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Drying harvested grain crops prior to storage is a crucial task in the prevailing climatic conditions of Europe. Drying is an extremely energy-intensive process. Its inappropriate application leads to environmental pollution, quality deterioration, and ultimately significant financial losses. Various methods are available for conducting drying operations, with the mixed flow dryer being one of the most employed approach. The mixed flow dryer utilizes air blower systems to redirect the flow of the granulate. Previous research has indicated that uneven distribution of grain flow around the air blower lamellae can cause drying irregularities. By leveraging insights from a long-established classical mechanical problem (the Brachistochrone problem) and harnessing the explicit dynamical modelling capabilities offered by contemporary computing technology (Discrete element method), we have successfully devised an optimized lamella geometry that minimizes the non-uniformity of particle flow. [ABSTRACT FROM AUTHOR]

In Europe, the increase in temperatures caused by climate change has been particularly fast in the cold season. Although the magnitude of this change is relatively well known, less research has been done on how the increase of temperatures is manifested in different large‐scale weather types, called weather regimes. For example, one could expect that the weather patterns in which air is flowing from the rapidly‐warming Arctic would have warmed faster than other weather patterns in recent decades. Here we show that such an asymmetric warming actually occurs in the four Euro‐Atlantic weather regimes. In northern Europe, the weather regime which is typically associated with cold airmasses from the Arctic (NAO–) has warmed about 25% faster than the cold‐season days on average, and about 60% faster than the regime where the air flows from the North Atlantic (NAO+). Consequently, the weather regime that on average brings the coldest weather is warming the fastest in a large part of northern Europe. In contrast, the weather regime that typically brings the warmest weather has warmed the slowest, especially in the continental Europe. Our results provide a new perspective on the reported decrease of sub‐seasonal temperature variability. [ABSTRACT FROM AUTHOR]

The study specifies the circulation conditions, the frequency of occurrence, long‐term changes, and thermal characteristics of air masses over east‐central Europe in the years 1951–2020. The division of air masses utilized by The Polish Institute of Meteorology and Water Management was used, where, based on the geographical location of the source areas, Arctic (A), Polar maritime fresh (mPf), Polar maritime old (transformed) (mPo), Polar maritime warm (mPw), Polar continental (cP), and Tropical (T) air masses are distinguished. It has been shown that western circulation dominates in this area (60% of days on average), during which the advection of maritime air masses occurs. The share of Arctic air mass flowing from the north (about 12% of days a year) and Tropical air mass from the southern sector (4% of days) is clearly smaller. The results of the research have shown that the frequency of the majority of the analysed air masses was subject to short‐term changes in the studied period. On the other hand, long‐term changes in this frequency concerned two air masses flowing from lower latitudes (mPw and T). In the case of mPw, in the period 1951–2020 there was a significant increase in frequency, not only on a yearly basis, but also in all seasons. In the last two decades, the frequency of Tropical air mass has also increased significantly, while the increase took place only in the summer period. Therefore, the increase in air temperature recorded in east‐central Europe since the 1990s, mainly in the warm half of the year, should to a large extent be attributed to both the greater frequency of the inflow of air masses from lower latitudes (mPw and T) and the increase in temperature in virtually all separated air masses, which in turn is a result of progressing global warming. [ABSTRACT FROM AUTHOR]

Since the World Health Organization announced the COVID-19 pandemic, indoor airflows became a synonym for virus super-spreaders and the focus point for the scientific community and professional associations across the globe, disrupting all daily life dimensions. Europe's quick response to control the disease led the REHVA board to address mitigation guidelines, reassessed by each member association's following national specifics. The present study aims to quantify the energy consumption and CO 2 emissions of "large office" buildings in top-five European economies under the COVID-19 guidelines under the post-pandemic telework forecast. Methodology resorted to a standard model under Building Energy Simulation assessment to compare prior and posterior scenarios. The latter displays a tendency to increase energy and CO 2 emissions in all locations, in the first form 10.18% (Rome) to 69.48% (Paris); and second 5.80% (Rome) and 120.61% (Paris), which will affect national energy production and imports, urban pollution and business competitiveness. On a different scope, future HVAC guidelines need to address the incoming figures, particularly in highly dense urban areas. Also, to comply with the goals set by the Paris Accord. • Europe promptly reacts to mitigate SARS-CoV-2 in indoor spaces. • REHVA publishes the COVID-19 guidelines although these are understood differently in the community. • COVID-19 guidelines under BES reveal the impact on European large office building. • COVID-19 guidelines tend to an overall increase energy consumption and CO2 emissions. • Warm to hot locations show energy and CO2 savings under COVID-19 guidelines. [ABSTRACT FROM AUTHOR]

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Past work has shown that models incorporating human travel can improve the quality of influenza forecasts. Here, we develop and validate a metapopulation model of twelve European countries, in which international translocation of virus is driven by observed commuting and air travel flows, and use this model to generate influenza forecasts in conjunction with incidence data from the World Health Organization. We find that, although the metapopulation model fits the data well, it offers no improvement over isolated models in forecast quality. We discuss several potential reasons for these results. In particular, we note the need for data that are more comparable from country to country, and offer suggestions as to how surveillance systems might be improved to achieve this goal. Author summary: In our increasingly connected world, infectious diseases are more capable than ever of rapid spread over large geographical distances. Previous research has shown that human travel can be used to better forecast the transmission of influenza, which may in turn help public health and medical practitioners to prepare for outbreaks with increasing lead time. Here, we developed a model of twelve European countries, in which countries are connected based on rates of commuting and air travel between them. We then used this model, along with publicly available influenza incidence data, to forecast future incidence in Europe. We found that forecasts produced with the network model were not more accurate than those produced for individual countries in isolation. We emphasize the need for aligned influenza data collection practices that are comparable between different countries and which will likely improve forecast accuracy. [ABSTRACT FROM AUTHOR]

The driving factors that influence the spatial and annual variability of thunderstorms across Europe are still poorly understood. Due to a lack of long‐term, reliable and consistent information about the occurrence of convective storms, a weather type classification has been developed that estimates thunderstorm probability from a combination of appropriate meteorological quantities on the mesoscale. Based on this approach, the temporal and spatial variability of convection‐favouring environments is investigated between 1958 and 2014 using a high‐resolution reanalysis dataset. To identify potential drivers for convective days, typical upper‐level flow patterns were deduced using a multivariate approach. Our results suggest a strong link between local‐scale thunderstorm activity and large‐scale flow and air mass properties, such as stability, moisture, or vertical lifting. For example, while all over central Europe the most prominent pattern is given by a southwesterly flow type over the respective area, distinct regional discrepancies regarding further favourable flow types are observed. The crucial role of large‐scale flow is further studied by assessing the relation between Northern Hemisphere teleconnection patterns and widespread convective activity. It is found that positive phases of the East Atlantic or Scandinavian patterns go along with a significant enhancement of convection‐favouring conditions in several European regions, which can be explained by anomalies in the large‐scale temperature and flow fields. Sea‐surface temperature over the Bay of Biscay likewise impacts the convective environment, with the largest positive effect over the western part of the study area. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO) observations registered at El Arenosillo observatory (Southwestern Europe), during three years (2019–2022) were used to explore levels, temporal variations and patterns. The seasonal mean hourly oscillated between 127 ± 21 and 97 ± 14 ppb, with extreme peaks measured under wildfire plume arrival. A remarkable monthly evolution was observed with peaks in cold months (135 ± 20 ppb in January) and minimum in summer (90 ± 11 ppb in June). Seasonal daily patterns showed a different nocturnal behavior depending on the season, with a clear maximum at 7:00–9:00 UTC, a decrease during diurnal time, and a minimum at 17:00–18:00 UTC. To determine the potential trends from 2002 to 2022, the observations of the AIRS (Atmospheric Infrared Sounder) instrument and the emissions from the global emission inventory of CAMS (Copernicus Atmosphere Monitoring Service) were used. A downward trend for emissions of −31% decade−1 was found, whereas the decrease from AIRS was −9.8% decade−1. The effort to reduce CO emissions is being countered by other processes. The CO behavior was investigated under weather conditions governed by the synoptic and mesoscale processes. Background levels (∼90 ppb) were obtained under Atlantic airflows, while an increase of ∼40% was observed with the impact of urban plumes from continental areas. CO even lower than 90 ppb was obtained under non-pure sea-land breezes, whereas, with pure breezes, reached peaks above 120 ppb, affecting the atmosphere at the surface and up to 1–1.2 km in the air. The extreme level was registered under wildfire plume arrival, with peaks exceeding 350 ppb. Climate change is modifying weather patterns and modulating breezes; in addition, it is also increasing the frequency and intensity of wildfires. These processes could be counteracting the efforts carried out to reduce emissions. • Carbon monoxide was analyzed in Southwestern Europe. • Monthly and daily temporal evolutions were found. • AIRS observations and emissions showed downward trends in the last two decades. • CO behavior is strongly modulated by weather scenarios. • Extreme CO was observed under the impact of a wildfire plume. [ABSTRACT FROM AUTHOR]

The aim of the article was to provide a detailed analysis of pressure conditions, employing the anomalies of geopotential heights, during the occurrence of heat waves in Central Europe, but also in the days preceding and following their occurrence. The study uses data from 1966 to 2015 from the Institute of Meteorology and Water Management—National Research Institute, Deutscher Wetterdienst and the National Centre for Environmental Prediction/National Centre for Atmospheric Research (NCEP/NCAR). A heat wave was defined as a sequence of at least 3 days with a maximum daily air temperature of >30°C. The study showed an increase in the number of hot days, which was statistically significant in the majority of the area. In the analysed years, an increasing number of heat waves were recorded, and this occurrence was associated with high pressure systems. Anticyclonic blocking in the summer inhibits the zonal flow of air masses and intensifies meridional flow, which in Central Europe in the summer means the presence of polar continental and tropical air masses. During heat waves, there were positive anomalies of isobaric surface heights over the study area with a maximum in the upper troposphere. On average, anomalies at the 300 hPa pressure level began to form over the Atlantic Ocean. Determining atmospheric preconditions of persisting blocking events in summer resulting in heat waves may be helpful in predicting thereof. [ABSTRACT FROM AUTHOR]

The objective of this paper is to develop a refined gravity model for the quantitative assessment of competitive hub status of cities between 2000 and 2012 from the perspective of international air traffic movements. Its focus of attention is Europe and Asia, where cross border competition has been witnessed among major cities for the role as a key international air traffic hub. To this end, the research incorporates global network connectivity (GNC) as a measure of business connections into an established gravity model that previously relied on GDP per head, population and distance to account for international air links. The results confirm the dynamic change of the air transport city hierarchy, demonstrating a stronger presence of a number of previously secondly ranked cities as international air traffic hubs over this period. The paper concludes with suggestions that possible extension of geographical scope and incorporation of domestic air traffic could enrich the insight of this approach. • Hub status of cities is assessed from an international air traffic perspective. • Networks of inter-city air traffic flows in Europe and Asia are explored. • Business connectivity is the most powerful in explaining international air links. • Secondly ranked cities are now more prominent in the region's urban hierarchies. • New airports and integrators' hubs have significant effect on cities' mobility. [ABSTRACT FROM AUTHOR]

The aim of the research was to identify connections between the occurrence of heat load across Poland and large-scale factors, which will allow statistical models to be derived that are useful to describe bioclimatic conditions in Poland in the summer. Atmospheric circulation over the North Atlantic Ocean and Europe and near-surface air temperature over the central part of Europe were considered. The monthly frequency of the occurrence of combined "moderate, strong, very strong and extreme heat stress" based on the assessment scale of the Universal Thermal Climate Index (UTCI) in the summer months accounted for 6% to more than 30% of all cases. The statistical downscaling procedure of canonical correlation analysis (CCA) with respect to the period 1971–2000 was applied to extract the main modes of large-scale factors and their local responses. The greatest explained variance of local field response to atmospheric circulation as well as to near-surface air temperature is above 70%. Warm air flow from the east and from the southeast has the strongest influence on the increase in frequency of the occurrence of heat stress on human beings in Poland. The spatial differentiation of the air temperature anomaly over central Europe is an important determinant of the occurrence of heat stress in Poland. The validation of constructed models encompassed the periods 1951–1970 and 2001–2010. The best reliability of results was reached for the reconstructed series in July. The results are less useful in June and August and in the coastal region. [ABSTRACT FROM AUTHOR]

Circulation in the mid-troposphere in moderate and high latitudes of the Northern Hemisphere can be characterised by the Vangenheim-Girs (VG) circulation macro-forms. The aim of the research was to analyse the VG macro-forms as a factor determining the general characteristics of the atmospheric circulation in mid-troposphere in the Euro-Atlantic region and low-troposphere airflow characteristics in the profile (zonal belt) crossing Central Europe from Ireland to Kazan in Russia (5°30'W–44°00'E). Alongside the VG macro-form calendar, ERA-INTERIM data were used. The utilised meteorological variables comprised 500hPa geopotential height, SLP and air temperature at 995 sigma level. The temporal scope of the research was 35 years (1981–2015) and the resolution was 24h (12.00 UTC). The circulation in the low-troposphere was characterised by the geostrophic wind vector characteristics directly resulting from SLP and air temperature fields. Subsequently, derived indices (e.g. wind direction stability) were used. The presented results indicate that the variability of anemological conditions at SLP in the area of 50–60°N over Europe is in direct connection with the mid-troposphere circulation features. The differences are statistically significant across nearly the entire research area. This includes the reversal of the dominant air flow direction in some areas. The greatest variability in geostrophic wind characteristics due to W, E and C VG macro-forms is revealed in the central and eastern part of the 50–60°N zone – between the southern Baltic Sea and the western border of Russia. [ABSTRACT FROM AUTHOR]

Operating rooms for patients undergoing infection-prone surgery often have unidirectional flow supply air systems. Many systems installed in Europe have low air velocities, i.e. equal and below 0.3 m/s, while other supply air systems have velocities about 0.4 m/s. The velocity, given by the supplier, is mostly the inlet air velocity just below the filter screen of the unidirectional flow system. The purpose of this paper is to describe contamination risks in unidirectional airflow without obstacles at different air velocities. To evaluate contamination risks, the method for limitation of risks, the LR-Method, has been used. The results show that the convection flows and arm movements from a person standing in the unidirectional airflow system have a great impact on the contamination risks at air velocities below 0.4 m/s and that the air velocity should at least be 0.4 m/s to achieve a good protection efficacy. [ABSTRACT FROM AUTHOR]

Frosting inside heat/energy exchangers are common especially in cold climates and result a significant decrease in the performance of the exchangers. Using experimental effectiveness data from a previous research [1] and ambient temperature/enthalpy duration curves the effect of preheating the outdoor air and bypassing the outdoor airflow (supply side closing) techniques on annual heating energy consumption of ventilation are predicted in three different weather European locations (in Helsinki in Finland as Cold climate, in Krakow in Poland as North Temperate climate and in Palermo in Italy as Mediterranean climate). The results are presented separately based on the analyzed techniques: supply side closing, pre-heating and frosting effect ignoring. The results show the outdoor air preheating technique results higher energy saved than the supply side closing and if the indoor air quality requirements are lower, then using a sensible heat recovery unit is suitable for heat recovery and the investment cost is lower. [ABSTRACT FROM AUTHOR]

The long-term monitoring of the cosmogenic 7Be activity concentrations has been used to better understand the influence of large-scale atmospheric circulation dynamics in the troposphere. With an aim, this study analyzes weekly 7Be data from 15 sampling stations in Europe over 2005–2014. We first define peak (or extremely high) events in each station as those activity concentrations above the 90th percentile, and then investigate their temporal and spatial variability. These events are most frequent in the spring and summer seasons, with a notable latitudinal variability in their number. Next, we use back-trajectory cluster analysis to identify the main advection pathways associated with these high concentrations. To achieve this, persistent periods, i.e., sampling periods over which at least 60% of the calculated backward trajectories arriving at a given site correspond to the same airflow pattern, are taken as reference. This method reveals large differences in the association between the airflow patterns observed at different stations in connection with the 7Be peaks. A comparison between stations shows no clear spatial pattern, which suggests a further influence of mesoscale/local physical processes on the surface 7Be activity concentrations. Finally, the main airflow pattern at each sampling site and the associated 7Be peaks, are related to the main teleconnection patterns of large scale and regional climate variability in Europe: North Atlantic Oscillation, Arctic Oscillation, East Atlantic, East Atlantic/Western Russia, Scandinavian pattern and Western Mediterranean Oscillation. The results point out the connection between the negative phases of NAO and We-MO, and the positive phase of EA with the spatial and temporal variability and occurrence of the 7Be peak activity concentrations. These results show a latitudinal division between northern and southern sites, with similar influence of teleconnection patterns, while those located in the central part of Europe present larger variability in the impact of teleconnection patterns. [Display omitted] • Evaluate the temporal and spatial variability of the extreme 7Be activity concentrations in Europe (2005–2014). • Evidence differences in airflow patterns associated with extreme 7Be concentrations in Europe. • Reveal the influence of the main teleconnection patterns on extreme 7Be concentrations. • Identify latitudinal differences according to extreme 7Be activity concentrations and meteorological factors. [ABSTRACT FROM AUTHOR]

The seasonal stability of snow cover (ISS) was defined as a percentage ratio of the real and the potential snow cover duration in a winter season. Main results of the study are as follows: (1) alternately occurring periods of high and low values of the index of snow cover stability did not appeared simultaneously in mountainous and non-mountainous areas; (2) in the majority of Poland area both zonal and meridional components of the atmospheric circulation influence the ISS; however, in south the meridional air flow reveals the stronger impact, mostly due to the intensification of the southern advection by the foehn effect; and (3) changes of two or three indices describing atmospheric circulation explain up to 50 % of the ISS in Poland. The diminishing stability of snow cover in Poland corresponds with an increasing intensity of the advection from the western sector in winter in the second half of the twentieth century in Europe. [ABSTRACT FROM AUTHOR]

Abstract: Granaries (hórreos) are bioclimatic conservation structures with various forms that have been used for over 2000 years in different countries across Europe and Asia. Galician raised granaries built upon “staddle stones” (pillars with a rodent-proof cap) are specialised barns. The importance of airflow in the preservation of stored grain is based on the use of air as an energy exchange fluid for exchanging heat or water with the grains. The preservation system is based on continuous ventilation inside the bin. Some granaries do not have a wooden slatted floor with gaps, although they should. The gapped, slatted floor particularly influences the thermodynamic behaviour, which is powered by solar radiation, improving ventilation efficiency and internal temperature regulation. This paper shows the important influence of floor grooving on improving grain conservation via better ventilation and limiting the rise in the internal temperature when the granary is subjected to solar radiation. [Copyright &y& Elsevier]

Air traffic trajectory optimization is a complex, multidimensional and non-linear optimization problem and requires a firm focus on the essential criteria. The criteria cover operational, economical, environmental, political, and social factors and differ from continent to continent. Since air traffic is a transcontinental transport system, the criteria may also change during a single flight. Historic flight track data allow observation and assess real flights, to extract essential criteria and to derive optimization strategies to increase air traffic efficiency. Real flight track data from the Chinese and European air traffic show significant differences in the routing structure in both regions. For that reason, reference trajectories of historic ADS-B 24-h air traffic data in China and Europe have been extracted and analyzed regarding horizontal flight efficiency and the most restrictive criteria of trajectory optimization. We found that prohibited areas might be the most powerful reason to describe deviations from the great circle distance in the Chinese air traffic system. Atmospheric conditions, network requirements, aircraft types and flight planning procedures are similar in China and Europe and only have a minor impact on flight efficiency during the cruise phase. In a multi-criteria trajectory optimization of the extracted reference trajectories considering the weather, operational constraints and prohibited areas, we found that flown ground distances could be reduced by 255 km in the Chinese airspace and 2.3 km in the European airspace. The resultant reference trajectories can be used for further analysis to increase the efficiency of continental air traffic flows. [ABSTRACT FROM AUTHOR]

Changes to the winter-to-spring switch-time of the upper air flow regime at the 850 and 500 hPa levels over the north-eastern Baltic Sea are analyzed based on a data set extending from 1955 to 2007. The long-term variation of the air flow in early spring (March) exhibits multiple regime shifts. The shifts are extracted by means of a vector analysis of the monthly mean air flow and using statistical shift detection technology. In the middle of the 1960s the average air flow turned from NW (WNW) to W (WSW) at the 500 (850) hPa level. The original regime was restored in the mid-1990s. The regime shifts in the average air flow in March can be interpreted as changes in the transition time from winter to summer circulation type. [ABSTRACT FROM AUTHOR]

Connectivity measures have been widely used by researchers and practitioners in the air transport industry to evaluate the degree of transport provision at different levels of detail. This paper adds to the literature by presenting a comprehensive study of the predictive performance of connectivity indices in estimating aggregate itinerary market shares. Our empirical analysis encompasses both nonstop and connecting itineraries that originated or destined in Europe during 2018. The predictive accuracies of the respective measures are assessed against actual market shares and an ad-hoc benchmark derived from a logit-based calibrated index and evaluated in terms of their prediction-error distributions. Our results suggest that the use of connectivity indices can significantly improve the assessment of itinerary market shares relative to conventional size-based measures (up to 16.9% gain in accuracy over itinerary frequency). These improvements, along with their use of standard formulations and lack of a calibration requirement, make connectivity models a valuable tool for practitioners to use in allocating aggregate air travel flows. An examination of different scenarios—short-/medium (SH/MH)-vs. long-haul (LH) and sizeable vs. thin markets—reveals that determination of the best index is not a straightforward task and provides guidance to selecting the best connectivity measure. • Comparison of different connectivity metrics to estimate flight itinerary market shares. • Connectivity indices found to significantly improve results with respect to size-based measures. • The NetScan model is the best performing on short/medium-haul markets while the GCI performs best on long-haul markets. • Dataset covering all European flights used to calibrate a new benchmark measure. [ABSTRACT FROM AUTHOR]

The present study proposes the possibility of implementing a clean, renewable technology that allow profitable value to be drawn from a highly contaminant waste, Two Phase Olive Mill Waste (TPOMW). An anaerobic digestion (AD) process under optimal conditions can significantly reduce the overall chemical oxygen demand (COD) by 46.87 ± 4.53% and ensure the stability of the process. For this the TPOMW has to be subjected to three procedures: (i) dilution, mixture formed by 30% de TPOMW and 70% water; (ii) a 5-day aeration pre-treatment at a 0.65 L/min flow rate of air per L of reactor; and (iii) pH monitoring and adjustment to 7 by the addition of a 10% calcium hydroxide solution. After these actions, biomethanation of TPOMW yielding a mean production of 12.69 ± 1.57 Nm³ methane/m³ substrate, allowing the sale of excess thermal energy to nearby companies. The study of the economic feasibility of an industrial plant, based on previous results, showed that it isn't profitable economically because the technology is emerging and it is necessary to improve process performance and reduce installation, operation and maintenance costs. However, the project presented is environmentally viable, since the carbon dioxide emissions that would be released to the atmosphere if the TPOMW were to decompose naturally are reduced by a factor of 7 times. This study thus constitutes an example of a "green and circular economy". Image 1 • The sequence of the two pretreatments ensures the stability of the anaerobic process. • The methane yield obtained with the pretreatments is 12.69 Nm³ CH 4 /m³ of substrate. • The project presented is environmentally viable. • The biomethanation plant would allow the recovery of 65% of the initial water of substrate. [ABSTRACT FROM AUTHOR]

• Airflow distribution uniformity affects thermal performance significantly • Seasonal heat gains can be 28% lower for real than for uniform airflow distribution • U-type exchangers have better airflow distribution and better thermal performance • Large diameter manifolds and long branches result in better thermal performance In multi-pipe structures of earth-to-air heat exchangers (EAHEs), the airflow distribution between parallel pipes is not uniform and depends on many geometrical parameters, primarily the relation between the diameters of parallel pipes and manifolds, and the length of branch pipes. The phenomenon of airflow non-uniformity is usually neglected in the thermal performance calculations. This report investigates the influence of airflow distribution patterns on the thermal performance of multi-pipe EAHEs in order to bridge this knowledge gap. The calculations have been performed for a winter-time season for exchangers located in the climatic conditions of Central Europe. Analysis was conducted for different airflow conditions characterized by an airflow distribution uniformity coefficient. Results show that the thermal performance calculated for real EAHEs, with branch-pipes of a length L = 76d and diameters equal to the main pipe diameters, can be up to 28% lower than for ideal (uniform) distribution of air in an analogous exchanger. For EAHEs with branch-pipes of a length L = 300d and main pipes 1.4 times larger in diameter than parallel branch-pipes, the differences are much lower, i.e., less than 13%. The correlation between the airflow distribution uniformity coefficient and the EAHE seasonal heat gains is presented for exchangers consisting of 3, 5, 7, or 10 parallel branch-pipes. These results can be applied in various energy and economic analyses to estimate the potential energy savings from designing energy efficient building HVAC systems equipped with EAHEs characterized by better airflow distribution. [ABSTRACT FROM AUTHOR]

• A hybrid model of the human lung airway has been constructed using images obtained from computed tomography (CT) and an idealized morphology. • An intermediate solid model section links the cylindrical sections of the idealized model to the non-cylindrical sections of the CT-based model. • The model was verified using two sets of simulations, steady inspiration/ expiration and transient simulation of forced spirometry. • The model development outlined here represents an important step toward computational simulation of lung dynamics for patient-specific applications. Health care costs represent a substantial an increasing percentage of global expenditures. One key component is treatment of respiratory diseases, which account for one in twelve deaths in Europe. Computational simulations of lung airflow have potential to provide considerable cost reduction and improved outcomes. Such simulations require accurate in silico modeling of the lung airway. The geometry of the lung is extremely complex and for this reason very simple morphologies have primarily been used to date. The objective of this work is to develop an effective methodology for the creation of hybrid pulmonary geometries combining patient-specific models obtained from CT images and idealized pulmonary models, for the purpose of carrying out experimental and numerical studies on aerosol/particle transport and deposition in inhaled drug delivery. For the construction of the hybrid numerical model, lung images obtained from computed tomography were exported to the DICOM format to be treated with a commercial software to build the patient-specific part of the model. At the distal terminus of each airway of this portion of the model, an idealization of a single airway path is connected, extending to the sixteenth generation. Because these two parts have different endings, it is necessary to create an intermediate solid to link them together. Physically realistic treatment of truncated airway boundaries in the model was accomplished by mapping of the flow velocity distribution from corresponding conducting airway segments. The model was verified using two sets of simulations, steady inspiration/expiration and transient simulation of forced spirometry. The results showed that the hybrid model is capable of providing a realistic description of air flow dynamics in the lung while substantially reducing computational costs relative to models of the full airway tree. The model development outlined here represents an important step toward computational simulation of lung dynamics for patient-specific applications. Further research work may consist of investigating specific diseases, such as chronic bronchitis and pulmonary emphysema, as well as the study of the deposition of pollutants or drugs in the airways. [ABSTRACT FROM AUTHOR]

Since households are one of the most energy-intensive sectors in Europe, retrofit of dwellings is promoted to increase energy efficiency. Recent research, however, shows that the energy performance after retrofit does not always meet the target values, which can be caused by amongst other things, a deviating building envelope performance. This paper compares the theoretical and measured building envelope performance for a real-life case study in post-retrofit state, in order to illustrate the limitations of calculation methods and characterization models. First, the performance is evaluated on building scale by verifying the correspondence between the default theoretical heat loss coefficient (HLC) and the measured HLC, which was determined by following the guidelines formulated within IEA EBC Annex 58 and Annex 71. In order to illustrate the limitations of the standard calculation method in real-life conditions, the theoretical variability of the HLC is evaluated, generated by variating infiltration heat losses and heat exchange with neighboring dwellings. Second, the performance is investigated on a component scale by assessing the theoretical and measured thermal resistances, identified from heat flux tests. Additionally, nonhomogeneous assembled components and air leaks are simulated to verify probable causes for the locally varying measured values and to illustrate the limitations of calculations and characterization methods. The results illustrate the limitations of the calculation methods by the assessment of the strong variability of the theoretical HLC, depending on assumptions regarding infiltration and heat exchange with neighboring dwellings. In addition, component simulations indicated that deficiencies on a component scale could be caused by a nonhomogeneous assembly and air cavity flows of the component. Moreover, a detailed assessment of an unreliable thermal resistance illustrates the limitations of the used characterization method. Finally, a contrast was found between the quite good performance on building scale (15% deviation between the theoretical and measured HLC) and poor performance on a component scale (only one out of nine monitored components met their theoretical target values), which illustrates the complexity of the building envelope performance. [ABSTRACT FROM AUTHOR]

Within the CO2 time series measured at the Environmental Research Station Schneefernerhaus (UFS), Germany, as part of the Global Atmospheric Watch (GAW) program, pollution episodes are traced back to local and regional emissions, identified by δ13C(CO2) as well as ratios of CO and CH4 to CO2 mixing ratios. Seven episodes of sudden enhancements in the tropospheric CO2 mixing ratio are identified in the measurements of mixing/isotopic ratios during five winter months from October 2012 to February 2013. The short-term CO2 variations are closely correlated with changes in CO and CH4 mixing ratios, achieving mean values of 6.0 ± 0.2 ppb/ppm for CO/CO2 and 6.0 ± 0.1 ppb/ppm for CH4/CO2. The estimated isotopic signature of CO2 sources (δs) ranges between −35‰ and −24‰, with higher values indicating contributions from coal combustion or wood burning, and lower values being the result of natural gas or gasoline. Moving Keeling plots with site-specific data selection criteria are applied to detect these pollution events. Furthermore, the HYSPLIT trajectory model is utilized to identify the trajectories during periods with CO2 peak events. Short trajectories are found covering Western and Central Europe, while clean air masses flow from the Atlantic Ocean and the Arctic Ocean. [ABSTRACT FROM AUTHOR]

The author applauds the announcement that Annex 1 requirements under a national application of the Pharmaceutical Inspection Cooperation Scheme regulatory programme in Europe will be subjected to a root and branch revision. Topics discussed include the author's experience with working a firm in Southeast Asia, an example illustrating the lack of clarity in the document, and the guidance on airflow velocity in Grade A unidirectional airflow systems.