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Inhalation toxicity testing of particulate materials is mandated for classification. According to CLP, particulate materials should be tested as marketed and many particulate materials are marketed as non-respirable particles. However, OECD TG 413 requires exposure to particle sizes that are respirable and reach the alveoli. The requirement for exposure of rats to respirable particles is thus in contrast to CLP and requires the application of high shear forces. The exposure to artificially small particles causes a number of issues that hamper the interpretation of the results of the testing. These issues are aerosol altering in the exposure system, assessment of the adversity of the inflammatory lung responses, inclusion of recovery groups, and extrapolation of the results to humans exposed under occupational condition. In addition, effects of many particulate materials after testing according to OECD 413 are not intrinsic properties, but a general reaction of the lung to the deposited material, show very similar NOAECs for chemical diverse materials, and often are completely reversible.

The most commonly used construction material nowadays is steel-reinforced concrete which underlies corrosion and thus buildings are susceptible for structural collapses. Recently, a new construction material resistant to oxidation and with a higher tensile strength called carbon concrete composite (C3) was developed. The new material allows resource-saving constructions using carbon fiber instead of steel reinforcement materials embedded in a concrete matrix. C3 reinforcements consist of carbon fibers coated with an organic polymer matrix. In this study, abrasive dust from a dry cutting process of two C3 reinforcement materials, as well as a C3 material were investigated with respect to the occurrence of toxic fibers or harmful organic compounds in the inhalable particulate matter (PM) fractions PM2.5 and PM10. It could be shown that the ratio between elemental and organic carbon in PM10 is dependent on the shape of the C3 reinforcement material due to different mechanisms of PM formation. This could have an impact on the toxicity of different C3 reinforcement materials. Harmful fibers according to the World Health Organization (WHO) definition like they are found in asbestos concrete were not found. However, bisphenol A (BPA) as well as the PAHs phenanthrene, anthracene, fluoranthene and pyrene were found due to pyrolysis of the organic matrix material at the edge of the sawblade differentiating the Carcinogenic Equivalency (TEQ) of investigated materials and their PM fractions. Furthermore, derivatives of BPA occurred in abrasive dust from C3 reinforcement materials potentially leading to genotoxicity and reproductive toxicity.

Background In the COVID-19 crisis, laparoscopic surgery is in focus as a relevant source of bioaerosol release. The efficacy of electrostatic aerosol precipitation (EAP) and continuous aerosol evacuation (CAE) to eliminate bioaerosols during laparoscopic surgery was verified. Study design Ex-vivo laparoscopic cholecystectomies (LCs) were simulated ± EAP or CAE in Pelvitrainer equipped with swine gallbladders. Release of bioaerosols was initiated by performing high-frequency electrosurgery with a monopolar electro hook (MP-HOOK) force at 40 watts (MP-HOOK40) and 60 watts (MP-HOOK60), as well as by ultrasonic cutting (USC). Particle number concentrations (PNC) of arising aerosols were analyzed with a condensation particle counter (CPC). Aerosol samples were taken within the Pelvitrainer close to the source, outside the Pelvitrainer at the working trocar, and in the breathing zone of the surgeon. Results Within the Pelvitrainer, MP-HOOK40 (6.4 × 105 cm-3) and MP-HOOK60 (7.3 × 105 cm-3) showed significantly higher median PNCs compared to USC (4.4 × 105 cm-3) (p = 0.001). EAP led to a significant decrease of the median PNCs in all 3 groups. A high linear correlation with Pearson correlation coefficients of 0.852, 0.825, and 0.759 were observed by comparing MP-HOOK40 (± EAP), MP-HOOK60 (± EAP), and USC (± EAP), respectively. During ex-vivo LC and CAE, significant bioaerosol contaminations of the operating room occurred. Ex-vivo LC with EAP led to a considerable reduction of the bioaerosol concentration. Conclusions EAP was found to be efficient for intraoperative bioaerosol elimination and reducing the risk of bioaerosol exposure for surgical staff., Graphical abstract

For the purpose of silica surface layer modulation, a pneumatic-controlled two-substance atomizer with inertia-based coarse droplet separation was operated at different system pressures for tetraet...

Background/aim To develop and validate a nebulizer device for anti-cancer research on pressurized intraperitoneal aerosol supply in a preclinical peritoneal metastases (PM) rat model. Material and methods For aerosol generation, an ultrasonic nebulizer (USN) was modified. Aerosol analyses were performed ex-vivo by laser diffraction spectrometry (LDS). Intraperitoneal (IP) 99mtechnetium sodium pertechnetate (99mTc) aerosol distribution and deposition were quantified by in-vivo single photon emission computed tomography (SPECT/CT) and compared to liquid IP instillation of equivalent volume/doses of 99mTc with and without capnoperitoneum. PM was induced by IP injection of HCT116-Luc2 human colon cancer cells in immunosuppressed RNU rats. Tumor growth was monitored by bioluminescence imaging (BLI), 18F-FDG positron emission tomography (PET) and tissues examination at necropsy. Results The USN was able to establish a stable and reproducible capnoperitoneum at a pressure of 8 to 10 mmHg. LDS showed that the USN provides a polydisperse and monomodal aerosol with a volume-weighted diameter of 2.6 μm. At a CO2 flow rate of 2 L/min with an IP residence time of 3.9 s, the highest drug deposition efficiency was found to be 15 wt.-%. In comparison to liquid instillation, nebulization showed the most homogeneous IP spatial drug deposition. Compared to BLI, 18F-FDG-PET was more sensitive to detect smaller PM nodules measuring only 1–2 mm in diameter. BLI, 18F-FDG PET and necropsy analyses showed relevant PM in all animals. Conclusions The USN together with the PM rat model are suitable for robust and species-specific preclinical pharmacological studies regarding intraperitoneal delivery of pressurized aerosolized drugs and cancer research.

Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) is a promising approach with a high optimization potential for the treatment of peritoneal carcinomatosis. To study the efficacy of PIPAC and drugs, first rodent cancer models were developed. But inefficient drug aerosol supply and knowledge gaps concerning spatial drug distribution can limit the results based on such models. To study drug aerosol supply/deposition, computed tomography scans of a rat capnoperitoneum were used to deduce a virtual and a physical phantom of the rat capnoperitoneum (RCP). RCP qualification was performed for a specific PIPAC method, where the capnoperitoneum is continuously purged by the drug aerosol. In this context, also in-silico analyses by computational fluid dynamic modelling were conducted on the virtual RCP. The physical RCP was used for ex-vivo granulometric analyses concerning drug deposition. Results of RCP qualification show that aerosol deposition in a continuous purged rat capnoperitoneum depends strongly on the position of the inlet and outlet port. Moreover, it could be shown that the droplet size and charge condition of the drug aerosol define the deposition efficiency. In summary, the developed virtual and physical RCP enables detailed in-silico and ex-vivo analyses on drug supply/deposition in rodents.

Though having been studied for more than four decades, photocatalysis is still hardly applied in large-scale water and wastewater treatment. This is mainly due to the low energy efficiency of conventional photocatalytic reactors. A recently introduced reactor concept, the fixed-bed photocatalytic membrane reactor (FPMR), can potentially overcome this shortcoming. Its performance for the degradation of organic compounds is examined for different modes of operation. For this purpose, FPMRs based on commercial submerged ceramic membranes were used, which are covered by a photocatalytic layer of pyrogenic titania. The FPMRs were performed in two operational modes: closed-loop reactor and continuous-flow reactor. Oxalic acid was used as a model organic compound to conduct photocatalysis. The influence of light intensity and catalyst layer thickness as well as mass transfer inside the layer were thoroughly studied. The evaluation of the reactors was based on the apparent quantum yield, the photocatalytic space–time yield and specific energy consumption. The results demonstrate that the FPMRs are considerably more efficient than other reported reactor concepts. Its apparent quantum yield can reach up to 11.1%. Furthermore, its specific light energy consumption is merely around 0.1 kWh/g (TOC). The results also reveal that closed-loop FPMRs achieve higher efficiencies than continuous-flow FPMRs. Last but not least, a quantitative model for calculating the reaction rate constant of a photocatalytic membrane from observed reaction rate constant of a photocatalytic membrane reactor was developed and experimentally verified.

The functionality of pigments and fillers is significantly affected by their state of dispersion at the point of application (e.g. in paints and varnishes). This state depends on the materials' original state of agglomeration and aggregation and on their processing, which typically aims at desagglomeration and partial disintegration by high shear stresses. In order to assess the dispersibility of pigments and fillers, a characterisation method is proposed, which comprises sample preparation by ultrasonic dispersion (USD) and particle size analysis by means of analytical centrifugation (AC). The characterisation method is tested within an interlaboratory comparison for four inorganic powders and involves different USD equipment and different AC techniques in different laboratories. The analyses delivered volume-weighted particle size distributions, which were statistically evaluated in order to assess the uncertainty of results within a laboratory and to quantify the variation among the different laboratories. Impacts of the material on the performance of the characterisation method are discussed as well as differences between the various AC techniques.

The lack of data for inhalation exposure concerning the handling of nanostructured materials is limiting the current nanomaterial risk assessment. However, there are numerous studies dealing with the origin of exposure, i.e., the release. The link between release and exposure are transport and transformation phenomena. Thus, propagation modeling was used to simulate transport from source to breathing zone in order to estimate quantitative exposure levels from measured release data for selected scenarios. On the basis of three ventilation and five release scenarios, exposure levels were calculated with and without human thermal plumes for both the nearfield and the farfield. Results show that the often neglected human-induced convective airflow can have a strong impact on the level of exposure, especially for natural ventilation or non-well-designed technical ventilation systems as typical for nonindustrial consumers or handicraft businesses.

Analytical centrifugation (AC) is a powerful technique for the measurement of particle size distributions. This study evaluates its performance for the grouping of particulate materials according to the European Commission's recommendation on the definition of a nanomaterial, which bases on the number-weighted median diameter. The focus lies on cuvette-type AC with turbidity detector and on the performance in the case of polydisperse, non-spherical real-world materials. Two grades of barium sulfate (nano and non-nano) were analysed. This study compares the repeatability of the measurement and the method precision including sample preparation, measurement and conversion into number-weighted particle size distributions. Experimental results show that the selected radiation wavelengths of 470 nm and 865 nm have only little impact on the number-weighted median diameter, but affect the intermediate precision of these values. However, the intermediate precision of the method is mainly determined by sample preparation up to 12.6% with respect to the number-weighted median diameter (x50,0). This paper provides information on particle sizing on real-world materials for the first time.

Ultrasonic dispersion (USD) constitutes an essential part of sample preparation for the characterisation of potential nanomaterials. Corresponding dispersion protocols require a high input of ultrasonic energy into small suspension volumes. The intention behind is to disintegrate agglomerates and aggregates as completely as possible into the constituent particles or at least into smallest dispersible units. However, it is demonstrated that the concept of complete dispersion fails for pyrogenic materials, which are composed of fractal-like aggregates. Moreover, abrasion of the ultrasonic probe sets practical limits on the ultrasonic energy, which should be employed for sample preparation. The paper also discusses strategies to cope with contaminant probe particles. Last but not least, the experimental data support the application of the energy density as the main parameter for comparing sample preparation based on USD.

Light scattering is a fundamental property that can be exploited to create essential devices such as particle analysers. The most common particle size analyser relies on measuring the angle-dependent diffracted light from a sample illuminated by a laser beam. Compared to other non-light-based counterparts, such a laser diffraction scheme offers precision, but it does so at the expense of size, complexity and cost. In this paper, we introduce the concept of a new particle size analyser in a collimated beam configuration using a consumer electronic camera and machine learning. The key novelty is a small form factor angular spatial filter that allows for the collection of light scattered by the particles up to predefined discrete angles. The filter is combined with a light-emitting diode and a complementary metal-oxide-semiconductor image sensor array to acquire angularly resolved scattering images. From these images, a machine learning model predicts the volume median diameter of the particles. To validate the proposed device, glass beads with diameters ranging from 13 to 125 µm were measured in suspension at several concentrations. We were able to correct for multiple scattering effects and predict the particle size with mean absolute percentage errors of 5.09% and 2.5% for the cases without and with concentration as an input parameter, respectively. When only spherical particles were analysed, the former error was significantly reduced (0.72%). Given that it is compact (on the order of ten cm) and built with low-cost consumer electronics, the newly designed particle size analyser has significant potential for use outside a standard laboratory, for example, in online and in-line industrial process monitoring., Analysis: Novel design uses machine learning for characterising materials Scientists have developed low-cost particle size analyser (PSA) for conducting quality control and product testing in a range of industries, including the pharmaceutical, food and cosmetics. Currently, laser diffraction PSAs that use static light scattering to measure the size distribution of particles from hundreds of nanometres to several millimetres are the most widely used technology. However, these devices are generally large, expensive and complicated to operate, making them impractical for many industrial applications. Led by Valerio Pruneri from ICFO-The Institute of Photonic Sciences in Spain, a team of researchers has made a low-cost, miniaturised PSA capable of determining the volume median diameter of particles suspended in liquids. The novel design incorporates a collimated beam configuration using a commonly available image sensor to capture scattering images and machine learning to predict the particle size distribution.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is gaining acceptance in clinical practice, but detailed information about the microinjection pump (MIP®), the generated aerosol and drug distribution is missing. Ex vivo granulometric analyses by means of laser diffraction spectrometry were performed for MIP® aerosol characterization. Beside the standard operation conditions, the impact of the volumetric liquid flow rate on the aerosol characteristics was investigated with different liquids. Granulometric results as well as the local drug distribution were verified by ex vivo gravimetric analyses. On the basis of determined MIP® characteristics, the aerosol droplet size, which is necessary for a homogenous intra-abdominal drug distribution, was calculated. Granulometric analyses showed that the MIP® aerosol consists of a bimodal volume-weighted particle size distribution (PSD3) with a median droplet diameter of x 50,3 = 25 µm. Calculations reveal that the droplet size for a homogenous intra-abdominal drug distribution during PIPAC therapy should be below 1.2 µm. We show that >97.5 vol% of the aerosolized liquid is delivered as droplets with ≥3 µm in diameter, which are primarily deposited on the surface beneath the MIP® by gravitational settling and inertial impaction. These findings were confirmed by ex vivo gravimetric analyses, where more than 86.0 vol% of the aerosolized liquid was deposited within a circular area with a diameter of 15 cm. The granulometric aerosol properties, as well as the aerodynamic conditions achieved by standard MIP® operation, do not support the idea of widespread or homogenous drug distribution in the abdominal cavity.

The project nanoGRAVUR (BMBF, 2015–2018) developed a framework for grouping of nanomaterials. Different groups may result for each of the three distinct perspectives of occupational, consumer and environmental safety. The properties, methods and descriptors are harmonised between the three perspectives and are based on: Tier 1 intrinsic physico-chemical properties (what they are) or GHS classification of the non-nano-form (human tox, ecotox, physical hazards); Tier 2 extrinsic physico-chemical properties, release from nano-enabled products, in vitro assays with cells (where they go; what they do); Tier 3 case-specific tests, potentially in vivo studies to substantiate the similarity within groups or application-specific exposure testing. Amongst all properties, dissolution and transformation are least modulated by different nanoforms within one substance, whereas dustiness, dispersion stability, abiotic and especially in vitro surface reactivity vary more often between different nanoforms. The methods developed or selected by nanoGRAVUR fill several gaps highlighted in the ProSafe reviews, and are useful to implement (i) the concept of nanoforms of the European Chemicals Agency (ECHA) and (ii) the concept of discrete forms of the United States Environmental Protection Agency (EPA). One cannot assess the significance of a dissimilarity, if the dynamic range of that property is unknown. Benchmark materials span dynamic ranges that enable us to establish bands, often with order-of-magnitude ranges. In 34 case studies we observed high biological similarity within each substance when we compared different (nano)forms of SiO2, BaSO4, kaolin, CeO2, ZnO, organic pigments, especially when we compared forms that are all untreated on the surface. In contrast, different Fe2O3 or TiO2 (nano)forms differ more significantly. The same nanoforms were also integrated in nano-enabled products (NEPs) for automotive coatings, clinker-reduced cements, cosmetic sunscreen, and lightweight polymers.

The granulometric characterization of synthetic amorphous silica (SAS) nanomaterials (NMs) still demands harmonized standard operation procedures. SAS is produced as either precipitated, fumed (pyrogenic), gel and colloidal SAS and these qualities differ, among others, with respect to their state of aggregation and aggregate strength. The reproducible production of suspensions from SAS, e.g., for biological testing purposes, demands a reasonable amount of dispersing energy. Using materials representative for each of the types of SAS, we employed ultrasonic dispersing (USD) at energy densities of 8&ndash, 1440 J/mL and measured resulting particle sizes by dynamic light scattering and laser diffraction. In this energy range, USD had no significant impact on particle size distributions of colloidal and gel SAS, but clearly decreased the particle size of precipitated and fumed SAS. For high energy densities, we observed a considerable contamination of SAS suspensions with metal particles caused by abrasion of the sonotrode&rsquo, s tip. To avoid this problem, the energy density was limited to 270 J/mL and remaining coarse particles were removed with size-selective filtration. The ultrasonic dispersion of SAS at medium levels of energy density is suggested as a reasonable compromise to produce SAS suspensions for toxicological in vitro testing.

ナノ粒子はその勝れた電気特性や光学特性で注目されているが、容易に凝集し、その凝集構造も粒子の特性に影響を与える。このため、ナノ粒子の凝集構造の評価方法に関心が集まり、多くの方法が提案されている。本研究ではその内の小角X線散乱法によるフラクタル次元解析に注目し、コロイド溶液のpHや電解質濃度を変えてナノ粒子の凝集プロセスの異なる試料を作製し、この解析方法が適切な評価を与えるかを検討した。表面フラクタル次元は凝集状態によらず一定値を示し、測定手法の妥当性を示した。しかしながら、体積フラクタルは凝集状態に対応して異なる値を示したが、フラクタル凝集理論から考えられる値の傾向と逆になった。, Nanoparticles (NPs) are recently attracted due to their unique properties, such as electrical or optical characteristics. However, most of these properties depend on the structure of aggregated NPs as well as the size or size distribution. From the view of this point, many evaluation methods were proposed to know the structure of aggregated NPs. One of their proposal methods is the fractal dimension analysis using the data of the scattered electromagnetic wave from aggregated NPs. In this paper, we examined the fractal dimension analysis using small angles X-ray scattering (SAXS) could be useful to evaluate the structure of aggregated NPs. Samples for the analysis were prepared by adding salt with silica colloid, and their aggregated structures were changed from reaction-limited cluster aggregation to diffusion-limited cluster aggregation. The fractal dimension could be obtained by the scattering data by SAXS with the scaling approach. The surface fractal dimension was almost constant even if the aggregation state was changed. On the other hand, the volume fractal dimension depended on the aggregation state, but this tendency was not same as that in the case of the fractal dimension estimated from the light scattering data., 本文の作成者の表記に誤りあり (誤)Ryuma MIYAMOTO → (正)Ryoma MIYAMOTO

The interdisciplinary field of particle characterization and particle release characterization, especially regarding environmental, health and safety aspects associate with nanotechnology, requires coordinated actions in standardization between measurement methods and application scenarios. This in turn, demands also a consistent terminology in context with nanotechnology. Established liaisons, represented by experts, between international standardization committees try to ensure detailed coordination in the daily work.

A method was developed to determine the dynamic shape factor of airborne particles as an integral parameter of the whole aerosol population from only one measurement using an Aerosol Particle Mass Analyzer and a Scanning Mobility Particle Sizer in parallel connection. The method was employed experimentally to determine the dynamic shape factor of test aerosols generated by chemical vapor synthesis. A sintering furnace was used to modify the shape of the particles from fractal-like aggregates to spheres as a result of coalescence.

An acoustic reflection measurement technique is presented, which detects and evaluates the ultrasonic waves backscattered at the particles within a liquid dispersion. The technique is based on an iterative pulse-echo method, which gathers a sufficiently high number of single reflection signals and eventually conducts a statistical analysis yielding two principal parameters of the backscattering signal: its maximum amplitude and its time-dependent decay. Theoretical considerations and experimental investigations show that maximum amplitude of the backscattering signal correlates with the averaged backscattering coefficient of the particles and that the decay rate of the backscattering signal can be attributed to sound attenuation, even though the impact of multiple scattering (i.e. non-linear concentration effects) is much more pronounced as for a transmission setup. Since the developed measurement technique is specifically designed for the in-situ characterisation of concentrated dispersion, it is necessary to adequately account for multiple scattering effects when evaluating the backscattering data. For this purpose a semi-empirical model is developed, which combines an established single particle scattering model with predictions of wave interference for defined microstructure of the dispersion. Experiments on two different types of dispersion confirm the applicability of this approach for concentrations up to 30 vol.%. The experimental results additionally show that the maximum backscattering amplitude is highly sensitive to particle size, whereas the decay rate particularly reflects the impact of particle concentration. Finally a scheme is proposed, which allows for calculating the mean particle size and the volume fraction of the dispersed phase.

Background: The delivery of aerosolised chemotherapeutic substances into pressurised capnoperitonea has been reported to be more effective than conventional liquid chemotherapy for the treatment of peritoneal carcinomatosis. However, recent reports reveal limitations of the currently available technology.Material and Methods: A novel approach for pressurised intraperitoneal aerosol chemotherapy (PIPAC), called hyperthermic intracavitary nanoaerosol therapy (HINAT), based on extracavitary generation of hyperthermic and unipolar charged aerosols, was developed. The aerosol size distribution, the spatial drug distribution and in-tissue depth penetration of HINAT were studied by laser diffraction spectrometry, differential electrical mobility analysis, time of flight spectrometry, scintigraphic peritoneography and fluorescence microscopy. All experiments were performed contemporaneous with conventional PIPAC for the purpose of comparison. Furthermore, a first proof of concept was simulated in anesthetised German Landrace pigs.Results: HINAT provides a nanometre-sized (63 nm) unipolar-charged hyperthermic (41 °C) drug aerosol for quasi uniform drug deposition over the whole peritoneum with significantly deeper drug penetration than that offered by conventional PIPAC.

Pyrogenic powders consist of fractal like aggregates with nanosized primary particles. The formation of such aggregates, their hydrodynamic behavior and their optical properties are in principle well understood. Even so, there is only little experience in interpreting results from particle sizing of such materials. Dramatic differences in size distribution obtained from different measurement techniques give frequently rise to confusion on the “true” aggregate size. However, such differences can be attributed to the different particle properties used for size measurement and to the different types of quantities, by which the frequency of the individual size fractions are weighted. For two conventional sizing techniques, Dynamic Light Scattering and Optical Centrifugation Analysis, the influence of the structural properties on the relevant optical and hydrodynamic aggregate properties is discussed on the basis of virtual aggregates as well as of empirical data for pyrogenic powders. Finally measurable size distributions are predicted in a case study.

This paper examines the interaction between the electric double layers of aggregates. Commonly, rather simplified models are used like the approximation of primary particle interaction (APPI), which just considers the interaction of the closest pair of primary particles having a double layer as if they were isolated. However, for nanoparticles the double layer thickness may be in the same order of magnitude as the particle size or even larger, what leads to a considerable double layer overlap inside the aggregates and between two interacting aggregates. Consequently, such approximations will fail. The paper presents a numerical scheme for the double layer interaction of arbitrarily shaped aggregates, which can e.g. help to establish criteria for the applicability of approximate models. The calculation employs a singularity method, which is based on the linearised Poisson–Boltzmann equation. Additionally, a linear model for charge regulation is implemented. The impact of charge regulation and double layer thickness were studied for fractal DLCA aggregates and hexagonal closed-packed aggregates.

The van-der-Waals forces between particles are of fundamental importance for agglomeration processes or their structuring in suspensions. The paper describes a calculation scheme for the corresponding energy potential when the interacting objects are aggregates of colloidal primary particles. This scheme is further employed to examine the impact of aggregate structure on the van-der-Waals interaction. Calculations were therefore conducted for deterministic aggregates with tuneable fractal dimension and for DLCA aggregates of varying size. It appears that the van-der-Waals interaction is governed by the closest pair(s) of primary particles. That results in an impact of the aggregate structure, when the interaction energy is plotted versus the aggregate centre distance. For DLCA aggregates this relationship can be described by a size-independent, but material specific mastercurve.

Nanoparticles are used in industrial and domestic applications to control customized product properties. But there are several uncertainties concerning possible hazard to health safety and environment. Hence, it is necessary to search for methods to analyze the particle release from typical application processes. Based on a survey of commercial sanding machines, the relevant sanding process parameters were employed for the design of a miniature sanding test setup in a particle-free environment for the quantification of the nanoparticle release into air from surface coatings. The released particles were moved by a defined airflow to a fast mobility particle sizer and other aerosol measurement equipment to enable the determination of released particle numbers additionally to the particle size distribution. First, results revealed a strong impact of the coating material on the swarf mass and the number of released particles.

A novel method for the quantification of the nanoparticle release into air from surface coatings was developed. The method is based on the combination of a defined abrasion process with highly sensitive methods to quantify airborne particle concentration. A standardized system for abrasion testing was employed to adjust a defined wear process. Details of the abrasion system are presented in combination with a downstream aerosol measurement technique (scanning mobility particle sizer, SMPS and condensation particle counter, CPC) which focuses on the quantification of a release rate from particles smaller than 100 nm. The interconnection between the aerosol measurement system and the abrasion process is described in detail. After the proof of sensitivity of the measuring system first measuring results of abraded surface coatings revealed a reasonable reproducibility of the generated wear particles in terms of total mass and a rather weak reproducibility in terms of the total number concentration. However, the total number of generated submicrometer particles or nanoparticles was extremely low and laid below the statistic significance threshold.

Dynamic light scattering (DLS) is a method used to size nanoscale and submicron particles by measuring their thermal motion (diffusion) in a liquid environment. The measured diffusion coefficients are related to the hydrodynamic particle size via the Stokes-Einstein equation. This paper addresses the application of DLS for the characterization of diluted suspensions of pyrogenic silica, which consist of polydisperse fractal-like aggregates composed of sintered spherical primary particles. Simulations are employed to establish a relationship between the structural properties of the aggregates and their diffusional behavior. Therefore, an algorithm is developed that enables the generation of aggregates with a tunable fractal dimension and an arbitrary number of primary particles. The results provide evidence that the hydrodynamic radii show a different scaling compared to the structural radius of gyration, which is of great relevance for the interpretation of DLS results. In addition, the influence of rotational diffusion has to be accounted for in the measurements.

Dynamic light scattering (DLS) is frequently used to characterize suspensions of pyrogenic silica which consists of polydisperse fractal aggregates of sintered spherical primary particles. As the method primarily measures temporal fluctuations of scattered light caused by the translational and rotational diffusive motion of the aggregates it is an important prerequisite to identify those structural properties that are measurable with DLS and to quantify the method’s sensitivity to changes in these properties. In a recent paper [1] we have investigated the structure-hydrodynamics relationship via simulations. Here, the validation of the simulation results by experimental data is presented. Therefore, the structure of different pyrogenic silica grades has been characterized by static light and X-ray scattering and the diffusional properties were obtained by multi-angle DLS measurements. It is shown that the hydrodynamic radii determined with DLS scale well with the mean aggregate radius of gyration but that the influence of rotational diffusion has to be accounted for in the measurements.

Der Wettbewerbsdruck in der chemischen Industrie macht es notwendig, Masnahmen zu ergreifen, durch die Prozesse drastisch verbessert werden, um auch zukunftig wettbewerbsfahig zu bleiben. Der Entwicklung und Implementierung derartiger, prozessintensivierender Masnahmen geht zweckmasigerweise eine ganzheitliche Analyse des betreffenden Prozesses voraus. Am Beispiel eines Zerkleinerungsprozesses fur einen partikularen Wirkstoff wird diese Vorgehensweise veranschaulicht. Durch den Einsatz zweier komplementarer Methoden der Partikelmesstechnik, der Ultraschallspektroskopie und der Laserbeugung werden Korrelationen zwischen Dispersitatsmerkmalen und Qualitatsmerkmalen des Produkts gefunden. Sowohl die Effizienz von Zerkleinerungsapparaten aber auch die des Prozesses konnen so bewertet werden. Die Ultraschallspektroskopie kann als Messmethode zur lokalen Prozesskontrolle eingesetzt werden.

The competitive pressure in the chemical industry makes it necessary to take measures that enable processes to be drastically improved in order to remain competitive also in the future. For the development and implementation of such process-intensive measures, it is expedient to perform a complete analysis of the process of interest. This approach is demonstrated using a size reduction process for a particulate active substance as an example. Correlations between the dispersion characteristics and quality characteristics of the product were found using two complementary methods of particle measurement technology, ultrasonic spectroscopy and laser diffraction. These methods make it possible to analyze the efficiency of the comminution apparatuses, but also of the processes. Ultrasonic spectroscopy can be used as a measurement method for local process control.

Fur die Energieversorgung medizinischer Implantate werden seit mehreren Jahren Lithium/Mangandioxid-Primarbatterien eingesetzt. Die Leistungsfahigkeit der Batterie wird dabei masgeblich durch die Struktur der porosen Kathode bestimmt. Diese kompaktierte Feststoffelektrode enthalt als elektrochemisch aktives Material Mangandioxid (MnO2) sowie weitere pulverformige Additive. Durch Fraktionierung des Aktivmaterials kann die Struktur der Kathode gezielt beeinflusst werden. Verringert man die mittlere Partikelgrose eines Pulversystems, vergrosert sich die spezifische Oberflache, zudem werden Diffusionswege fur Lithiumionen innerhalb des Einzelpartikels verkurzt. Es ist jedoch bekannt, dass bei Verringerung der Partikelgrose die Oberflachenkrafte dominieren und zu einer verstarkten Agglomerationsneigung des Pulvers fuhren. Hieraus resultieren Kathoden mit hoherer Porositat aber geringerer Packungsdichte. Mit zunehmender mittlerer Partikelgrose konnen grosere Packungsdichten erreicht werden, was zur Verbesserung der Aktivmassebeladung und der Energiedichte der Batterie beitragt. Die vorgestellte Untersuchung beschaftigt sich mit den Einflussen der Partikelgrosenverteilung der Aktivmasse auf die Struktur der Kathode und die hieraus resultierenden Eigenschaften von Primarbatterien. Entgegen dem Stand der Technik konnte der positive Einfluss der Partikelgrosenverringerung des Aktivmaterials fur die hier untersuchten Batterietypen nicht bestatigt werden.

A novel inline measuring system can be applied to polymer extrusion to achieve real time data on melt quality. Disturbing particles such as gels, unmolten resins, black spots or gas bubbles can be detected within flowing transparent polymer melts continuously without any lag of time directly during extrusion processing. In the first part of the present paper the state of the art related to particle monitoring in polymer melts in terms of 'process analytical technology (PAT)' will be presented briefly. After this the microphotometric measuring principle of the used inline process sensors from polymer melt particle (PMP) type will be described as well as various kinds of sensor adaptation to extruder machines. First experiments were realised on labscale extruders applying model particle systems to achieve detailed information on sensor performance characteristics. As a next step industrial polymer systems have been examined on pilot plant extruders. Finally results of these experiments contributed ...

The determination of particle size distributions from ultrasonic attenuation spectra requires the knowledge of a variety of parameters (material properties and particle concentration) when the analysis is based on analytical models. In this paper, two strategies are tested that allow for the elicitation of size information from attenuation spectra when the relevant model parameters are only partially known. The first strategy uses the data on measured sound speed as additional information, which facilitates the fitting of the unknown model parameters parallel to the calculation of the particle size distribution. The second strategy comprises the formation of an empirical model that is based on the principal components, which are obtained by decomposing a measured attenuation spectrum into a set of orthogonal basic spectra. Both strategies are tested with colloidal emulsions: the first one for the cases of unknown particle concentration and unknown specific heat of the droplets, the second one for monitoring changes in the state of dispersion and in the temperature.

Messsysteme der Photonenkorrelationsspektroskopie, die Mehrfachstreueffekte unterdrucken konnen, ermoglichen die Untersuchung von Partikelwechselwirkungen in kolloidalen Systemen. Dabei zeigen sich sowohl DLVO-Wechselwirkungseffekte als auch Struktureffekte, z. B. bei Aggregaten pyrogener Kieselsaure. Erganzend zum mittleren Diffusionskoeffizienten konnte die Verteilungsbreite als wichtiger Informationstrager identifiziert werden.