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Background: The use of targeted temperature management (TTM) after return of spontaneous circulation (ROSC) has improved the neurological outcome for patients with survived cardiac arrest. During this therapy precise measuring of the core body temperature (CBT) is integral as deviations from the recommended temperature might result in side effects such as arrhythmias, electrolyte imbalances, or infections. However, current measuring techniques are either invasive, imprecise, or difficult to use. A disposable, non-invasive temperature sensor using the heat flux approach (Double Sensor) has already been tested in different preclinical and intraoperative settings and results suggest a promising alternative. Methods: The Double Sensor was placed on the forehead of patients undergoing TTM and recorded the CBT for 48 hours. The data were then compared to the temperatures measured by an esophageal thermometer. A paired t-test was used to examine possible differences between the two methods. To avoid the weaknesses of the oftenused Pearson's r, a Bland-Altman diagram, as well as the intraclass correlation coefficient (ICC) were used for this study to assess agreement and reliability of the Double Sensor. Additionally, the patients’ medication were recorded to rule out possible influence on measurements by anesthetic drugs or catecholamines. Results: From November 2015 to January 2017 data from 25 patients (M/F, median age 61 years) were recorded. The t-test showed no significant difference between the two measuring methods (t = 1.47, p = 0.14, n = 1,319). Bland-Altman results showed a mean bias of 0.02 °C (95% confidence interval 0.00 – 0.04) and 95% limits of agreement of −1.023 °C and 1.066 °C. The ICC was 0.94 (95% CI 0,93 – 0,95). The sensor caused no side effects such as rash or allergic reactions. In six patients the recorded temperatures differed from the rest of the participants. Possible explanations were a high Body-Mass-Index, prone positioning, or dislocation of the sensor during positioning of the patients. No sex-based differences could be identified. Influences on the measurements of the Double Sensor by catecholamines or sedatives administered could be ruled out. Conclusions: Measuring the CBT with a non-invasive, disposable sensor is a reliable alternative during TTM after ROSC. Integrating the sensor into other appliances such as pulse oximeters would even further increase its benefits. It is recommended to verify the results of the study with a larger patient cohort to possibly improve the limits of agreement., Hintergrund: Die Standardmethode zur exakten Bestimmung der Körperkerntemperatur in der Klinik ist die ösophageale oder pharyngeale Messung. Diese findet z.B. beim gezielten Temperaturmanagement (TTM) nach Herz-Kreislauf-Stillstand ihre Anwendung, ist jedoch invasiv und wird schlecht von wachen Patient:innen toleriert. Die exakte Messung der Körperkerntemperatur während des TTM nach Wiederkehr des Spontankreislaufs nach überlebtem Herzstillstand (ROSC) ist jedoch zwingend erforderlich, da Abweichungen von der empfohlenen Zieltemperatur zu Nebenwirkungen wie Herzrhythmusstörungen, Elektrolytstörungen oder Infektionen führen können. Ein nicht-invasiver Einweg-Temperatursensor, der nach dem Wärmestromprinzip funktioniert, könnte hier eine gute Alternative bieten. In der vorliegenden Studie wird dieser Sensor mit dem klassischen ösophagealen Sensor beim TTM nach ROSC verglichen. Methoden: Ein nicht-invasiver Einweg-Temperatursensor, welcher nach dem Wärmeflussprinzip funktioniert, wurde während ROSC unter TTM auf der Stirn erwachsener Patient:innen befestigt. Die aufgezeichneten Temperaturen wurden mit der etablierten Messmethode eines Ösophagusthermometers verglichen. Ein gepaarter t-Test wurde durchgeführt, um Unterschiede zwischen den Methoden zu untersuchen. Um die Schwächen des häufig verwendeten Pearson's r zu vermeiden, wurden ein Bland- Altman-Diagramm und der Intraklassenkorrelationskoeffizient (ICC) verwendet, um die Übereinstimmung zwischen den Methoden sowie die Zuverlässigkeit des Doppelsensors zu bewerten. Um einen möglichen Einfluss auf die Messungen auszuschließen, wurde auch die Medikation der Patient:innen erfasst. Ergebnisse: Von November 2015 bis Januar 2017 wurden Temperaturdaten von 25 Patient:innen mit ROSC über einen Zeitraum von 48 Stunden während TTM aufgezeichnet und nach zeitlicher Paarung miteinander verglichen. Der t-Test zeigte keinen signifikanten Unterschied zwischen den beiden Messmethoden (t = 1,47, p = 0,14, n = 1319). Das Bland-Altman-Diagramm zeigte eine mittlere Abweichung von 0,02 °C (95% Konfidenzintervall (CI) 0,00 - 0,04) und 95% Übereinstimmungsgrenzen von -1,023 °C und 1,066 °C. Der Intraklassenkorrelationskoeffizient lag bei 0,94 (95% CI 0,93 – 0,95). Hautreizungen oder allergische Reaktionen auf den Sensor konnten nicht beobachtet werden. Bei sechs Patient:innen unterschied sich die Abweichung der Sensoren merklich vom Rest der Proband:innen. Mögliche Erklärungen waren ein hoher Body- Mass-Index, Bauchlagerung oder eine Dislokation des Sensors bei der Lagerung der Patient:innen. Es konnten keine geschlechtsspezifischen Unterschiede festgestellt werden. Eine Beeinflussung der Messungen des Doppelsensors durch verabreichte Medikamente konnte ebenfalls ausgeschlossen werden. Schlussfolgerungen: Die Messung der Körpertemperatur mit einem nicht-invasiven Einweg-Doppelsensor zeigt eine hohe Zuverlässigkeit während TTM nach ROSC. Eine Temperaturüberwachung mit dem Sensor ist bei diesen Fällen möglich. Der Einsatz des Sensors in anderen Anwendungsbereichen wie z. B. Pulsoximetern würde den Nutzen noch weiter erhöhen. Es wird empfohlen, die Ergebnisse der Studie mit einer größeren Patientenkohorte zu verifizieren, um möglicherweise die Übereinstimmungsgrenzen zu verbessern.

Agriculture is a major emitter of particulate matter (PM), which causes health problems and can act as a carrier of the pathogen material that spreads diseases. The aim of this study was to investigate an open-source solver that simulates the transport and dispersion of PM for typical agricultural applications. We investigated a coupled Eulerian–Lagrangian solver within the open source software package OpenFOAM. The continuous phase was solved using transient large eddy simulations, where four different subgrid-scale turbulence models and an inflow turbulence generator were tested. The discrete phase was simulated using two different Lagrangian solvers. For the validation case of a turbulent flow of a street canyon, the flowfield could be recaptured very well, with errors of around 5% for the non-equilibrium turbulence models (WALE and dynamicKeq) in the main regions. The inflow turbulence generator could create a stable and accurate boundary layer for the mean vertical velocity and vertical profile of the turbulent Reynolds stresses R11. The validation of the Lagrangian solver showed mixed results, with partly good agreements (simulation results within the measurement uncertainty), and partly high deviations of up to 80% for the concentration of particles. The higher deviations were attributed to an insufficient turbulence regime of the used validation case, which was an experimental chamber. For the simulation case of PM dispersion from manure application on a field, the solver could capture the influence of features such as size and density on the dispersion. The investigated solver is especially useful for further investigations into time-dependent processes in the near-source area of PM sources.

Die Bestimmung von Luftwechselraten und Emissionen aus frei gelüfteten Tierhaltungssystemen ist mit großen Unsicherheiten behaftet. Das Ziel dieser Dissertation war die Untersuchung des Einfusses von Probenahmepositionen auf die Bestimmung von Luftwechselraten und Emissionen sowie die Optimierung und Weiterentwicklung derzeit angewandter Methoden. Dazu wurden drei methodische Ansätze in Form eines Drei-Säulen-Modells angewendet: (1) Langzeitmessungen im Experimentalstall - Aufnahme von Gaskonzentrationen zur Ermittlung von Luftwechselraten und Ammoniakemissionen mittels indirekter Massenbilanzmethoden, (2) Versuche im atmosphärischen Grenzschichtwindkanal - Messsungen von Geschwindigkeiten und Gaskonzentrationen an einem Modell des Experimentalstalles zur Ermittlung von Luftwechselraten und Emissionen und (3) numerische Untersuchungen des Modells mit zwei quelloffenen transienten Strömungslösern. Die Ergebnisse zu (1) wiesen, abhängig von der Gasprobenahmestrategie, maximale systematische Unterschiede zwischen den Methoden von bis zu 26 % für die Ammoniakemissionen und 94 % für die Luftwechselraten auf. Basierend auf den Ergebnissen konnten Empfehlungen für Gasprobenahmestrategien in Abhängig der vorherrschenden Strömungsszenarien bei der Anwendung indirekter Massenbilanzmethoden abgeleitet werden. Die Ergebnisse zu (2) zeigten systematische Fehler bei der Ermittlung der Emissionen von bis zu +97 %, wenn Konzentrationsund Geschwindigkeitsmessungen auf einer konstanten Höhe durchgeführt wurden. Dieser Fehler konnte unter 5 % gesenkt werden, wenn die Gaskonzentrationen als vertikale Mischprobe gemessen wurden. Die Ergebnisse zu (3) zeigten eine gute Eignung quellofener, transienter Strömungslöser für den Anwendungsfall eines durchströmten frei gelüfteten Stalles. Die Luftwechselraten konnten mit einem relativen Fehler, The determination of air exchange rates and emissions from naturally ventilated livestock systems is subject to great uncertainty. The aim of this thesis was to investigate the infuence of the number and positions of gas and velocity samplings on the determination of AER and emissions as well as to optimize and further develop currently applied methods. For this purpose, three diferent methods were applied in a three-column approach: (1) on-farm, long-term measurements of gas concentrations in a naturally ventilated dairy barn for the determination of air exchange rates and ammonia emissions by indirect mass balance methods, (2) boundary layer wind tunnel measurements of velocities and gas concentrations on a scaled down model of same the dairy barn for the determination of air exchange rates and emissions by direct measurement and (3) numerical investigations of the scaled down model with two open source transient fow solvers. The results of (1) showed, depending on the gas sampling strategy, maximum systematic differences between the used strategies of up to 26 % for ammonia emissions and 94 % for air exchange rates. Based on the results, recommendations for gas sampling strategies could bederived depending on the prevailing fow scenarios when using indirect mass balance methods. The results of (2) showed systematic errors in the determination of emissions of up to +97 % when concentration and velocity measurements were performed at a constant height. This error could be reduced below 5 % when gas concentrations were measured as vertical composite sample. The results of (3) showed a good feasibility of open source, transient fow solvers for the application of a cross fow through a naturally ventilated barn. The air exchange rates could be simulated with a relative error < 4 %. The fow solvers thus ofer a great potential for detailed further simulations of the air exchange rates and emissions of naturally ventilated animal housing systems. For each of the three methods their respective advantages and limitations could be shown, as well as the synergy efects between the methods. The three-column approach has therefore proven to be a promising approach for the investigation of the complex emission system of naturally ventilated animal housing systems.

Die Bestimmung von Luftwechselraten und Emissionen aus frei gelüfteten Tierhaltungssystemen ist mit großen Unsicherheiten behaftet. Das Ziel dieser Dissertation war die Untersuchung des Einfusses von Probenahmepositionen auf die Bestimmung von Luftwechselraten und Emissionen sowie die Optimierung und Weiterentwicklung derzeit angewandter Methoden. Dazu wurden drei methodische Ansätze in Form eines Drei-Säulen-Modells angewendet: (1) Langzeitmessungen im Experimentalstall - Aufnahme von Gaskonzentrationen zur Ermittlung von Luftwechselraten und Ammoniakemissionen mittels indirekter Massenbilanzmethoden, (2) Versuche im atmosphärischen Grenzschichtwindkanal - Messsungen von Geschwindigkeiten und Gaskonzentrationen an einem Modell des Experimentalstalles zur Ermittlung von Luftwechselraten und Emissionen und (3) numerische Untersuchungen des Modells mit zwei quelloffenen transienten Strömungslösern. Die Ergebnisse zu (1) wiesen, abhängig von der Gasprobenahmestrategie, maximale systematische Unterschiede zwischen den Methoden von bis zu 26 % für die Ammoniakemissionen und 94 % für die Luftwechselraten auf. Basierend auf den Ergebnissen konnten Empfehlungen für Gasprobenahmestrategien in Abhängig der vorherrschenden Strömungsszenarien bei der Anwendung indirekter Massenbilanzmethoden abgeleitet werden. Die Ergebnisse zu (2) zeigten systematische Fehler bei der Ermittlung der Emissionen von bis zu +97 %, wenn Konzentrationsund Geschwindigkeitsmessungen auf einer konstanten Höhe durchgeführt wurden. Dieser Fehler konnte unter 5 % gesenkt werden, wenn die Gaskonzentrationen als vertikale Mischprobe gemessen wurden. Die Ergebnisse zu (3) zeigten eine gute Eignung quellofener, transienter Strömungslöser für den Anwendungsfall eines durchströmten frei gelüfteten Stalles. Die Luftwechselraten konnten mit einem relativen Fehler

Background: Precisely measuring the core body temperature during targeted temperature management after return of spontaneous circulation is mandatory, as deviations from the recommended temperature might result in side effects such as electrolyte imbalances or infections. However, previous methods are invasive and lack easy handling. A disposable, non-invasive temperature sensor using the heat flux approach (Double Sensor), was tested against the standard method: an esophagus thermometer. Methods: The sensor was placed on the forehead of adult patients (n = 25, M/F, median age 61 years) with return of spontaneous circulation after cardiac arrest undergoing targeted temperature management. The recorded temperatures were compared to the established measurement method of an esophageal thermometer. A paired t-test was performed to examine differences between methods. A Bland-Altman-Plot and the intraclass correlation coefficient were used to assess agreement and reliability. To rule out possible influence on measurements, the patients' medication was recorded as well. Results: Over the span of 1 year and 3 months, data from 25 patients were recorded. The t-test showed no significant difference between the two measuring methods (t = 1.47, p = 0.14, n = 1,319). Bland-Altman results showed a mean bias of 0.02 degrees C (95% confidence interval 0.00-0.04) and 95% limits of agreement of -1.023 degrees C and 1.066 degrees C. The intraclass correlation coefficient was 0.94. No skin irritation or allergic reaction was observed where the sensor was placed. In six patients the bias differed noticeably from the rest of the participants, but no sex-based or ethnicity-based differences could be identified. Influences on the measurements of the Double Sensor by drugs administered could also be ruled out. Conclusions: This study could demonstrate that measuring the core body temperature with the non-invasive, disposable sensor shows excellent reliability during targeted temperature management after survived cardiac arrest. Nonetheless, clinical research concerning the implementation of the sensor in other fields of application should be supported, as well as verifying our results by a larger patient cohort to possibly improve the limits of agreement.

A reliable quantification of greenhouse gas emissions is a basis for the development of adequate mitigation measures. Protocols for emission measurements and data analysis approaches to extrapolate to accurate annual emission values are a substantial prerequisite in this context. We systematically analyzed the benefit of supervised machine learning methods to project methane emissions from a naturally ventilated cattle building with a concrete solid floor and manure scraper located in Northern Germany. We took into account approximately 40 weeks of hourly emission measurements and compared model predictions using eight regression approaches, 27 different sampling scenarios and four measures of model accuracy. Data normalization was applied based on median and quartile range. A correlation analysis was performed to evaluate the influence of individual features. This indicated only a very weak linear relation between the methane emission and features that are typically used to predict methane emission values of naturally ventilated barns. It further highlighted the added value of including day-time and squared ambient temperature as features. The error of the predicted emission values was in general below 10%. The results from Gaussian processes, ordinary multilinear regression and neural networks were least robust. More robust results were obtained with multilinear regression with regularization, support vector machines and particularly the ensemble methods gradient boosting and random forest. The latter had the added value to be rather insensitive against the normalization procedure. In the case of multilinear regression, also the removal of not significantly linearly related variables (i.e., keeping only the day-time component) led to robust modeling results. We concluded that measurement protocols with 7 days and six measurement periods can be considered sufficient to model methane emissions from the dairy barn with solid floor with manure scraper, particularly when periods are distributed over the year with a preference for transition periods. Features should be normalized according to median and quartile range and must be carefully selected depending on the modeling approach.

The mandate to limit global temperature rise calls for a reliable quantification of gaseous pollutant emissions as a basis for effective mitigation. Methane emissions from ruminant fermentation are of particular relevance in the context of greenhouse gas mitigation. The emission dynamics are so far insufficiently understood. We analyzed hourly methane emission data collected during contrasting seasons from two naturally ventilated dairy cattle buildings with concrete floor and performed a second order polynomial regression. We found a parabolic temperature dependence of the methane emissions irrespective of the measurement site and setup. The position of the parabola vertex varied when considering different hours of the day. The circadian rhythm of methane emissions was represented by the pattern of the fitted values of the constant term of the polynomial and could be well explained by feeding management and air flow conditions. We found barn specific emission minima at ambient temperatures around 10 &deg, C to 15 &deg, C. As this identified temperature optimum coincides with the welfare temperature of dairy cows, we concluded that temperature regulation of dairy cow buildings with concrete floor should be considered and further investigated as an emission mitigation measure. Our results further indicated that empirical modeling of methane emissions from the considered type of buildings with a second order polynomial for the independent variable air temperature can increase the accuracy of predicted long-term emission values for regions with pronounced seasonal temperature fluctuations.

Airflow inside naturally ventilated dairy (NVD) buildings is highly variable and difficult to understand due to the lack of precious measuring techniques with the existing methods. Computational fluid dynamics (CFD) was applied to investigate the effect of different seasonal opening combinations of an NVD building on airflow patterns and airflow rate inside the NVD building as an alternative to full scale and scale model experiments. ANSYS 2019R2 was used for creating model geometry, meshing, and simulation. Eight ventilation opening combinations and 10 different reference air velocities were used for the series of simulation. The data measured in a large boundary layer wind tunnel using a 1:100 scale model of the NVD building was used for CFD model validation. The results show that CFD using standard k-�� turbulence model was capable of simulating airflow in and outside of the NVD building. Airflow patterns were different for different opening scenarios at the same external wind speed, which may affect cow comfort and gaseous emissions. Guiding inlet air by controlling openings may ensure animal comfort and minimize emissions. Non-isothermal and transient simulations of NVD buildings should be carried out for better understanding of airflow patterns.

Naturally ventilated livestock buildings (NVLB) represent one of the most significant sources of ammonia emissions. However, even the dispersion of passive gas in an NVLB is still not well understood. In this paper, we present a detailed investigation of passive pollutant dispersion in a model of a cattle barn using the wind tunnel experiment method. We simulated the pollution of the barn by a ground-level planar source. We used the time-resolved particle image velocimetry (TR-PIV) and the fast flame ionisation detector (FFID) to study the flow and dispersion processes at high spatial and temporal resolution. We employed the Proper Orthogonal Decomposition (POD) and Oscillating Patterns Decomposition (OPD) methods to detect the coherent structures of the flow. The results show that the type of atmospheric boundary layer (ABL) and sidewall opening height have a significant impact on the pollutant dispersion in the barn, while the presence of animals and doors openings are insignificant under conditions of winds perpendicular to the sidewall openings. We found that the dynamic coherent structures, developed by the Kelvin-Helmholtz instability, contribute to the pollutant transport in the barn. We demonstrate that in any of the studied cases the pollutant was not well mixed within the barn and that a significant underestimation (up to by a factor 3) of the barn ventilation might be obtained using, e.g. tracer gas method. �� 2020 The Authors