Agricultural Engineering Research, Volume 8 (2002)

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Now showing 1 - 13 of 13

Techniques of Land Use for Open Landscape Maintenance in Former Military Training Areas
(2002) Prochnow, Annette; Schlauderer, Ralf
Valuable open landscape biotopes characterized by great biodiversity cover large surfaces of military training areas. Their conservation requi- res appropriate measures which allow them to be kept open. Potential techniques are grazing by domestic or wild animals, mowing and clea- ring or mulching, the uncovering of the soil using tillage implements or sod cutting, as well as controlled burning and shrub removal. However, knowledge regarding the impact of these techniques on vegetation and fauna, process organization, and the expenditures under the specific conditions of military training areas is still insufficient. On the basis of interviews with maintenance contractors, accompanying process- technological measurements, and information provided by the literature, results regarding process organization and economic assessment are presented.
Dynamics of Odour Release from a Pig Stall - Part 2 : Results of Parallel Measurements with Olfactometry and the ?EURoeElectronic Nose?EUR?
(2002) Brose, Gregor; Hartung, Eberhard; Jungbluth, Thomas
The heavily fluctuating operating conditions in pig husbandry due to cli- matic and biological changes (alterations of temperature and air flow ra- te between day and night as well as between summer and winter, increa- sing animal mass during the fattening process, etc.) exert a significant in- fluence on the amount of actual odour emission. The examination pro- gramme of the presented project comprised the measurement of seasonal (fattening course), daytime-related, and short-term (feeding) dynamic ef- fects of odour release, as well as the identification of potential factors which influence the amount of odour emitted. Parallel to “classic” olfac- tometry, an “electronic nose” with a chemosensor array of ten metal oxide sensors was employed. The largest odour emissions are measured on hot summer days, while the lowest emissions were determined on cold winter days. On the one hand, the sensor signals of the “electronic nose” exhibit considerable differences on days with large air flow rate alterati- ons. On the other hand, continuous measurement with the “electronic nose” allows changes in the gas- and odorant composition of the exhaust air during the feeding times to be shown. From the measurement results, recommendations for odour sampling, the consideration of seasonal odour emission fluctuations in odour spreading calculations, and the use of “electronic noses” for the evaluation of odour emissions have been derived.
Piglet Rearing in the Outdoor Climate Stall - Animal Welfare and Biological Performance
(2002) Snell, Hinrich; Dellwisch, Stephan; Van den Weghe, Herman
In an outdoor climate stall for rearing piglets in large group husbandry, the stall climate as well as the behaviour and the biological performance of the animals was examined during two fattening periods in the cold season. The results prove that the tested housing system provides good animal performance despite simple construction. Numerous (especially technical) indicators suggest that the examined housing system can be termed animal-friendly.
Process Safety Agricultural Machinery Electronics - Implement Guided Tractor Control
(2002) Martinus, Marcus; Freimann, Rüdiger
The project “Process Safety of Agricultural Machinery Electronics” supported by the German Society for the Advancement of Scientific Re- search (DFG) is intended to study the functional safety of electronically controlled work processes and automated systems in tractor-/implement combinations and self-propelled agricultural machines. The goal is the elaboration of a concept of development steps, methods, and tools which allows for the safety-related development of mechatronic systems. Re- search focuses on the methods of system- and risk analysis as well as a universal development model for electronic control units, which are de- scribed in general and using an example.
Piglet Rearing with an Automatic Tube Mash Dispenser or Interval Feeding
(2002) Snell, Hinrich; Hofsommer, Jürgen; Van den Weghe, Herman
During two rearing periods, a newly developed automatic interval fee- ding mash dispenser was compared with a conventional automatic tube mash dispenser with regard to its suitability for piglet rearing. The use of the automatic interval mash dispenser did not lead to im- proved rearing performance. Feed consumption, however, increased. The design of the feed trough as well as the kind of feed metering must be dis- cussed as possible reasons. Animal behaviour was also significantly influenced by the feeding sys- tem. At the automatic tube feed dispenser, more eating processes were observed, and fewer animals showed interest in eating without actually doing it. The results of the first rearing period indicate that increased aggression must be expected if the setting of automatic interval feeding mash dispensers is relatively restrictive.
Brown Coal reduces Slurry Emissions - Basic Investigations of the Reduction of Emissions from Slurry through Treatment with Fine-Grain Brown Coal
(2002) Hörnig, Günter; Brunsch, Reiner; Biegel, Anita; Noack, Michael
Fine-grain brown coal from the Lausitz region has been tested in the la- boratory at dosages of 3 and 5 mass-% as an alternative to swimming layers of slurry and straw. Three series of trials were carried out using slurry with dry matter contents (DM) common in practice: cattle slurry with DM = 5%, 7%, and 8.9% as well as pig slurry having a DM = 5.2% and 7.6% Together with floating slurry particles, fine-grain brown coal forms dense swimming layers, which cause a drastic reduction in odorant emission. In cattle slurry stored under undisturbed conditions, the reduc- tion amounted to approximately 70% and, after homogenizing, to 90% to 98%. In pig slurry, a 92% to 98% reduction was achieved, both before and after homogenizing. The addition of brown coal reduces the pH-value of the slurry by about 0.2 to 0.3 units and NH3 release by up to 30%. The treatment of pig slurry with fine-grain brown coal improves the con- ditions for effective solid-liquid separation into an easily conveyable liquid and a well-transportable solid with high contents of nutrients and humin. Investigations regarding the use of the large humin content of this brown coal for the long-term formation of humus remain to be carried out. In addition, questions concerning process engineering and the economic efficiency of slurry treatment with brown coal still need to be answered.
Environmentally Compatible Fattening Pig Husbandry II : Comparison of Emission Rates
(2002) Gallmann, Eva; Hartung, Eberhard; Jungbluth, Thomas
During the course of continuous emission measurements of ammonia (NH3 ), carbon dioxide (CO 2 ), and methane (CH4 ) for the evaluation of the environmental impact of housing systems for fattening pigs, a fully slatted floor system with forced ventilation (FSF) and a kennel housing system with natural ventilation (KN) were examined. Through long-term measurements over four consecutive fattening periods from October 1999 until April 2001, enough data from different seasons and fattening stages were gained on the one hand, while on the other hand it was pos- sible to carry out a comprehensive verification of data along with selec- tion based on clear verification criteria. For the comparison of the emis- sion rates on the basis of the daily mean values, approximately 60% of the measuring days and of the data were taken into account. Stocking (in livestock units) and the liquid manure parameters as mar- ginal conditions did not exhibit any significant differences between the housing systems FSF and KN. With increasing fattening duration and liquid manure quantity, an increase in the ammonium-nitrogen content of the liquid manure from approximately 2 to 5 g/kg in the fresh substance was recorded. The air temperature and relative humidity in the interior of the system KN largely followed the outside conditions. In principle and also on warm days, the interior temperatures ranged below the values for the FSF system. However, the opposite was true for relative humidity, which clearly exhibited higher values in the KN system. Due to the differ- ent modes of operation of the ventilation systems, clear differences could also be discerned between the housing systems, especially in the winter when the air flow rates in the KN systems were 2 to 4 times higher as compared with the winter air flow rate of forced ventilation in the FSF system, for example. The gas concentrations in the exhaust air of the FSF system generally exhibited significantly higher values. On all measuring days considered, the daily mean values of the NH3 , CO2 , and CH4 emis- sion rates [(g/d)*LU-1 ] for the KN system were lower by a factor of ap- proximately 1.5 as compared with the FSF system. The comparison of the average emission rates per fattening period between the housing systems showed a very significant difference in favour of the KN housing system. During the four observed fattening periods, the mean value of the NH 3 emission rate for one fattening period varied between 67 and 96 (g/d)*LU-1 in the KN system and between 100 and 149 (g/d)*LU-1 in the FSF system. The CO2 emission rates ranged between 10 to 13 (kg/d)*LU-1 (KN) and 17 to 23 (kg/d)*LU-1 (FSF). In the KN system, the mean values of the CH4 emission rates per fattening period (17 to 36 (g/d)*LU-1 ) were also lower than in the FSF system at 62 to 134 (g/d)*LU-1.
Energy Efficiency of Brazilian Hammer Mills Grinding Maize
(2002) Scholz, Volkhard; Pereira Dias, Gutemberg; Rodrigues, Denilson Eduardo; Coelho, Ronaldo Flora Flora
A law adopted after the latest energy crisis in Brazil prohibits the pro- duction and marketing of machines with low energetic efficiency. For this reason, a measuring stand was built as part of a German-Brazilian pro- ject, and the energy consumption as well as the grinding quality of five Brazilian hammer mills DPM during maize grinding were determined and evaluated. In addition, the validity of different energetic calculation models known from the literature was examined. The results show the in- fluence of mass flow, rpm, and sieve hole diameter on specific energy consumption as well as its dependence on the comminution degree of the material.
Exhaust Emissions of Biogas-Driven Combined Heat- and Power Plants
(2002) Schlattmann, Markus; Effenberger, Mathias; Gronauer, Andreas
In order to determine the actual volume of emissions from agricultural biogas-driven heat- and power plants, the exhaust emissions of selected practically operated plants with pilot-injection engines were measured over a longer period. These measurements showed that none of the units measured entirely met the emission limits of the TA Luft (Technical Regulations Concerning Air Pollution). At the discretion of the licensing authorities, these limits for plants with a thermal firing output of a total of 1 MW or more can also be applied in construction permit procedures for smaller plants like those frequently used in practice for agricultural biogas combustion. If necessary, however, more practice-oriented emission limits like those recommended by the Bavarian Environmental Protection Agency must be employed in such cases. Optimized engine settings and regular maintenance could significantly reduce the emission potential.
Measurements and Modelling of Full-Scale Concentration Fluctuations : Open-field experiments using krypton-85 and tetrahydrothiophen as tracers
(2002) Lung, Thomas; Müller, Hans-Joachim; Gläser, Manfred; Möller, Bernd
The simulation of odour frequencies near animal housing facilities or industrial plants requires a model of the frequency distribution of con- centration. Generally, for this purpose two-parameter distribution func- tions are used, which, depending upon the mean value and the variance of odour concentration, provide information about the probability of oc- currence. In order to examine how well the simulations coincide with reality, the calculation results are compared with measurement data. In model construction this examination step is also termed validation. Open-field experiments with tracers serve to examine the dispersion and fluctuation behaviour of airborne material in the atmospheric wind field. If in particular one intends to analyze the concentration fluctuations of odours, measuring techniques with high temporal resolution must be employed because odours can be perceived by the human nose within one second. In this examination, the artificially produced gas krypton-85 ser- ves as a tracer, whose concentration was measured by a group of detec- tors each at different distances from the source in one-second intervals. Based on the measurement data, mean values, variance, and higher sta- tistical moments of the tracer concentration are calculated and compared with the corresponding results of model simulations. Observed and simu- lated exceedance probabilities are compared, and the statistical charac- teristics of the models used are discussed. Do the results of the tracer measurement can be directly applied to odour frequencies? In order to answer this question, in some field experiments, the odourant tetrahydrothiophen, whose odour effects were registered by test persons at selected detector positions, was released at the same time as the tracer krypton-85. In contrast to the precise, unambiguous tracer measurement, the perception and assessment of odours is dependent u- pon sensation so that the application of the exceedance probability de- termined through measurement to the frequency of sensory perception needs to be statistically validated.
Membranes for the Downstreaming of Lactic Acid from Grain
(2002) Reimann, Winfried
In addition to lactic acid, which is present as sodium lactate, the reaction mixture which results from the production of lactic acid from grain hydrolysates through fermentation contains impurities which must be removed depending on the kind of product and the purity requirements it must fulfill. Membrane techniques are increasingly being used as an alternative to conventional methods. Nanofiltration in the form of diafiltration and electrodialysis count among these techniques. They not only allow uncharged components, such as sugar and proteins, but also foreign ions, such as chloride ions, to be removed from the target product.
Possibilities of Community-Encompassing Transborder Farming Using Zeilitzheim as an Example
(2002) Rothmund, Matthias; Auernhammer, Hermann; Demmel, Markus
Virtual land consolidation in the form of transborder farming of entire community areas offers farmers in small-structured areas the possibility of using the advantages of larger field sizes both in the long and the short run without requiring field rearrangement, which is often difficult to accomplish. The reduction of time requirements, necessary operating resources, forecrop areas, and overlapping areas equally reduce the burden on the environment, the soil, and the farmer´s wallet. The use of automatic data acquisition allows all yields and expenditures related to the cooperatively used transborder fields to be attributed to the partici- pating farmers according to their property.
Environmentally Compatible Fattening Pig Husbandry III : Daytime-Related Effects
(2002) Gallmann, Eva; Hartung, Eberhard; Jungbluth, Thomas
As part of continuous emission measurements in the experimental stall for fattening pigs in Hohenheim, a conventional stall with fully slatted floor and forced ventilation (FSF) was compared with a naturally ventilated kennel housing system (KN) during four fattening periods from October 1999 until April 2001. The third contribution to the article series about environmentally compatible fattening pig housing focuses on the description and analysis of daytime-related effects and the course of emissions. The courses of three measuring periods during the second fattening period which were chosen as examples as well as multiple regression analyses were studied to answer the question of what variables mainly determine the different daily courses of NH3 - and CO2 -emission and to what extent emission reduction strategies may influence the daily course. In accordance with the literature, the FSF housing system largely showed a positive correlation between temperature, volume flow, and emission. In the KN housing system, however, a reduction in emissions was observed combined with increasing volume flows, which generally occurred in particular at low temperatures. Animal activity, which was strongly influenced by the feeding times, was reflected by significant peaks of CO 2 concentration and –emission as well as NH3 emission. In the FSF housing system, the percentage of variance in the daily course of the emission rates during the selected measuring periods which can be explained through variables able to be used for practicable stall climate recording and –control and able to be influenced through measures of emission reduction ranged between 12 % and 75 % for NH3 and between 39 % and 47 % for CO2 . In the KN housing system, the percentage of explainable variance is lower at 52 % to 64 % (NH3 ) and 18 % to 28 % (CO2 ).

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