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Three-dimensional plotting of micro-extruded filaments is a promising method for the manufacture of porous structures in thermoplastic polymers. However, it has been noted that conventional dispense head systems for this microextrusion are unsuitable for the reliable processing of thermally sensitive polymers like poly(-lactic acid) (PLA): the batch polymer remains in the molten state prior to processing and it will degrade under this thermal load, leading to polymer chain reduction. Therefore, a new dispense head system was developed which thermally separates a cold material supply zone from the hot extrusion zone and allows for the processing of PLA-based polymers without severe degradation. This manuscript discusses the design of the new dispense head and compares its thermoregulation with that of a conventional system by means off mite element modeling and infrared imaging. POLYM. ENG. SCI., 53:273-282, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION A growing application for biodegradable polymers is the manufacture of scaffolds for tissue engineering, an advanced multidisciplinary research field which endeavors to meet the growing demand for donor organs [...]

Background: The following position statement from the Union of the European Phoniatricians, updated on 25th May 2020 (superseding the previous statement issued on 21st April 2020), contains a series of recommendations for phoniatricians and ENT surgeons who provide and/or run voice, swallowing, speech and language, or paediatric audiology services. Objectives: This material specifically aims to inform clinical practices in countries where clinics and operating theatres are reopening for elective work. It endeavours to present a current European view in relation to common procedures, many of which fall under the aegis of aerosol generating procedures. Conclusion: As evidence continues to build, some of the recommended practices will undoubtedly evolve, but it is hoped that the updated position statement will offer clinicians precepts on safe clinical practice. [ABSTRACT FROM AUTHOR]

Ambient measurements of PM1 aerosol chemical composition at Cabauw, the Netherlands, implicate higher ammonium concentrations than explained by the formation of inorganic ammonium salts. This additional particulate ammonium is called excess ammonium (eNH4). Height profiles over the Cabauw Experimental Site for Atmospheric Research (CESAR) tower, of combined ground based and airborne aerosol mass spectrometric (AMS) measurements on a Zeppelin airship show higher concentrations of eNH4 at higher altitudes compared to the ground. Through flights across the Netherlands, the Zeppelin based measurements furthermore substantiate eNH4 as a regional phenomenon in the planetary boundary layer. The excess ammonium correlates with mass spectral signatures of (di-)carboxylic acids, making a heterogeneous acid–base reaction the likely process of NH3 uptake. We show that this excess ammonium was neutralized by the organic fraction forming particulate organic ammonium salts. We discuss the significance of such organic ammonium salts for atmospheric aerosols and suggest that NH3 emission control will have benefits for particulate matter control beyond the reduction of inorganic ammonium salts. [ABSTRACT FROM AUTHOR]

A first direct intercomparison of aerosol vertical profiles from Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations, performed during the Cabauw Intercomparison Campaign of Nitrogen Dioxide measuring Instruments (CINDI) in summer 2009, is presented. Five out of 14 participants of the CINDI campaign reported aerosol extinction profiles and aerosol optical thickness (AOT) as deduced from observations of differential slant column densities of the oxygen collision complex (O4) at different elevation angles. Aerosol extinction vertical profiles and AOT are compared to backscatter profiles from a ceilometer instrument and to sun photometer measurements, respectively. Furthermore, the near-surface aerosol extinction coefficient is compared to in situ measurements of a humidity-controlled nephelometer and dry aerosol absorption measurements. The participants of this intercomparison exercise use different approaches for the retrieval of aerosol information, including the retrieval of the full vertical profile using optimal estimation and a parametrised approach with a prescribed profile shape. Despite these large conceptual differences, and also differences in the wavelength of the observed O4 absorption band, good agreement in terms of the vertical structure of aerosols within the boundary layer is achieved between the aerosol extinction profiles retrieved by the different groups and the backscatter profiles observed by the ceilometer instrument. AOTs from MAX-DOAS and sun photometer show a good correlation (R>0.8), but all participants systematically underestimate the AOT. Substantial differences between the near-surface aerosol extinction from MAX-DOAS and from the humidified nephelometer remain largely unresolved. [ABSTRACT FROM AUTHOR]

Intensive measurements of submicron aerosol particles and their chemical composition were performed with an Aerosol Chemical Speciation Monitor (ACSM) at the Cabauw Experimental Site for Atmospheric Research (CESAR) in Cabauw, NL. The campaign lasted nearly one year from July 2012 to June 2013 as part of the ACTRIS project. Including black carbon data an average particulate mass concentration of 9.50 μg m-3 was obtained during the whole campaign with dominant contributions from ammonium nitrate (45%), organic aerosol (OA, 29%), and ammonium sulfate (19%). 12 exceedances of the World Health Organization (WHO) PM2.5 daily mean limit (25 μg m-3) were observed at this rural site using PM1 instrumentation only. Ammonium nitrate and OA represented the largest contributors to total particulate matter during periods of exceedance. Source apportionment of OA was performed season-wise by Positive Matrix Factorization (PMF) using the Multilinear Engine 2 (ME-2) controlled via the source finder (SoFi). Primary organic aerosols were attributed mainly to traffic (8-16% contribution to total OA, averaged season-wise) and biomass burning (0-23%). Secondary organic aerosols (SOA, 61-84%) dominated the organic fraction during the whole campaign, particularly on days with high mass loadings. A SOA factor which is attributed to humic-like substances (HULIS) was identified as a highly oxidized background aerosol in Cabauw. This shows the importance of atmospheric ageing processes for aerosol concentration at this rural site. Due to the large secondary fraction, the reduction of particulate mass at this rural site is challenging on a local scale. [ABSTRACT FROM AUTHOR]

Abstract: The contribution of regional, urban and traffic sources to PM2.5 and PM10 in an urban area was investigated in this study. The chemical composition of PM2.5 and PM10 was measured over a year at a street location and up- and down-wind of the city of Rotterdam, the Netherlands. The 14C content in EC and OC concentrations was also determined, to distinguish the contribution from “modern” carbon (e.g., biogenic emissions, biomass burning and wildfires) and fossil fuel combustion. It was concluded that the urban background of PM2.5 and PM10 is dominated by the regional background, and that primary and secondary PM emission by urban sources contribute less than 15%. The 14C analysis revealed that 70% of OC originates from modern carbon and 30% from fossil fuel combustion. The corresponding percentages for EC are, respectively 17% and 83%. It is concluded that in particular the urban population living in street canyons with intense road traffic has potential health risks. This is due to exposure to elevated concentrations of a factor two for EC from exhaust emissions in PM2.5 and a factor 2–3 for heavy metals from brake and tyre wear, and re-suspended road dust in PM10. It follows that local air quality management may focus on local measures to street canyons with intense road traffic. [Copyright &y& Elsevier]

Three-dimensional plotting of micro-extruded filaments is a promising method for the manufacture of porous structures in thermoplastic polymers. However, it has been noted that conventional dispense head systems for this microextrusion are unsuitable for the reliable processing of thermally sensitive polymers like poly(lactic acid) (PLA): the batch polymer remains in the molten state prior to processing and it will degrade under this thermal load, leading to polymer chain reduction. Therefore, a new dispense head system was developed which thermally separates a cold material supply zone from the hot extrusion zone and allows for the processing of PLA-based polymers without severe degradation. This manuscript discusses the design of the new dispense head and compares its thermoregulation with that of a conventional system by means of finite element modeling and infrared imaging. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The development of a radiation fog layer at the Cabauw Experimental Site for Atmospheric Research (51.97°N, 4.93°E) on 23 March 2011 was observed with ground-based in situ and remote sensing observations to investigate the relationship between visibility and radar reflectivity. The fog layer thickness was less than 200 m. Radar reflectivity values did not exceed −25 dB Z even with visibilities less than 100 m. The onset and evaporation of fog produce different radar reflectivity-visibility relationships. The evolution of the fog layer was modeled with a droplet activation model that used the aerosol size distribution observed at the 60-m altitude tower level as input. Radar reflectivity and visibility were calculated from model drop size spectra using Mie scattering theory. Since radiative cooling rates are small in comparison with cooling rates due to adiabatic lift of aerosol-laden air, the modeled supersaturation remains low so that few aerosol particles are activated to cloud droplets. The modeling results suggest that the different radar reflectivity-visibility relationships are the result of differences in the interplay between water vapor and cloud droplets during formation and evaporation of the fog. During droplet activation, only a few large cloud droplets remain after successfully competing for water vapor with the smaller activated droplets. These small droplets eventually evaporate (deactivate) again. In the fog dissolution/evaporation stage, only these large droplet need to be evaporated. Therefore, to convert radar reflectivity to visibility for traffic safety products, knowledge of the state of local fog evolution is necessary. [ABSTRACT FROM AUTHOR]

A three-dimensional regional chemical transport model (CTM) with detailed aerosol microphysics, PMCAMx-UF, was applied to the European domain to simulate the contribution of direct emissions and secondary formation to total particle number concentrations during May 2008. PMCAMx-UF uses the Dynamic Model for Aerosol Nucleation and the Two-Moment Aerosol Sectional (TOMAS) algorithm to track both aerosol number and mass concentration using a sectional approach. The model predicts nucleation events that occur over scales of hundreds up to thousands of kilometers especially over the Balkans and Southeast Europe. The model predictions were compared against measurements from 7 sites across Europe. The model reproduces more than 70% of the hourly concentrations of particles larger than 10 nm (N10) within a factor of 2. About half of these particles are predicted to originate from nucleation in the lower troposphere. Regional nucleation is predicted to increase the total particle number concentration by approximately a factor of 3. For particles larger than 100 nm the effect varies from an increase of 20% in the eastern Mediterranean to a decrease of 20% in southern Spain and Portugal resulting in a small average increase of around 1% over the whole domain. Nucleation has a significant effect in the predicted N50 levels (up to a factor of 2 increase) mainly in areas where there are condensable vapors to grow the particles to larger sizes. A semi-empirical ternary sulfuric acid-ammonia-water parameterization performs better than the activation or the kinetic parameterizations in reproducing the observations. Reducing emissions of ammonia and sulfur dioxide affects certain parts of the number size distribution. [ABSTRACT FROM AUTHOR]

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In the field, aerosol in-situ measurements are often performed under dry conditions (relative humidity RH<30--40%). Since ambient aerosol particles experience hygroscopic growth at enhanced RH, their microphysical and optical properties -- especially the aerosol light scattering -- are also strongly dependent on RH. The knowledge of this RH effect is of crucial importance for climate forcing calculations or for the comparison of remote sensing with insitu measurements. Here, we will present results from a four-month campaign which took place in summer 2009 in Cabauw, The Netherlands. The aerosol scattering coefficient σ sp(λ) was measured dry and at various, predefined RH conditions between 20 and 95% with a humidified nephelometer. The scattering enhancement factor f (RH,λ) is the key parameter to describe the effect of RH on σ sp(λ) and is defined as σ sp(RH,λ) measured at a certain RH divided by the dry σ sp(dry,λ). The measurement of f (RH,λ) together with the dry absorption measurement (assumed not to change with RH) allows the determination of the actual extinction coefficient σ ep(RH,λ) at ambient RH. In addition, a wide range of other aerosol properties were measured in parallel. The measurements were used to characterize the effects of RH on the aerosol optical properties. A closure study showed the consistency of the aerosol in-situ measurements. Due to the large variability of air mass origin (and thus aerosol composition) a simple parameterization of f (RH,λ) could not be established. If f (RH,λ) needs to be predicted, the chemical composition and size distribution need to be known. Measurements of four MAX-DOAS (multi-axis differential optical absorption spectroscopy) instruments were used to retrieve vertical profiles of σ ep(λ). The values of the lowest layer were compared to the in-situ values after conversion of the latter ones to ambient RH. The comparison showed a good correlation of R² = 0.62--0.78, but the extinction coefficients from MAX-DOAS were a factor of 1.5--3.4 larger than the insitu values. Best agreement is achieved for a few cases characterized by low aerosol optical depths and low planetary boundary layer heights. Differences were shown to be dependent on the applied MAX-DOAS retrieval algorithm. The comparison of the in-situ extinction data to a Raman LIDAR (light detection and ranging) showed a good correlation and higher values measured by the LIDAR (R² = 0.82-0.85, slope of 1.69--1.76) if the Raman retrieved profile was used to extrapolate the directly measured extinction coefficient to the ground. The comparison improved if only nighttime measurements were used in the comparison (R² =0.96, slope of 1.12). [ABSTRACT FROM AUTHOR]

In the field, aerosol in-situ measurements are often performed under dry conditions (relative humidity RH<30-40%). Since ambient aerosol particles experience hygroscopic growth at enhanced RH, also their microphysical and optical properties - especially the aerosol light scattering - are strongly dependent on RH. The knowledge of this RH effect is of crucial importance for climate forcing calculations or for the comparison of remote sensing with in-situ measurements. Here, we will present results from a four-month campaign which took place in summer 2009 in Cabauw, The Netherlands. The aerosol scattering coefficient σsp(λ) was measured dry and at various, predefined RH conditions between 20 and 95% with a humidified nephelometer. The scattering enhancement factor f(RH, λ) is the key parameter to describe the effect of RH on σsp(λ) and is defined as σsp(RH, λ)measured at a certain RH divided by the dry σsp(dry, λ). The measurement of f(RH, λ) together with the dry absorption measurement (assumed not to change with RH) allows the determination of the actual extinction coefficient σep(RH, λ) at ambient RH. In addition, a wide range of other aerosol properties were measured in parallel. The measurements were used to characterize the effects of RH on the aerosol optical properties. A closure study showed the consistency of the aerosol in-situ measurements. Due to the large variability of air mass origin (and thus aerosol composition) a simple parameterization of f(RH,λ) could not be established. If f(RH,λ) needs to be predicted, the chemical composition and size distribution needs to be known. Measurements of four MAX-DOAS (multi-axis differential optical absorption spectroscopy) instruments were used to retrieve vertical profiles of σep(λ). The values of the lowest layer were compared to the in-situ values after conversion of the latter to ambient RH. The comparison showed a good correlation of R² = 0.62-0.78, but the extinction coefficients were a factor of 1.5-3.4 larger than the in-situ values. Best agreement is achieved for a few cases characterized by low aerosol optical depths and low planetary boundary layer heights. Differences showed to be dependent on the applied MAX-DOAS retrieval algorithm. The comparison of the in-situ data to a Raman lidar (light detection and ranging) showed a good correlation and higher values measured by the lidar (R² = 0.79, slope of 1.81) if the Raman retrieved profile was used to extrapolate the directly measured extinction coefficient to the ground. The comparison improved if only nighttime measurements were used in the comparison (R² = 0.93, slope of 1.19). [ABSTRACT FROM AUTHOR]

We present comprehensive results on continuous atmospheric cluster and particle measurements in the size range ~1-42 nm within the European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) project. We focused on characterizing the spatial and temporal variation of new particle formation events and relevant particle formation parameters across Europe. Different types of air ion and cluster mobility spectrometers were deployed at 12 field sites across Europe from March 2008 to May 2009. The measurements were conducted in a wide variety of environments, including coastal and continental locations as well as sites at different altitudes (both in the boundary layer and the free troposphere). New particle formation events were detected at all of the 12 field sites during the year-long measurement period. From the data, nucleation and growth rates of newly formed particles were determined for each environment. In a case of parallel ion and neutral cluster measurements, we could also estimate the relative contribution of ion-induced and neutral nucleation to the total particle formation. The formation rates of charged particles at 2 nm accounted for 1-30% of the corresponding total particle formation rates. As a significant new result, we found out that the total particle formation rate varied much more between the different sites than the formation rate of charged particles. This work presents, so far, the most comprehensive effort to experimentally characterize nucleation and growth of atmospheric molecular clusters and nanoparticles at ground-based observation sites on a continental scale. [ABSTRACT FROM AUTHOR]

The article presents a study on several correction algorithms of the Aethalometer (AE) absorption coefficients including Weingartner, Arnott, and Schmid. It notes that all corrections were tested, evaluated, and analyzed on six datasets which represent different aerosol types. The study poses several recommendations including the storage of measured attenuation values in databases, the modification of the absorption coefficient wavelength dependence, and the use of the filter-loading correction.

Most estimates of sea spray aerosol source functions have used indirect means to infer the rate of production as a function of wind speed. Only recently has the technology become available to make high frequency measurements of aerosol spectra suitable for direct eddy correlation determination of the sea spray particle flux. This was accomplished in this study by combining a newly developed fast aerosol particle counter with an ultrasonic anemometer which allowed for eddy covariance measurements of size-segregated particle fluxes. The aerosol instrument is the Compact Lightweight Aerosol Spectrometer Probe (CLASP) - capable of measuring 8-channel size spectra for mean radii between 0.15 and 3.5μm at 10 Hz. The first successful measurements were made during the Waves, Air Sea Fluxes, Aerosol and Bubbles (WASFAB) field campaign in October 2005 in Duck (NC, USA). The method and initial results are presented and comparisons are made with recent sea spray source functions from the literature. [ABSTRACT FROM AUTHOR]

Primary marine aerosol fluxes were measured using eddy covariance (EC), a condensation particle counter (CPC) and an optical particle counter (OPC) with a heated inlet. The later was used to discriminate between sea salt and total aerosol. Measurements were made from the 25m tower at the research station Mace Head at the Irish west coast, May to September 2002. The aerosol fluxes were dominated by upward fluxes, sea spray from bubble bursting at the ocean surface. The sea salt aerosol number emissions increased two orders of magnitude with declining diameter from 1 to 0.1 µm where it peaked at values of 105 to 107 particles m-2s-1. The sea salt emissions increased at all sizes in the wind range 4 to 22 ms-1, in consistency with a power function of the wind speed. The sea salt emission data were compared to three recent sub micrometer sea salt source parameterisations. The best agreement was with Måartensson et al. (2003), which appear to apply from 0.1 to 1.1 µm diameters in temperate water (12°C) as well as tropical water (25°C). The total aerosol emissions were independent of the wind speed below 10 ms-1, but increased with the wind above 10 ms-1. The aerosol volume emissions were larger for the total aerosol than for the sea salt at all wind speeds, while the sea salt number emissions approached the total number emissions at 15 ms-1. It is speculated that this is caused by organic carbon in the surface water that is depleted at high wind speeds. The data are consistent with an internal aerosol mixture of sea salt, organic carbon and water. Using the aerosol model by Ellison et al. (1999) (a mono-layer of organic carbon surrounding a water-sea-salt brine) we show that the total and sea salt aerosol emissions are consistent. This predict that the organic carbon fraction increase with decreasing diameter from a few % at 1 µm over 50% at about 0.5 µm to about 90% at 0.1 µm, in consistency with simultaneous chemical data by Cavalli et al. (2004). The combined models of Mårtensson et al. (2003) and Ellison et al. (1999) reproduce the observed total aerosol emissions and offer an approach to model the organic sea spray fraction. [ABSTRACT FROM AUTHOR]

Sun photometer measurements at the AERONET station at the North Sea coast in The Hague (The Netherlands) provide a climatology of optical and physical aerosol properties for the area. Results are presented from the period January 2002 to July 2003. For the analysis and interpretation these data are coupled to chemical aerosol data from a nearby station of the Dutch National Air Quality Network. This network provides PM10 and black carbon concentrations. Meteorological conditions and air mass trajectories are also used. Due to the location close to the coast, the results are strongly dependent on wind direction, i.e. air mass trajectory. In general the aerosol optical properties are governed by industrial aerosol emitted form various industrial, agricultural and urban areas surrounding the site in almost all directions over land. For maritime air masses industrial aerosols are transported from over the North Sea, whereas very clean air is transported from the NW in clean polar air masses from the North Atlantic. In the winter the effect of the production of sea salt aerosol at high wind speeds is visible in the optical and physical aerosol data. In these cases fine and coarse mode radii are similar to those reported in the literature for marine aerosol. Relations are derived between the Ångström coefficients with both the fine/coarse mode fraction and the ratio of black carbon and PM10. [ABSTRACT FROM AUTHOR]

Transsexualism implies that an anatomically normal individual feels that he or she is actually a member of the opposite sex. Treatment usually includes real-life experience along with hormone therapy and sex reassignment surgery. Voice modification surgery may be necessary, as pass ability in general is still in a large extent dependent on the aspects of voice in transsexual people. Often male-to-female patients report being addressed in telephone conversations as their genetic gender, which is experienced as a disability. The purpose of this study was to evaluate the impact of voice on the quality of life in transsexuals.In order to detect the disability caused by a voice disorder, the validated assessment method the Voice Handicap Inventory (VHI) was used. An additional question about the way patients were addressed in a telephone conversation was added.As part of a study describing general health in transsexual persons, done at the Ghent University Hospital Belgium, a total of 48 patients were evaluated. In female-to-male transsexuals the median scores were very low, suggesting testosterone treatment led to an acceptable voice alteration. A higher serum LH level was significantly correlated with higher total, functional and emotional VHI scores. In male-to-female transsexuals the scores were significantly higher than those of the female-to-male transsexuals, but still there was no indication of a real disability/handicap. The extra telephone question was scored higher suggesting male-to-female transsexuals did experience a disability caused by their voice. From this study it is concluded that the VHI values did not demonstrate a handicapping effect. [ABSTRACT FROM AUTHOR]

A small optical device has been constructed to determine aerosol total area concentrations from angular scattering. Particles in the open sample volume are irradiated by a pulsed laser diode. Radiation scattered at angles between 15° and 35° is detected by a photodiode. The amplified signals are processed with a sample/hold circuit. This instrument has been applied for measurements on sea spray aerosol near the air-sea interface. Wave-induced fluctuations were clearly demonstrated. Other applications are indicated. [ABSTRACT FROM AUTHOR]

The need for multidisciplinary and multiprofessional management of dysphagia is constantly increasing and creating a major challenge for healthcare professionals and society, especially in terms of professional expertise and human resources. The distribution of tasks among the dysphagia team members, which includes phoniatricians, otolaryngologists, and speech-language therapists, is flexible and overlapping. For assessing dysphagia, the (fibreoptic) flexible endoscopic evaluation of swallowing (FEES), with or without videofluoroscopy, is a pivotal diagnostic tool. This position paper aims to illustrate the phoniatrician's role in performing a FEES, which is an indispensable component of the diagnostic workup of patients suffering from oropharyngeal dysphagia. It is based on the current collaborative expert view of the Swallowing Committee of the Union of European Phoniatricians and a literature review. A FEES is one of the core competences of phoniatricians due to their endoscopic expertise and experience in the field of dysphagia and diseases of the upper aerodigestive tract. Therefore, the phoniatrician is an important member of the dysphagia team, for the medical diagnostics of the aerodigestive tract and dysphagia as well as for FEES. Phoniatric competence is especially important for head and neck cancer patients, infants, and complex cases., (© 2022. The Author(s).)

Practitioners in the field of voice are often faced with patients who are 'dysphonic', but who do not have identifiable abnormalities of the vocal tract structures or any neural or hormonal alteration affecting the phonatory function. For lack of better nomenclature describing the origin of the disorder, this group of patients has been labeled as having 'non-organic' or 'functional' dysphonia. 'Non-organic' only states what the dysphonia is not, and 'functional' does not have any etiological implication. Hence 'functional disorder' as a determination of the origin is at best vague, imprecise and often misleading. In truth, the terms "functional" and 'non-organic' are by now so muddled and confused in everyday clinical usage and parlance that it is unclear what they mean in any given clinical setting or for any particular clinical case. Thus, the UEP Voice Committee (VC) has come to the conclusion that it is best to adopt a new term that is clearly defined, universally agreed to, and indicative of a different and more useful perspective. We have reviewed the literature relating to terminology of these phonatory disorders. We now propose replacement of the phrase 'functional dysphonia' with 'malregulative dysphonia', since the indication of faulty regulation represents an etiological connotation. We also propose a restructuring of the etiological terminology of phonation disorders. We believe this to be a biologically clearer framework for the labeling of 'non-organic' phonatory disorders, and hope that its routine use will allow for more clarity of presentation and discussion in the future., (Copyright © 2020 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)