Recent advances in the simulation of particle-laden flows

A substantial number of algorithms exists for the simulation of moving particles suspended in fluids. However, finding the best method to address a particular physical problem is often highly non-trivial and depends on the properties of the particles and the involved fluid(s) together. In this report we provide a short overview on a number of existing simulation methods and provide two state of the art examples in more detail. In both cases, the particles are described using a Discrete Element Method (DEM). The DEM solver is usually coupled to a fluid-solver, which can be classified as grid-based or mesh-free (one example for each is given). Fluid solvers feature different resolutions relative to the particle size and separation. First, a multicomponent lattice Boltzmann algorithm (mesh-based and with rather fine resolution) is presented to study the behavior of particle stabilized fluid interfaces and second, a Smoothed Particle Hydrodynamics implementation (mesh-free, meso-scale resolution, similar to the particle size) is introduced to highlight a new player in the field, which is expected to be particularly suited for flows including free surfaces.Comment: 16 pages, 4 figure

Closed-Form Prediction of Nonlinear Dynamic Systems by Means of Gaussian Mixture Approximation of the Transition Density

Recursive prediction of the state of a nonlinear stochastic dynamic system cannot be efficiently performed in general, since the complexity of the probability density function characterizing the system state increases with every prediction step. Thus, representing the density in an exact closed-form manner is too complex or even impossible. So, an appropriate approximation of the density is required. Instead of directly approximating the predicted density, we propose the approximation of the transition density by means of Gaussian mixtures. We treat the approximation task as an optimization problem that is solved offline via progressive processing to bypass initialization problems and to achieve high quality approximations. Once having calculated the transition density approximation offline, prediction can be performed efficiently resulting in a closed-form density representation with constant complexity

A Systematic Literature Review of Blockchain-Based Traceability Solutions

Blockchain technology shows great potential in providing object-related end-to-end traceability in complex multitiered supply networks. However, the first systematic literature reviews indicate the immaturity of current blockchain-based solutions and highlight difficulties in assessing their object traceability capabilities. Therefore, this paper provides a systematic literature review of blockchain-based traceability solutions and analyses their object-related mapping capabilities. As the systematic literature reveals, the vast majority of the identified traceability solutions deal with low-complexity architectures without the ability to map objects' compositional changes. Here, food and medical supply chains represent the most dominant domains. Supply chains in the automotive and manufacturing domain place the highest requirements for mapping object-related supply chain events. In this context, solutions incorporating the tokenisation of objects show the most advanced object-related mapping capabilities. However, the identified advanced solutions show limitations regarding their ability to map object deletions, aggregations, and disaggregations. Furthermore, current blockchain-based traceability solutions provide only limited validations based on industrial case studies

Proceedings of the International Workshop on 'Combined Environmental Exposure: Noise, Air Pollutants and Chemicals'

The issue of combined exposure to noise, air pollution and chemicals has raised recently the interest of several bodies of the European Commission such as DG Environment, DG SANCO and DG Research in the context of the EC 7th Framework Programme. There are open questions whether prevailing environmental concentrations of air pollutants and chemicals can lead to ototoxic health impacts. Therefore this issue needs to be thoroughly explored and investigated to help the EC to revise the existing standards and guidelines concerning combined exposure to noise, air pollutants and chemicals. The aim of the workshop was to review and discuss the existing scientific evidence whether prevailing environmental exposures to single and concomitant agents together with noise could lead to ototoxic or other health impacts. The final aim was to identify the research needs and to give recommendations for research and policy making in the EU level. It was agreed that research in the future should be focused on really established combinations (high correlations) and interactions (known effect) with main perspective on the traffic bundle of exposure. It was also discussed and agreed upon that the best knowledge exists on the health effects due to combined exposure to noise and solvents or heavy metals in occupational environments, especially on most of the auditory and non-auditory effects. Possible factors that may have confounding or aggravating effects on the results of noise studies were identified. Such factors are: age, gender, smoking, obesity, alcohol, socio-economic status, occupation, education, family status, active military, experience, hereditary disease, medication, medical status, race and ethnicity, physical activity, noisy leisure activities, stress reducing activities, diet & nutrition, housing condition (crowding), and residential status. Research priorities and recommendations for the future. The highest priority was given to issues related to research on noise and outdoor air pollutants. This is due to the fact that it may concern the largest population compared to the other stressors in this analysis and there is some evidence of serious health outcomes such as cardiovascular effects. The next priority was given to the research on the effects of noise and solvents in occupational settings and to research on noise and organophosphates. In the future research, priority should be given to: 1. evaluation of existing data collections whether re-analyses are possible with respect to combined exposure from traffic sources (road, rail and air), 2. analyses of existing data concerning noise and other stressors interactions in both occupational and environmental settings, 3. detailed assessment of combined exposures to noise, vibrations and PM, CO, NOx, and VOCs with specific studies in urban areas and, especially, cardiovascular health endpoints should be studied as priority health endpoints, 4. identification of causal mechanisms through careful review of toxicological experimental studies.JRC.I.5-Physical and chemical exposure

Arthroscopic repair of posterosuperior rotator cuff tears with bioabsorbable patch augmentation: a magnetic resonance–controlled case series with 1-year follow-up

Background: Among many advances in the treatment of rotator cuff tears, arthroscopic augmentation techniques with patches of various biological and synthetic graft materials have been introduced to reinforce the repair. However, structural and functional outcomes after patch augmentation vary, and reinforcing the tendon healing remains a challenge. The aim of this study was to evaluate clinical and radiologic outcomes 1 year after arthroscopic posterosuperior (PS) rotator cuff repair with bioabsorbable patch augmentation. Methods: From October 2014 to December 2017, all patients with PS rotator cuff tears undergoing arthroscopic repair with patch augmentation using a resorbable, biologically derived poly-4-hydroxybutyrate patch (Biofiber; Wright, Memphis, TN, USA) were enrolled in this study. Only full-thickness PS lesions with ≥1 of the following tear patterns were augmented with a patch and were the subject of this study: large U- and L-shaped tear, transtendinous tear, delamination, and fraying of the bursal layer. Patients were examined preoperatively and at 1 year postoperatively with a standardized examination protocol and magnetic resonance imaging (MRI). Results: Sixteen patients were included in this study; 1 patient was lost to follow-up. One patient only underwent clinical follow-up. We detected 1 repair failure (6.7%) with dislocation of the lateral-row anchors on computed tomography scanning at 3 months postoperatively. MRI was performed in 14 patients after 1 year; in all of them, the cuff repair was intact. The Sugaya tendon integrity score was 1.7 ± 0.9. The Constant-Murley score improved from 44 to 89 points (P < .001). Muscular strength improved in the supraspinatus (from 2.6 to 4.8), infraspinatus (from 3.2 to 4.9), and subscapularis (from 4 to 4.9) (all P < .001). Overall, patient satisfaction was high (3.6 ± 0.6). Discussion: This small-sized case series is the first to prospectively assess clinical and radiologic outcomes after patch augmentation of PS rotator cuff tears using bioabsorbable poly-4-hydroxybutyrate patches. Good to excellent structural and functional outcomes were observed with a low retear rate (6.7%) and good tendon integrity on 1-year postoperative MRI, and the graft did not cause any complications. The use of bioabsorbable patches could be beneficial when unfavorable PS tear patterns are encountered in which a stable repair of the full tendon thickness at its insertion is otherwise difficult to reach

Articular cartilage and labral lesions of the glenohumeral joint: diagnostic performance of 3D water-excitation true FISP MR arthrography

Objective: To evaluate the diagnostic performance of MR arthrography in the detection of articular cartilage and labral lesions of the glenohumeral joint using a transverse 3D water-excitation true fast imaging with steady-state precession (FISP) sequence. Materials and Methods: Seventy-five shoulders were included retrospectively. Shoulder arthroscopy was performed within 6months of MR arthrography. MR images were evaluated separately by two radiologists. They were blinded to clinical and arthroscopic information. Arthroscopy served as the reference standard. Results: For the detection of humeral cartilage lesions, sensitivities and specificities were 86% (12/14)/89% (50/56) for observer 1 and 93%/86% for observer 2) for the transverse true FISP sequence and 64%/86% (50%/82% for observer 2) for the coronal intermediate-weighted spin-echo images. The corresponding values for the glenoidal cartilage were 60% (6/10)/88% (51/58) (80%/76% for observer 2) and 70%/86% (60%/74% for observer 2) respectively. For the detection of abnormalities of the anterior labrum (only assessed on true FISP images) the values were 94% (15/16)/84% (36/43) (88%/79% for observer 2). The corresponding values for the posterior labrum were 67% (8/12)/77% (36/47) (observer 2: 25%/74%). The kappa values for the grading of the humeral and glenoidal cartilage lesions were 0.81 and 0.55 for true FISP images compared with 0.49 and 0.43 for intermediate-weighted fast spin-echo images. Kappa values for true FISP evaluation of the anterior and posterior part of the labrum were 0.81 and 0.70. Conclusion: Transverse 3D true FISP MR arthrography images are useful for the difficult diagnosis of glenohumeral cartilage lesions and suitable for detecting labral abnormalitie

Analysis of Thunderstorms Producing Terrestrial Gamma Ray Flashes With the Meteosat Second Generation

Up to now, only few works focused on the meteorological context leading to the production of Terrestrial Gamma ray Flashes (TGFs). In this study, we carry out, for the first time, an analysis on large scale of the meteorological scenario linked to 278 TGFs detected by RHESSI, AGILE, and Fermi, by using the Meteosat Second Generation geostationary satellites. These satellites are useful as they continuously monitor the same geographic region in time, allowing investigations on thunderstorms' development; moreover, they are endowed with channels and products that provide information about the meteorological context under analysis, such as the cloud top temperature and altitude, the cloud extension, the drop effective radius and the cloud phase. Our work confirms what previously found in other studies about the TGF‐associated thunderstorms, by using a different approach and by using for the first time the Meteosat satellites: we find TGFs mostly linked to the development phase of deep convective thunderstorm systems, exhibiting typical characteristics of tropical storms, and providing a first picture on large scale of the TGF‐associated thunderstorm systems.publishedVersio

Opportunities And Challenges Of The Asset Administration Shell For Holistic Traceability In Supply Chain Management

Due to changing regulatory environments, evolving sustainability requirements, and the need to perform effective supply chain risk management, traceability systems have become an increasingly important aspect of supply chain management. However, globalized, interconnected supply chains require a dynamic mapping of direct and indirect relationships between companies and assets, driving traceability systems' complexity. Here, the standardization of data formats provides an essential aspect to facilitate asset-related information sharing across companies. In this regard, the Asset Administration Shell is available as a holistic standardized digital representation of an asset. The representation of an asset via an Administration Shell includes data ensuring a clear identification of the Administration Shell and its assets as well as data describing aspects of the asset's technical functionality in so-called submodels. Based on current literature and available prototypical concepts, this paper identifies the opportunities and challenges of the Asset Administration Shell when aiming to map interconnected multi-tier supply chains holistically and contextualizes their role in achieving holistic supply chain traceability

Review of Blockchain-based Tokenization Solutions for Assets in Supply Chains

Recently, blockchain-based tokens have earned an important role in fields such as the art market or online gaming. First approaches exist, which adopt the potentials of blockchain tokens in supply chain management to increase transparency, visibility, automation, and disintermediation of supply chains. In context, the tokenization of assets in supply chains refers to the practice of creating virtual representations of physical assets on the blockchain. Solutions in supply chain management based on the tokenization of assets vary in terms of application objectives, token types, asset characteristics, as well as the complexities of supply chain events to be mapped on the blockchain. Currently, however, no review exists that summarizes the characteristics of blockchain-based tokens and their scope of applications. This paper provides a clear terminological distinction of existing blockchain token types and therefore distinguishes between fungible tokens, non-fungible tokens, smart non-fungible tokens, and dynamic smart non-fungible tokens. Subsequently, the token types are classified regarding their traceability, modifiability, and authorization to evaluate suitability for mapping assets in supply chains. Given the potential of blockchain in supply chain management, the results of the review serve as a foundation for a practical guide supporting the selection process of suitable token types for industrial applications