermore, whereas almost all conventional methods determine the viscosity in a relative manner, for the SLS technique no calibration procedure using a fluid of known viscosity is needed. In the present work, for temperatures between (283.15 and 313.15) K, corresponding to a viscosity range of about (250 to 50) mPa·s, an expanded uncertainty (k2) of less than ±1.4 % could be achieved for the viscosity of DIDP by carrying out a data evaluation procedure based on an exact description of the hydrodynamic capillary wave problem for a free liquid surface. [ABSTRACT FROM AUTHOR]

Presents an optical scattering cell for the determination of the particle diffusion coefficient by dynamic light scattering which can be utilized for particle size analysis and viscosity measurements. Advantage of the light scattering setup; Results for the diffusion coefficient of silica particles in water.

The spontaneous Raman scattering technique is an excellent tool for a quantitative analysis of multi-species gas mixtures. It is a noninvasive optical method for species identification and gas phase concentration measurement of Raman active molecules, since the intensity of the molecule specific Raman signal is linearly dependent on the concentration. Applying a continuous wave (cw) laser it typically takes a few seconds to capture a gas phase Raman spectrum at room temperature. Nevertheless in contrast to these advantages the weak Raman signal intensity is a major drawback. Thus, it is still challenging to detect gas phase Raman spectra in a low-pressure regime with a temporal resolution of only a few 100 ms. In the presented study a fully functional gas phase Raman system for measurements in the low-pressure regime ( p ≥ 980 hPa (absolute)) is presented; it overcomes the drawback of the weak Raman effect by using a multipass cavity to enhance the Raman signal. The signal amplification of a retro-reflecting cavity is experimentally compared to a near-confocal cavity. A description of this sensor setup as well as of the calibration procedure, which also allows the quantification of condensable gases, is presented. Moreover the functionality of the sensor system is demonstrated in a measurement campaign at an anesthesia simulator under clinical relevant conditions and in comparison to a conventional gas monitor. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Although nuanced parameterization of sexual behavior may improve estimates from mathematical models of human immunodeficiency virus and sexually transmitted infection transmission, prospective estimates of the incidence of specific sexual behaviors among men who have sex with men (MSM) are limited. From December 2014 to July 2018, MSM with and without nongonococcal urethritis (NGU) completed weekly diaries over 3–12 weeks. Incidence rates of any sex, receptive anal sex, insertive anal sex, insertive oral sex, receptive rimming, and receptive hand–penile contact were 1.19, 0.28, 0.66, 0.90, 0.24, and 0.85 episodes per person-week, respectively, among 104 MSM with NGU at baseline, and 1.33, 0.54, 0.32, 0.95, 0.44, and 0.88 episodes per person-week, respectively, among 25 MSM without NGU at baseline. Most receptive anal sex (NGU + 83%, NGU − 86%) and insertive anal sex (NGU + 85%, NGU − 76%) episodes were condomless. MSM engaged in sex just over once per week, and condom use was infrequent. Insertive oral sex and receptive hand–penile contact were the most common behaviors. [ABSTRACT FROM AUTHOR]

This manuscript reports for the first time, to the best of the authors' knowledge, the in situ and non-invasive characterization of both solid and gaseous phases involved in a catalytic chemical vapor deposition (CCVD) process applied with the aim to grow carbon nanotubes (CNTs). The here reported characterization comprises the simultaneous in situ analysis of carbon nanostructure formation and growth, the deactivation of the catalyst as well as the in situ monitoring of the carbon source conversion and the accompanying thermal effects in the gas phase. Raman spectroscopy is used as in situ measurement technique and after the CCVD process, as ex situ measurement tool aiming to confirm the in situ measurements performed at harsh conditions inside the reactor (temperatures up to 1000K). The in situ Raman results have also been compared with post-CCVD SEM and TEM analysis, from which the ambiguous meaning of the D/G-ratio was extracted. [ABSTRACT FROM AUTHOR]

The paper reports on a routine to extract the composition of multi-component mixtures from their Raman spectra at elevated pressures. The strategy is based on fitting weighted Raman spectra of the pure compounds to the measured Raman spectrum of the mixture, also considering the effects of intermolecular interactions onto the Raman spectra by applying Gaussian and Voigt profile deconvolution of the Raman peaks. Thereby, an improved accuracy compared to previous evaluation strategies could be obtained. The more accurate data of the ternary mixtures of carbon dioxide, water and organic solvents are presented. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] Application of a high-pressure micro capillary system. [•] Investigation into an ethyl acetate in water emulsion in contact with supercritical CO2. [•] Simultaneous quantification of parallel mass transfer processes. [•] Non-invasive determination of mass transfer rates using shadowgraphy. [ABSTRACT FROM AUTHOR]

Highlights: [•] Development and characterization of a flexible Raman sensor. [•] Introduction of a straight forward spectra evaluation procedure. [•] Non-invasive determination of mixture composition. [•] Composition quantification in ternary systems. [ABSTRACT FROM AUTHOR]

Highlights: [•] Crystallization of acetaminophen can be explained by the overall supersaturation during the SAS process. [•] Occurrence of primary and secondary crystal structures of acetaminophen can be assigned to level of supersaturation. [•] Paracetamol crystals can be adjusted between monoclinic and orthorhombic by varying the solvent composition. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents an analytical model to calculate the condensation heat transfer coefficient on an integral finned tube. The model depends on elemental calculations by dividing the tube wall into small annular elements. It takes into consideration the local temperature distribution on the outside surface of the finned tube, the local heat transfer rate and the height of condensate in the channel between fins. The model is able to predict the heat transfer for different fin profiles. Gravity force and surface tension forces are included in the model, where for the latter a linear pressure distribution over the fin is assumed. For the verification of the present model, experimental data for a copper standard finned tube with 1, 1, 1, 2-tetrafluoroethane (R134a) and propane (R290) from our experimental work were used. Within this work, experiments were performed for a steel standard finned tube with R290. For tubes having more than 40 fins per inch (FPI), it could be shown that the channel between fins can be approximated to be trapezoidal or rectangular. This approximation is also applicable for the condensation on tubes having 26 FPI or larger if the subcooling between the saturated vapour and the tube wall is larger than a certain value depending on the working fluid. In comparison to previous analytical models, the present model agrees well with the experimental data and predicts these data with a mean absolute percentage deviation of 4.7%. [Copyright &y& Elsevier]

Abstract: In order to improve the efficiency of processes using supercritical (sc) carbon dioxide (CO2) to micronize the carotenoid “lycopene”, it is important to know the solubility of lycopene in mixtures of the organic solvent ethyl acetate (EA) and the antisolvent CO2 at elevated pressures. The solubility of lycopene has been determined for different temperatures (313–333K), pressures (12–16MPa) and CO2 molar fractions (0.58–1). The obtained data show that CO2 acts as an antisolvent in the system lycopene/EA/CO2 in the range of CO2/EA ratios studied. The solubility of lycopene is rather small with lycopene molar fractions ranging from 0.1×10−6 to 46×10−6. The solubility of lycopene increases with temperature, pressure and EA concentration. [Copyright &y& Elsevier]

Abstract: A versatile guarded parallel-plate instrument for the measurement of the thermal conductivity in steady state is presented. The instrument stands out due to its applicability for fluids as well as solid bodies, bulk solids, and compressible solids. Besides flexibility regarding sample material and thickness, the instrument design is aimed at the minimization of parasitic heat flows due to convection, radiation, or heat leakages. Remaining effects of radiative heat transfer can be taken into account by appropriate calculation methods. A precise and automated measurement and control system for temperature and heat flow including objective criteria for identifying steady-state conditions allows convenient and accurate measurements. A comparison of results obtained for water, toluene, air, and a PTFE disk at temperatures between 308.15K and 368.15K with reference data confirms that uncertainties of less than 3% can be achieved by choosing adequate sample thicknesses and temperature differences between the plates. For compressible materials, the accessibility of the equivalent quantities overall heat transfer coefficient, overall thermal resistance, and apparent thermal conductivity in dependence on the degree of compression is demonstrated. [Copyright &y& Elsevier]

We show that the threshold of stimulated Raman scattering (SRS) from single micro-droplets increases with the bandwidth of the pulsed excitation laser radiation. SRS thresholds were experimentally investigated for two droplet sizes and two excitation bandwidths. For the narrowband excitation, a frequency doubled Nd:YAG laser with a central wavelength of 532 nm, a full width half maximum (FWHM) bandwidth of 0.05 nm and a repetition rate of 10 Hz was used. For the comparison with the broadband excitation, a dye resonator containing Rhodamine 6G being pumped by the Nd:YAG laser was utilized with a central wavelength of 566 nm and a FWHM bandwidth of 4 nm. Droplets of 89 and 116 µm diameters, respectively, were illuminated by a vertical light sheet. If the broadband excitation is applied instead of the narrowband excitation - for both droplet sizes - the pulsed excitation energies can be increased by a factor of approximately 5 before the SRS threshold is reached. The multiplication register of an emCCD detector was used to detect low signals. The gain factor of the detector was calibrated and adapted to different excitation energies and signal intensities. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: A new type of titanium boronitride (TiBN) coating was prepared by chemical vapor deposition (CVD) on low carbon steel (LCS). The coating morphology, chemical composition and crystal structure were studied by different characterization techniques, before and after corrosion testing. Corrosion testing was carried out by electrochemical techniques (open-circuit potential, polarization curves, impedance spectroscopy) in simulated soil solution. The TiBN coating provides an excellent corrosion protection for the steel substrate, up to the tested 90 days of immersion. Even though minor changes in the coating composition and phase structure were observed after long-term immersion, this does not decrease the protective nature of the coating. An analysis of the impedance data indicates that the coating may initially contain very small defects (pinholes), which gradually are blocked by corrosion products, improving the corrosion resistivity of the coated steel. [Copyright &y& Elsevier]

Abstract: Particle image velocimetry (PIV) was applied to characterize the flow field in a vertically oriented cold wall reactor, which is used for the catalytic chemical vapor deposition (CCVD) of carbon nanotubes (CNTs). Quantitative information about the radial and axial profiles of the velocity components has been obtained and on their basis, actual volumetric flow rates, gas temperatures, the jet Reynolds number, the working regime as well as the residence time curves and the minimum impingement time of the feed flow into the substrate surface at different operation conditions were estimated. The reliability of the PIV measurements has been assessed with respect to the effect of the thermophoretic force, being partially compromised at defined regions attached to the substrate surface. [Copyright &y& Elsevier]

Lasers are common tools in the field of combustion diagnostics. In some respects, however, they have disadvantages. Therefore, there is a need for new light sources delivering radiation in the required wavelength regions with high stability and reliability at low cost. Light-emitting diodes (LED) in the near- and mid-infrared spectral region have proven their potential for spectroscopic applications in the past. In the present work we demonstrate the feasibility of using ultraviolet LEDs for flame diagnostics. For this purpose, OH and CH radicals are detected in premixed methane/air flames. The LED emission is found to be stable after thermal equilibrium is reached. This was the case after a warming-up period in the order of minutes. The spectral characteristics were stable during a 24-h test. [ABSTRACT FROM AUTHOR]

Stable dropwise condensation of saturated steam was achieved on stainless-steel tube bundles implanted with nitrogen ions by plasma ion implantation. For the investigation of the condensation heat transfer enhancement by plasma ion implantation, a condenser was constructed in order to measure the heat flow and the overall heat transfer coefficient for the condensation of steam on the outside surface of tube bundles. For a horizontal tube bundle of nine tubes implanted with a nitrogen ion dose of 1016 cm- 2, the enhancement ratio, which represents the ratio of the overall heat transfer coefficient of the implanted tube bundle to that of the unimplanted one, was found to be 1.12 for a cooling-water Reynolds number of about 21,000. The heat flow and the overall heat transfer coefficient were increased by increasing the steam pressure. The maximum overall heat transfer coefficient of 2.22 kW · m-2· K-1 was measured at a steam pressure of 2 bar and a cooling-water Reynolds number of about 2,000. At these conditions, more dropwise condensation was formed on the upper tube rows, while the lowest row received more condensate, which converted the condensation form to filmwise condensation. [ABSTRACT FROM AUTHOR]

The density, refractive index, interfacial tension, and viscosity of ionic liquids (ILs) [EMIM][EtSO 4] (1-ethyl-3-methylimidazolium ethylsulfate), [EMIM][NTf 2] (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide), [EMIM][N(CN) 2] (1-ethyl-3-methylimidazolium dicyanimide), and [OMA][NTf 2] (trioctylmethylammonium bis(trifluoromethylsulfonyl)imide) were studied in dependence on temperature at atmospheric pressure both by conventional techniques and by surface light scattering (SLS). A vibrating tube densimeter was used for the measurement of density at temperatures from (273.15 to 363.15) K and the results have an expanded uncertainty ( k= 2) of ±0.02%. Using an Abbe refractometer, the refractive index was measured for temperatures between (283.15 and 313.15) K with an expanded uncertainty ( k= 2) of about ±0.0005. The interfacial tension was obtained from the pendant drop technique at a temperature of 293.15 K with an expanded uncertainty ( k= 2) of ±1%. For higher and lower temperatures, the interfacial tension was estimated by an adequate prediction scheme based on the datum at 293.15 K and the temperature dependence of density. For the ILs studied within this work, at a first order approximation, the quantity directly accessible by the SLS technique was the ratio of surface tension to dynamic viscosity. By combining the experimental results of the SLS technique with density and interfacial tension from conventional techniques, the dynamic viscosity could be obtained for temperatures between (273.15 and 333.15) K with an estimated expanded uncertainty ( k= 2) of less than ±3%. The measured density, refractive index, and viscosity are represented by interpolating expressions with differences between the experimental and calculated values that are comparable with but always smaller than the expanded uncertainties ( k= 2). Besides a comparison with the literature, the influence of structural variations on the thermophysical properties of the ILs is discussed in detail. The viscosities mostly agree with values reported in the literature within the combined estimated expanded uncertainties ( k= 2) of the measurements while our density and interfacial tension data differ by more than ±1% and ±5%. [ABSTRACT FROM AUTHOR]

Abstract: Stable dropwise condensation (DWC) of saturated steam has been achieved on an aluminum alloy Al 6951 disc with an average surface finish of about 0.15μm by means of ion beam implantation technology with an ion dose of 1016 N+ cm−2 and an implantation energy of 20keV. Measurements of the condensation heat transfer coefficient at steam pressures of 1200 and 1400mbar were carried out as a function of surface subcooling on vertical plates of the same material which is commonly used for heat transfer equipment. Probably due to alloy inhomogeneities, only on about 50% of the plate surface DWC could be achieved, resulting in a maximum enhancement factor of 2.0 for DWC in comparison with theoretical values calculated by a corrected form of the Nusselt film theory. The heat transfer coefficient increases with increasing steam pressure and decreases with increasing surface subcooling. Furthermore, it was shown that condensation heat transfer cannot be enhanced if the ion implantation does not induce DWC. For the investigations, two different condensers have been used, one for the stability tests on discs and one for the heat transfer measurements on plates. [Copyright &y& Elsevier]

The vibrational structure of two room-temperature ionic liquids with the cation 1-ethyl-3-methylimidazolium [EMIM] and the respective anions bis(trifluoromethylsulfonyl)imide [TFSI] and ethylsulfate [EtOSO3] is investigated. In particular, attenuated total reflection (ATR) infrared (IR) as well as Raman spectra in the spectral range from 500 to 3500 cm−1 have been recorded and analyzed. Moreover, the depolarization ratios of the Raman lines are determined. The individual peaks are assigned to the corresponding vibrational modes of the molecules. While the CH stretching region around 3000 cm−1 is dominating in Raman spectra, it is remarkably weak in IR spectra. Finally, the results for 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide are compared to previous studies of single ions available in the literature. This comparison shows good agreement. [ABSTRACT FROM AUTHOR]

An analytical approach for heat transfer modelling of jet impingement boiling is presented. High heat fluxes with values larger than 10 MW/m2 can be observed in the stagnation region of an impinging jet on a red hot steel plate with wall temperatures normally being associated with film boiling. However, sufficiently high degrees of subcooling and jet velocity prevent the formation of a vapor film, even if the wall superheat is large. Heat transfer is governed by turbulent diffusion caused by the rapid growth and condensation of vapor bubbles. Due to the high population of bubbles at high heat fluxes it has to be assumed that a laminar sublayer cannot exist in the immediate vicinity of a red hot heating surface. A mechanistic model is proposed which is based on the assumption that due to bubble growth and collapse the maximum turbulence intensity is located at the wall/liquid interface and that eddy diffusivity decreases with increasing wall distance. [Copyright &y& Elsevier]

In gas turbines, lean premixed combustion is executed in strongly turbulent flow fields and under high-pressure to allow large thermal loads within small-size combustors. Previous research on turbulent premixed flames has revealed the vital importance of flame-vortex interactions, but most of these investigations have been performed only at atmospheric pressure disregarding the large pressure dependency of the flame front dynamics. We report about spatially high-resolved laser-induced predissociation fluorescence imaging of OH (OH-LIPF) in premixed, high-pressure bluff-body stabilized methane/air flames. For each of the two measurement series with different equivalence ratio (φ = 0.7 and φ = 1.0), the planar flame topology at different pressures (0.1 to 1.1 MPa) but constant exit velocity was detected and stored for analysis. As the pressure was increased, the flame front contour of both equivalence ratios became strongly wrinkled with formation of highly curved flame front elements. For quantification of this phenomenon, the probability density function of flame curvature was evaluated with definition of the mean curvature radius as representative folding scale. To discuss different mechanisms of flame front disturbances according to their relevance, the flame curvature is compared with characteristic turbulence scales of the flow field and with the expected folding scale derived with Sivashinsky‘s formulation of linear flame instability theory. Significant changes become obvious especially if the pressure is increased up to 0.5 MPa. The mean curvature radius decreases distinctly and can be linked to the decreasing size of the Taylor length. Additionally, the formation of highly convoluted flame front elements is enforced by the increasing flame instability behavior. As the results show, the flame stoichiometry has a strong impact on the flame front topology at increasing pressures due to the differences of their flame dynamics. [Copyright &y& Elsevier]

Background: Antimicrobial resistance (AMR) in Mycoplasma genitalium (MG) is high and MG is on the Watch List of AMR Threats. However, US sexual health clinics (SHCs) have only recently implemented MG testing and trend data are limited. We conducted surveillance of MG and AMR in 7 US cities from 2020-2022. Methods: SHCs in Birmingham AL, Denver CO, Greensboro NC, Indianapolis IN, New York NY, Seattle WA, and St. Louis MO collected a quota sample of urogenital specimens from symptomatic and asymptomatic males and females each year. We detected MG and macrolide resistance mutations (MRMs) using the Aptima assay and analyte-specific reagents, respectively (Hologic, Inc). We calculated adjusted prevalence ratios (aPR) using Poisson regression with robust standard errors. Results: Among 9,621 patients (2,638 asymptomatic/2,443 symptomatic males; 2,151 asymptomatic/2,389 symptomatic females), 53.0%, 21.6%, and 14.9% were Non-Hispanic (NH) Black, NH White, and Hispanic, respectively. Median age was 29 years [interquartile range=24-36]. Overall MG prevalence [16.6% (95%CI=15.9-17.4%)] did not differ by year (aPR=0.9; 0.88-1.01) but did differ across sites (range 9.5%-21.6%) and was significantly lower in Seattle (Table). Prevalence was highest in < 18-year-olds (28.7%) and declined by 3% for each increasing year of age (aPR=0.97; 0.962-0.973). Prevalence was 21.4% in NH Black, 10.0% in NH White and 10.8% in Hispanic persons (p< 0.001). MG prevalence was associated with female sex (aPR=1.5;1.29-1.68), same-sex partners (aPR=1.5; 1.29-1.72), symptoms (males only) (aPR=1.6; 1.38- 1.79), male urethritis (aPR=1.6; 1.22-1.97), chlamydia (CT) (aPR=1.8; 1.56-2.16), gonorrhea (GC) (aPR=1.4; 1.10-2.16) and bacterial vaginosis (aPR=2.3; 1.54-3.51). MG was detected in 24.1% of CT/GC-negative-urethritis, 16.1% of CT/GC-negativecervicitis, and 6.3% of CT/GC-negative-PID. MRM prevalence was 58.8% (56.2-61.3%) and did not vary by year (aPR=1.0; 0.91-1.03). Relative to Seattle, only St. Louis had significantly higher MRM prevalence (aPR=1.3; 1.06-1.52). MRM was associated with female sex (aPR=1.2; 1.02-1.33), symptoms (males) (aPR=1.2; 1.08-1.40), male urethritis (aPR=1.6; 1.22- 1.97), and declined 1% for each increasing year of age (aPR=0.99; 0.982-0.994). Conclusions: MG, including macrolide resistant-MG, is common among SHC patients and associated with STIs, STI syndromes, younger age, and same-sex partners. We saw no change over time in prevalence. These findings support making MG testing consistently available in SHCs. [ABSTRACT FROM AUTHOR]

Background: Incidence and risk factors for nongonococcal urethritis (NGU) remain poorly defined. We conducted a cohort study to estimate the incidence of NGU and identify risk factors in men who have sex with women.Methods: We enrolled cisgender male sexually transmitted disease clinic attendees 16 years or older who reported exclusively female partners. At enrollment and 6 monthly follow-up visits, men underwent a clinical examination, provided urethral swab and urine specimens, completed a sexual behavior survey and biweekly diaries, and were tested for Chlamydia trachomatis (CT) and Mycoplasma genitalium (MG) using Aptima assays (Hologic, Inc). Nongonococcal urethritis was defined as ≥5 polymorphonuclear leukocytes per high-power field plus either urethral symptoms or visible discharge. We estimated the incidence of NGU overall, asymptomatic and symptomatic NGU, non-CT/non-MG NGU, and CT/MG-associated NGU using Poisson regression for clustered outcomes. We performed relative risk binomial regression for clustered data to identify characteristics associated with incident NGU.Results: From August 2014 to July 2018, 307 participants at risk for NGU contributed 109.4 person-years. Median age was 32 years, and 52% were White. At enrollment, 107 men had NGU; of these, 88% were symptomatic, 27% had CT, and 22% had MG. Fifty men had 60 cases of incident NGU (incidence rate, 56 per 100 person-years; 95% confidence interval, 43-74). Unlike prevalent NGU at enrollment, CT/MG-associated incident NGU was rare (incidence rate, 7; 95% confidence interval [CI], 4-15), and most (78%) incident NGU was asymptomatic. Risk factors for incident NGU were ≤ high school education (adjusted rate ratio [ARR], 2.45; 95% CI, 1.19-5.00), history of CT (ARR, 2.15; 95% CI, 1.08-4.27), history of NGU (ARR, 2.67; 95% CI, 1.27-5.62), and NGU at enrollment (ARR, 2.03; 95% CI, 1.04-3.98). Neither condom use nor having a new partner was associated with incident NGU; Black race was only associated with incident symptomatic and non-CT/non-MG NGU.Conclusions: Incidence of NGU was high, predominantly non-CT/non-MG and asymptomatic. Future studies should investigate the etiology and clinical significance of asymptomatic NGU. [ABSTRACT FROM AUTHOR]

Background: Rectal Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) are increasingly recognized as common infections among women. Little is known about the prevalence of rectal Mycoplasma genitalium (MG), rectal MG/CT/GC co-infection, or MG antimicrobial resistance patterns among women.Methods: In 2017-2018 we recruited women at high risk for CT from Seattle's municipal STD clinic. Participants self-collected vaginal and rectal specimens for CT/GC nucleic acid amplification testing (NAAT). We retrospectively tested samples for vaginal and rectal MG using NAAT, and tested MG-positive specimens for macrolide resistance-mediating mutations (MRM) and ParC quinolone resistance-associated mutations (QRAMs).Results: Of 50 enrolled women, 13 (26%) tested positive for MG, including 10 (20%) with vaginal MG and 11 (22%) with rectal MG; 8 (62%) had concurrent vaginal/rectal MG. Five (38%) were co-infected with CT; none with GC. Only 2 of 11 women with rectal MG reported anal sex in the prior year. Of MG-positive specimens, 100% of rectal and 89% of vaginal specimens had a MRM. There were no vaginal or rectal MG-positive specimens with ParC QRAMs previously associated with quinolone failure. Five MG-infected women received azithromycin for vaginal CT, four of whom had a MG MRM detected in their vaginal and/or rectal specimens.Conclusions: We observed a high prevalence of macrolide-resistant vaginal and rectal MG among a population of women at high risk for CT. This study highlights how the use of antimicrobials designed to treat an identified infection - in this case CT - could influence treatment outcomes and antimicrobial susceptibility in other unidentified infections. [ABSTRACT FROM AUTHOR]

Background: Standard counseling at nongonococcal urethritis (NGU) diagnosis includes advice to abstain from sex for at least 7 days and until symptoms resolve.Methods: From December 2014 to July 2018, we enrolled men who have sex with men and received azithromycin (1 g) for NGU at the Public Health-Seattle and King County STD Clinic. Over 12 weeks of follow-up, participants reported daily urethral symptoms and sexual activity on web-based diaries. Nongonococcal urethritis was defined as urethral symptoms or visible urethral discharge plus 5 or greater polymorphonuclear leukocytes per high-power field. Time of symptom resolution was defined as the first of 5 consecutive asymptomatic days.Results: Of 100 participants with NGU and no Chlamydia trachomatis (CT)/Mycoplasma genitalium (MG) coinfection, 36 (36%), 22 (22%), and 42 (42%) had CT-NGU, MG-NGU, and non-CT/non-MG NGU, respectively. Among men with MG-NGU, 94% had a macrolide resistance mutation. For all etiologies, median time to symptom resolution after azithromycin was 7 days (95% confidence interval [CI], 5-9); 37% had symptoms lasting longer than 7 days. For men with CT-NGU, MG-NGU, and non-CT/non-MG NGU, median time to symptom resolution was 4 days (95% CI, 2-6; 16% >7 days), undefined days (95% CI, 7 to undefined; 60% >7 days), and 7 days (95% CI, 5-11; 46% >7 days), respectively. Median time to first sexual activity (any type) was 12 days (95% CI, 11-17); it was 16 days (95% CI, 12-18) to first urethral sexual exposure. Twenty-seven percent did not avoid urethral exposure for the recommended period.Conclusions: Counseling at NGU diagnosis should educate patients that symptoms may persist more than 7 days, particularly for non-CT NGU, and emphasize the rationale for the 7-day abstinence period. [ABSTRACT FROM AUTHOR]

Background: Rectal Chlamydia trachomatis (CT) is common among clinic-attending women, but little is known about clearance and health implications of rectal CT.Methods: At the municipal sexually transmitted disease clinic in Seattle, Washington, in 2017-2018, we enrolled women at high risk for urogenital CT into an 8-week prospective study. Women received standard CT treatment at enrollment. Women self-collected daily rectal and vaginal specimens for nucleic acid amplification tests (NAATs) and completed weekly sexual exposure diaries. We performed CT culture on the enrollment rectal specimen.Results: We enrolled 50 women; 13 (26%) tested positive for vaginal (n = 11) and/or rectal (n = 11) CT. Sixty percent of women with rectal CT per NAAT were also culture positive. Median time to CT clearance after azithromycin treatment was 8.0 days for vaginal CT and 7.0 days for rectal CT. Eight women with rectal CT at enrollment had at least 1 rectal CT-positive NAAT after clearance of the initial infection; none reported anal sex.Conclusions: Most NAAT-positive rectal infections were culture positive, suggesting active infection. Time to NAAT clearance of rectal and genital tract CT was similar, and intermittent rectal CT positivity was common in the absence of anal sexual exposure. The cause of recurrent/intermittent rectal CT and the clinical implications of these infections require further study. [ABSTRACT FROM AUTHOR]

Project: To evaluate and improve the response to the local mpox outbreak, Public Health -- Seattle & King County (PHSKC) conducted a community feedback survey among those most impacted by mpox. From August 22 to October 1, 2022, people 14 years of age and older who identified as men who have sex with men (MSM) or transgender persons who have sex with men completed an online survey that quantitatively and qualitatively assessed mpox knowledge, attitudes, and risk behaviors. Openended questions explored perceived stigma, public health communication, and vaccine distribution. The survey was advertised at community vaccination events, the PHSKC Sexual Health Clinic, and over social media. A rapid qualitative analysis identified patterns and themes within the open-ended questions. Issue: By August 2022, mpox cases in King County, WA were beginning to plateau, yet mpox vaccines remained limited and discontent with the public health response was growing among impacted communities. This survey aimed to understand community knowledge, experiences, and perceptions of mpox, and solicit feedback regarding communication and vaccine delivery. Results: Among the 359 survey respondents, most identified as gay or lesbian (84%), white (74%), and reported living in King County, WA (92%). Nearly all participants (96%) were at least a little concerned about mpox while 31% were very concerned. Over half (59%) reported at least one mpox risk factor and the majority (69%) felt that mpox information had been stigmatizing toward MSM and transgender persons. Qualitative responses articulated divergent perspectives on public health communications with responses falling into two main themes. One group found communications stigmatizing and felt that public health should have de-emphasized the role of sexual behaviors and identity in the outbreak. In contrast, another group of respondents felt public health should have clearly indicated that mpox is an STI highly concentrated in MSM populations. Dominant themes relating to vaccine distribution included the need to broaden vaccine criteria, expand access, and emphasize BIPOC groups. Lesson Learned: Our findings highlight the challenge of communicating the reality of the mpox epidemic without stigmatizing the affected population. Efforts to diversify communication methods, include factbased information, and utilize concise nonjudgmental language may improve effective public health communication. [ABSTRACT FROM AUTHOR]

Background: Approximately 233,898 individuals in the Veterans Affairs healthcare network are hepatitis C virus (HCV)-infected, making the Veterans Affairs the single largest provider of HCV care in the USA. Direct-acting antiviral treatment regimens for HCV offer high cure rates. However, these medications pose an enormous financial burden, and whether HCV cure is associated with decreased healthcare costs is poorly defined.Aims: To measure downstream healthcare costs in a national population of HCV-infected patients up to 9 years post-HCV antiviral treatment, to compare downstream healthcare costs between cured and uncured patients, and to assess impact of cirrhosis status on cost differences.Methods: This is a retrospective cohort study (2004-2014) of hepatitis C-infected patients who initiated antiviral treatment within the United States Veterans Affairs healthcare system October 2004-September 2013. We measured inpatient, outpatient, and pharmacy costs after HCV treatment.Results: For the entire cohort, cure was associated with mean cumulative cost savings in post-treatment years three-six, but no cost savings by post-treatment year nine. By post-treatment year nine, cure in cirrhosis patients was associated with a mean cumulative cost savings of $9474 (- 32,666 to 51,614) per patient, while cure in non-cirrhotic patients was associated with a mean cumulative cost excess of $2526 (- 12,211 to 7159) per patient.Conclusions: Among patients with cirrhosis at baseline, cure is associated with absolute cost savings up to 9 years post-treatment compared to those without cure. Among patients without cirrhosis, early post-treatment cost savings are counterbalanced by higher costs in later years. [ABSTRACT FROM AUTHOR]

The general influence of electric fields on flames has been known for many years, the underlying mechanisms, however, are not finally identified yet. The changes observable in the flame structure and the pollutant emission when a flame is exposed to an electric field are mainly attributed to the ionic wind. Yet, especially the resulting flame temperature under the influence of electric fields is still an open research topic. Thus, in the present study the temperature distributions in a laminar premixed Bunsen type flame were measured for different air–fuel-mixtures using point-wise vibrational coherent-anti-Stokes Raman spectroscopy (vibrational-CARS) when a static electric field is activated. Additionally, CH 2 O- and OH-PLIF (planar laser-induced fluorescence) and particle image velocimetry (PIV) were applied to identify the best-suited locations for the temperature measurements and to visualize changes in the flame structure induced by the electric field for clarifying the underlying mechanisms. The results show that the electric field leads to increased fresh gas and maximum flame temperatures and that this effect is most distinct for rich premixed flames. Both PIV/PLIF and CARS experiments confirm that the flame is constricted and pushed towards the burner due to the ionic wind, which explains the increased temperature of the fresh gas and of the exhaust gas. The increased burner and fresh gas temperatures due to the ionic wind were verified by additional thermocouple measurements. The ionic wind is maximal for the fuel-rich flame, which is explained by the lowest electric resistance due to high charge carrier concentration, and larger flame area, which reduces the gap between the flame and the positively charged electrode. Furthermore, a clear broadening of the hot exhaust gas region was measured, which increases the burn out of UHC and CO reported in the literature. Furthermore, this effect increases the residence time that could also contribute to changed pollutant emission for flames under the influence of electric fields. It can be concluded that the change of the flame temperature is mainly the result of the modified velocity field induced by the ionic wind. Consequently, the ionic wind is the dominant mechanism for many effects observed in flames when applying weak electric fields. [ABSTRACT FROM AUTHOR]

Thetechnique of laser-induced gratings (LIGs) has been appliedto the simultaneous determination of speed of sound and thermal diffusivityof four 1-ethyl-3-methylimidazolium ([EMIm])-based room temperatureionic liquids (RTILs)[EMIm][N(CN)2], [EMIm][MeSO3], [EMIm][C(CN)3], and [EMIm][NTf2]atambient pressure (1 bar (0.1 MPa)) and temperature (28 °C (301K)). Transient laser-induced gratings were created as a result ofthermalization of a quasi-resonant excitation of highly lying combinationalvibrational states of the RTIL molecules and electrostrictive compressionof the liquid by radiation of a pulse-repetitive Q-switched Nd:YAGpump laser (1064 nm). The LIGs temporal evolution was recorded usingBragg diffraction of the radiation from a continuous-wave probe laser(532 nm). By fitting the temporal profiles of the LIG signals, thespeed of sound and thermal diffusivity were determined, and the isentropiccompressibility and thermal conductivity were calculated. Independently,the special experimental arrangement allowed the measurement of thedamping of the laser-excited acoustic waves and the derivation ofthe RTIL bulk viscosity for the first time. [ABSTRACT FROM AUTHOR]

Abstract: Flame spray synthesis of silica nanoparticles is characterized by a set of complementary optical techniques. By means of laser-sheet based Mie scattering imaging, 2D-chemiluminescence imaging and coherent anti-Stokes Raman spectroscopy (CARS) local information on spatial droplet distribution, combustion zone, nucleation zone and temperature in the flame could be obtained. In addition, the outcomes from optical metrology are validated by thermophoretic sampling at different flame heights and the synthesized powders were analyzed by N2 gas sorption. By comparing these results the flame can be quantitatively classified into three distinct zones: (i) the droplet zone where precursor atomization and evaporation take place, (ii) the nucleation zone indicated by SiO⁎/Si⁎ radicals as a preliminary species before SiO2 particle formation and (iii) the sintering zone characterized by the highest temperatures in flame. In addition the spatial spreading of the nucleation zone as a function of precursor concentration is investigated. Theoretical calculations and experimental results show an extended nucleation regime for the lowest precursor concentration compared to higher concentrations. Although this study is performed with hexamethyldisiloxane (HMDS) precursor to synthesize silica nanoparticles as a model system, dimensionless analysis shows that the results, concerning the spray formation, can be transferred to the synthesis of other materials as well. [Copyright &y& Elsevier]

Abstract: A straight forward and non-invasive strategy to quantify vapour–liquid equilibria (VLE) of the ternary system acetone, water and carbon dioxide (CO2) is reported. The strategy is based on extracting the composition of a ternary mixture from its Raman spectrum. An isolated Raman signal of acetone, which is not interfered with Raman signals of water or CO2, is used as a reference signal. The capability of the strategy introduced is demonstrated by the agreement with VLE data obtained by the other authors that used conventional methods at elevated pressures up to 10MPa and temperatures up to 353K. The advantages of the introduced method are its non-invasive sampling method, its insensitivity to misalignment or distortions of the excitation and signal paths as well as power fluctuations of the excitation beam, its fast accessibility to the mixture composition and the general transferability to all systems whose Raman spectrum shows a spectrally isolated strong Raman signal which can be assigned to one specific compound. [Copyright &y& Elsevier]

The applicability of shifted-excitation Raman difference spectroscopy (SERDS) in combination with signal regression analysis as an alternative and non-invasive approach for monitoring the cultivation of phototrophic microorganisms producing complex molecules of pharmaceutical relevance in a bioreactor is demonstrated. As a model system, the cultivation of the red unicellular algae Porphyridium purpureum is used for focusing on the segregation of sulfated exopolysaccharides (EPS) which exhibit antiviral activity. The spectroscopic results obtained by partial linear least squares regression (PLSR) and by nonlinear support vector regression (SVR) are discussed against the corresponding results from the reference analytics based on the phenol–sulfuric acid assay. The SERDS-approach turns out to have strong potential as a non-invasive tool for online-monitoring of biotechnological processes. [ABSTRACT FROM AUTHOR]

Hybrid femtosecond/picosecond (fs/ps) vibrational coherent anti-Stokes Raman scattering was demonstrated for high-speed, in-situ measurements of CH4/N2 mole fractions in binary gas mixtures with temporal nonresonant suppression. A single broadband, 100-fs laser source was used to simultaneously excite CH4 and N2 vibrational Raman transitions, characterized by a spectral separation of ~584 cm−1, followed by frequency-domain detection with a time-delayed ps probe pulse. In this manner, the temporal evolution of the nonresonant background and vibrational wavepackets of CH4 and N2 could be evaluated to maximize signal and minimize interferences. A typical accuracy of ~95% was achieved for experimental CH4 mole fractions between 0.02 and 0.70, and a precision of ~4% was achieved by maximizing relative excitation energy through induced chirp in the pump and Stokes pulses. It was further shown that mole-fraction measurements were not affected by variations in bi-molecular broadened linewidths over a wide range of mixture fractions. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

To enhance the efficiency of direct injection engines, the understanding of the combustible mixture formation after a liquid fuel spray is injected is crucial; hence, the need is readily apparent for experimental methods that allow determining characteristic parameters such as fuel/air ratio and gas temperature. The paper demonstrates the potential of the laser-induced grating technique to determine simultaneously the local vapor phase fuel concentration and the temperature during the temporal evolution of a direct-injected spray. The precision and the accuracy of the experimental approach and of the applied data treatment procedure were evaluated by using calibration measurements in a constant volume cell under known stationary conditions. The test measurements of fuel vapor concentration and gas temperature were carried out in an injection chamber using a high-pressure swirl injector. Liquid propane as the main component of liquefied petroleum gas was directly injected into the chamber under flash-boiling conditions. Injection and ambient pressure were varied, whereas fuel and ambient temperature remained constant. The measurements were performed inside the fuel jet at different distances from the injector outlet along the axis of propane injection. The results are indicative of small evaporative cooling of the gas in the jet. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Mass transport between organic solvents (S) and carbon dioxide (CO2) has been investigated at pressures below the mixture critical pressure (MCP). Acetone and dimethyl sulfoxide (DMSO) have been used as organic solvents. Profiles of the mixture composition have been measured through liquid solvent drops pendant at steady conditions in a pressurized CO2 environment. The drop has been kept steady by feeding exactly that amount of liquid through a feed glass capillary into the pendant drop that evaporated at the same time from the drop into the CO2 environment. The liquid fed into the pendant drop has been either pure organic solvent or organic solvent with some CO2 dissolved. Profiles of the mixture composition have been quantified applying an optical Raman line imaging technique and the respective involved mass transport mechanisms are discussed comprehensively. Evaporative cooling was shown to dominate the temperature change at the inner margin of the drop, while mixing enthalpies were shown to be of minor importance. By fitting a mass transport model to DMSO concentration profiles, calculated from the mass fraction composition profiles, the mass transport properties diffusivity D, Biot-number Bi and mass transfer coefficient β could be derived. When acetone has been used as solvent, no steady drops could be formed not allowing a model based quantification of the mass transport. [Copyright &y& Elsevier]

Biofuels and alternative fuels are increasingly being blended to conventional gasoline fuel to reduce the overall CO emissions. The effect on NOx and soot formation is still unclear as the atomization and evaporation of gasoline with biocomponents differ depending on fuel specific physiochemical properties. This work focuses on describing the biofuel evaporation behavior of gasoline sprays at homogeneous charge (early injection timing) and stratified-charge conditions (late injection timing mode) used in modern direct injection spark ignition engines (DISI). A spray plume of a 6-hole solenoid injector is analyzed in terms of liquid spray propagation, and local droplet sizes studied in an injection chamber. Depending on the operating conditions, different physiochemical properties are found to dominate the atomization and evaporation processes: For low and moderate ambient temperature and pressure, high-boiling point components show a strong influence on the spray droplet size distribution. However, at elevated temperature and pressure, the evaporation behavior changes completely. Due to a high degree of evaporation, the evaporation cooling effect dominates the local droplet sizes. Fuel mixtures owing a larger heat of vaporization show larger droplet sizes-even if these fuels have a lower boiling point. Depending on the local evaporation behavior, the different remaining droplet momentum in the spray controls the air entrainment and the subsequent progress of evaporation and mixing. Overall, it can be stated that the heat of vaporization is a dominating physiochemical property for the droplet evaporation rate at high-level supercharged conditions. [ABSTRACT FROM AUTHOR]

Abstract: This article addresses burner design and flame measurement based on the heat flux method which is among the most precise ways of determining the laminar burning velocity of premixed flames. Chemical data are available for gaseous fuel flames using a variety of burner setups. However, the data for the laminar burning velocities of liquid fossil fuels and alternative biofuel blends, are still either incomplete, inaccurate or vary strongly for different setups, burner types and boundary conditions. A modified heat flux approach is found to increase the accuracy of the results of laminar burning velocities. For this purpose, a heat flux gas burner was combined with a novel liquid-fuel injection evaporating system called ‘HeatFluxER’ to achieve precise data for various biofuels and blends. Nevertheless, the purpose of this work is to obtain a robust inexpensive system for reproducible measurements. The gained measurement data of ethanol and isooctane depending on the initial gas temperature are in good agreement with recently presented studies of other groups and setups. [Copyright &y& Elsevier]

Mutual diffusivities for binary mixtures of the ionicliquids (ILs)[EMIM][N(CN)2] (1-ethyl-3-methylimidazolium dicyanimide),[EMIM][NTf2] (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide),and [HMIM][NTf2] (1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide)with acetone and ethanol were studied in dependence on compositionin the temperature range from 283.15 to 323.15 K, applying dynamiclight scattering (DLS). The influence of experimental parameters on theachievable uncertainties was analyzed to ensure the acquisition ofaccurate data in adequate measurement times. For all probed systems,increasing binary diffusion coefficients were found for increasingtemperatures. The systematic variation of anion and cation of theinvestigated ILs as well as a comparison with the literature datademonstrates the considerable influence of different ions on the resultingbinary diffusion coefficients. Mutual diffusivities were found tobe lower for the mixtures with ethanol than for those with acetone,which could be related to the formation of hydrogen bonds betweenethanol and the ions. Most of the investigated IL solvent mixturesshow increasing binary diffusion coefficients with increasing solventconcentration. For the mixtures of [EMIM][NTf2] with ethanol,however, a minimum of the mutual diffusivities was found in the ethanolmole fraction range from 0.7 to 0.8, which may hint at the vicinityof a critical demixing point. The viscosity of the pure ILs turnedout to be no reliable indicator for the mutual diffusivity in mixtureswith the same solvent. [ABSTRACT FROM AUTHOR]

Abstract: CO2 sorption in molten poly(ε-caprolactone) (PCL) has been investigated by temporally resolved Raman line imaging, which is introduced here as a new technology for the direct measurement of gas mass fraction profiles inside polymers during transient sorption experiments. Molten PCL was exposed to pressurized carbon dioxide in an optically accessible pressure cell at 80 °C and pressures up to 7.1 MPa. During sorption, Raman spectra were acquired temporally and spatially resolved across the PCL drop, allowing the evaluation of the PCL/CO2 mutual diffusivity, of the CO2 solubility in PCL, and the determination of temporal evolution of mass fraction profiles of carbon dioxide inside PCL. [Copyright &y& Elsevier]

Abstract: For the refrigerants 1,1,1,2-tetrafluoroethane (R134a) and propane (R290), the condensation heat transfer was investigated on coated and uncoated horizontal smooth, standard finned and high performance tubes by experiments and computational fluid dynamics (CFD)-simulations. Measurements were carried out at a saturation temperature of 37°C varying the heat flux between 4kWm−2 and 102 kWm−2. In comparison to the Nußelt theory, enhancement factors of 12.8 to 30.2 were experimentally found for single standard finned and single high performance tubes. For both refrigerants, the high performance tubes showed a larger bundle effect than the standard finned tubes, although the latter show a lower heat transfer performance. In general, experimental results for coated tubes show a slightly lower heat transfer performance and no improvements of the condensate drainage could be observed for the modification. CFD-simulations were used to predict the condensation heat transfer on single tubes for the first time. Our experimental data and CFD-simulations were compared with analytical models available in the literature. [Copyright &y& Elsevier]

Abstract: The determination of temperature distribution is an essential task when flames are characterized. We propose a new approach for flame thermometry based on laser-induced breakdown spectroscopy (LIBS) utilizing the temperature dependency of the breakdown threshold laser pulse energy. Calibration measurements are carried out in heated gas flows and post-combustion gases. Compositional effects on the breakdown threshold are corrected employing a straightforward procedure. For this purpose, the elemental composition is derived from the LIBS spectra and this information is then used for correcting the measured threshold laser pulse energy. A series of proof-of-concept measurements in a laminar methane/air flame on a Bunsen burner is conducted and compared to reference data from coherent anti-Stokes Raman scattering (CARS). The corrected LIBS temperatures show excellent agreement with those obtained by CARS. Therefore, our approach represents a simple and straightforward alternative to traditionally used thermometry methods. [Copyright &y& Elsevier]

The design of reciprocating pumps for the chemical industry requires a detailed knowledge of the apparent phenomena such as undesirable pipe pulsation and harmful cavitation. Since the detailed understanding of the entire mechanism is rather limited, emphasis will be put on the verification of a fluid-dynamic cavitation model for reciprocating positive displacement pumps. This model was established by means of particle image velocimetry (PIV) measurements carried out at a repetition rate of 2 kHz. The PIV results indicate that the fluid-dynamic cavitation model corresponds with the physical reality. While common practice dictates that cavitation should be prevented at all times, the proposed model offers a great opportunity for manufacturers to predict a limit for the extent of occurring cavitation. [ABSTRACT FROM AUTHOR]