TY - CHAP A1 - Ocakci, Elif A1 - Draghici, Anca A1 - Niemann, Jörg ED - Leipzig, Konrad von ED - Sacks, Natasha ED - Mc Clelland, Michelle T1 - Resources Collaboration and Optimization in Industry 4.0 Environments T2 - Smart, Sustainable Manufacturing in an Ever-Changing World: Proceedings of International Conference on Competitive Manufacturing (COMA ’22) KW - Industrie 4.0 KW - Operative Planung KW - Kapazitätsplanung KW - Planungsprozess Y1 - 2023 SN - 9783031156014 U6 - https://doi.org/10.1007/978-3-031-15602-1_35 SN - 2194-0525 SP - 483 EP - 494 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Weber, Konradin A1 - Eliasson, J. A1 - Vogel, A. A1 - Fischer, C. A1 - Pohl, T. A1 - van Haren, G. A1 - Meier, M. A1 - Grobéty, B. A1 - Dahmann, D. T1 - Airborne in-situ investigations of the Eyjafjallajökull volcanic ash plume on Iceland and over north-western Germany with light aircrafts and optical particle counters JF - Atmospheric Environment KW - Luftreinhaltung Y1 - 2012 U6 - https://doi.org/10.1016/j.atmosenv.2011.10.030 SN - 1352-2310 VL - 48 SP - 9 EP - 21 PB - Elsevier ER - TY - JOUR A1 - Petit, Y. A1 - Henin, S. A1 - Kasparian, J. A1 - Wolf, J. P. A1 - Rohwetter, P. A1 - Stelmaszczyk, K. A1 - Hao, Z. Q. A1 - Nakaema, W. M. A1 - Wöste, L. A1 - Vogel, A. A1 - Pohl, T. A1 - Weber, Konradin T1 - Influence of pulse duration, energy, and focusing on laser-assisted water condensation JF - Applied Physics Letters N2 - We investigate the influence of laser parameters on laser-assisted water condensation in the atmosphere. Pulse energy is the most critical parameter. Nanoparticle generation depends linearly on energy beyond the filamentation threshold. Shorter pulses are more efficient than longer ones with saturation at ∼1.5 ps. Multifilamenting beams appear more efficient than strongly focused ones in triggering the condensation and growth of submicronic particles, while polarization has a negligible influence on the process. The data suggest that the initiation of laser-assisted condensation relies on the photodissociation of the air molecules rather than on their photoionization. KW - Luftreinhaltung Y1 - 2011 U6 - https://doi.org/10.1063/1.3546172 SN - 0003-6951 VL - 98 IS - 4 PB - AIP Publishing ER - TY - CHAP A1 - Schäfer, Klaus A1 - Harig, Roland A1 - Blumenstock, Thomas A1 - Höfert, Norbert A1 - Weber, Konradin ED - Picard, Richard H. ED - Schäfer, Klaus ED - Comeron, Adolfo ED - van Weele, Michiel T1 - Development of a VDI guideline for passive FTIR measurements in the atmosphere T2 - Remote sensing of clouds and the atmosphere XV : 21 - 23 September 2010, Toulouse, France KW - Luftreinhaltung Y1 - 2010 U6 - https://doi.org/10.1117/12.866466 SN - 0277-786X VL - 7827 PB - SPIE CY - Bellingham, Wash. ER - TY - JOUR A1 - Weber, Stephan A1 - Weber, Konradin T1 - Coupling of urban street canyon and backyard particle concentrations JF - Meteorologische Zeitschrift KW - Luftreinhaltung Y1 - 2008 U6 - https://doi.org/10.1127/0941-2948/2008/0286 SN - 0941-2948 VL - 17 IS - 3 SP - 251 EP - 261 PB - Schweizerbart ER - TY - CHAP A1 - Weber, Konradin A1 - Fischer, Christian A1 - van Haren, Günther A1 - Krause, Horst A1 - Bunte, Gudrun A1 - Schweikert, Wenka A1 - Härdle, Thomas ED - Schubert, Hiltmar ED - Rimski-Korsakov, A. T1 - Stand-Off Detection of Explosives of Suicide Bombers by Means of Open-Path FTIR Spectroscopy T2 - Stand-Off Detection of Suicide Bombers and Mobile Subjects KW - Luftreinhaltung Y1 - 2006 SN - 9781402051579 U6 - https://doi.org/10.1007/1-4020-5159-X_16 SP - 135 EP - 143 PB - Springer Netherlands CY - Dordrecht ER - TY - CHAP A1 - Weber, Konradin ED - Wener, Christian ED - Klein, Volker ED - Weber, Konradin T1 - Bestimmung von Verfahrenskenngrößen bei Meßverfahren für gasförmige Luftverunreinigungen nach VDI-Richtlinien und DIN/ISO-Normen T2 - Laser in der Umweltmeßtechnik / Laser in Remote Sensing: Vorträge des 10. Internationalen Kongresses / Proceedings of the 10th International Congress KW - Lasermesstechnik KW - Luftqualität KW - Telemetrie KW - Luftreinhaltung Y1 - 1992 SN - 9783540552482 U6 - https://doi.org/10.1007/978-3-642-50980-3_20 SP - 131 EP - 140 PB - Springer Nature CY - Berlin, Heidelberg ER - TY - CHAP A1 - Diehl, W. A1 - Klein, V. A1 - Weber, Konradin ED - Werner, Christian ED - Klein, Volker ED - Weber, Konradin T1 - Optische Fernmeßverfahren zur Bestimmung gasförmiger Luftschadstoffe in der Troposphäre T2 - Laser in der Umweltmeßtechnik / Laser in Remote Sensing: Laser in der Umweltmeßtechnik / Laser in Remote Sensing: Vorträge des 10. Internationalen Kongresses / Proceedings of the 10th International Congress KW - Lasermesstechnik KW - Telemetrie KW - Luftreinhaltung Y1 - 1992 SN - 9783540552482 U6 - https://doi.org/10.1007/978-3-642-50980-3_18 SP - 113 EP - 121 PB - Springer Nature CY - Berlin, Heidelberg ER - TY - CHAP A1 - Özman, Cansu A1 - Gül, Fethi A1 - Diederich, Michael A1 - Benim, Ali Cemal A1 - Janoske, Uwe T1 - Computational and Experimental Investigation of Flow and Convective Heat Transfer along Rough Surfaces T2 - Proceedings of CONV-22: Int. Symp. on Convective Heat and Mass Transfer June 5 – 10, 2022, Turkey KW - Numerische Strömungssimulation KW - Wärmeübertragung KW - Rauigkeit KW - Turbulenzmodell Y1 - 2022 U6 - https://doi.org/10.1615/ICHMT.2022.CONV22.590 SP - 447 EP - 454 PB - Begellhouse ER - TY - CHAP A1 - Biedermann, Till M. A1 - Moutamassik, Youssef A1 - Kameier, Frank T1 - Assessment of the Impeller/Volute Relationship of Centrifugal Fans From an Aerodynamic and Aeroacoustic Perspective T2 - ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition N2 - Heavy-duty centrifugal fans require high reliability and first-class performance. Besides, extreme conditions and harsh environments are often encountered, such as in the papermaking process, in steel or cement plants or the chemical and petrochemical industry. Therefore, the design of high performance heavy-duty industrial fans requires robust yet efficient solutions. Previous work indicates a high aerodynamic and aeroacoustic sensitivity concerning the specific position of the volute cut-off (tongue). This effect will be further investigated, not by directly changing the orientation of the cutoff, but by varying the position of the impeller relative to a fixed volute casing. The initial evaluation is done through a numerical study of three influencing parameters, which allows the aerodynamic dependencies to be modelled using low-layer artificial networks. Subsequently, extensive experimental studies were carried out to validate the aerodynamic dependencies and also to incorporate information on the aeroacoustic performance. The obtained results show that the operating point represents the key factor in determining the optimal positioning, with qualitatively comparable dependencies found for both tested fans. From an aeroacoustic point of view, the determined optimal configuration does not necessarily coincide with the observed aerodynamic desires, so careful analysis and a reasonable compromise are required, motivating for a multi-objective optimisation process. KW - Ventilator KW - Strömungsakustik KW - Aerodynamik Y1 - 2022 U6 - https://doi.org/10.1115/GT2022-79389 VL - Volume 5: Education; Electric Power; Fans and Blowers PB - American Society of Mechanical Engineers ER - TY - JOUR A1 - Deckert, Carsten A1 - Schomaker, Rahel A1 - Hafizi, Meggi T1 - Zeit ist Geld … und Innovation – Wie sich das Lebenstempo auf das nationale Entrepreneurship auswirkt JF - Der Betriebswirt KW - Zeitwahrnehmung KW - Innovationsfähigkeit Y1 - 2023 U6 - https://doi.org/10.3790/dbw.64.1.69 SN - 2628-7846 VL - 64 IS - 1 SP - 69 EP - 81 PB - Duncker & Humblot ER - TY - JOUR A1 - Leppelmann, Max A1 - Deckert, Carsten A1 - Niemann, Jörg T1 - Innovations-Reporting von DAX-Unternehmen JF - Der Betriebswirt KW - Deutscher Aktienindex KW - Innovation KW - Bericht Y1 - 2021 U6 - https://doi.org/10.3790/dbw.62.3.177 SN - 2628-7846 VL - 62 IS - 3 SP - 177 EP - 190 PB - Duncker & Humblot ER - TY - JOUR A1 - Mabrouk, Riheb A1 - Naji, Hassane A1 - Benim, Ali Cemal A1 - Dhahri, Hacen T1 - A State of the Art Review on Sensible and Latent Heat Thermal Energy Storage Processes in Porous Media: Mesoscopic Simulation JF - Applied Sciences KW - DOAJ Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-40343 VL - 12 IS - 14 PB - MDPI ER - TY - JOUR A1 - Bhattacharyya, Suvanjan A1 - Chattopadhyay, Himadri A1 - Benim, Ali Cemal T1 - Computational investigation of heat transfer enhancement by alternating inclined ribs in tubular heat exchanger JF - Progress in Computational Fluid Dynamics KW - CFD KW - forced convection KW - transitional turbulence KW - inclined ribs KW - heat transfer enhancement Y1 - 2017 U6 - https://doi.org/10.1504/PCFD.2017.088818 SN - 1468-4349 VL - 17 IS - 6 SP - 390 EP - 396 PB - Inderscience Enterprises Limited ER - TY - JOUR A1 - Mabrouk, Riheb A1 - Benim, Ali Cemal A1 - Naji, Hassane A1 - Dhahri, Hacen T1 - Investigation of Pulsed Flow Effects on the Phase Change Within an Open-Cell Metal Foam Using Thermal Lattice Boltzmann Method JF - Transport in Porous Media KW - Thermal lattice Boltzmann method KW - Energetic and exergetic efficiencies KW - Local thermal non-equilibrium KW - Solidification process KW - Melting KW - Porous media KW - Pulsating flow Y1 - 2023 U6 - https://doi.org/10.1007/s11242-023-01903-x SN - 0169-3913 VL - 147 IS - 2 SP - 225 EP - 257 PB - Springer Nature ER - TY - JOUR A1 - Farooq, Asma A1 - Ali, Ramzan A1 - Benim, Ali Cemal T1 - Soret and Dufour effects on three dimensional Oldroyd-B fluid JF - Physica A: Statistical Mechanics and its Applications Y1 - 2018 U6 - https://doi.org/10.1016/j.physa.2018.02.204 SN - 0378-4371 VL - 503 SP - 345 EP - 354 PB - Elsevier ER - TY - JOUR A1 - Queval, Loic A1 - Coty, Alain A1 - Vido, Lionel A1 - Gottkehaskamp, Raimund A1 - Multon, Bernard T1 - A Switched Reluctance Motor Drive Using Photovoltaic Transistors: Principle, Prototype, Experimental, and Numerical Results JF - IEEE Transactions on Industry Applications Y1 - 2017 U6 - https://doi.org/10.1109/TIA.2017.2718493 SN - 0093-9994 VL - 53 IS - 5 SP - 4886 EP - 4893 PB - IEEE ER - TY - JOUR A1 - Benim, Ali Cemal A1 - Canal, Cansu Deniz A1 - Boke, Yakup Erhan T1 - Computational investigation of oxy-combustion of pulverized coal and biomass in a swirl burner JF - Energy Y1 - 2022 U6 - https://doi.org/10.1016/j.energy.2021.121852 SN - 0360-5442 VL - 238 IS - C PB - Elsevier ER - TY - JOUR A1 - Başaran, Anıl A1 - Benim, Ali Cemal A1 - Yurddas, Ali T1 - Numerical Simulation of the Condensation Flow of the Isobutane (R600a) inside Microchannel JF - Heat Transfer Engineering Y1 - 2021 U6 - https://doi.org/10.1080/01457632.2021.1874668 SN - 0145-7632 VL - 43 IS - 3-5 SP - 337 EP - 361 PB - Taylor & Francis ER - TY - JOUR A1 - Bhattacharyya, Suvanjan A1 - Benim, Ali Cemal A1 - Chattopadhyay, Himadri A1 - Banerjee, Arnab T1 - Experimental investigation of heat transfer performance of corrugated tube with spring tape inserts JF - Experimental Heat Transfer Y1 - 2019 U6 - https://doi.org/10.1080/08916152.2018.1531955 SN - 0891-6152 VL - 32 IS - 5 SP - 411 EP - 425 PB - Taylor & Francis ER - TY - JOUR A1 - Laux, Christoph A1 - Gotter, Andreas A1 - Eckert, Frank A1 - Neef, Matthias T1 - Experimental results of a low-pressure steam Rankine cycle with a novel water lubricated radial inflow turbine for the waste heat utilization of internal combustion engines JF - Energy Conversion and Management Y1 - 2022 U6 - https://doi.org/10.1016/j.enconman.2022.116265 SN - 0196-8904 VL - 271 PB - Elsevier ER - TY - JOUR A1 - Benim, Ali Cemal T1 - Introducing the “Mathematical Modelling and Numerical Simulation of Combustion and Fire” Section of the Journal Fire JF - fire Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-40257 SN - 2571-6255 VL - 5 IS - 6 PB - MDPI ER - TY - JOUR A1 - Bhattacharyya, Suvanjan A1 - Benim, Ali Cemal A1 - Pathak, Manabendra A1 - Chamoli, Sunil A1 - Gupta, Ashutosh T1 - Thermohydraulic characteristics of inline and staggered angular cut baffle inserts in the turbulent flow regime JF - Journal of Thermal Analysis and Calorimetry Y1 - 2020 U6 - https://doi.org/10.1007/s10973-019-09094-8 SN - 1388-6150 VL - 140 IS - 3 SP - 1519 EP - 1536 PB - Springer Nature ER - TY - JOUR A1 - Niemann, Joerg A1 - Fussenecker, Claudia A1 - Schloesser, Martin A1 - Ocakci, Elif T1 - THE WORKERS PERSPECTIVE - EYE TRACKING IN PRODUCTION ENVIRONMENTS JF - ACTA TECHNICA NAPOCENSIS SERIES-APPLIED MATHEMATICS MECHANICS AND ENGINEERING Y1 - 2021 SN - 1221-5872 VL - 64 IS - 1 SP - 7 EP - 14 PB - Technical University of Cluj-Napoca ER - TY - JOUR A1 - Biedermann, Till M. A1 - Czeckay, Pasquale A1 - Hintzen, Nils A1 - Kameier, Frank A1 - Paschereit, C. O. T1 - Applicability of Aeroacoustic Scaling Laws of Leading Edge Serrations for Rotating Applications JF - acoustics KW - DOAJ KW - ISAVE Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-40311 SN - 2624-599X VL - 2 IS - 3 SP - 579 EP - 594 PB - MDPI ER - TY - JOUR A1 - Pfeiffelmann, Bjorn A1 - Ozman, Cansu A1 - Benim, Ali Cemal A1 - Joos, Franz T1 - Analysis of the effect of nonuniform surface temperature distribution on the performance of a thermoelectric generator JF - Sustainable Energy Technologies and Assessments Y1 - 2022 U6 - https://doi.org/10.1016/j.seta.2022.102375 SN - 2213-1388 VL - 53 IS - A PB - Elsevier ER - TY - JOUR A1 - Biswas, Nirmalendu A1 - Mandal, Dipak Kumar A1 - Manna, Nirmal K. A1 - Benim, Ali Cemal T1 - Enhanced energy and mass transport dynamics in a thermo-magneto-bioconvective porous system containing oxytactic bacteria and nanoparticles: cleaner energy application JF - Energy Y1 - 2023 U6 - https://doi.org/10.1016/j.energy.2022.125775 SN - 0360-5442 VL - 263 IS - B PB - Elsevier ER - TY - JOUR A1 - Ali, Ramzan A1 - Farooq, A. A1 - Shahzad, A. A1 - Benim, Ali Cemal A1 - Iqbal, A. A1 - Razzaq, M. T1 - Computational approach on three-dimensional flow of couple-stress fluid with convective boundary conditions JF - Physica A: Statistical Mechanics and its Applications Y1 - 2022 U6 - https://doi.org/10.1016/j.physa.2019.124056 SN - 0378-4371 VL - 553 PB - Elsevier ER - TY - CHAP A1 - Prusas, Benedik T1 - Simulation of Germany’s security of supply: long-term forecasting of electric load profiles using machine learning. T2 - ENERDAY 2022 - 16th international conference of energy economics and technology, 30.9.2022, Dresden KW - KiVi KW - Vortrag Y1 - 2022 PB - Technische Universität Dresden CY - Dresden ER - TY - RPRT A1 - Deckert, Carsten T1 - Good Vibrations from Electronic Circuits: The Technological Development of the Synthesizer T3 - Business Cases in Industrial Engineering - 4 Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-44394 SN - 2941-4075 ER - TY - CHAP A1 - Jäger, Lukas A1 - Hart, Scott A1 - Reguera, Remo A1 - Grote-Ramm, Wolfgang A1 - Neef, Matthias T1 - Autonome Nachführungssteuerung eines Parabolrinnen-Teststands mittels Microcontroller T2 - Beitrag zur 7. Regenerativen Energietechnik Konferenz, Nordhausen, 08. - 09. Februar 2024 N2 - Parabolrinnen nutzen parabolisch gekrümmte Spiegel, um die direkte Globalstrahlung auf ein Vakuum-Absorberrohr zu konzentrieren. Eine Effizienzsteigerung dieser Technologie wird durch eine vollständige Automatisierung der Sonnennachführung optimiert. Die an einem Parabolrinnen-Versuchsträger der Hochschule Düsseldorf realisierte Steuerung und Berechnung der Nachführung werden kontinuierlich über einen Microcontroller realisiert. Eine Kalibrierung der Parabolrinne im Labormaßstab zur Erkennung des Winkels erfolgt über Infrarotsensoren. Die Berechnung des Sonnenstandes, durch den Algorithmus, kann unabhängig von einer Stromzufuhr durch eine Real-Time-Clock bestimmt werden. Mittels Schrittmotor und Treiber verfährt die Parabolrinne in die errechnete Position. Die Feinausrichtung der Parabolrinne erfolgt über ein Verschattungsmodul und zwei Photowiderstände. Durch den Einsatz von 3D-gedruckten Bestandteilen sind die genutzten Komponenten kostengünstig und können standortunabhängig reproduziert werden. Durch das Zusammenspiel der Komponenten ist ein autonomer Einsatz möglich. KW - Parabolrinnen KW - Sonnenenergie KW - Microcontroller Y1 - 2024 CY - Nordhausen ER - TY - JOUR A1 - Benim, Ali Cemal T1 - Investigation into the Computational Analysis of High–Speed Microjet Hydrogen–Air Diffusion Flames JF - Fire N2 - High-speed microjet hydrogen–air diffusion flames are investigated computationally. The focus is on the prediction of the so-called bottleneck phenomenon. The latter has been previously observed as a specific feature of the present flame class and has not yet been investigated computationally. In the configuration under consideration, the nozzle diameter is 0.5 mm and six cases with mean nozzle injection velocities (U) between 306 m/s and 561 m/s are considered. The flow in the nozzle lance is analyzed separately to obtain detailed inlet boundary conditions for the flame calculations. It is confirmed by calculation that the phenomenon is mainly determined by the transition to turbulence in the initial parts of the free jet. The transitional turbulence proves to be the biggest challenge in predicting this class of flames, as the generally available turbulence and turbulent combustion models reach the limits of their validity in transitional flows. In a Reynolds-Averaged Numerical Simulation framework, the Shear Stress Transport model is found to perform better than alternative two-equation models and is used as the turbulence model. By neglecting the interactions between the turbulence and chemistry (no-model approach), it is possible to predict the morphology of the bottleneck flame and its dependence on U qualitatively. However, the position of the bottleneck is overpredicted for U < 561 m/s. The experimental flames in the considered U range are all attached to the nozzle. This is also predicted by the no-model approach. The Eddy Dissipation Concept (EDC) used as the turbulence combustion model predicts, however, lifted flames (with increasing lift-off height as U decreases). With the EDC, no bottleneck morphology is observed for U = 561 m/s. For lower U, the EDC results for the bottleneck position are generally closer to the measurements. It is demonstrated that accuracy in predicting the bottleneck position can be improved by ad hoc modifications of the turbulent viscosity. KW - Turbulenzmodell KW - Diffusionsflamme KW - hydrogen combustion KW - bottleneck flame KW - diffusion flame KW - microjet flame KW - transitional turbulence KW - turbulence modelling KW - combustion modelling Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-46345 SN - 2571-6255 VL - 7 IS - 9 PB - MDPI ER - TY - JOUR A1 - Başaran, Anıl A1 - Benim, Ali Cemal T1 - Condensation Flow of Refrigerants Inside Mini and Microchannels: A Review JF - Applied Sciences N2 - Nowadays, the demand for obtaining high heat flux values in small volumes has increased with the development of technology. Condensing flow inside mini- and microchannels has been becoming a promising solution for refrigeration, HVAC, air-conditioning, heat pumps, heat pipes, and electronic cooling applications. In these applications, employing mini/microchannels in the condenser design results in the working fluid, generally refrigerant, undergoing a phase change inside the mini/microchannels. On the other hand, the reduction in the hydraulic diameter during condensation gives rise to different flow regimes and heat transfer mechanisms in the mini- and microchannels compared to the conventional channels. Therefore, the understanding of fluid flow and heat transfer characteristics during condensation of refrigerant inside mini- and microchannels has been gaining importance in terms of condenser design. This study presents a state-of-the-art review of condensation studies on refrigerants inside mini- and microchannels. The review includes experimental studies as well as correlation models, which are developed to predict condensation heat transfer coefficients and pressure drop. The refrigerant type, thermodynamical performance, and compatibility, as well as the environmental effects of refrigerant, play a decisive role in the design of refrigeration systems. Therefore, the environmental impacts of refrigerants and current regulations against them are also discussed in the present review. KW - Kondensation KW - Druckabfall KW - Kältemittel KW - condensation KW - microchannels KW - minichannels KW - heat transfer coefficient KW - pressure drop KW - refrigerants KW - Wärmeübergangszahl Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-46358 SN - 2076-3417 VL - 14 IS - 7 PB - MDPI ER - TY - JOUR A1 - Zengin, İbrahim A1 - Erdoğan, Beytullah A1 - Benim, Ali Cemal T1 - CFD and Taguchi based optimization of air driven single stage partial admission axial turbine blade profiles JF - Energy KW - Taguchi-Methode KW - Numerische Strömungssimulation KW - Axialturbine KW - Beschaufelung KW - Optimierung KW - Impulse turbine KW - Partial-admission Y1 - 2024 U6 - https://doi.org/10.1016/j.energy.2024.130333 SN - 0360-5442 VL - 290 PB - Elsevier ER - TY - JOUR A1 - Yalçınkaya, Orhan A1 - Durmaz, Ufuk A1 - Tepe, Ahmet Ümit A1 - Benim, Ali Cemal A1 - Uysal, Ünal T1 - Heat and Flow Characteristics of Aerofoil-Shaped Fins on a Curved Target Surface in a Confined Channel for an Impinging Jet Array JF - Energies N2 - The main purpose of this investigation was to explore the heat transfer and flow characteristics of aero-foil-shaped fins combined with extended jet holes, specifically focusing on their feasibility in cooling turbine blades. In this study, a comprehensive investigation was carried out by applying impinging jet array cooling (IJAC) on a semi-circular curved surface, which was roughened using aerofoil-shaped fins. Numerical computations were conducted under three different Reynolds numbers (Re) ranging from 5000 to 25,000, while nozzle-to-target surface spacings (S/d) ranged from 0.5 to 8.0. Furthermore, an assessment was made of the impact of different fin arrangements, single-row (L1), double-row (L2), and triple-row (L3), on convective heat transfer. Detailed examinations were performed on area-averaged and local Nusselt (Nu) numbers, flow properties, and the thermal performance criterion (TPC) on finned and smooth target surfaces. The study’s results revealed that the use of aerofoil-shaped fins and the reduction in S/d, along with surface roughening, led to significant increases in the local and area-averaged Nu numbers compared to the conventional IJAC scheme. The most notable heat transfer enhancement was observed at S/d = 0.5 utilizing extended jets and the surface design incorporating aerofoil-shaped fins. Under these specific conditions, the maximum heat transfer enhancement reached 52.81%. Moreover, the investigation also demonstrated that the highest TPC on the finned surface was achieved when S/d = 2.0 for L2 at Re = 25,000, resulting in a TPC value of 1.12. Furthermore, reducing S/d and mounting aerofoil-shaped fins on the surface yielded a more uniform heat transfer distribution on the relevant surface than IJAC with a smooth surface, ensuring a relatively more uniform heat transfer distribution to minimize the risk of localized overheating. KW - Beschaufelung KW - Kühlung KW - aerofoil-shaped fin KW - impinging jet array KW - cooling of turbine blades KW - heat transfer uniformity KW - pin-fin row KW - Wärmeübertragung KW - Turbine Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-46387 SN - 1996-1073 VL - 17 IS - 5 PB - MDPI ER - TY - JOUR A1 - Başaran, Anıl A1 - Benim, Ali Cemal T1 - Development of Correlations Based on CFD Study for Microchannel Condensation Flow of Environmentally Friendly Hydrocarbon Refrigerants JF - Energies N2 - A CFD simulation of the condensation flow of R600a and R290 within microchannels was conducted to explore the effect of mass flux, hydraulic diameter, and vapour quality on heat transfer rate and pressure drop. Data obtained from CFD simulations were used to develop new heat transfer and pressure drop correlations for the condensation flows of R600a and R290, which are climate-friendly refrigerants. Steady-state numerical simulations of condensation flow of refrigerants were carried out inside a single circular microchannel with diameters varying between 0.2 and 0.6 mm. The volume of fluid approach was used in the proposed model, calculating the interface phase change using the Lee model. The CFD simulation model was validated via a comparison of the simulation results with the experimental data available in the literature. It is found that the newly developed Nu number correlation shows a deviation, with an Ave-MAE of 11.16%, compared to those obtained by CFD simulation. Similarly, the deviation between friction factors obtained by the newly proposed correlation and those obtained by CFD simulation is 20.81% Ave-MAE. Widely recognized correlations that are applicable to the condensation of refrigerants within small-scale channels were also evaluated by comparing newly developed correlations. It is concluded that the newly proposed correlation has a higher accuracy in predicting the heat transfer coefficient and pressure drop. This situation can contribute to the creation of a sustainable system via the use of microchannels and climate-friendly refrigerants, like R600a and R290. KW - Druckabfall KW - Numerische Strömungssimulation KW - Kältemittel KW - condensation flow KW - heat transfer coefficient KW - pressure drop KW - microchannel KW - CFD simulation KW - climate-friendly refrigerants KW - hydrocarbon refrigerants Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-46398 SN - 1996-1073 VL - 17 IS - 7 PB - MDPI ER - TY - JOUR A1 - Sulaiman, Mohammed A. A1 - Adham, Ahmed M. A1 - Hasan, Hasan F. A1 - Benim, Ali Cemal A1 - Anjal, Hassan A. T1 - Performance analysis of novel dew point evaporative cooler with shell and tube design through different air-water flow configurations JF - Energy KW - Verdunstungskühlung KW - Dew point evaporator KW - Chilled air-water production KW - Energy and thermal performance analysis KW - Heat and mass diffusion Y1 - 2024 U6 - https://doi.org/10.1016/j.energy.2023.129922 SN - 0360-5442 VL - 289 PB - Elsevier ER - TY - JOUR A1 - Benim, Ali Cemal A1 - Korucu, Ayse T1 - Computational investigation of non-premixed hydrogen-air laminar flames JF - International Journal of Hydrogen Energy KW - Wasserstoff KW - Laminare Strömung KW - Reaktionsmechanismus KW - Stickstoffoxide KW - Hydrogen combustion KW - Non-premixed combustion KW - Laminar flames KW - Reaction mechanisms KW - Nitrogen oxide formation Y1 - 2023 U6 - https://doi.org/10.1016/j.ijhydene.2022.12.248 SN - 0360-3199 VL - 48 IS - 38 SP - 14492 EP - 14510 PB - Elsevier ER - TY - JOUR A1 - Biswas, Nirmalendu A1 - Mandal, Dipak Kumar A1 - Bose, Sharmistha A1 - Manna, Nirmal K. A1 - Benim, Ali Cemal T1 - Experimental Treatment of Solar Chimney Power Plant — A Comprehensive Review JF - Energies N2 - Solar chimney power plants (SCPPs) are encouraging sustainable energy sources due to their low cost, abundance, low maintenance, and eco-friendliness. However, despite significant efforts to optimize SCPP design, their efficiency and power generation capabilities remain limited. Researchers have explored modifications in plant geometry and hybridization to improve efficiency. Despite extensive work in this area, commercialization of SCPPs has not yet been achieved. Most of the research is numerical and may differ from real-world practical use. The number of experimental studies is also relatively small. To facilitate commercialization, further investigation with practical and feasible dimensions is required. This comprehensive review paper aims to provide an in-depth analysis of experimental approaches and advancements in the field of SCPPs. The paper begins with an introduction, highlighting the background, significance, and objectives of the review. It provides an overview of the plants, discussing their principles and operation as innovative renewable energy systems. The historical development and evolution of solar chimneys are explored, shedding light on their progression over time. Case studies of operational hybrid SCPPs are examined to showcase real-world applications and performance. The paper also addresses environmental impacts and sustainability considerations associated with SCPPs. Furthermore, recommendations for future research and development in this field are provided to guide researchers and industry professionals. This study focuses on the possibility of commercialization of both standalone and hybrid SCPPs. KW - Erneuerbare Energien KW - Aufwindkraftwerk KW - Nachhaltigkeit KW - Zukunftserwartung KW - renewable energy KW - solar chimney power plant KW - SCPP KW - experimental KW - hybrid system KW - environmental impact KW - sustainability KW - challenges KW - future perspectives Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-46139 SN - 1996-1073 VL - 16 IS - 17 PB - MDPI ER - TY - JOUR A1 - Mandal, Dipak Kumar A1 - Bose, Sharmistha A1 - Biswas, Nirmalendu A1 - Manna, Nirmal K. A1 - Cuce, Erdem A1 - Benim, Ali Cemal T1 - Solar Chimney Power Plants for Sustainable Air Quality Management Integrating Photocatalysis and Particulate Filtration: A Comprehensive Review JF - Sustainability N2 - Urban air pollution has become a pressing challenge in recent times, demanding innovative solutions. This review delves into the potential of Solar Chimney Power Plants (SCPPs) as a sustainable approach to mitigating air pollution. The idea of mitigation of pollution may be an added advantage to the use of SCPPs in practice. Recent advancements, such as the integration of photocatalytic reactors (PCRs) for the elimination of greenhouse gases (GHGs), emphasizing the importance of addressing non-CO2 GHGs like CH4 and N2O are analyzed. The novelty of this review is that it not only focuses on the shifting and removal of particulate matter but also on the removal of greenhouse gases. Numerous case studies, ranging from filter-equipped SCPPs to Solar-Assisted Large-Scale Cleaning Systems (SALSCSs), are reviewed, providing a comprehensive understanding of their design, performance, and potential benefits. This review serves as a guide for researchers and policymakers, emphasizing the need for multifaceted approaches to address the intricate nexus of air pollution, renewable energy generation, and climate change mitigation. KW - solar chimney KW - air pollution KW - greenhouse gases KW - particulate matter KW - photocatalysis KW - Luftverschmutzung KW - Photokatalyst KW - Treibhausgas KW - Feinstaub KW - Aufwindkraftwerk Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-45814 SN - 2071-1050 VL - 16 IS - 6 PB - MDPI ER - TY - JOUR A1 - Rückert, Frank Ulrich A1 - Ibrar, Burhan A1 - Ahmed, Arslan A1 - Allweyer, Benjamin A1 - Hübner, Dirk A1 - Klinger, Friedrich A1 - Knaus, Hermann A1 - Benim, Ali Cemal T1 - Fluid flow and heat transfer of a novel passive cooling system for gearless wind turbines with a power range of 3–12 MW JF - Energy N2 - Today, the gearless horizontal axis wind turbines are mainstream in wind energy industry. High demands of electric power led to bigger systems and active cooling reduces the overall efficiency of the turbines. Passive cooling systems have been examined for the first time for a gearless wind energy generator with power range of 3–12 MW. With further developed heat conductors, it is possible to operate a wind generator in a larger power class with passive cooling components. This is accompanied by enormous cost savings due to elimination of costs for active cooling elements such as the use of fans, pumps, and heat exchangers. An additional factor is the significant reduction in necessary maintenance due to the minimized incidence of corrosion and wear. Design of the cooling fins and an ideal position of the generator within the housing of the wind turbine has been objectives. Mandatory is that maximum temperatures of the generator fins should stay under 155 °C, which could be reached with several designs for different heat exchanger geometries. KW - Windturbine KW - Wärmeübertragung KW - Numerische Strömungssimulation KW - Generator KW - Kühlung KW - Passive cooling KW - Gearless wind turbine Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-46594 SN - 0360-5442 VL - 312 PB - Elsevier ER - TY - JOUR A1 - Winter, Franziska Luise A1 - Diehl, Patrick A1 - Telaar, Pascal A1 - Watermann, Clara Maria A1 - Kaluza, Stefan A1 - Muhler, Martin A1 - Apfel, Ulf-Peter A1 - Zeidler-Fandrich, Barbara T1 - Influence of the catalyst precursor for cobalt on activated carbon applied in ammonia decomposition JF - Catalysis Today N2 - Ammonia is a key compound for storing and transporting green hydrogen. However, the efficient release of stored hydrogen through thermocatalytic ammonia decomposition is achievable only at temperatures around 600 °C, particularly with non-noble metal-based catalysts, which prove to be both ecologically and economically more feasible. In this study, electrically conductive activated carbon was selected as the catalyst support, chosen specifically for its suitability in achieving more energy-efficient direct reactor heating through the ohmic resistance of the catalysts. Cobalt salts were wet impregnated on activated carbon investigating the influence of different precursors (cobalt nitrate and cobalt acetate) and pyrolysis temperatures (400 °C and 600 °C) under N2 flow on the cobalt particle size and the incorporation of cobalt into the carbon matrix. TEM imaging and CO-chemisorption revealed well dispersed cobalt particles with sizes below 10 nm for the catalysts synthesized from the cobalt nitrate precursor. On the other hand, cobalt acetate led to about nine times larger Co agglomerates, which were partially detached from the carbon matrix. Moreover, this substantial difference in the Co particle size results in a significantly higher ammonia conversion for cobalt nitrate-based catalysts, achieving 94 % of ammonia conversion at 600 °C. Furthermore, the long-term stability test of the cobalt nitrate-based catalyst resulted in a slight deactivation of only 2 % ammonia conversion at 500 °C. KW - Katalyse KW - Ammoniak KW - Grüner Wasserstoff KW - Ammonia decomposition KW - Carbon supported cobalt KW - Synthesis design KW - Cobalt acetate KW - Cobalt nitrate KW - Resistance heating Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-46600 SN - 0920-5861 VL - 429 PB - Elsevier ER - TY - JOUR A1 - Kretschmar, Dominik A1 - Schmieder, Matthias A1 - Niemann, Jörg T1 - Knowledge Management Concept to Compensate a High Employee Fluctuation JF - Acta Technica Napocensis. Series: Applied Mathematics, Mechanics and Engineering N2 - Knowledge is our most valuable asset! Due to the increasing fluctuation caused by demographic change, the change in society and the industry, companies are increasingly confronted with knowledge management. Therefore, companies have problems with carrying out projects effectively. There are several models, methods and tools to develop an effective concept for knowledge management. Can the process capability of projects be ensured despite high fluctuation? What appropriate methods and tools are available to manage knowledge? These and more questions are clarified in the course of this work and presented in a conceptual proposal. KW - knowledge management KW - Wissensmanagement KW - project management KW - Projektmanagement KW - collaboration KW - Kollaboration Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-44818 UR - https://atna-mam.utcluj.ro/index.php/Acta/article/view/1031 VL - 61 IS - III SP - 483 EP - 488 ER - TY - INPR A1 - Priesmann, Jan A1 - Münch, Justin A1 - Ridha, Elias A1 - Spiegel, Thomas A1 - Reich, Marius A1 - Adam, Mario A1 - Nolting, Lars A1 - Praktiknjo, Aaron T1 - Artificial Intelligence and Design of Experiments for Assessing Security of Electricity Supply: A Review and Strategic Outlook N2 - Assessing the effects of the energy transition and liberalization of energy markets on resource adequacy is an increasingly important and demanding task. The rising complexity in energy systems requires adequate methods for energy system modeling leading to increased computational requirements. Furthermore, with complexity, uncertainty increases likewise calling for probabilistic assessments and scenario analyses. To adequately and efficiently address these various requirements, new methods from the field of data science are needed to accelerate current methods. With our systematic literature review, we want to close the gap between the three disciplines (1) assessment of security of electricity supply, (2) artificial intelligence, and (3) design of experiments. For this, we conduct a large-scale quantitative review on selected fields of application and methods and make a synthesis that relates the different disciplines to each other. Among other findings, we identify metamodeling of complex security of electricity supply models using AI methods and applications of AI-based methods for forecasts of storage dispatch and (non-)availabilities as promising fields of application that have not sufficiently been covered, yet. We end with deriving a new methodological pipeline for adequately and efficiently addressing the present and upcoming challenges in the assessment of security of electricity supply. Y1 - 2021 U6 - https://doi.org/https://doi.org/10.48550/arXiv.2112.04889 PB - arXiv ER - TY - CHAP A1 - Galle, Bo A1 - Arellano, Santiago A1 - Conde, Vladimir A1 - Pfeffer, Melissa A1 - Barsotti, Sara A1 - Stefansdottir, Gerður A1 - Bergsson, Baldur A1 - Bergsson, Bergur A1 - Ingvarsson, Thorgils A1 - Weber, Konradin T1 - Ground based measurements of the gas emission from the Holuhraun volcanic fissure eruption on Iceland 2014/2015 T2 - Geophysical Research Abstracts: EGU General Assembly 2015 N2 - The since 31 August 2014 ongoing volcanic eruption at Holuhraun on Iceland is by far the strongest source of sulfur dioxide in Europe over the last 230 years with sustained emission rates exceeding 100 000 ton/day. This gas emission severely affects local population and has become a concern also for air traffic. The eruption has in December continued at constant pace for 3.5 months. Three scenarios are envisaged for the future; (1) the eruption stops, (2) the fissure extends under the Vattnajökul glacier and (3) Bardarbunga volcano erupts. The two later scenarios will cause increased gas emission, severe ash emissions and extended flooding. Under the scope of the EU-project FUTUREVOLC, a project with 3.5 years duration, aiming at making Iceland a supersite for volcanological research as a European contribution to GEO, we are developing a version of the Scanning DOAS instrument that is adapted to high latitudes with low UV radiation and severe meteorological conditions. Since the first day of the eruption several of these novel instruments has been monitoring the SO2 emission from the eruption. Data from our instruments are still after 3.5 months the only sustained ground-based monitoring of this gas emission. A lot of work is however needed to sustain this operation at a very remote site and under severe field conditions. At the same time the very high concentrations in the gas plume, in combination with bad meteorological conditions require the development of novel methods to derive reliable flux estimates. In this presentation we will discuss the instrumental issues and present the latest version of the emission estimates made from our measurements. KW - Luftreinhaltung KW - Vulkanismus KW - Messtechnik KW - Schwefeldioxid Y1 - 2015 UR - https://web.archive.org/web/20240616051633/https://meetingorganizer.copernicus.org/EGU2015/EGU2015-1722-1.pdf N1 - Vortragsabstract VL - 17 PB - Copernicus CY - Göttingen ER - TY - CHAP A1 - Weber, Konradin A1 - Eliasson, Jonas A1 - Arnason, Gylfi A1 - Rögnvaldsson, Ólafur A1 - Thorsteinsson, Throstur A1 - Palsson, Thorgeir A1 - Böhlke, Christoph A1 - Fischer, Christian A1 - Smith, Paul A1 - Jones, Roderic L. A1 - Tirpitz, Lukas A1 - Platt, Ulrich T1 - Airborne Investigations and WRF - Model Calculations of the Bardarbunga-Holuhraun Eruption Plume T2 - Geophysical Research Abstracts: EGU General Assembly 2015 N2 - The eruption in Holuhraun is the largest producer of lava and gas in Iceland since 1783. The Volcanic Ash Research (VAR) group organized an airborne measurement campaign including 10 flights, where emissions of SO2 and ash concentrations were measured at the source and at the far plume. The highest SO2 concentration at the source was nearly up to 100 mg/m3. This is an extremely high value, compared to other airborne campaigns and a contamination considered to cause serious illness by the Icelandic Directorate of Health. Volcanic ash consisted of very fine particles, but the concentration was low when compared to other recent eruptions. Measurements of the far plume showed that scavenging is very active. The dispersion was successfully modeled with the Weather Research and Foreast (WRF-chem) model and analysis using the model showed that a large amount of the sulphur was precipitated in the Icelandic highlands. KW - Luftreinhaltung KW - Vulkanismus KW - Vulkanasche KW - Messtechnik KW - Atmosphärisches Aerosol KW - Schwefeldioxid Y1 - 2015 UR - https://web.archive.org/web/20240719170649/https://meetingorganizer.copernicus.org/EGU2015/EGU2015-10846-1.pdf N1 - Vortragsabstract VL - 17 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Eliasson, Jonas A1 - Yoshitani, Junichi A1 - Weber, Konradin A1 - Yasuda, Nario A1 - Iguchi, Masato A1 - Vogel, Andreas T1 - Airborne Measurement in the Ash Plume from Mount Sakurajima: Analysis of Gravitational Effects on Dispersion and Fallout JF - International Journal of Atmospheric Sciences N2 - Volcanic ash concentrations in the plume from Sakurajima volcano in Japan are observed from airplanes equipped with optical particle counters and GPS tracking devices. The volcano emits several puffs a day. The puffs are also recorded by the Sakurajima Volcanological Observatory. High concentrations are observed in the puffs and fallout driven by vertical air current, called streak fallout. Puffs dispersion is analyzed by the classical diffusion-advection method and a new gravitational dispersion method. The fluid mechanic of the gravitational dispersion, streak fallout, and classical diffusion-advection theory is described in three separate appendices together with methods to find the time gravitational dispersion constant and the diffusion coefficient from satellite photos. The diffusion-advection equation may be used to scale volcanic eruptions so the same eruption plumes can be scaled to constant flux and wind conditions or two eruptions can be scaled to each other. The dispersion analyses show that dispersion of volcanic plumes does not follow either theories completely. It is most likely diffusion in the interface of the plume and the ambient air, together with gravitational flattening of the plumes core. This means larger boundary concentration gradients and smaller diffusion coefficients than state of the art methods can predict. KW - Luftreinhaltung KW - Vulkanismus KW - Vulkanasche KW - Messtechnik KW - Atmosphärisches Aerosol Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-50955 SN - 2314-4122 VL - 2014 PB - Wiley ER - TY - JOUR A1 - Deckert, Carsten A1 - Schomaker, Rahel M. A1 - Aydogan, Manolya T1 - Leistung, Ansehen und Muße: Der Einfluss der Leistungsorientierung auf die nationale Innovationfähigkeit JF - Ideen- und Innovationsmanagement N2 - Die Leistungsfähigkeit einer Gesellschaft spielt eine entscheidende Rolle für ihre Wachstumsmöglichkeiten. Zentrale Figur ist dabei der Entrepreneur, welcher durch seine Eigenschaften in Bezug auf Risikobereitschaft, Verantwortungsübernahme oder Ergebnisorientierung innovativ tätig ist und somit das Wirtschaftswachstum vorantreibt. Der vorliegende Beitrag untersucht, wie Leistungsorientierung und Innovationsfähigkeit auf nationaler Ebene miteinander verbunden sind. Zunächst wird Leistungsorientierung im Kontext der Kulturforschung eingeordnet. Anschließend wird deraktuelle Stand der Forschung zum Zusammenhang zwischen Leistungsorientierung und Innovationskraft reflektiert. Im weiteren Verlauf erfolgt die Diskussion eigener empirischer Ergebnisse mit Fokus auf die Kulturdimension „Achievement versus Ascription“ (Leistung contra Ansehen), bevor ein Fazit über den Einfluss von Leistung im Hinblick auf Ansehen und Muße gezogen wird. Y1 - 2025 U6 - https://doi.org/10.37307/j.2198-3151.2025.01.03 SN - 2198-3143 IS - 1 PB - Erich Schmidt Verlag ER - TY - CHAP A1 - Weber, Konradin A1 - Fischer, Christian A1 - Vogel, Andreas A1 - Pohl, Tobias A1 - Böhlke, Christoph A1 - Lau, Hendrik A1 - Eliasson, Jonas A1 - Palsson, Thorgeir ED - Mladenov, Valeri ED - Tasho, Tashev ED - Hui, Wang ED - Ivan, Kralov ED - Sergey, Stankevich ED - Pelin, Yildiz ED - Jon, Burley T1 - First results of an airborne release of volcanic ash for testing of volcanic ash plume measurement instruments T2 - Recent Advances in Energy and Environmental Management KW - Luftreinhaltung KW - Vulkanasche KW - Messtechnik KW - Forschungsflugzeug Y1 - 2013 VL - Energy, Environmental and Structural Engineering Series 13 SP - 169 EP - 172 PB - WSEAS ER - TY - CHAP A1 - Ropertz, Alexander A1 - Lamp, Torsten A1 - Douard, Mathilde A1 - Weber, Konradin A1 - Gaertner, Andrea A1 - Elbers, C. A1 - Nitz, R. ED - Cecchi, Giovanna ED - Lamp, Torsten ED - Reuter, Rainer ED - Weber, Konradin T1 - Calibration of a high-resolution open-path FTIR spectrometer combined with an adjustable 100-m multipass cell T2 - SPIE Proceedings, Remote Sensing of Vegetation and Water, and Standardization of Remote Sensing Methods KW - Luftreinhaltung KW - FT-IR-Spektroskopie KW - Messtechnik KW - Kalibrieren (Messtechnik) Y1 - 1997 U6 - https://doi.org/10.1117/12.274749 SN - 0277-786X VL - 3107 SP - 137 EP - 147 PB - SPIE ER - TY - CHAP A1 - Weber, Konradin A1 - Eickel, Karl-Heinz ED - Cecchi, Giovanna ED - Lamp, Torsten ED - Reuter, Rainer ED - Weber, Konradin T1 - Standardization of open-path FTIR measurements in Germany T2 - SPIE Proceedings, Remote Sensing of Vegetation and Water, and Standardization of Remote Sensing Methods KW - Luftreinhaltung KW - FT-IR-Spektroskopie KW - Messtechnik Y1 - 1997 U6 - https://doi.org/10.1117/12.274753 SN - 0277-786X VL - 3107 SP - 174 EP - 176 PB - SPIE ER -