Peter Schulze Lammers

A miniaturized thermal desorption unit for chemical sensing below odor threshold

We present a thermal desorption unit with features designed for use with chemical sensors to enhance sensitivity and selectivity. A novel method is used to measure and empirically describe influences on breakthrough characteristics. A fast heating technique and low dead volume result in sharp desorption peaks (approx. 0.53 ml). Enrichment factors of more than 100-fold allow for detection of odorous substances below their odor threshold.

Fast and solvent-free quantitation of boar taint odorants in pig fat by stable isotope dilution analysis-dynamic headspace-thermal desorption-gas chromatography/time-of-flight mass spectrometry.

Boar taint is a specific off-odour of boar meat products, known to be caused by at least three unpleasant odorants, with very low odour thresholds. Androstenone is a boar pheromone produced in the testes, whereas skatole and indole originate from the microbial breakdown of tryptophan in the intestinal tract. A new procedure, applying stable isotope dilution analysis (SIDA) and dynamic headspace-thermal desorption-gas chromatography/time-of-flight mass spectrometry (dynHS-TD-GC/TOFMS) for the simultaneous quantitation of these boar taint compounds in pig fat was elaborated and validated in this paper. The new method is characterised by a simple and solvent-free dynamic headspace sampling. The deuterated compounds d3-androstenone, d3-skatole and d6-indole were used as internal standards to eliminate matrix effects. The method validation performed revealed low limits of detection (LOD) and quantitation (LOQ) with high accuracy and precision, thus confirming the feasibility of the new dynHS-TD-GC/TOFMS approach for routine analysis.

Computer Modelling for Assessing Means to Reduce Odour Emissions

When planning new livestock units, which might cause annoyances to nneighbouring residential areas, computer models are frequently used to predict odour ndispersion. In this way the expected emission situation can be anticipated and hence ndecisions whether the project is permissible can be made. In the following article an nanalytical model is introduced which is employed to evaluate reduction measures of nodour dispersion in the vicinity of agricultural enterprises. The effects of source nheight, an increased outlet speed and the use of windbreaks to avoid annoyance are ninvestigated.

Vermessung und Sortierung von Saatkörnern der Durchwachsenen Silphie zur Optimierung der Bestandesetablierung

By using cup plant ( Silphium perfoliatum L.), which is native to North America, as bioxadgas substrate, there is an economically interesting alternative or supplement to the predominantly used substrate maize. Due to its ecological advantages, it also contributes to the increase of biodiversity in the agricultural landscape. In order to establish an efficient crop stand with a long useful life of more than 10 years, a precise distribution of the seeds is necessary. The seeds are characterized by a strong heterogeneity in size and shape within a seed batch which negatively affects the quality of singling. The aim of the experiments was to quantify the size and geometry of seeds from different batches. In this context, seeds were measured and divided into fractions by using a self generated scheme and procedural analyses. In addition to optimize the singling by increasing the homogeneity, the study supports also the potential for improving the quality of commercially available seeds

Bestimmung der Korngeometrie der Durchwachsenen Silphie als Voraussetzung für die Einzelkornsaat

In search of economically and ecologically interesting alternatives and additions to maize, currently the predominantly used biogas substrate, cup plant (Silphium perfoliatum L.) has been found as a promising plant species. The perennial composite, which is located in North America, can be established by modified conventional seeders. Due to a long flowering period and different geographic origins of the plant material, seeds of different sizes and shapes can be found in the seed batch, which makes a precise singling of the seeds difficult. For the quantification of the geometric parameters the seeds were recorded and measured. The results of these researches were used to optimize the seeding in precision seeders.

Kameragesteuerte mechanische Unkrautbekämpfung in Pflanzenreihen

Am Institut fur Landtechnik der Universitat Bonn wurde ein Anbaugerat zur mechanischen Unkrautkontrolle von Reihenkulturen entwickelt und getestet. Ziel war es, den Bereich zwischen den Kulturpflanzen in der Reihe (intra-row) zu bearbeiten, ohne diese zu beschadigen. Als Schwerpunkt des Forschungsprojektes wurde die Pflanzenerkennung mithilfe einer kamerabasierten Bildverarbeitung entwickelt. Dabei sollten standardisierte Industriekomponenten und Kommunikationsstandards verwendet werden. Fur den Antrieb der Hackwerkzeuge wurden elektrische Servomotoren gewahlt. Die Ansteuerung erfolgt uber ein echtzeitfahiges EtherCAT- Bussystem, welches an einen Echtzeit-Controller angeschlossen ist. Dieser Aufbau ermoglicht die mechanische Unkrautbekampfung bis zu einer Fahrgeschwindigkeit von 7,2 km/h.

Bestimmung der Porosität von Böden durch Messung der Oberflächenrauhigkeit

Die Bodenbearbeitung zielt auf eine fur die Einbettung und den Auflauf von Samen gunstigeStruktur der Oberflache ab. Die Oberflachenrauhigkeit und Oberflachenporositat sind zwei Grosen, die die physikalischen Bedingungen der Oberflache beschreiben und deshalb das Ergebnis der Bodenbearbeitung reprasentieren. Eine kurzfristige Ermittlung dieser beiden Parameter erlaubt daher eine Beurteilung der Qualitat der Bodenbearbeitung. Wahrend die Oberflachenrauhigkeit mit einem Relief-Laserscanner im Feld durchgefuhrt werden kann, muss die Porositat im Labor bestimmt werden. Die Untersuchung befasst sich deshalb mit dem Zusammenhang beider Grosen und ergibt in einem mittelfristigen Zeitraum (< 3 Wochen), der fur die Saatbettbereitung von vorrangiger Bedeutung ist, eine hohe Korrelation zwischen der Oberflacherauhigkeit und der Oberflachenporositat.