Implementation, demonstration and validation of a user-defined wall-function for direct precipitation fouling in ANSYS Fluent

In a previous paper (Johnsen et al., 2015) and presentation (Johnsen et al., 2016), we developed and demonstrated a generic modelling framework for the modelling of direct precipitation fouling from multi-component fluid mixtures that become super-saturated at the wall. The modelling concept involves the 1-dimensional transport of the fluid species through the turbulent boundary layer close to the wall. The governing equations include the Reynolds-averaged (RANS) advection-diffusion equations for each fluid species, and the axial momentum and energy equations for the fluid mixture. The driving force for the diffusive transport is the local gradient in the species' chemical potential. Adsorption mechanisms are not modelled per se, but the time-scale of adsorption is reflected in the choice of Dirichlet boundary conditions for the depositing species, at the fluid-solid interface. In this paper, the modelling framework is implemented as a user-defined function (UDF) for the CFD software ANSYS Fluent, to act as a wall boundary condition for mass-transfer to the wall. The subgrid, 1-dimensional formulation of the model reduces the computational cost associated with resolving the fine length-scales at which the boundary-layer mass transfer is determined, and allows for efficient modelling of industry-scale heat exchangers suffering from fouling. The current paper describes the modelling framework, and demonstrates and validates its applicability in a simplified 2D heat exchanger geometry (experimental and detailed CFD modelling data by P\"a\"akk\"onen et al. (2012, 2016)). By tuning the diffusivity, only, good agreement with the experimental data and the detailed CFD model was obtained, in terms of area-averaged deposition rates.Comment: 12th International Conference on CFD in Oil & Gas, Metallurgical and Process Industries, SINTEF, Trondheim, NORWAY, May 30th - June 1st, 2017, 9 pages, 9 figure

Re-thinking risk communication: information needs of patients, health professionals and the public regarding MRSA – the communicative behaviour of a public health network in Germany responding to the demand for information

Objectives: Multidrug resistant organisms (MDRO), including Meticillin-resistant Staphylococcus aureus (MRSA), and health care associated infections (HCAIs) are pressing issues for health care systems across the world. Information and communication are considered key tools for the prevention and management of infectious diseases. Public Health Authorities (PHA) are in a unique position to communicate with health care professionals, patients and the public regarding the health risks. Study design: We used PHA helpdesk interaction data to first ascertain the information requirements of those getting in contact with the service, and secondly to examine the communicative behaviour of the PHA, with a view to improving the quality of communication strategies. Methods: Data on helpdesk interactions between 2010 and 2012 were obtained from a MDRO network of nine German PHAs. 501 recordings were coded and descriptive statistics generated for further qualitative thematic analysis. Results: Our analysis revealed a similar pattern of questions among different groups. Key areas of need for information were around eradication, cleaning and isolation measures. Reported problems were a lack of expert knowledge and continuity of treatment. The helpdesk response was mainly a conversation offering scientific advice, but also included other communication services that went beyond the provision of scientific facts, such as follow-up calls, referral suggestions and consultations on behalf of the caller. These social communication activities seem to have an important impact on the acceptability of public health recommendations and use of the helpdesk

War Guilt Propaganda Conducted by the German Foreign Ministry During the 1920s

Après la signature du Traité de Versailles, à la suite de la première guerre mondiale, le Ministère des Affaires étrangères de l'Allemagne mena une véritable campagne de propagande contre l'article 231 de ce traité qui, à ses yeux, était de nature à engendrer un sentiment de culpabilité en Allemagne parce qu'il constituait une certaine condamnation morale du peuple allemand.L'auteur se penche ici sur les moyens qu'ont pris, tour à tour, le Kriegsschuldreferat (Section étudiant la culpabilité face à la guerre), le Zentralstelle fur Erforschung der Khegsursachen (Centre d'étude des causes de la guerre) ainsi que le comité directeur de toute cette entreprise, soit le Arbeitsausschuss Deutscher Verbande (Comité de coordination des Associations allemandes) pour enrayer ce sentiment de culpabilité que ressentait le peuple allemand vis-à-vis de la guerre.Selon lui, il est difficile d'évaluer le succès de cette campagne de propagande tellement il y a d'éléments divers qui s'y sont greffés; cependant, elle s'intègre fort bien dans le mouvement révisionniste que l'on observe à l'époque tant en Europe qu'en Amérique; de plus, certains estiment même qu'elle a contribué à accroître l'impopularité déjà grandissante du Traité de Versailles en ce début des années 1920

Re-thinking risk communication: information needs of patients, health professionals and the public regarding MRSA – the communicative behaviour of a public health network in Germany responding to the demand for information

Objectives: Multidrug resistant organisms (MDRO), including Meticillin-resistant Staphylococcus aureus (MRSA), and health care associated infections (HCAIs) are pressing issues for health care systems across the world. Information and communication are considered key tools for the prevention and management of infectious diseases. Public Health Authorities (PHA) are in a unique position to communicate with health care professionals, patients and the public regarding the health risks. Study design: We used PHA helpdesk interaction data to first ascertain the information requirements of those getting in contact with the service, and secondly to examine the communicative behaviour of the PHA, with a view to improving the quality of communication strategies. Methods: Data on helpdesk interactions between 2010 and 2012 were obtained from a MDRO network of nine German PHAs. 501 recordings were coded and descriptive statistics generated for further qualitative thematic analysis. Results: Our analysis revealed a similar pattern of questions among different groups. Key areas of need for information were around eradication, cleaning and isolation measures. Reported problems were a lack of expert knowledge and continuity of treatment. The helpdesk response was mainly a conversation offering scientific advice, but also included other communication services that went beyond the provision of scientific facts, such as follow-up calls, referral suggestions and consultations on behalf of the caller. These social communication activities seem to have an important impact on the acceptability of public health recommendations and use of the helpdesk

Demonstration of a novel instrument for online monitoring of absorber emissions to air

A novel concept for online monitoring of nitrosamines, solvent amines and their degradation products in amine absorber emissions to air was demonstrated at the Tiller CO2-lab pilot facility. The monitoring concept is based on SINTEF patent No. PCT/EP2011/073557. The measurement method applies gas sampling by capture of analytes in a condensate stream from a single stage condensate collector unit. An improved design for the SINTEF prototype for online gas and liquid measurements has been established as part of the CCUS-ALIGN project. The new design has low complexity and improved robustness, making it applicable as integrated part of industrial monitoring systems. The established prototype was successfully tested for monitoring of trace gas emission from a CO2 capture pilot plant, demonstrating measurements of nitrosamines at levels far below the lower detection limits of commercial industrial online analyzers. Results from testing of a condensate collector prototype indicate high capture efficiency for analytes of interest, including analytes present in aerosols during operation conditions where the absorber emit mist to the atmosphere. The measurement concept has potential for significantly reducing the costs related to manual gas measurements for critical trace gas components in plant operation. Application of the concept can enable continuous measurements of nitrosamines and other critical trace gas analytes in the emissions to air not currently available in absorption-based CO2 capture processes.publishedVersio

Modeling the Growth of Clostridium beijerinckii NCIMB 8052 on Lignocellulosic Sugars

To our knowledge, this is the first growth model of Clostridium beijerinckii NCIMB 8052 on glucose and xylose as representative lignocellulosic sugars, which considers the synergistic effects of sugars on the growth rate. We fitted models with different types of interactions between the substrates to the growth rate data obtained with varying sugar concentrations. Noncompetitive binary substrate growth model gave the best fit with the smallest mean standard errors (MSE), and sum of squares error (SSE), 0.0778 and 0.0071, respectively. Confidence intervals for the parameter estimates showed that the substrate affinity constant for xylose, KsX (g/l) had the largest uncertainty, while the maximum specific growth rate on xylose, µmaxX (h-1) had the smallest. The correlation matrix showed that the model parameters were highly correlated. Carbon cataboliterepression (CCR) effect on the growth rate was of the noncompetitive type. Validation with other sugar concentration values is necessary to evaluate the prediction capability of the proposed model. A transcriptional study will be beneficial to understand global gene regulation mechanisms as guidance for improving the efficiency of lignocellulosic fermentation processes.publishedVersio

Decision-making criteria among European patients: exploring patient preferences for primary care services

Background: Health economics preference-based techniques, such as discrete choice experiments (DCEs), are often used to inform public health policy on patients’ priorities when choosing health care. Although there is general evidence about patients’ satisfaction with general-practice (GP) care in Europe, to our knowledge no comparisons are available that measure patients’ preferences in different European countries, and use patients’ priorities to propose policy changes. Methods: A DCE was designed and used to capture patients’ preferences for GP care in Germany, England and Slovenia. In the three countries, 841 eligible patients were identified across nine GP practices. The DCE questions compared multiple health-care practices (including their ‘current GP practice’), described by the following attributes: ‘information’ received from the GP, ‘booking time’, ‘waiting time’ in the GP practice, ‘listened to’, as well as being able to receive the ‘best care’ available for their condition. Results were compared across countries looking at the attributes’ importance and rankings, patients’ willingness-to-wait for unit changes to the attributes’ levels and changes in policy. Results: A total of 692 respondents (75% response rate) returned questionnaires suitable for analysis. In England and Slovenia, patients were satisfied with their ‘current practice’, but they valued changes to alternative practices. All attributes influenced decision-making, and ‘best care’ or ‘information’ were more valued than others. In Germany, almost all respondents constantly preferred their ‘current practice’, and other factors did not change their preference. Conclusion: European patients have strong preference for their ‘status quo’, but alternative GP practices could compensate for it and offer more valued care