Combined On-Line and Run-to-Run Optimization of Batch Processes with Terminal Constraints

This paper describes the optimization of batch processes in the presence of uncertainty and constraints. The optimal solution consists of keeping certain path and terminal constraints active and driving the sensitivities to zero. The case where the terminal constraints have a larger bearing on the cost than the sensitivities is considered, for which a two-time-scale methodology is proposed. The problem of meeting the active terminal constraints is addressed on-line using trajectory tracking, whilst pushing the sensitivities to zero is implemented on a run-to-run basis. The paper also discusses the run-to-run improvement of trajectory tracking via iterative learning control. The proposed methodology is illustrated in simulation on a batch distillation system

Investigation of chemical modifiers for the determination of cadmium and chromium in fish oil and lipoid matrices using HR-CS GF AAS and a simple ‘dilute-and-shoot’ approach

The authors are grateful to the Conselho Nacional de Desenvolvimento Científico and Tecnológico (CNPq), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support and scholarships. The present research was mostly financed through Project no. CNPq 406877/2013-0. The authors are also grateful to Analytik Jena for financial support and the donation of the contrAA 600.Peer reviewedPostprin

Two-photon interference with true thermal light

Two-photon interference and "ghost" imaging with entangled light have attracted much attention since the last century because of the novel features such as non-locality and sub-wavelength effect. Recently, it has been found that pseudo-thermal light can mimic certain effects of entangled light. We report here the first observation of two-photon interference with true thermal light.Comment: 4 pages, 5 figures, PRA72, 043805 (2005

Longitudinal excitations in quantum antiferromagnets

By extending our recently proposed magnon-density-waves to low dimensions, we investigate, using a microscopic many-body approach, the longitudinal excitations of the quasi-one-dimensional (quasi-1d) and quasi-2d Heisenberg antiferromagnetic systems on a bipartite lattice with a general spin quantum number. We obtain the full energy spectrum of the longitudinal mode as a function of the coupling constants in the original lattice Hamiltonian and find that it always has a non-zero energy gap if the ground state has a long-range order and becomes gapless for the pure isotropic 1d model. The numerical value of the minimum gap in our approximation agrees with that of a longitudinal mode observed in the quasi-1d antiferromagnetic compound KCuF${}_3$ at low temperature. It will be interesting to compare values of the energy spectrum at other momenta if their experimental results are available.Comment: 19 pages, 4 figure

Three-dimensional structure of the radiation beam in atomic absorption spectrometry

The results of an investigation of the three-dimensional distribution of radiant intensity in the probing radiation beam produced in a conventional atomic absorption spectrometer by hollow cathode lamps and electrodeless discharge lamps are presented. The investigation is based on the use of a photodiode array-based digital imaging system. The results obtained revealed that the probing radiation beam is highly non-uniform, both longitudinally and radially. The character of the non-uniformities is greatly dependent on the type of the primary source. An interpretation of the results is given and the possible consequences of the radiation beam non-uniformities for the application of Beer-Lambert's law are discussed

Optimierung einer Batch-Destillationskolonne unter Unsicherheiten basierend auf Messungen

C. Welz, B. Srinivasan, D. Bonvin Laboratoire d’Automatique Ecole Polytechnique Fédérale de Lausanne CH-1015 Lausanne, Schweiz O. Naef Département de Chimie Ecole d’Ingénieurs de Fribourg CH-1705 Fribourg, Schweiz Optimierung einer Batch-Destillationskolonne unter Unsicherheiten basierend auf Messungen Das Ziel der dynamischen Optimierung von binären Batch-Destillationskolonnen ist die Maximierung der Destillatmenge am Ende einer Charge bei gleichzeitiger Erfüllung der Endpunktbedingung für die Reinheit des Destillats. Das optimale Steuerungsprofil für das interne Rücklaufverhältnis (0 ≤ r ≤ 1) wird durch 2 Intervalle angenähert: 1) Anlaufphase mit vollem Rücklauf (r = 1), 2) Destillationsphase zur Produktion des Destillats (0 ≤ r ≤ 1). I m Fall von Prozessunsicherheiten muss eine konservative und suboptimale Prozessführungsstrategie gewählt werden, um die Endpunktbedingung zu erfüllen. Anstelle einer konservativen Strategie schlägt dieser Beitrag die Implementierung der notwendigen Optimalitätsbedingungen vor, die aus Rand- und SensibilitätsBedingungen bestehen. Entscheidend für das gegebene Optimierungsproblem ist es, d i e Randbedingungen zu erfüllen, insbesondere die Endpunktbedingung. Die Endpunktbedingung für die Reinheit des Destillats wird unter Verwendung von Messungen aktiv gehalten. Dies kann während einer Charge durch die Verfolgung eines Referenzprofils für die Reinheit des Destillats realisiert werden. Anstatt ein Modell zu aktualisieren, welches die Endpunktbedingung während der Destillation voraussagt, wird das System durch V e r f o l g u n g des Referenzprofils zu der Endpunktbedingung geführt. Dieses R e f e r e n z p r o f i l wird mit Hilfe eines Tendenzmodells des Systems bestimmt. U n s i c h e r h e i t e n in der Verdampfungsrate werden durch eine Vorregelung in Abhängigkeit von der Destillatmenge kompensiert, welche den Fortschritt der Destillation charakterisiert. Die Methode ist in der Lage, die Konservativität zu reduzieren und die Produktivität u n m i t t e l b a r zu steigern. Abbildung 1 zeigt die Verfolgung eines linearen Referenzprofils für die Reinheit des Destillats in einer Kolonne im Labormaßstab. Gegenüber einer suboptimalen Fahrweise mit konstanter Destillatzusammensetzung kann der Ertrag dabei um 11% gesteigert werden. Abbildung 1: Verfolgung einer Referenz für die Destillatzusammensetzung mit dem Ziel, die Endpunktbedingung zu erfüllen

Spatial distribution of radiant intensity from primary sources for atomic absorption spectrometry. Part II: Electrodeless discharge lamps

The spatial distribution of radiant intensity from electrodeless discharge lamps (EDLs) used as radiation sources in atomic absorption spectrometry is investigated with a digital photodiode array imaging system. Intensity distribution over the radial and longitudinal sections of Pb and Hg lamps is measured for both atomic and ionic lines of the analyte and the filler gas. The plasma in the EDLs is highly structured, with metal and filler gas excited species being distributed nonuniformly but in different ways. The clouds of emitting metal and Ar atoms are spatially separated in the volume of the Pb EDL. The excited Pb atoms detected from both the resonance and nonresonance lines have the form of a thin layer concentric to the bulb walls located near the surface of the bulb ("optical skin effect"). In contrast, the emission distribution for Ar atomic lines is bell-shaped with a maximum at the center of the plasma. The spatial distribution of emitting Ar ions is more complex - there is a bulk maximum coinciding with Ar atomic emission maximum and another maximum concentric to the walls coinciding with the maximum of metal atom emission. In the Hg EDL the difference between the spatial intensity profiles of metal and filler gas (Ar) lines is less pronounced because of the use of an increased filler gas pressure in the lamp. Emitting species of both Ar and metal are primarily located in the bulk of the plasma with, however, a small depletion in the vicinity of the lamp axis. Evolution of the spatial intensity profiles during warm-up of the lamps is investigated as well. In both lamps the radial and longitudinal intensity distributions of metal lines are established during the first minutes after lamp ignition, after which there is a slow and monotonic increase of the established intensity profiles. This result implies thermal vaporization as a mechanism of analyte supply to the plasma. The spatial intensity profiles for Ar lines are established in the first seconds after lamp ignition, after which only the absolute values of the established distributions change. The approach to the steady-state intensity of Ar atomic and ionic lines is nonmonotonic; there is a clearly pronounced initial overshoot in intensity of Ar atomic lines that coincides with a decline in the intensity of Ar ion lines. An interpretation for the observed spatial intensity profiles is given on the basis of radial cataphoresis theory

Construction of a combined sorghum linkage map from two recombinant inbred populations using AFLP, SSR, RFLP, and RAPD markers, and comparison with other sorghum maps

Sorghum [Sorghum bicolor (L.) Moench] is an important crop in the semi-arid tropics that also receives growing attention in genetic research. A comprehensive reference map of the sorghum genome would be an essential research tool. Here, a combined sorghum linkage map from two recombinant inbred populations was constructed using AFLP, SSR, RFLP and RAPD markers. The map was aligned with other published sorghum maps which are briefly reviewed. The two recombinant inbred populations (RIPs) analyzed in this study consisted of 225 (RIP 1) and 226 (RIP 2) F3:5 lines, developed from the crosses IS 9830 × E 36-1 (RIP 1) and N 13 × E 36-1 (RIP 2), respectively. The genetic map of RIP 1 had a total length of 1,265 cM (Haldane), with 187 markers (125 AFLPs, 45 SSRs, 14 RFLPs, 3 RAPDs) distributed over ten linkage groups. The map of RIP 2 spanned 1,410 cM and contained 228 markers (158 AFLPs, 54 SSRs, 16 RFLPs) in 12 linkage groups. The combined map of the two RIPs contained 339 markers (249 AFLPs, 63 SSRs, 24 RFLPs, 3 RAPDs) on 11 linkage groups and had a length of 1,424 cM. It was in good agreement with other sorghum linkage maps, from which it deviated by a few apparent inversions, deletions, and additional distal region