DIN EN ISO Research Articles

Laser-based powder bed fusion of Ti-6Al-4V powder modified with SiO2 nanoparticles

In laser-based powder bed fusion of metals (PBF-LB/M), residual oxygen in the processing atmosphere is regarded as disruptive and disadvantageous for the manufacturing process and the resulting component properties. A novel approach to eliminate residual oxygen is to add small amounts of silane to the argon process gas. Silane eliminates residual oxygen and forms SiO2 nanoparticles, which in turn can be incorporated into the powder during the process. It is therefore necessary to evaluate the influence of these nanoparticles admixed to the metal powder. In this work, Ti-6Al-4V powder was modified with pyrogenic SiO2 nanoparticles generated by the reaction of a silane argon gas mixture with ambient air. Modified and unmodified powder was analyzed and processed using statistically designed experiments. An improvement of the flow rate according to DIN EN ISO 4490 (from 33.3 to 32.5 s/50 g) and increase of apparent density according to DIN EN ISO 3923 (from 2.52 to 2.58 g/cm3) could be observed after powder modification. No statistically significant effects of the modification on roughness, porosity, and hardness were found. The results demonstrate that powder modification using silane can lead to enhanced flowability without affecting the PBF-LB processing window of Ti-6Al-4V.

Passive dosing: Assessing the toxicity of individual PAHs and recreated mixtures to the microalgae Raphidocelis subcapitata

Risk assessment of hydrophobic organic compounds (HOCs) is difficult because maintaining a well-defined exposure during aquatic toxicity testing is challenging due to the limited water solubility and various loss processes such as volatilization, biodegradation and sorption. Passive dosing techniques help to overcome these challenges by providing a well-controlled and solvent-free exposure. In this study, the algal growth inhibition test (DIN EN ISO 8692) was converted into a miniaturized passive dosing setting. For this purpose, biocompatible O-rings were used as substance reservoirs and loaded with polycyclic aromatic hydrocarbons (PAHs). The growth inhibition of the microalgae Raphidocelis subcapitata induced by single PAHs (log KOW 3.24-5.91) was investigated. In addition, recreated PAH mixtures were tested representing field compositions of the pore water North Sea sediments. Some of the single PAHs revealed strong growth inhibiting effects on the algal growth, while the recreated mixture compositions had slightly lower effect on the growth inhibition in the highest concentrations. Overall, the toxicity of the PAHs generally increased with the maximum chemical activities (amax) of the PAHs and the inhibition data could be fitted with one maximum chemical activity response curve. Therefore, the miniaturized passive dosing approach appears as a promising practical and economical method that can be used for toxicity testing of the different trophic levels to improve comprehensive risk assessment.

Accreditation in pathology and neuropathology in Germany : General regulations and requirements

Accreditation in pathology and neuropathology in Germany is based on the requirements of the DIN EN ISO/IEC 17020 standard, which defines general requirements for the bodies performing inspections. In Germany, the national accreditation body of the Federal Republic of Germany (DAkkS) assumes the official task of accreditation. Evaluation in this area is based on acomprehensive assessment by board-certified pathologists (inspection) and is focused on correct diagnosis. The requirement of the DIN EN ISO 15189 standard on quality and competence in medical laboratories is taken into account. In Germany, more than 100 institutes of pathology and neuropathology have successfully performed the accreditation process. Interest in accreditation has been significantly growing in recent months, especially due to changes in the European law with the "Verordnung EO 2017/746 des Europäischen Parlaments und des Rates vom 05.April 2017 über Invitro-Diagnostica".However, accreditation is ademanding process that requires very good preparation. Necessary resources for accreditation should be secured before starting the process. Important framework conditions and requirements, but also some challenges that can arise during the accreditation process, are summarized in this article.

Adhesion properties of tartaric sulfuric acid anodic films assessed by a fast and quantitative peel tape adhesion test

The adhesion capabilities of sulfuric acid and tartaric-sulfuric-acid anodic oxide films on cladded AA2024-T3 aluminium substrates have been investigated in a quantitative manner. A relatively simple, versatile and industrially applicable test methodology based on DIN EN ISO 29862 has been used. In addition, the effect of anodising process parameters on the oxide film morphology has been studied and correlated with the adhesion results. The process parameters considered are the chemistry of the acidic pickling pre-treatment step, the addition of tartaric acid to the sulfuric acid electrolyte, the formation voltage, and the electrolyte temperature. The suggested tape peel adhesion test is able to differentiate among pre-treatments and anodising conditions showing a good correlation with the morphological features at the ultimate surface. High peel adhesion strengths are measured when topographies such as pore mouth widening and dissolution-driven roughness take place. These morphologies are typically found in anodic layers formed at elevated electrolyte temperatures. The proposed method can be beneficial for a fast assessment of anodising parameters for good adhesion, which is of special interest for the industrial optimisation of anodising processes.

Development of an Alternative Alloying Concept for Additive Manufacturing Using PVD Coating

New alloys are needed to adapt the material properties and to improve the weldability of arc-based additive manufacturing processes. The classic development of welding filler materials is time-consuming and cost-intensive. For this reason, an alternative alloy concept is investigated and qualified here. This is based on the thin-film coating of welding filler materials by means of PVD coating. An HSLA steel DIN EN ISO 14341-A G 50 7 M21 is used as the base material. This is alloyed with the elements Al, Cr, Nb, Ni and Ti by means of PVD thin-film coating. This procedure represents an alternative alloy concept. In the scope of the qualification, the influence of the process and material properties is investigated, and the alternative alloying concept is compared with the classical alloying concept of secondary metallurgy. The investigations have shown that the thin film coating on the surface of the welding filler metal affects the process properties in the form of a changed arc length. Furthermore, the mechanical properties and the effect on the microstructure morphology were investigated. These were compared in the same chemical composition with a Mn4Ni2CrMo produced by secondary metallurgy. The results are in agreement with regard to the mechanical properties and the effect on the microstructure morphology.

Acceptance and reverification testing for industrial computed tomography – a simulative study on geometrical misalignments

Abstract. Acceptance and reverification testing for industrial X-ray computed tomography (CT) is described in different standards (E DIN EN ISO 10360-11:2021-04, 2021; VDI/VDE 2630 Blatt 1.3, 2011; ASME B89.4.23-2020, 2020). The characterisation and testing of CT system performance are often achieved with test artefacts containing spheres. This simulative study characterises the influence of different geometrical error sources – or geometrical misalignments – on these sphere measurements. The two measurands on which this study focuses are the sphere centre-to-centre distances and the sphere probing form errors. One difference between the current draft of the ISO 10360-11 standard (E DIN EN ISO 10360-11:2021-04, 2021) and the VDI/VDE standard 2630 part 1.3 (VDI/VDE 2630 Blatt 1.3, 2011) as well as the ASME standard B89.4.23 (ASME B89.4.23-2020, 2020) are the differences for the sphere centre-to-centre distances that need to be measured. The VDI/VDE standard and the ASME standard require measurements of these kinds of distances of up to 66 % of the possible maximum distance within the measurement volume, while the ISO draft asks for measurements of up to 85 % of the possible maximum distance. This requirement needs to be considered in connection with the maximum permissible error (MPE) specification for these sphere distance measurements. This MPE should be specified as a linear function of the nominal distance or a constant value or a combination thereof (compare definition 9.2 of ISO 10360-1:2000 + Cor.1:2002 (DIN EN ISO 10360-1:2003-07, 2003)), and thus, the linearity of the length-dependent maximum measurement error of the sphere distance measurements is of interest. This simulative study inspects to what extent this linearity can be observed for CT measurements under the influence of different geometric errors. Further, the question is whether measurement lengths above 66 % necessitate a change in the MPE specification. Thus, an automatic identification of cases that might affect the MPE specification is proposed, and these cases are inspected manually. A second aspect of this study is the impact of geometrical misalignments on the probing form errors of a measured sphere. The probing form error also needs to be specified. Thus, whether and how it is influenced by the misalignments is also of interest. Based on our simulations, we conclude that probing form errors and sphere centre-to-centre distances of up to 66 % of the maximum possible measurement length within the measurement volume are sufficient for acceptance testing concerning geometrical misalignments – each geometrical misalignment can be detected well with at least one of these two measurands.

Analysis of pore morphology in oxide electroceramics by automatic image analysis

Abstract Porosity represents one of the key parameters in the characterization of ceramic materials. Pores remaining after sintering often constitute the origin of direct mechanical or dielectric material failure. Isolated and large-scale pores in the microstructure are particularly problematic; many times these are larger than the average pore diameter. Their detection poses a particular challenge for analytics. The analytical methods used for ceramic materials either detects only part of the porosity or are greatly limited in view of area measurements. Moreover, the analysis of the morphology of detected pores is hardly possible or even impossible for the majority of methods. This research paper offers a detailed account of the qualitative analysis of porosity in oxide ceramics, with the primary focus being on possibilities for pore detection, the measured distribution functions, and the advantages of this method. This paper will show that the use of digital light microscopy together with coaxial illumination is capable of determining pore morphology and distribution in a fraction of time that would be required by conventional methods. The comparison of the measurement results, aided by well established methods for pore characterization, such as the linear intercept method (according to DIN EN ISO 13383), will enable a reliable validation of the results. Final FESEM analysis was used to enable a detailed study of the identified pores and to verify the results.

In Vivo Biocompatibility Analysis of a Novel Barrier Membrane Based on Bovine Dermis-Derived Collagen for Guided Bone Regeneration (GBR).

Collagen-based barrier membranes are nowadays the prevalent option for Guided Bone Regeneration (GBR) procedures. Xenogeneic collagen is highly biocompatible as it shares a similar structure to native human collagen, which prevents it from eliciting an exaggerated host immune response. Most commercially available collagen barrier membranes are porcine-derived, while bovine-derived alternatives are still rarely available. The aim of the present study was to investigate the tissue responses and the barrier functionality of a novel GBR membrane composed of bovine collagen type I (BM). Therefore, the subcutaneous implantation model in Wistar rats was performed to compare the novel medical device with two already clinically used native porcine-based barrier membranes, i.e., Jason® membrane (JM) and Bio-Gide® (BG), at 10-, 30-, 60-, and 90-days post implantationem. Histochemical and immunohistochemical stains were used for histopathological evaluation including a biocompatibility scoring according to the DIN EN ISO 10993-6 norm as well as histomorphometrical analyses of the occurrence of M1 and M2 macrophages and the transmembraneous vascularization. The bovine membrane exhibited a host tissue reaction that was comparable to both control materials, which was verified by the scoring results and the histomorphometrical macrophage measurements. Moreover, the novel membrane exhibited an integration pattern without material fragmentation up to day 60. At day 90, material fragmentation was observable that allowed for “secondary porosity” including transmembrane vascularization. The results of this study suggest that the novel bovine barrier membrane is fully biocompatible and suitable for indications that require GBR as a suitable alternative to porcine-sourced barrier membranes.

MOF@chitosan Composites with Potential Antifouling Properties for Open-Environment Applications of Metal-Organic Frameworks

Metal-organic frameworks (MOFs) are promising materials for a myriad of applications because of their easy synthesis and large variability through the organic linker. For open-environment applications, the organic content can, however, give rise to fouling, that is, biofilm formation. Biofilms can destroy the MOF and reduce the sorption capacity. Therefore, it is necessary to formulate MOFs for open-environment application to avoid the growth of microorganisms. Chitosan is a polysaccharide biopolymer, obtained from chitin shells of shrimps by alkaline deacetylation, and has known fungistatic properties. Here, chitosan is used as a matrix for MOF@chitosan composites with different aluminum-based MOFs to implement the fungistatic effect of chitosan to MOFs. The obtained composites with the highest possible MOF loadings of up to 90% were tested according to DIN EN ISO 846 to examine the fungistatic material properties against the fungi Chaetomium globosum and Aspergillus falconensis.

Intensive Care ventilation-New norm establishes a uniform nomenclature for ventilation modes

The current naming of ventilation modes in anesthesiology and critical care is characterized by manufacturer-specific inconsistent acronyms. This is confusing for users and potentially life-threatening for patients. The standard, published in August 2021 in its German version as DIN EN ISO 19223:2021, aims to introduce auniform classification with corresponding nomenclature. To present the new standard and its consequences for the user. Review and summary of DIN EN ISO 19223:2021 with a critical appraisal of its strengths and weaknesses. Asimplified scheme shows the group classification of ventilation modes based on similar characteristics. These are further specified by additional variables. Areference table contrasts the new nomenclature of ventilation modes with those currently in use. Accordingly, the new classification scheme appears inconsistent and the variables are difficult to distinguish. Standardized terminology and semantics in respiratory care are necessary and desirable for error reduction. However, the recently presented standard fulfils these expectations only to some extent and in its current form will probably lead to further ambiguities and problems in the clinical routine. Accordingly, it is imperative that this first version of DIN EN ISO 19223:2021 be understood as the starting point for adiscussion of its content, even outside the standards committees, so that its obvious weaknesses can be eradicated and the nomenclature made suitable for everyday use.

Influence of exoskeleton use on welding quality during a simulated welding task.

The aim of this study is to investigate the effects of wearing exoskeletons during welding on the quality of the weld seam. A total of n=15 young healthy subjects with welding experience took part in the study. The study design defines a 1-hr workflow that abstracts welding and grinding tasks. The sequence is based on standard DIN EN ISO 9606-1 and reproduces authentic work sequences in the constrained body positions PF-workpiece in front of the body and PE-workpiece overhead. Each subject completed the entire workflow once with and once without passive shoulder exoskeleton in a randomized order. The evaluation shows that the use of passive shoulder exoskeletons has a significant influence (p=.006 for Position PF; p=.029 for Position PE) on the welding parameter travel speed which significantly influences the quality of the weld seam. The quality scale (by the used augmented reality (AR) welding simulator) of the travel speed, which significantly determines the permissibility of the weld, increases by 5.80% in the constrained body position PF and by 28.87% in the constrained body position PE when using an exoskeleton. The score of the welding parameter travel speed, which is essential for the permissibility of the seam, shows a statistically significant increase when an assistance system is used. Further research during real welding with exoskeletons could be based on the setup and workflow of this study.

Influence of the Age of Bamboo Culm and Its Vertical Position on the Technological Properties of Bamboo Fibers: A Case of <i>Bambusa vulgaris</i> Species from Cameroonian Culture

Due to their interesting properties, bamboo fibers are more and more used as reinforcements in polymer matrices as a substitute for synthetic fibers. For their future service life, it is important to understand their physical and mechanical behavior over time in order to control the aging phenomenon within this fiber. The paper analyzed the influence of the age of the bamboo thatch and the vertical position of the Bambusa vulgaris species cultivated in Cameroon on the physicomechanical properties of the fibers extracted from the thatch. Fibers were mechanically extracted from three bamboo culms aged respectively 3 years (BV3), 4 years (BV4) and 5 years (BV5). The culms were thus identified according to their number of ramifications, and were felled no abated for a total of three culms. A section of about one meter on each of the parts (lower part, middle part, upper part) of these three culms was made for the opposite technological studies. Each age was therefore represented by three portions of thatch, one from the upper part, one from the middle part and the last from the lower part of the thatch, all giving a total number of nine samples taken and marked BV3inf, BV3moy, BV3sup, BV4inf, BV4moy, BV4sup, BV5inf, BV5moy, BV5sup before handling in the laboratory. Physical (density, moisture absorption rate) and mechanical (tensile tests according to DIN EN ISO 13934-1, natural durability) characterizations were used to better understand the mechanisms of this influence. In view of all the results obtained, the fiber from the upper part of the 3-year-old thatch (BV3sup) is the one with the best characteristics and is recommended for a better elaboration of bamboo fiber composites: (Density: 0.83; Absorption rate 11.7%; Young’s modulus: 7.4 GPa; Maximal stress: 64.3 MPa; Elongation at rupture: 1.1; Loss of mass natural durability: 7.63%).

In Vitro Analysis of the Cytocompatibility of a Novel Porcine Aortic Patch for Vascular Reconstruction.

Cardiovascular diseases are one of the most common causes of morbidity and mortality in the world. In the case of severe arteriosclerotic damage, surgical treatment is necessary. Although the use of autologous vessels is still considered to be the gold standard, sufficient autologous vessels for transplantation are lacking. In the present study, histological examination and in vitro cytotoxicity analysis according to DIN EN ISO 10993-5 were performed on a newly developed porcine vascular graft from a decellularized aorta. A conventional bovine graft was used as control. The ex vivo-histological analysis revealed the effectiveness of a new purification process on the microstructure and the removal of xenogeneic antigen-bearing structures in the new vessels. Furthermore, cell viability and cytotoxicity assays revealed full cytocompatibility. The novel graft shows no structural damage and gets completely decellularized by the purification process. Superior cytocompatibility, compared with the bovine-derived vascular graft, was demonstrated.

The Effect of Collagen-I Coatings of 3D Printed PCL Scaffolds for Bone Replacement on Three Different Cell Types

Introduction The use of scaffolds in tissue engineering is becoming increasingly important as solutions need to be found to preserve human tissues such as bone or cartilage. Various factors, including cells, biomaterials, cell and tissue culture conditions, play a crucial role in tissue engineering. The in vivo environment of the cells exerts complex stimuli on the cells, thereby directly influencing cell behavior, including proliferation and differentiation. Therefore, to create suitable replacement or regeneration procedures for human tissues, the conditions of the cells’ natural environment should be well mimicked. Therefore, current research is trying to develop 3-dimensional scaffolds (scaffolds) that can elicit appropriate cellular responses and thus help the body regenerate or replace tissues. In this work, scaffolds were printed from the biomaterial polycaprolactone (PCL) on a 3D bioplotter. Biocompatibility testing was used to determine whether the printed scaffolds were suitable for use in tissue engineering. Material and Methods An Envisiontec 3D bioplotter was used to fabricate the scaffolds. For better cell-scaffold interaction, the printed polycaprolactone scaffolds were coated with type-I collagen. Three different cell types were then cultured on the scaffolds and various tests were used to investigate the biocompatibility of the scaffolds. Results Reproducible scaffolds could be printed from polycaprolactone. In addition, a coating process with collagen was developed, which significantly improved the cell-scaffold interaction. Biocompatibility tests showed that the PCL-collagen scaffolds are suitable for use with cells. The cells adhered to the surface of the scaffolds and as a result extensive cell growth was observed on the scaffolds. The inner part of the scaffolds, however, remained largely uninhabited. In the cytotoxicity studies, it was found that toxicity below 20% was present in some experimental runs. The determination of the compressive strength by means of the universal testing machine Z005 by ZWICK according to DIN EN ISO 604 of the scaffolds resulted in a value of 68.49 ± 0.47 MPa.

In situ Forming Hyperbranched PEG-Thiolated Hyaluronic Acid Hydrogels With Honey-Mimetic Antibacterial Properties.

The rapidly increasing resistance of bacteria to currently approved antibiotic drugs makes surgical interventions and the treatment of bacterial infections increasingly difficult. In recent years, complementary strategies to classical antibiotic therapy have, therefore, gained importance. One of these strategies is the use of medicinal honey in the treatment of bacterially colonized wounds. One of the several bactericidal effects of honey is based on the in situ generation of hydrogen peroxide through the activity of the enzyme glucose oxidase. The strategy underlying this work is to mimic this antibacterial redox effect of honey in an injectable, biocompatible, and rapidly forming hydrogel. The hydrogel was obtained by thiol–ene click reaction between hyperbranched polyethylene glycol diacrylate (HB PEGDA), synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization, and thiolated hyaluronic acid (HA-SH). After mixing 500 µL HB PEGDA (10%, w/w) and 500 µL HA-SH (1%, w/w) solutions, hydrogels formed in ∼60 s (HB PEGDA/HA-SH 10.0–1.0), as assessed by the tube inverting test. The HB PEGDA/HA-SH 10.0–1.0 hydrogel (200 µL) was resistant to in vitro dissolution in water for at least 64 days, absorbing up to 130 wt% of water. Varying glucose oxidase (GO) amounts (0–500 U/L) and constant glucose content (2.5 wt%) were loaded into HB PEGDA and HA-SH solutions, respectively, before hydrogel formation. Then, the release of H2O2 was evaluated through a colorimetric pertitanic acid assay. The GO content of 250 U/L was selected, allowing the formation of 10.8 ± 1.4 mmol H2O2/L hydrogel in 24 h, under static conditions. The cytocompatibility of HB PEGDA/HA-SH 10.0–1.0 hydrogels loaded with different GO activities (≤ 500 U/L) at a constant glucose amount (2.5 wt%) was investigated by in vitro assays at 24 h with L929 and HaCaT cell lines, according to DIN EN ISO 10993-5. The tests showed cytocompatibility for GO enzyme activity up to 250 U/L for both cell lines. The antibacterial activity of HB PEGDA/HA-SH 10.0–1.0 hydrogels loaded with increasing amounts of GO was demonstrated against various gram-positive bacteria (S. aureus and S. epidermidis), antibiotic-resistant gram-positive bacteria (MRSA and MRSE), gram-negative bacteria (P. aeruginosa, E. coli, and A. baumanii), and antibiotic-resistant gram-negative strains (P. aeruginosa and E. coli) using agar diffusion tests. For all gram-positive bacterial strains, increasing efficacy was measured with increasing GO activity. For the two P. aeruginosa strains, efficacy was shown only from an enzyme activity of 125 U/L and for E. coli and A. baumanii, efficacy was shown only from 250 U/L enzyme activity. HB PEGDA/HA-SH 10.0–1.0 hydrogels loaded with ≤250 U/L GO and 2.5 wt% glucose are promising formulations due to their fast-forming properties, cytocompatibility, and ability to produce antibacterial H2O2, warranting future investigations for bacterial infection treatment, such as wound care.

COPSOQ III in Germany: validation of a standard instrument to measure psychosocial factors at work

BackgroundOver the last almost 20 years COPSOQ (Copenhagen Psychosocial Questionnaire) has become a well-established instrument to measure psychosocial stress at work. In Germany, a first validated version of COPSOQ was introduced in 2005. After the COPSOQ international network took over responsibility for the development of COPSOQ, a new version was published in 2019 (COPSOQ III). The German version of this questionnaire is now to be validated.MethodsMeasurement qualities of German COPSOQ III are explored in adherence to the to the usual requirements of a validation study as defined by DIN EN ISO 10075-3. A sample of observations from more than 250,000 participants surveyed with the COPSOQ in Germany is used for univariate and multivariate statistical analysis.ResultsWith its 84 items the German COPSOQ III includes all psychosocial work factors that are internationally obligatory and is still compatible with almost 70% of the content in the 2005 German version. Typical psychometric properties of the questionnaire (e. g., validity and reliability) are either good or very good for most of the 84 items and 31 scales. Beyond basic results, congruences with widely used theoretical approaches like the Demand-Control(−Support) model or the Job Demands-Resources model are generally satisfactory.ConclusionsWith the launch of COPSOQ III in Germany, new workplace psychosocial aspects could be explored. Like the preceding version, the questionnaire is a highly useful instrument for research as well as for risk assessment in enterprises. COSPQO III covers a multitude of theoretical approaches and gives comprehensive information on psychosocial working conditions to deduce actions for their improvement.

Issues of long-term durability of paper – Labest Papier

Abstract. In the project “Labest Papier – Langzeitbeständigkeit von Papier” (Labest Paper – Long-term durability of paper), the suitability of paper to serve as a permanently undamaged information carrier for at least 500 years is to be assessed by the Department of Paper Manufacturing and Mechanical Process Engineering (PMV) for the Federal Office for the Safety of Nuclear Waste Disposal (BASE). The ageing mechanisms of paper are known, as are countermeasures. This leads to standards and recommendations for the use of paper for documents. DIN EN ISO 9706 (2010) is the main proponent of the direction that longevity can be ensured solely via the composition of the paper and the initial situation at the beginning of ageing. DIN 6738 (2007), on the other hand, takes as its basis the approach of assessing the physical ageing of the paper based on artificial ageing and the strength losses observed in the process. Other standards vary the approaches somewhat or mix them in part, for which the lecture presents a comparison table. The usability of a document depends on two essential factors. Firstly, the residual strength after an ageing process must be high enough for the document to be usable. Secondly, the information written on it must still be legible or at least recognisable. The limits of the possibilities for dealing with damage that has already occurred are almost only set by complete destruction. Otherwise, forensic means can restore the information in a document, at least in part, with the appropriate investment of time and money. The lecture provides examples, such as the reprocessing of shredded Stasi files. Even the loss of knowledge of writing and language need not be a final obstacle, as the decipherment of hieroglyphics proves. The costs of measures to deal with damage depend individually on the condition of the documents and on the objectives in dealing with the damage. Prevention is an effective means of avoiding damage and costs in the first place. Paper is an information carrier well known for over 2000 years and has already proven its suitability for storing long-term information. Despite the fact that an intactness in the sense of being completely untouched is never given, paper has the advantage of a long migration time and that no reading or decoding device is necessary compared to modern information storage media, such as digital media or microfilm. Which grade of paper will ultimately meet the demands, however, depends on the overall consideration of the availability of the grade, the expected damage and the possibilities and costs of handling it. There is still a need for research, especially with respect to the assessment of the effect of printing inks and auxiliaries used in paper production on the longevity as well as the classification of recycled paper. An extensive measurement program is investigating this during the current project. After the project is accomplished, BASE will be able to decide in which way the already existing types of papers including marking can be preserved for as long as necessary and how the state-of-the-art optimised system “paper ink” must be prepared to ensure long-term durability. The paper is based on two working stage reports, AP1 (Schaffrath, 2020) and AP2 (Schaffrath, 2021).

Examination of common swifts (Apus apus) for salmonella shedding in the area of Hannover, Lower Saxony, Germany.

The available literature indicates a high prevalence of the zoonotic pathogen Salmonella (S.) enterica serovar Infantis in the common swift (Apus apus). This long-distance migrant, which only consumes aerial plankton, can reach high population densities in places with suitable breeding sites. Dedicated competent private persons take part in the hand rearing of juvenile common swifts in wildlife rescue centres, which unavoidably results in close contact with these avian patients. For this reason, we examined common swifts for shedding of Salmonella spp. In the years 2014 and 2019, intestinal swabs or fresh faeces of common swifts (2014: n = 54; 2019: n = 62) were examined microbiologically (DIN EN ISO 6579; Annex D) in the area of Hannover, Lower Saxony, Germany. Salmonella spp. could not be detected in any of the examined common swifts within the investigation period and the studied area in 2014 and 2019. The results illustrate that the common swift is unlikely to be a natural reservoir of Salmonella spp. For the transmission of salmonella by swifts the local conditions with the corresponding environmental impact seem to play a significant role, and the risk of transmission should be assessed according to the region to be examined.

Tracking blood pressure changes by means of non-invasive intermittent blood pressure measurements in clinical application

Abstract Considering accuracy/precision cut-offs of 5 ± 8 mmHg and cut-off values for inter-class correlation coefficients (ICC=0.37...1, from DIN EN ISO 81060-2), absolute and relative errors in time independent measurement of blood pressure changes with non-invasive intermittent devices (NiBP) are derived mathematically for mean arterial blood pressure range of 40-180 mmHg. As a clinically relevant value for change of arterial blood pressure 20% of the baseline blood pressure is considered. The mean ratio between the change of BP measured by the NiBP and measured by the invasive reference device (TE%) were proposed as quality measure for the evaluation of NiBP device tracking capability. The proposed measure TE%is theoretically independent of absolute accuracy but depends on precision and ICC of a device. NiBP devices show considerable maximum TE% of 41% in tracking mean blood pressure changes respectively. In 10% of the measurements in the low blood pressure range TE% exceeding 100%. The mean 50th/90th TE% percentile over the whole blood pressure range were 25/61%, respectively. Furthermore, TE% was relatively insensitive to assumed blood pressure range but sensitive to ICC. NiBP devices have high relative error in tracking blood pressure changes that make those devices not well-suited for tracking blood pressure changes. The proposed tracking error allows the definition of reasonable accuracy/precision requirements of NBP devices.

Linearization of Thermal Equivalent Temperature Calculation for Fast Thermal Comfort Prediction

Virtual simulations and calculations are a key technology for future development methods. A variety of tools and methods for calculating thermal comfort have not gained sufficient acceptance in practice due to their inherent complexity. This article investigates alternative means of determining thermal comfort, namely, the linearization of the equivalent temperature calculation. This enables a wide range of users to evaluate thermal comfort in a fast and easy manner, for example, for energy efficiency simulation. A flow and thermal model were created according to the requirements of DIN EN ISO 14505 to determine heat transfer coefficients under calibration conditions. The model to simulate the equivalent temperature in calibration conditions comprises a geometrically realistic 3D model of a human test person according to the standard. The influence of the turbulence model, as well as the influence of the equivalent temperature on the heat transfer coefficient in calibration conditions, was investigated. It was found that the dependence of the equivalent temperature is mandatory. The dependence between the heat transfer and the equivalent temperature was taken into account with a continuous linearization approach. An equation-based implementation methodology is proposed, enabling a quick implementation of comfort evaluation in future simulation models. Two test cases show the capabilities of the new model and its application in future work.