Characterisation of a collection of perennial Panicum species

A collection of 74 perennial Panicum accessions, belonging to 6 different species, maintained at the field genebank of the International Livestock Research Institute, was described using 49 agromorphological characters in a multivariate analysis. Fifty-four accessions, for which coordinates of the collection site were available, were further characterised using environmental data obtained through use of geographic information systems. Three drought-tolerant species, P. antidotale, P. turgidum and P. phragmitoides, were very different agro-morphologically from the other species. Of these drought-tolerant species, P. phragmitoides appeared to have the best agromorphological attributes for use as forage in dry areas. P. maximum, P. coloratum and P. infestum appeared more similar, and were not entirely separated using cluster analysis. The accessions of these 3 species could be divided into 5 different clusters with similar characteristics. The majority of the P. maximum accessions belonged to 2 clusters, mainly differing in the size and robustness of the plants. A strong correlation was found between characters describing the robustness of the P. maximum plant and the annual precipitation at the collection site. Promising P. maximum accessions for use in cut-and-carry systems were identified

Tramp Ship Scheduling Problem with Berth Allocation Considerations and Time-dependent Constraints

This work presents a model for the Tramp Ship Scheduling problem including berth allocation considerations, motivated by a real case of a shipping company. The aim is to determine the travel schedule for each vessel considering multiple docking and multiple time windows at the berths. This work is innovative due to the consideration of both spatial and temporal attributes during the scheduling process. The resulting model is formulated as a mixed-integer linear programming problem, and a heuristic method to deal with multiple vessel schedules is also presented. Numerical experimentation is performed to highlight the benefits of the proposed approach and the applicability of the heuristic. Conclusions and recommendations for further research are provided.Comment: 16 pages, 3 figures, 5 tables, proceedings paper of Mexican International Conference on Artificial Intelligence (MICAI) 201

Cloud phase identification of Arctic boundary-layer clouds from airborne spectral reflection measurements: Test of three approaches

Arctic boundary-layer clouds were investigated with remote sensing and in situ instruments during the Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) campaign in March and April 2007. The clouds formed in a cold air outbreak over the open Greenland Sea. Beside the predominant mixed-phase clouds pure liquid water and ice clouds were observed. Utilizing measurements of solar radiation reflected by the clouds three methods to retrieve the thermodynamic phase of the cloud are introduced and compared. Two ice indices IS and IP were obtained by analyzing the spectral pattern of the cloud top reflectance in the near infrared (1500–1800 nm wavelength) spectral range which is characterized by ice and water absorption. While IS analyzes the spectral slope of the reflectance in this wavelength range, IS utilizes a principle component analysis (PCA) of the spectral reflectance. A third ice index IA is based on the different side scattering of spherical liquid water particles and nonspherical ice crystals which was recorded in simultaneous measurements of spectral cloud albedo and reflectance. Radiative transfer simulations show that IS, IP and IA range between 5 to 80, 0 to 8 and 1 to 1.25 respectively with lowest values indicating pure liquid water clouds and highest values pure ice clouds. The spectral slope ice index IS and the PCA ice index IP are found to be strongly sensitive to the effective diameter of the ice crystals present in the cloud. Therefore, the identification of mixed-phase clouds requires a priori knowledge of the ice crystal dimension. The reflectance-albedo ice index IA is mainly dominated by the uppermost cloud layer (τ<1.5). Therefore, typical boundary-layer mixed-phase clouds with a liquid cloud top layer will be identified as pure liquid water clouds. All three methods were applied to measurements above a cloud field observed during ASTAR 2007. The comparison with independent in situ microphysical measurements shows the ability of the three approaches to identify the ice phase in Arctic boundary-layer clouds

Retrieval of Cirrus Optical Thickness and Assessment of Crystal Shape from Ground-Based Imaging Spectrometry

An imaging spectrometer (AisaEAGLE) is applied for ground-based measurements of downward spectral radiance fields with high spatial (1024 spatial pixels within 36.7° field of view), spectral (488 spectral pixels, 400-970 nm, 1.25 nm full width at half maximum) and temporal (4-30 Hz) resolution. The calibration, measurement, and data evaluation procedures are introduced. A method is presented that retrieves the cirrus optical thickness tci using the spectral radiance data collected by AisaEAGLE. On the basis of four measurement cases during the second campaign of the Cloud Aerosol Radiation and tuRbulence of trade wInd cumuli over BArbados (CARRIBA) project in 2011 the spatial inhomogeneity of the investigated cirrus is characterized by the standard deviation of the retrieved tci, as well as the width of the frequency distribution of the retrieved tci. By comparing measured and simulated downward solar radiances as a function of scattering angle, a first estimation of the detected cirrus ice crystal shape is given and used in the retrieval of tci.Ein abbildendes Spektrometer (AisaEAGLE) wurde bodengebunden zur Messung von Feldern abwärts gerichteter spektraler Strahldichten mit hoher räumlicher (1024 Raumpixel auf 36.7° FOV), spektraler (488 spektrale Pixel, 400-970 nm, 1.25 nm FWHM) und zeitlicher (4-30 Hz) Auflösung verwendet. Die Kalibrierungsprozedur, das Messverfahren sowie die Datenauswertung werden hier vorgestellt. Weiter wird eine Methode zur Ableitung der Zirrus optischen Dicke tci unter Verwendung dieser bodengebundenen spektralen Strahldichtedaten vorgestellt. Auf der Grundlage von vier Messzeiträumen während der zweiten Kampagne des Cloud Aerosol Radiation and tuRbulence of trade wInd cumuli over BArbados (CARRIBA) Projektes in 2011 wird die räumliche Inhomogenität der untersuchten Zirren durch die Standardabweichung der abgeleiteten tci, wie auch der Breite ihrer Häufigkeitsverteilungen charakterisiert. Vergleiche der gemessenen Strahldichten mit Simulationen abwärts gerichteter solarer Strahldichten als Funktion der Streuwinkel ermöglichen eine erste Abschätzung der Eiskristallform im detektierten Zirrus und gehen in die Ableitung der tci ein

Optical thickness and effective radius of Arctic boundary-layer clouds retrieved from airborne nadir and imaging spectrometry

Arctic boundary-layer clouds in the vicinity of Svalbard (78° N, 15° E) were observed with airborne remote sensing and in situ methods. The cloud optical thickness and the droplet effective radius are retrieved from spectral radiance data from the nadir spot (1.5°, 350–2100 nm) and from a nadir-centred image (40°, 400–1000 nm). Two approaches are used for the nadir retrieval, combining the signal from either two or five wavelengths. Two wavelengths are found to be sufficient for an accurate retrieval of the cloud optical thickness, while the retrieval of droplet effective radius is more sensitive to the number of wavelengths. Even with the comparison to in-situ data, it is not possible to definitely answer the question which method is better. This is due to unavoidable time delays between the in-situ measurements and the remote-sensing observations, and to the scarcity of vertical in-situ profiles within the cloud

Solving Fuzzy Job-Shop Scheduling Problems with a Multiobjective Optimizer

International audienceIn real-world manufacturing environments, it is common to face a job-shop scheduling problem (JSP) with uncertainty. Among different sources of uncertainty, processing times uncertainty is the most common. In this paper, we investigate the use of a multiobjective genetic algorithm to address JSPs with uncertain durations. Uncertain durations in a JSP are expressed by means of triangular fuzzy numbers (TFNs). Instead of using expected values as in other work, we consider all vertices of the TFN representing the overall completion time. As a consequence, the proposed approach tries to obtain a schedule that optimizes the three component scheduling problems (corresponding to the lowest, most probable, and largest durations) all at the same time. In order to verify the quality of solutions found by the proposed approach, an experimental study was carried out across different benchmark instances. In all experiments, comparisons with previous approaches that are based on a single-objective genetic algorithm were also performed

Desoxidation von gasgetragenen Pulvern

Metallische Pulver gelten als wichtige Ausgangsmaterialien in vielen Fertigungsprozessen, z. B. bei Fügeverfahren, additiver Fertigung, Beschichtung usw. Bei der Herstellung metallischer Pulver werden die Partikeloberflächen, selbst bei der Handhabung in der Inertgas-Umgebung, infolge von Sauerstoffspuren mit einer Oxidschicht bedeckt, welche für die Weiterverarbeitung und die Qualität der Endprodukte negativ sein kann. Das Projekt zielt darauf ab, die Desoxidation metallischer Pulver durch Wechselwirkung mit aktivierten Wasserstoffspezies zu realisieren. Um dieses Ziel zu erreichen, wurden Pulver in einer Wirbelschicht mit den aktivierten Wasserstoffspezies in Kontakt gebracht. Die Aktivierung wurde mittels dielektrischer Barriere-Entladung (DBD) erzielt und mit den Resultaten der rein thermisch aktivierten Wasserstoffspezies verglichen. Für die Einbringung der DBD-aktivierten Spezies wurden verschiedenen Geometrien untersucht, welche vom konvektiven Transport der DBD-Spezies in die Wirbelschicht bis zu der direkten Erzeugung des Plasmas in der Wirbelschicht reichen. Anhand einer einfachen Analytik basierend auf der Schüttdichte der Pulver konnte gezeigt werden, wie effektiv die verschiedenen Desoxidationsmethoden sind

A new method for deriving aerosol solar radiative forcing and its first application within MILAGRO/INTEX-B

We introduce a method for deriving aerosol spectral radiative forcing along with single scattering albedo, asymmetry parameter, and surface albedo from airborne vertical profile measurements of shortwave spectral irradiance and spectral aerosol optical thickness. The new method complements the traditional, direct measurement of aerosol radiative forcing efficiency from horizontal flight legs below gradients of aerosol optical thickness, and is particularly useful over heterogeneous land surfaces and for homogeneous aerosol layers where the horizontal gradient method is impractical. Using data collected by the Solar Spectral Flux Radiometer (SSFR) and the Ames Airborne Tracking Sunphotometer (AATS-14) during the MILAGRO (Megacity Initiative: Local and Global Research Observations) experiment, we validate an over-ocean spectral aerosol forcing efficiency from the new method by comparing with the traditional method. Retrieved over-land aerosol optical properties are compared with in-situ measurements and AERONET retrievals. The spectral forcing efficiencies over ocean and land are remarkably similar and agree with results from other field experiments

Fostering Transnational Research, Innovation and Education Through an International Europe and Africa Collaboration Project

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