Using bi-spectral imaging technology for simulated online-weed control in winter wheat and maize

In spring 2011, two field trials on site-specific weed control in winter wheat and maize were carried out at Ihinger Hof research station of the University of Hohenheim. For the image acquisition, bi-spectral cameras were mounted on a vehicle. These cameras are able to take images free from disturbances by soil, mulch and stones. Images and the corresponding GPS-data were stored on-the-go. Afterwards, the images were analyzed by a weed recognition software. Weed infestation was mapped in consideration of weed species and weeds grouped according to their herbicide sensitivity. In order to simulate an online herbicide application, a onesided moving average of order five was used for the weed mapping. This kind of rearward calculation uses only the data of weed infestation which were already assessed behind or directly in the current position of the vehicle. The calculated weed distribution maps were checked by visual grid sampling. Herbicide application maps were generated by applying weed thresholds on the weed distribution maps. The herbicide application based on the maps was conducted by a multiple sprayer which allows the application of up to three herbicides independently from each other in a single pass across the field. Later on, the performance of the herbicide application was controlled again by visual grid sampling. Compared to a uniform herbicide application, the sitespecific weed control saved 83 % and 58 % herbicides respectively in winter wheat and 66 % in maize. The average efficacy of the site-specific herbicide application system in winter wheat was 70 % of the conventional herbicide application. Keywords: Bi-spectral cameras, herbicide application, image analysis, site-specific, weed controlSimulation einer online Unkrautkontrolle in Winterweizen und Mais unter Verwendung von BispektralkamerasIm Frühjahr 2011 wurden auf der Versuchsstation Ihinger Hof der Universität Hohenheim Feldversuche zur teilschlagspezifischen online-Unkrautkontrolle in den Kulturen Winterweizen und Mais durchgeführt. Die Bildaufnahme für die Erfassung der Verunkrautung mit Hilfe von digitaler Bildverarbeitung erfolgte mit einem Kamerafahrzeug, auf welchem Bispektralkameras montiert waren. Die Verwendung dieser Kameras gewährleistet die Aufnahme von Bildern, die von Boden, Steinen und Mulch weitestgehend ungestört sind. Zusammen mit den Bildern wurden die korrespondierenden Geokoordinaten gespeichert. Nach der anschließenden Bildauswertung unter Verwendung digitaler Bildauswerteverfahren erfolgte eine Kartierung der ermittelten Verunkrautung nach Unkrautarten bzw. Unkräuter gruppiert gemäß der Herbizidempfindlichkeit. Für die Kartierung wurden einseitig gleitende Mittelwerte der fünften Ordnung berechnet. Die Bestimmung des Mittelwertes erfolgte jeweils mit den vier Messwerten die zeitlich gesehen hinter dem aktuellen Messwert lagen und dem aktuellen Messwert. Durch diese rückwärtsgewandte Mittelwertbildung wurde die online Bildverarbeitung simuliert. Zur Überprüfung der Plausibilität der berechneten Unkrautverteilungskarten wurden die aus einer visuellen Rasterbonitur stammenden Daten herangezogen.Unter Verwendung von Schadschwellen wurden die auf der Basis der Bildanalyse erstellten Unkrautverteilungskarten für die Berechnung von Applikationskarten benutzt. Die Umsetzung der Applikationskarten erfolgte mit einer Dreikammerspritze, welche eine simultane Applikation von bis zu drei Herbiziden unabhängig voneinander erlaubt. Eine Erfolgskontrolle der durchgeführten Herbizidapplikation erfolgte im zeitlichen Abstand wiederum anhand einer visuellen Rasterbonitur. Im Vergleich zur betriebsüblichen Variante wurde durch die teilschlagspezifische Herbizidapplikation im Winterweizen eine Herbizideinsparung von 83 % bzw. 58 % und im Mais von 66 % realisiert. Die durchschnittliche Wirksamkeit der teilschlagspezifischen Herbizidmaßnahme im Winterweizen betrug 70 % der betriebsüblichen Variante. Stichwörter: Bildverarbeitung, Bispektralkameras, Herbizidapplikation, teilschlagspezifisch, Unkrautkontroll

Optimizing precision agricultural operations by standardized cloud-based functions

Aim of study: An approach to integrate knowledge into the IT-infrastructure of precision agriculture (PA) is presented. The creation of operation relevant information is analyzed and explored to be processed by standardized web services and thereby to integrate external knowledge into PA. The target is to make knowledge integrable into any software solution. Area of study: The data sampling took place at the Heidfeld Hof Research Station in Stuttgart, Germany. Material and methods: This study follows the information science’s idea to separate the process from data sampling into the final actuation through four steps: data, information, knowledge, and wisdom. The process from the data acquisition, over a professional data treatment to the actual application is analyzed by methods modelled in the Unified Modelling Language (UML) for two use-cases. It was further applied for a low altitude sensor in a PA operation; a data sampling by UAV represents the starting point. Main results: For the implemented solution, the Web Processing Service (WPS) of the Open Geospatial Consortium (OGC) is proposed. This approach reflects the idea of a function as a service (FaaS), in order to develop a demand-driven and extensible solution for irregularly used functionalities. PA benefits, as on-farm processes are season oriented and a FaaS reflects the farm’s variable demands over time by origin and extends the concept to offer external know-how for the integration into specific processes. Research highlights: The standardized implementation of knowledge into PA software products helps to generate additional benefits for PA

Structural Characterization and Lifetimes of Triple‐Stranded Helical Coinage Metal Complexes: Synthesis, Spectroscopy and Quantum Chemical Calculations

This work reports on a series of polynuclear complexes containing a trinuclear Cu, Ag, or Au core in combination with the fac-isomer of the metalloligand [Ru(pypzH)$_{3}$](PF$_{6}$)$_{2}$ (pypzH=3-(pyridin-2-yl)pyrazole). These (in case of the Ag and Au containing species) newly synthesized compounds of the general formula [{Ru(pypz)$_{3}$}$_{2}$M$_{3}$](PF$_{6}$) (2: M=Cu; 3: M=Ag; 4: M=Au) contain triple-stranded helical structures in which two ruthenium moieties are connected by three N-M-N (M=Cu, Ag, Au) bridges. In order to obtain a detailed description of the structure both in the electronic ground and excited states, extensive spectroscopic and quantum chemical calculations are applied. The equilateral coinage metal core triangle in the electronic ground state of 2–4 is distorted in the triplet state. Furthermore, the analyses offer a detailed description of electronic excitations. By using time-resolved IR spectroscopy from the microsecond down to the nanosecond regime, both the vibrational spectra and the lifetime of the lowest lying electronically excited triplet state can be determined. The lifetimes of these almost only non-radiative triplet states of 2–4 show an unusual effect in a way that the Au-containing complex 4 has a lifetime which is by more than a factor of five longer than in case of the Cu complex 2. Thus, the coinage metals have a significant effect on the electronically excited state, which is localized on a pypz ligand coordinated to the Ru atom indicating an unusual cooperative effect between two moieties of the complex

Chromium(0) and Molydenum(0) Complexes with a Pyridyl-Mesoionic Carbene Ligand: Structural, (Spectro)electrochemical, Photochemical, and Theoretical Investigations

This work reports on the synthesis and in-depth electrochemical and photochemical characterization of two chromium(0) and molydenum(0) metal complexes with bidentate pyridyl-mesoionic carbene (MIC) ligands of the 1,2,3-triazol-5-ylidene type and carbonyl coligands. Metal complexes with MIC ligands have turned out to have very promising electrocatalytic and photochemical properties, but examples of MIC-containing complexes with early-transition-metal centers remain extremely rare. The electrochemistry of these new MIC complexes was studied by cyclic voltammetry and especially spectroelectrochemistry in the IR region consistent with a mainly metal-centered oxidation, which is fully reversible in the case of the chromium(0) complex. At the same time, the two reduction steps are predominantly ligand-centered according to the observed near-IR absorbance, with the first reduction step being reversible for both systems. The results of the electron paramagnetic resonance studies on the oxidized and reduced species confirm the IR spectroelectrochemistry experiments. The photochemical reactivity of the complexes with a series of organic ligands was investigated by time-resolved (step-scan) Fourier transform infrared (FTIR) spectroscopy. Interestingly, the photoreactions in pyridine and acetonitrile are fully reversible with a slow dark reverse reaction back to the educt species over minutes and even hours, depending on the metal center and reagent. This reversible behavior is in contrast to the expected loss of one or several CO ligands known from related homoleptic as well as heteroleptic M(CO)4L2 α-diimine transition-metal complexes.Fil: Bens, Tobias. Universitat Stuttgart; AlemaniaFil: Boden, Pit. Freie Universität Berlin; AlemaniaFil: Di Martino-Fumo, Patrick. Freie Universität Berlin; AlemaniaFil: Beerhues, Julia. Universitat Stuttgart; AlemaniaFil: Albold, Uta. Freie Universität Berlin; AlemaniaFil: Sobottka, Sebastian. Universitat Stuttgart; AlemaniaFil: Neuman, Nicolás Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Gerhards, Markus. Freie Universität Berlin; AlemaniaFil: Sarkar, Biprajit. Universitat Stuttgart; Alemani

Investigation of Luminescent Triplet States in Tetranuclear Cu-I Complexes : Thermochromism and Structural Characterization

To develop new and flexible Cu-I containing luminescent substances, we extend our previous investigations on two metal-centered species to four metal-centered complexes. These complexes could be a basis for designing new organic light-emitting diode (OLED) relevant species. Both the synthesis and in-depth spectroscopic analysis, combined with high-level theoretical calculations are presented on a series of tetranuclear Cu-I complexes with a halide containing Cu4X4 core (X=iodide, bromide or chloride) and two 2-(diphenylphosphino)pyridine bridging ligands with a methyl group in para (4-Me) or ortho (6-Me) position of the pyridine ring. The structure of the electronic ground state is characterized by X-ray diffraction, NMR, and IR spectroscopy with the support of theoretical calculations. In contrast to the para system, the complexes with ortho-substituted bridging ligands show a remarkable and reversible temperature-dependent dual phosphorescence. Here, we combine for the first time the luminescence thermochromism with time-resolved FTIR spectroscopy. Thus, we receive experimental data on the structures of the two triplet states involved in the luminescence thermochromism. The transient IR spectra of the underlying triplet metal/halide-to-ligand charge transfer (M-3/XLCT) and cluster-centered ((CC)-C-3) states were obtained and interpreted by comparison with calculated vibrational spectra. The systematic and significant dependence of the bridging halides was analyzed.Peer reviewe

Remarkable high efficiency of red emitters using Eu(III) ternary complexes

We have synthesized Eu(iii) ternary complexes possessing record photoluminescence yields up to 90%. This high luminescence performance resulted from the absence of quenching moieties in the Eu coordination environment and an efficient energy transfer between ligands, combined with a particular symmetry of the coordination environment

Highly soluble fluorine containing Cu(i) AlkylPyrPhos TADF complexes

Luminescent Cu(i) AlkylPyrPhos complexes with a butterfly-shaped Cu2I2 core and halogen containing ancillary ligands, with a special focus on fluorine, have been investigated in this study. These complexes show extremely high solubilities and a remarkable (photo)chemical stability in a series of solvents. A tunable emission resulting from thermally activated delayed fluorescence with high quantum yields was determined by luminescence and lifetime investigations in solvents and solids. Structures of the electronic ground states were analyzed by single crystal X-ray analysis. The structure of the lowest excited triplet state was determined by transient FTIR spectroscopy, in combination with quantum chemical calculations. With the obtained range of compounds we address the key requirement for the production of organic light emitting diodes based on solution processing.Peer reviewe