DYNAMIC DISPERSION MODELLING OF ODOURS AND AEROSOLS

The transmission of dust particles is one of the interesting processes in the dispersion of aerosols. Due to the fact that it is impossible to follow the track of every single particle, a lot of effects and their parameters must be known to simulate the dispersion. At the Harmo 7 conference a dynamic model to simulate the dispersion of odours was presented, before. This model is based on a numerical solution of the Navier-Strokes equation. Building upon this effort the dispersion model was enhanced, so that it is now possible to simulate the dispersion of aerosol particles. Extensive modifications were necessary to consider the aerodynamic and physical characteristics of polydisperse aerosols. Effects as sedimentation, deposition, resuspension and agglomeration of aerosols are or will be integrated into the simulation model. In order to realize a validation of such a complex dispersion model, our research group is developing two independent aerosol tracer systems. Primary attention is paid to the environmental compatibility of the tracer dust. Both procedures are based on fluorescence marked particles, but they differ from each other with regard to their methods of detection. This enables us to practice both procedures at the same time. The dispersion model as well as the validation methods is objects of this paper

Locomotion behavior of dairy cows on traditional summer mountain farms in comparison with modern cubicle housing without access to pasture.

Pasture based systems enable cattle to express their natural behavior and are thus expected to provide better welfare than the majority of confinement systems. The aim of this study was to objectively measure locomotion activity of healthy dairy cattle kept on mountain pastures (n = 44) compared with cows kept in cubicle housing systems (n = 38). Selected cows were equipped with a validated 3D-accelerometer on one hind limb, and locomotion behavior was recorded for 48 hours. The 1-hour summaries of the variables lying time, walking time, standing bouts, walking bouts and number of strides were summed up to 24-hour summaries, and the means of the stride distance and stride duration were weighted by the variable number of strides. Mountain pasture cows had higher locomotor activity levels in comparison to cubicle cows. Mountain pasture cows spent less time lying down (528.1±109.5 min/day vs. 693.3±73.8 min/day; P<0.0001) and more time walking (75.6±25.9 min/day vs. 38.8±15.8 min/day; P <0.0001) than cubicle cows. Lying bout duration was longer in cubicle than in mountain pasture cows (90.9± 15.2 min/bout vs. 74.2 ± 21.1 min/bout; P = 0.0001), whilst the number of walking bouts was higher in mountain pasture cows than cubicle cows (199.1 ± 49.1 vs. 123.8 ± 43.8 bouts per day; P < 0.001). Likewise, the number of strides was higher in mountain pasture cows than cubicle cows (2040.5 ± 825.3 vs. 916.7 ± 408.6; P < 0.001). Mountain pasture cows had shorter stride duration (P < 0.0001) and shorter strides (P = 0.0002) than cubicle cows (1.8 ± 0.1 s/stride vs 2 ± 0.2 s/stride and 126.3 ± 18.1 vs 142.1 ± 17.8 m/stride, respectively). In summary, cows kept on mountain pasture were more active and spent longer than 12 hours / day standing. Lying markedly less than 12 hours per day seems to represent the normal behavior of pastured cows searching for fresh grass. This does not cause any obvious damage to the locomotor system as claws of cattle are well adapted to long periods of movement on mountain pastures

Continuously measurement of the dry matter content using near-infrared spectroscopy

Near-infrared spectroscopy (NIRS) was used in agriculture and food chemistry in the early 1960s. NIR is located at a wavelength range between 800 nm and 2,500 nm. Although NIRS technology is a rapid, repeatable, highly precision and environmentally friendly technology for recording of spectra without destroying the samples, it is a complex method and the spectrometer calibration with a validated primary reference analysis is required. This study aimed at testing the suitability of NIRS for documenting the dry matter (DM) content of the stored silage in plastic bags. Accordingly NIRS sensors were installed in a commercial silo bagging machine after preliminary experiments in small scale were done. Maize and grass silage DM content was detected continuously using NIRS during storage process. The mean reference values for maize silage were significantly 6.6% higher than the NIRS values. With grass silage, NIRS values were only 0.6% below the mean reference value. The results of the NIRS sensor in the grass silage bag were less uniform than those of the maize silage due to no continuous direct contact between the measuring window and the substrate. NIRS sensor proved generally to be a suitable means of determining the DM in the crop flow of the pressing machine. However, continuous contact between the ensiled material and the NIRS sensor must be ensured, to guarantee that measurements are correct

Effects of Biogas Substrate Recirculation on Methane Yield and Efficiency of a Liquid-Manure-Based Biogas Plant

Biogas plants are the most complex systems and are heavily studied in the field of renewable energy. A biogas system is mainly influenced by biological and technical parameters that strongly interact with each other. One recommended practice when operating a biogas plant is the recirculation of the substrate from the second fermenter into the first fermenter, which extends the recirculation amount (RA) and, in turn, the recirculation rate (RR). This technique should be applied to support and secure the biogas process. In this investigation, the RA was varied, starting with the recommended “best practice” of 10.0 m3/d (RR 40%). Every ten days, the RA was reduced in steps of 1.5 m3/d, with 5.5 m3/d (RR 27%) being the final value. The basic question to be addressed concerns to what extent the RR influences the methane yield and thereby influence the efficiency of a manure-based biogas plant in practice. Diverting the “best practice” to a RR of 27% stabilised the fermentation process and lead to significantly higher methane yields with smaller standard deviations. In addition, with a reduced RR, the standard optimal acid concentration within the biogas substrate was approximately reached

Improving the forecast of fine dust emission and transmission from cattle barns: a comprehensive data package and analysis

Abstract The livestock sector emits harmful gases and bioaerosols, impacting animals, plants, and human health. Ventilation systems in livestock buildings disperse polluted air, affecting nearby air quality depending on the wind patterns and atmospheric stability. Understanding pollutant emission and transmission is crucial for environmental mitigation. This study focuses on fine dust dispersion from dairy cattle buildings. Chemical and microscopic analyses were conducted to identify the cattle barn dust sources. Particle mass emissions were quantified by measuring particle mass concentrations and air volume flow using the tracer gas decay method. Seasonal and daily effects on dust emissions were studied. Remarkably, particle emissions remained below prescribed values in Germany. Additionally, particle transmission, including resuspension and adsorption parameters, was investigated using a developed wind tunnel. Resuspension measurements revealed minimal resuspended particle mass due to low ground wind speeds. Notably, wheat, as a model plant, exhibited high adsorption rates, which increased with particle size. Overall, the findings for resuspension and adsorption parameters provide an initial database for understanding fine dust transmission from cattle barns

AP-2 family members regulate basal and cAMP-induced expression of human chorionic gonadotropin

The AP-2 family of transcriptional regulator proteins has three members, α, β and γ. AP-2α and γ are expressed in placenta and in the human trophoblast cell line JEG-3. AP-2 has been shown to regulate expression of the placental human chorionic gonadotropin (hCG) α- and β-subunit genes, however, previous work did not distinguish between the family members. Tryptic peptides of the AP-2 protein complexes purified from JEG-3 cells by oligo-affinity chromatography using the hCGα AP-2 site match the amino acid sequence of AP-2γ. The fact that AP-2γ is present at significant levels and binds the hCGα trophoblast-specific element suggests that AP-2γ is at least part of the binding complex in vivo and plays a role in regulating hCG expression. We show that mutation of each of four AP-2 binding sites within the hCGβ promoter decreases expression in transfection assays, demonstrating that all four sites are required for maximal expression in JEG-3 cells. Furthermore, we find differences in regulation of the family members: AP-2α mRNA levels increase in response to cAMP while AP-2γ mRNA levels do not. The demonstrated importance of the AP-2 sites in controlling hCGα and β expression and the likely involvement of more than one family member suggest that a balance in AP-2 proteins is involved in coordinate regulation of these genes. Moreover, many placenta-restricted genes are regulated by AP-2 proteins, thus members of this family may play an important overall role in placenta-specific expression

Developing a Penetrometer-Based Mapping System for Visualizing Silage Bulk Density from the Bunker Silo Face

For silage production, high bulk density (BD) is critical to minimize aerobic deterioration facilitated by oxygen intrusion. To precisely assess packing quality for bunker silos, there is a desire to visualize the BD distribution within the silage. In this study, a penetrometer-based mapping system was developed. The data processing included filtering of the penetration friction component (PFC) out of the penetration resistance (PR), transfer of the corrected penetration resistance (PRc) to BD, incorporation of Kriged interpolation for data expansion and map generation. The experiment was conducted in a maize bunker silo (width: 8 m, middle height: 3 m). The BD distributions near the bunker silo face were represented using two map groups, one related to horizontal- and the other to vertical-density distribution patterns. We also presented a comparison between the map-based BD results and core sampling data. Agreement between the two measurement approaches (RMSE = 19.175 kg·m−3) demonstrates that the developed penetrometer mapping system may be beneficial for rapid assessment of aerobic deterioration potential in bunker silos

An Assessment of Three Different In Situ Oxygen Sensors for Monitoring Silage Production and Storage

Oxygen (O2) concentration inside the substrate is an important measurement for silage-research and-practical management. In the laboratory gas chromatography is commonly employed for O2 measurement. Among sensor-based techniques, accurate and reliable in situ measurement is rare because of high levels of carbon dioxide (CO2) generated by the introduction of O2 in the silage. The presented study focused on assessing three types of commercial O2 sensors, including Clark oxygen electrodes (COE), galvanic oxygen cell (GOC) sensors and the Dräger chip measurement system (DCMS). Laboratory cross calibration of O2 versus CO2 (each 0–15 vol.%) was made for the COE and the GOC sensors. All calibration results verified that O2 measurements for both sensors were insensitive to CO2. For the O2 in situ measurement in silage, all O2 sensors were first tested in two sealed barrels (diameter 35.7 cm; height: 60 cm) to monitor the O2 depletion with respect to the ensiling process (Test-A). The second test (Test-B) simulated the silage unloading process by recording the O2 penetration dynamics in three additional barrels, two covered by dry ice (0.6 kg or 1.2 kg of each) on the top surface and one without. Based on a general comparison of the experimental data, we conclude that each of these in situ sensor monitoring techniques for O2 concentration in silage exhibit individual advantages and limitations