Academic literature on the topic 'Light harvesting methods'
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Journal articles on the topic "Light harvesting methods"
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Chen, Ming, Kenneth P. Ghiggino, Albert W. H. Mau, Ezio Rizzardo, San H. Thang, and Gerard J. Wilson. "Synthesis of light harvesting polymers by RAFT methods." Chemical Communications, no. 19 (September 11, 2002): 2276–77. http://dx.doi.org/10.1039/b206166j.
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Parveen, Farhana, Basavaraja Sannakki, Mohanrao V. Mandke, and Habib M. Pathan. "Copper nanoparticles: Synthesis methods and its light harvesting performance." Solar Energy Materials and Solar Cells 144 (January 2016): 371–82. http://dx.doi.org/10.1016/j.solmat.2015.08.033.
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Park, Nam-Gyu. "Methods to Improve Light Harvesting Efficiency in Dye-Sensitized Solar Cells." Journal of Electrochemical Science and Technology 1, no. 2 (December 30, 2010): 69–74. http://dx.doi.org/10.5229/jecst.2010.1.2.069.
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Wang, S., and G. C. Bazan. "Optically Amplified RNA–Protein Detection Methods Using Light-Harvesting Conjugated Polymers." Advanced Materials 15, no. 17 (September 3, 2003): 1425–28. http://dx.doi.org/10.1002/adma.200305099.
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Jurinovich, Sandro, Lucas Viani, Carles Curutchet, and Benedetta Mennucci. "Limits and potentials of quantum chemical methods in modelling photosynthetic antennae." Physical Chemistry Chemical Physics 17, no. 46 (2015): 30783–92. http://dx.doi.org/10.1039/c5cp00986c.
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A critical overview of quantum chemical approaches to simulate the light-harvesting process in photosynthetic antennae is presented together with a perspective on the developments that need to be introduced to reach a quantitative predictive power.
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Kluender, Richard A., and Bryce J. Stokes. "Productivity and Costs of Three Harvesting Methods." Southern Journal of Applied Forestry 18, no. 4 (November 1, 1994): 168–74. http://dx.doi.org/10.1093/sjaf/18.4.168.
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Abstract Three stands were harvested by either clearcut, shelterwood, or single-tree selection methods. The single-tree selection method consisted of a light thinning in an even-aged stand as the initial basal area reduction cut required to convert the stand to uneven-aged structure. The contractor used two skidders (one grapple, one choker) and production chain saws to harvest all three tracts. Harvested sites were all similar in slope (10-15%), average dbh (12-14 in.), and preharvest number of stems by dbh. In the felling study, fell, walk, and limb-top time were all greater for the single-tree selection method. Time to process a tree was lowest for the clearcut, intermediate for shelterwood, and highest for single-tree selection method. For skidding, bunch building time was highest for the single-tree selection and lowest for the clearcut method. Average volume per cycle was consistently higher for the grapple skidder than the choker skidder; volume per cycle was lowest for the single-tree selection and highest for the clearcut method for both skidders. Time per cycle was consistently lower for the grapple skidder than the cable skidder. Time per cycle was lowest for the clearcut and highest for the single-tree selection method. Factors that affected felling productivity (in decreasing order) were: dbh of harvested stems, intertree distance, and method of harvest. Factors that affected skidding productivity (in decreasing order) were: skidder type, pull distance, average volume per cycle, and the method of harvest. Costs of felling and skidding were highest on the single-selection stand and lowest on the clearcut stand. Total percentage of stand area trafficked was lowest for the single tree stand. However, the total area disturbed to meet a wood procurement budget was lowest for the clearcut and highest for the single-tree method. South. J. Appl. For. 18(4): 168-174.
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Mustardy, Laszlo, Francis X. Cunningham, and Elisabeth Gantt. "Localization and Quantitation of Chloroplast Enzymes and Light-Harvesting Components Using Immunocytochemical Methods." Plant Physiology 94, no. 1 (September 1, 1990): 334–40. http://dx.doi.org/10.1104/pp.94.1.334.
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Zhou, Dekai, Rencheng Zhuang, Xiaocong Chang, and Longqiu Li. "Enhanced Light-Harvesting Efficiency and Adaptation: A Review on Visible-Light-Driven Micro/Nanomotors." Research 2020 (August 25, 2020): 1–25. http://dx.doi.org/10.34133/2020/6821595.
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As visible light accounts for a larger proportion of solar energy and is harmless to living organisms, it has the potential to be the energy source of micro/nanomotors, which transform visible-light energy into mechanical motion, for different applications, especially in environmental remediation. However, how to precisely control the motion of visible-light-driven micro/nanomotors (VLD-MNMs) and efficiently utilize the weak visible-light photon energy to acquire rapid motion are significant challenges. This review summarizes the most critical aspects, involving photoactive materials, propulsion mechanisms, control methods, and applications of VLD-MNMs, and discusses strategies to systematically enhance the energy-harvesting efficiency and adaptation. At first, the photoactive materials have been divided into inorganic and organic photoactive materials and comprehensively discussed. Then, different propulsion mechanisms of the current VLD-MNMs are presented to explain the improvement in the actuation force, speed, and environmental adaptability. In addition, considering the characteristics of easy control of VLD-MNMs, we summarized the direction, speed, and cluster control methods of VLD-MNMs for different application requirements. Subsequently, the potential applications of VLD-MNMs, e.g., in environmental remediation, micropumps, cargo delivery, and sensing in microscale, are presented. Finally, discussions and suggestions for future directions to enhance the energy-harvesting efficiency and adaptation of VLD-MNMs are provided.
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Friedmans, Alan L., and Randall S. Alberte. "PHYLOGENETIC DISTRIBUTION OF THE MAJOR DIATOM LIGHT-HARVESTING PIGMENT-PROTEIN DETERMINED BY IMMUNOLOGICAL METHODS." Journal of Phycology 23, no. 3 (September 1987): 427–33. http://dx.doi.org/10.1111/j.1529-8817.1987.tb02528.x.
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Wang, Xiaoqing, Gerhard Ritschel, Sebastian Wüster, and Alexander Eisfeld. "Open quantum system parameters for light harvesting complexes from molecular dynamics." Physical Chemistry Chemical Physics 17, no. 38 (2015): 25629–41. http://dx.doi.org/10.1039/c5cp03891j.
Full textDissertations / Theses on the topic "Light harvesting methods"
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JANA, SOURAV KANTI. "Light harvesting methods in photovoltaic devices with superficial treatments." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2012. http://hdl.handle.net/10281/28621.
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Photovoltaics is fast emerging as an attractive renewable energy technology due to concerns of global warming, pollution and scarcity of fossil fuels supplies. However to compete in the global energy market, solar cells need to be cheaper and more energy efficient. Silicon is the favourite semiconductor used in solar photovoltaic cells because of its abandoned in nature, well established technology and non toxicity. But due to its indirect band gap, silicon is poor absorber of light and theoretical limiting efficiency of single junction wafer based silicon solar cells is ~31% which is called Shockley Queisser limit. But up to now the maximum achievable efficiency in laboratory for single crystal single junction silicon solar cells is ~ 24.7%. So far the cost of the wafer based silicon photovoltaics is high. Also thin film cells play an important role in low cost photvoltaics, but efficiency of the cost reduced cells is lower compared to wafer based cells. So light trapping into photovoltaic cells is a great issue inorder to increase the carrier generation inside the active layer of both bulk as well as thin film cells with out disturbing their fabrication technology. There many light harvesting methods; among them Surface Plasmon method using metal nanoparticles and spectrum downshifting method using nanocrystals are discussed here.
Metal nanoparticles support surface plamson when light is incident on them, which cause the scatter light into the underlying substrate. This process is realized on standard silicon solar cells. The feasible light scattering related enhancement was examined using spectral response and I-V measurements. Relative increases of the total delivered power under simulated solar irradiation were observed for cells both with and without antireflection coating using both silver and gold nanoparticles. The relative enhancement of External Quantum Efficiency derived from the spectral response measurements was observed for both the silicon cells. The better results obtained from both spectral response and I-V measurements were ascribed in the case of cells without antireflection coating. The results from I-V measurements under Air Mass 1.5 irradiation on the cells (without antireflection coating) correspond to a clear increase of the short circuit current due to both silver (relative increase of 7.5%) and gold (relative increase of 6.1%) nanoparticles. Also there is a relative enhancement (1.5%) of short circuit current was ascribed in the cells (with antireflection coating). Further realization of this method on copper indium gallium selenide based thin film solar cells attributed the enhancement of external quantum efficiency in the red wavelength region where these cells have already a poor spectral response.
Spectral downshifting method by the nanocrystals was investigated on the silicon based solar cells. Down shifting of photons on the silicon solar cells is realized by the absorption and emission property of the manganese doped zinc sulfide nanocrystals. The variation of band gap and photoluminescence intensity of different nanocrystals due to different doping concentration was observed. Relative enhancement of External Quantum Efficiency has been attributed in UV region (where silicon solar cells have poor spectral response) due to lower concentration of nanocrystals. A strong concentration quenching effect which causes decrease of external quantum efficiency in both UV and visible region has been observed.
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Xu, Sheng. "Oxide nanowire arrays for energy sciences." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/42876.
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Oxide nanowire arrays are playing an important role in energy sciences nowadays, including energy harvesting, energy storage, and power management. By utilizing a wet chemical growth method, we demonstrated the capabilities of synthesizing density controlled vertical ZnO nanowire arrays on a general substrate, optimizing the aspect ratio of the vertical ZnO nanowire arrays guided by a statistical method, epitaxially growing patterned vertical ZnO nanowire arrays on inorganic substrates, epitaxially growing patterned horizontal ZnO nanowire arrays on non-polar ZnO substrates, and the lift-off of the horizontal ZnO nanowire arrays onto general flexible substrates. In addition, single crystalline PbZrxTi1-xO3 (PZT) nanowire arrays were epitaxially grown on conductive and nonconductive substrates by hydrothermal decomposition. Beyond that, based on the as-synthesized ZnO nanowire arrays, we demonstrated multilayered three dimensionally integrated direct current and alternating current nanogenerators. By integrating a ZnO nanowire based nanogenerator with a ZnO nanowire based nanosensor, we demonstrated solely ZnO nanowire based self-powered nanosystems. Also, utilizing a commercial full-wave bridge rectifier, we rectified the alternating output charges of the nanogenerator based on PZT nanowire arrays, and the rectified charges were stored into capacitors, which were later discharged to light up a laser diode (LD). In addition, blue/near-ultraviolet (UV) light emitting diodes (LED) composed of ordered ZnO nanowire arrays on p-GaN wafers were presented.
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Wang, Junjie. "Energy Harvesting Circuit for Indoor Light based on the FOCV Method with an Adaptive Fraction Approach." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/94319.
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The proposed energy harvesting circuit system is designed for indoor solar environment especially for factories where the light energy is abundant and stable. The designed circuits are intended to power wireless sensor nodes (WSNs) or other computing unit such as microcontrollers or DSPs to provide a power solution for Internet of Things (IoTs). The proposed circuit can extract maximum power from the PV panel by utilizing the maximum power point tracking (MPPT) technique. The power stage is a synchronous dual-input dual-output non-inverting buck-boost converter operating in discontinuous conduction mode (DCM) and constant on-time pulse skipping modulation (COT-PSM) to achieve voltage regulation and maximum power delivery to the load. Battery is used as secondary input also as secondary output to achieve a longer lifecycle, a fast load response time and support higher load conditions. The proposed MPPT technique doesn't require any current sensor or computing units. Fully digitalized simple circuits are used to achieve sampling, store, and comparing tasks to save power.
The whole circuits including power stage and control circuits are designed and will fabricate in TSMC BCDMOS 180 nm process. The circuits are verified through schematic level simulations and post-layout simulations. The results are validated to prove the proposed circuit and control scheme work in a manner.Master of Science
With the growing energy demands, the efficient energy conversion systems caught great attentions. Especially, in the era of Internet of Things, powering those wireless devices can be extremely difficult. Nowadays, lots of devices such as consumer electronics, wireless sensor nodes, computing and mission system etc. are still powered by the batteries. Regular changing the batteries of those devices can be inconvenient or expensive. Energy harvesting provides a good solution to this issue because there are lots of ambient energy source is available. To design an energy efficient energy harvesting circuit system can help extend the device lifecycle per charging cycle. Even with some specific energy source which power scale is high enough, meanwhile the load doesn’t require too much power, the devices can be power-independent or standalone. In this work, the proposed circuit targets for indoor solar energy harvesting via solar panel. The target powering devices are wireless sensor nodes (WSNs). Meanwhile, WSNs can monitor the temperature, humidity, pressure, noise level etc. The proposed circuit design combines the power stage and control circuit on an integrated chip (IC), only few components are off-chip. It provides a very compact, endurable, and economical solution to the current IoT powering issue.
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Wormit, Michael [Verfasser]. "Development and application of reliable methods for the calculation of excited states : from light-harvesting complexes to medium-sized molecules / von Michael Wormit." 2009. http://d-nb.info/99693779X/34.
Full textBooks on the topic "Light harvesting methods"
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Stańczykiewicz, Arkadiusz. Prawdopodobieństwo wystąpienia szkód w odnowieniach podokapowych wskutek pozyskiwania drewna oraz model ich szacowania. Publishing House of the University of Agriculture in Krakow, 2018. http://dx.doi.org/10.15576/978-83-66602-34-2.
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An analysis of the existing literature on the issue of damage to regeneration caused by timber harvesting, revealed that a great majority of results reported in those publications was obtained through laborious and time-consuming field research conducted in two stages. Field research methods for gathering data, employed by various authors, differed in terms of the manner of establishing trial plots, the accuracy of counting and evaluating the number of saplings growing on the investigated sites, classification systems used for distinguishing particular groups of regeneration based on quantitative (diameter at breast height, tree height) and qualitative features (biosocial position within the certain layer and the entire stand), classification systems used for identifying types of damage caused by cutting and felling, as well as transporting operations, and finally the duration of observation intervals and time spent on gathering data on the response of damaged saplings from both, the individual and collective perspectives. Obviously, the most reliable manner of gathering such data would be to count all damaged elements of the environment being a subject of interest of particular investigators at the certain point of time. However, due to time and work consumption of this approach, which is besides very costly, any research should be designed in such a manner as to reduce the above-mentioned factors. This paper aimed to (1) analyse the probability of occurrence of damage to regeneration depending on the form of timber assortments dragged from the felling site to the skidding routes, and timber harvesting technology employed in logging works, and (2) identify a method ensuring that gathered data is sufficient for performing reliable evaluation of share of damage to regeneration at acceptable accuracy level, without necessity to establish trial plots before commencing harvesting works. The scope of these studies enclosed a comparison between two motor-manual methods of timber harvesting in thinned stands, with dragging of timber in the first stage of skidding from the stand to landings. According to one of these methods, a classical one, operations of felling and delimbing of trees were carried out by sawmen at the felling site. Timber obtained using different methods was skidded by carters and horses, and operators of a light-duty cable winch, driven by the chainsaw’s engine, as well as operators of cable winches combined with farm tractors. In the latter, alternative method, sawmen performed only cutting and felling of trees. Delimbing and cross-cutting of trunks, dragged from the felling sites, was carried out by operators of processors combined with farm tractors, worked on skidding routes. The research was conducted in the years 2002–2010 in stands within the age classes II–IV mostly, located in the territories of Regional Directorates of State Forests in Krakow and Katowice, and in the Forest Experimental Unit in Krynica-Zdrój. In the course of a preliminary stage of investigations 102 trial plots were established in stands within early and late tinning treatments. As a result of the field research carried out in two stages, more than 3.25 thsd. circular sites were established and marked, on the surface of which over 25 thsd. saplings constituting the regeneration layer were inventoried. Based on the results of investigations and analyses it was revealed that regardless of the category of thinning treatment, the highest probability of occurrence of destroying P(ZN) to regeneration (0.24–0.44) should be expected when the first stage of timber skidding is performed using cable winches. Slightly lower values of probability (0.17–0.33) should be expected in stands where timber is skidded by horses, while in respect to processor-based skidding technology the probability of destroying occurrence oscillates between 0.12 and 0.27, depending on the particular layer of regeneration. P(ZN) values, very close to those of skidding technology engaging processors, were recorded for skidding performed using the light-duty cable winch driven by the chainsaw’s engine (0.16–0.27). The highest probability of damage P(USZK) to regeneration (0.16–0.31) can be expected when processors are used in the first stage of timber skidding. Slightly lower values of probability (0.14–0.23) were obtained when skidding was performed with the use of cable winches, whereas engaging horses for hauling of trunks results in probability of damage occnrrence oscillating between 0.05–0.20, depending on the particular layer of regeneration. With regard to the probability of occurrence of both, destroying and damage P(ZNUSZK) to regeneration (0.33–0.54), the highest values can be expected when cable winches are engaged in the first stage of skidding. Little lower (0.30–0.43) was the probability of their occurrence if processor-based technology of skidding was employed, while in respect to horse skidding these values oscillated between 0.27–0.41, depending on the layer of regeneration. The lowest values of probability of occurrence of damage P(USZK), and destroying and damage treated collectively P(ZNUSZK), within all layers of regeneration, were recorded in stands where thinning treatments were performed using the light-duty cable winch driven by the chainsaw’s engine. The models evaluated and respective equations, developed based on those models, for evaluating the number of destroyed saplings ZNha (tab. 40, 42, 44, 46, 48) could be used for determining the share of damage expressed as a percentage, upon conducting only one field research at the investigated felling sites, once the timber harvesting and skidding would have been completed. As revealed by the results of analyses, evaluation of statistically significant regression models was possible for all layers of regeneration (tab. 39, 41, 43, 45, 47). Nevertheless, the smallest part of these models that could be considered positively verified, were those for the natural young regeneration, although almost a half of them revealed to be significant. Within the medium-sized regeneration over three-fourths of all models could be considered positively verified, four of which explained more than 50% of variability. Within the high-sized regeneration almost two-thirds of evaluated regression models were statistically significant, five of which were verified positively, moreover, one of them explained more than 50% of variability. The most promising results were those obtained for the advance growth. Nearly 90% of the evaluated models revealed to be statistically significant, ten of which could be considered positively verified. Furthermore, four statistically significant models explained over 50% of general variability. With regard to the entire regeneration more than 80% of evaluated models were statistically significant. However, due to insignificant coefficients of regression, eight of them could be considered positively verified. At this point it should be stressed that in respect to logging technology employing the light-duty cable winch FKS it was impossible to evaluate statistically significant models of regression. Whereas, in the case of processor-based logging technology, firstly regarding the advance growth, and then the entire regeneration, all of the evaluated statistically significant models could be considered positively verified, in terms of both, all of the stands, and particular categories of thinning treatments individually. This latter case also revealed the highest degree of matching of evaluated models (R2 popr 0.73–0.76 for advance growth and 0.78–0.94 for the entire regeneration). A significant impact of the kind of form of hauled timber on the probability of damage occurrence P(USZK), mainly in early thinning treatments, could have been reflected in the results obtained for all stands (early and late thinning treated collectively). Moreover, due to an insignificant impact of the form of hauled timber and logging technology employed, on the probability of occurrence of damage in late thinned stands, and a significant impact of the above-mentioned variables on early thinned stands, it should be assumed that for performing an evaluation of destroying and damage caused by timber harvesting the both thinning treatment categories should be analysed separately. Furthermore, when evaluating the probability of occurrence of destroying and damage caused by timber harvesting, the layers of natural young regeneration and advance growth should be analysed separately. As proved by the results presented in this paper, varying values of probability computed for each of the layers of regeneration seem to indicate that when investigating damage to regeneration caused by timber harvesting, it would be reasonable and recommended to perform a separate analysis of damage to the highest saplings as well, namely individuals with diameter at breast height close to 7 cm. In respect to studies on damage to regeneration caused by logging technologies mentioned above, the evaluation of number of destroyed saplings within the advance growth can be carried out using the proportions of damaged and undamaged saplings per 1 ha of the stand. The numbers evaluated in this manner can be used to calculate the damage share expressed in relative values (percentage of damaged saplings compared with the entire number of saplings before commencing the logging works). However, one should keep in mind that this is true only if the field research have been carried out based on the methodology described in this paper.
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Fontgalland, Glauco. Smart Systems: Theory and Advances. Amplla Editora, 2022. http://dx.doi.org/10.51859/amplla.sst631.1122-0.
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This book aims to highlight the strength and state-of-art of some techniques and methods applied to intelligent systems. Rather to cover the variety of techniques and methods available in the literature, which is out of scope of this book, it focuses on those consolidated and applied and on those with high potential of implementation to smart systems. This book has fourteen chapters covering abroad range of topics in communications. The first three chapters are devoted to state-of-art and review papers on planar filters, unmanned aerial vehicles (UAV), negative group delay, nanoclusters, and tunable lights, while the remain chapters cover specific topics such as smart monitoring, V2I, high-speed links, RF and Optical sensors, composite material, metamaterial, energy harvesting, radar, SWIPT, and electromagnetic sources.
Book chapters on the topic "Light harvesting methods"
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Rühle, Wolfgang, and Harald Paulsen. "Preparation of Native and Recombinant Light-Harvesting Chlorophyll-a/b Complex." In Methods in Molecular Biology, 113–25. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-925-3_11.
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Liu, Zhenfeng, and Wenrui Chang. "Crystallization Methods of Membrane Proteins: Practical Aspects of Crystallizing Plant Light-Harvesting Complexes." In Biophysical Techniques in Photosynthesis, 77–96. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-8250-4_5.
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Yamazaki, Yasuomi. "Synthesis of Novel Multinuclear Complexes for Light-Harvesting Systems Using the Coupling Reactions with Ring-Shaped Multinuclear Re(I) Complexes as Building Blocks." In Development of Synthetic Methods for Novel Photofunctional Multinuclear Complexes, 85–102. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-7148-7_5.
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"Advanced Ultrafast Spectroscopy Methods." In Light Harvesting in Photosynthesis, edited by Roberta Croce, Rienk van Grondelle, Herbert van Amerongen, and Ivo van Stokkum, 427–48. Boca Raton : Taylor & Francis/CRC Press, 2017. | Series: Foundations of biochemistry and biophysics: CRC Press, 2018. http://dx.doi.org/10.1201/9781351242899-18.
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Hamouda, Ragaa A., Nada M. Doleib, and Muhammad A. Abuelmagd. "Scaling Up and Harvesting of Algae." In Handbook of Research on Algae as a Sustainable Solution for Food, Energy, and the Environment, 197–227. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-2438-4.ch008.
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The scaling up and increment of the algal cultures cultivation process is a complex task that requires experienced staff. Some parameters such as biomass yield, biomass productivity, and specific growth should be calculated using the findings of laboratory scale that might be relevant for large-scale production as it provides a baseline to visualize and to verify production balance-related problems in the algal production system. The main goal of scale-up is to increase the production quantities with comparable or higher productivity and product quality. The harvesting process of the algal biomass represents a major hindrance in microalgae industry as it is approximately ranged from 20 to 30% of the total cost of the cultivation. There are many harvesting techniques such as physical, chemical, biological methods, and magnetic particle facilitated separation. This chapter has summarized the research progress in algal scaling up by optimizing different parameters such as light, temperature, nutrients, and strain selection.
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Jagdishbhai Patel, Mayur, Himangshu Baishya, Ritesh Kant Gupta, Rabindranath Garai, and Parameswar Krishnan Iyer. "Thin Film Solution Processable Perovskite Solar Cell." In Recent Advances in Multifunctional Perovskite Materials. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106056.
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Perovskite has emerged as a promising light-harvesting material for solar cells due to its higher absorption coefficient, bandgap tunability, low-exciton binding energy, and long carrier diffusion length. These lead to high power conversion efficiency >25% for thin film-based perovskite solar cells (PSCs). Additionally, PSCs can be fabricated through simple and cost-effective solution processable techniques, which make this technology more advantageous over the current photovoltaic technologies. Several solution-processable methods have been developed for fabrication of PSCs. In this chapter, the advantages and disadvantages of various solution processable techniques and their scope for large-scale commercialization will be discussed.
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Adolphs, Julia. "Photosynthesis." In Handbook of Research on Systems Biology Applications in Medicine, 573–87. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-076-9.ch034.
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This chapter introduces the theory of optical spectra and excitation energy transfer of light harvesting complexes in photosynthesis. The light energy absorbed by protein bound pigments in these complexes is transferred via an exciton mechanism to the photosynthetic reaction center where it drives the photochemical reactions. The protein holds the pigments in optimal orientation for excitation energy transfer and creates an energy sink by shifting the local transition energies of the pigments. In this way, the excitation energy is directed with high efficiency (close to 100 %) to the reaction center. In the present chapter, this energy transfer is studied theoretically. Based on crystal structure data, the excitonic couplings are calculated taking into account also the polarizability of the protein. The local transition energies are obtained by two independent methods and are used to predict the orientation of the FMO protein relative to the reaction center.
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Aamir Iqbal, Muhammad, Naila Ashraf, Wajeehah Shahid, Muhammad Awais, Abdullah Khan Durrani, Khurram Shahzad, and Mujtaba Ikram. "Nanophotonics: Fundamentals, Challenges, Future Prospects and Applied Applications." In Nonlinear Optics [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98601.
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Nanophotonics encompasses a wide range of nontrivial physical effects including light-matter interactions that are well beyond diffraction limits, and have opened up new avenues for a variety of applications in light harvesting, sensing, luminescence, optical switching, and media transmitting technologies. Recently, growing expertise of fusing nanotechnology and photonics has become fundamental, arising outskirts, challenging basic experimentation and opportunities for new technologies in our daily lives, and played a central role in many optical systems. It entails the theoretical study of photon’s interactions with matter at incredibly small scales, known as nanostructures, in order to prepare nanometer scale devices and accessories for processing, development, slowing down, influencing, and/or regulating photons through comprehending their behavior while interacting with or otherwise traveling via matter. This multidisciplinary field has also made an impact on industry, allowing researchers to explore new horizons in design, applied science, physical science, chemistry, materials science, and biomedical technologies. The foundations, nano-confinements, quantum manifestations, nanoscale interactions, numerical methods, and peculiarities of nonlinear optical phenomena in nano-photonics as well as projected nano-photonics consumption’s in our cutting-edge world, will be covered in this chapter.
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Floyd, Daniel, and Mahmoud Shafik. "An Ultrasonic Piezoelectric Power Generator for Public and Industrial Buildings Application." In Advances in Transdisciplinary Engineering. IOS Press, 2021. http://dx.doi.org/10.3233/atde210043.
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This paper presents an ultrasonic micro power generator using the piezoelectric direct effect phenomena. The micro power generator consists of 2 main elements, a movement matt including PZT elements and an energy harvesting circuit. The movement matt is made up of a four PZT elements each element creating a cantilever beam. The energy harvesting circuit is made up of an LTC3588 Evaluation Board and an LDR night light. Computer simulation and modelling using finite element analysis for the proposed generation method is discussed and used in the design and development process. Finite element analysis has been used to evaluate the PZT structure by performing an algebraic solution of a set of equations, describing an ideal model structure, with a finite number of variables. The simulation and modelling enabled to select the material and best method of operation. A prototype of the proposed generator was built and tested. This demonstrated that piezoelectric material could produce up to 36V, although the overall impedance of such devices was shown to be linear depending on the force applied with an average of 36MΩ. The Energy harvesting circuit allowed an output super capacitor to be step charged taking an average time of 35-minutes to charge and 2-minutes to discharge through the selected load.
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Li, Gao, Ali Raza, Sarfraz Ali, and Zhiwen Li. "MXene-Based Nanocomposite Photocatalysts for Wastewater Treatment." In Innovative Nanocomposites for the Remediation and Decontamination of Wastewater, 53–81. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-4553-2.ch003.
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Two-dimensional (2D) MXene has been considered as a hotspot toward environmental photocatalysis because of its outstanding structural stability, highly efficient conductivity, and versatile hydrophilicity. As an efficient photocatalytic candidate, MXenes offer rapid photogenerated charge carrier isolation, thereby providing plentiful availability for surface functional groups in respect of light-harvesting promising materials, and additionally executing a suitable foundation in favor of superior photoconversion proficiency. This chapter summarizes a comprehensive analysis of recent studies on fabrication method for MXene photocatalysts and photocatalytic performance for contaminant degradations. More significantly, MXenes are frequently employed as cocatalysts to boost the efficacy of photocatalytic activities when combined with other traditional photocatalysts such as metal oxide, metal sulfide, g-C3N4, and so on. Furthermore, in an effort to disclose the unique qualities of MXene-based nanocomposites, the stability of MXene-based nanocomposite photocatalysts is briefly examined.
Conference papers on the topic "Light harvesting methods"
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Mennucci, Benedetta, Carles Curutchet, Roberto Cammi, Gregory D. Scholes, Theodore E. Simos, and George Maroulis. "How the Molecular Environment Controls Excitation Energy Transfer and Light Harvesting: a Quantum Mechanical Model." In COMPUTATIONAL METHODS IN SCIENCE AND ENGINEERING: Theory and Computation: Old Problems and New Challenges. Lectures Presented at the International Conference on Computational Methods in Science and Engineering 2007 (ICCMSE 2007): VOLUME 1. AIP, 2007. http://dx.doi.org/10.1063/1.2836081.
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Linnanto, Juha Matti, and Arvi Freiberg. "Preface of the "Symposium on progress in computational studies of solar light harvesting - Computational approaches to biology"." In INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2014 (ICCMSE 2014). AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4897661.
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Doria, Alberto, Federico Moro, and Domenico Tommasino. "Vibration Energy Harvesting in Light Vehicles: Road Tests and Interpretative Models." In ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/detc2022-89093.
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Abstract The interest towards piezoelectric energy harvesters has been fostered in recent years by the development of ultra-low power electronics. An experimental analysis approach based on modal testing is here proposed in order to detect the best position on a bicycle of a piezo-harvester. Road tests show that vibrations are in the low frequency range so that the energy harvester has to be properly tuned to get its largest electrical response. Different tuning strategies of the same piezo-harvester, mounted in the best location, are tested and compared. The best setup is selected by considering as figures of merit the average stress inside the piezo-layer of the harvester (which affects its lifespan) and the maximum electric power which can be harvested. These figures are both analytically estimated from the measured power spectral density of the output open circuit voltage, which is experimentally determined. It is shown that the configuration with the largest tip mass provides the largest delivered power. Nevertheless, in order to preserve the device lifespan, harvesters with oscillator and liquid tip mass may represent a good tradeoff between the amount of generated stress and delivered power. The methods presented in this paper can be also adopted for predicting the behavior of harvesters mounted on other light vehicles.
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Beck, Warren F., Martin Debreczeny, Xinwei Yan, and Kenneth Sauer. "Picosecond Transient Absorption and Dichroism Studies of Excitation Transfer in the Cyanobacterial Light-Harvesting Proteins C-Phycocyanin and Allophycocyanin." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/up.1990.mc7.
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C-phycocyanin and allophycocyanin are light-harvesting proteins that occur in the phycobilisome in cyanobacteria.1 They represent relatively simple systems in which the structural factors that govern the direction and rate of excitation transfer can be addressed through the methods of picosec-ond spectroscopy. Several aspects of the structure of C-phycocyanin, as recently determined by X-ray crystallographic methods,2 present challenges to current theories for excitation transfer in light-harvesting proteins. We have begun a detailed characterization of the picosecond transient absorption and dichroism kinetics of C-phycocyanin in order to compare measured patterns of excitation transfer in C-phycocyanin with those indicated by direct calculation, using the known coordinates and orientations of the pigment molecules bound by the protein. We are also examining excitation transfer processes in allophycocyanin, a similar phycobiliprotein that directs excitation energy received from C-phycocyanin towards the photosystem II reaction center.
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Pšenčík, J., M. Vácha, F. Adamec, M. Ambrož, J. Dian, J. Boček, and J. Hála. "Spectral Hole Burning in Chlorosomes of Green Photosynthetic Bacteria Chlorobium limicola." In Spectral Hole-Burning and Luminescence Line Narrowing: Science and Applications. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/shbl.1992.tub19.
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Chlorobium limicola is a green sulfur photosynthetic bacteria. Its light harvesting system consists of huge extra-membrane ellipsoidal structures (100-150 nm long and 30-40 nm in diameter) called chlorosomes. Each chlorosome contains several thousands of bacteriochlorophyll-c (BChl-c) molecules (organized in long rod-like pigment-protein complexes) together with a significant amount of carotenoids. The whole chlorosome is enveloped with a BChl-a containing layer and attached to the cytoplasmic membrane through a water soluble BChl-a polypeptide link complex. Light energy absorbed in BChl-c is transfered via BChl-a in the envelope and via BChl-a in the link polypeptide complex to the BChl-a containing core antenna which surrounds the reaction center and is located within the cytoplasmic membrane. In the last few years, the dynamics of the excited energy transport (EET) in the whole light harvesting system of Chlorobium limicola and related species have been extensively studied. Fast EET from BChl-c to BChl-a was studied by means of ps absorption [1] and ps fluorescence decay [2]. Both methods yield similar values of the shortest decay components which characterize the EET: 21 ps and 26 ps, respectively. Detailed hole burning study of the BChl-a containing link antenna of Prosthecochloris aestuarii revealed excitonic structure of the antenna subunits and provided the decay times (on the order of 100 fs) of upper excitonic levels [3].
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Yuanpei, Xu, and Xuan Yimin. "Light-Harvesting and Photon Management in GaAs Solar Cells for Photovoltaic-Thermoelectric Hybrid Systems." In ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/mnhmt2016-6357.
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The utilization of solar energy in photovoltaics is limited due to the band gap of the materials. Hence, photovoltaic–thermoelectric hybrid system was proposed to utilize solar energy in the full spectrum of AM1.5G. On this basis, a novel design of GaAs solar cell is proposed in this paper for the full spectrum absorption in the cell structure, which consists of an ultra-thin GaAs layer with nanocones on the surface and a nanogrid–AZO–Ag back contact. The Finite Difference Time Domain method is used to analyze the full spectrum absorption features for TE and TM polarizations over the incident angles varying from 0° to 60°. The designed structure shows high absorption in the full spectrum. For GaAs layer, it is shown that the solar usable energy for GaAs solar cells in 300–900nm is absorbed by GaAs almost perfectly due to the anti–reflection property of the nanocone array. The absorbed energy in the back contact in the longer wavelengths over 900nm is due to the Fabry-Perot and the localized plasmonic resonances. The structure can collect full-spectrum incident photons efficiently in GaAs solar cells for the application of photovoltaic–thermoelectric hybrid system.
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Kudtarkar, Kaushik A., Thomas W. Smith, Patricia Iglesias, and Michael J. Schertzer. "Microfluidic Synthesis of Polymer Ionic Liquid Gel Beads for Energy Harvesting Applications." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67018.
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In the operation of many common devices and processes, more than 60% of consumed energy is wasted in many common processes. These loses come in many forms including heat, friction, and vibration. Energy harvesters are devices that can recapture some of this waste energy and convert it into electrical energy. This work will focus on electrostatic energy harvesting devices that recapture vibrational energy. Electrostatic energy harvesters recapture mechanical energy when a conductive mass translates or deforms in an electric field. Polymer ionic liquid gel beads may serve as a useful replacement for fluid droplets in electrostatic energy harvesters. This work uses a recently developed method for reliable synthesis of polymer gel beads. These beads are synthesized using a micro-reactor, which generates monomeric droplets in a silicon oil carrier fluid. The monomer solution also contains a photoinitiator and cross linker, which enables the monomer to polymerize when exposed to UV light. The present work demonstrates a method to rapidly synthesize uniform beads with a variety of chemical compositions. These chemical compositions can be used to tune the electromechanical properties of the beads to improve performance in applications such as energy harvesting devices.
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Uddin, Mohammed Jasim, Tarik J. Dickens, Jin Yan, David O. Olawale, Okenwa I. Okoli, and Federico Cesano. "Solid-State Dye Sensitized Optoelectronic Carbon Nanotube-Wires: An Energy Harvesting Damage Sensor With Nanotechnology Approach." In ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/smasis2012-8200.
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A novel preparation method of solid state photovoltaic carbon nanotubes (CNT) yarns has been successfully developed by depositing and grafting TiO2 thin films on CNT yarn substrates using a simple sol–gel method and designed for use in structural health monitoring (SHM) applications. The interaligned, ultrastrong and flexible CNYs display excellent electrical conductivity, mechanical integrity and their catalytic properties have been successfully used as working and counter electrodes. The TiO2 nanoparticles have been found to form a homogeneous thin film on the yarn surface, which shows efficient photovoltaic properties with remarkable stability when exposed to simulated solar light (AM 1.5). The yarns’ structure is not altered upon sol-gel treatment and light exposure. The TiO2 film is firmly anchored and the photovoltaic performance is retained even after multiple irradiation cycles. This preparation technique can also be applied to CNT yarn reinforced composite for an innovative in-situ and real-time self damage-sensing properties with infused triboluminescent (TL) materials.
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Zafar, Sayem, and Mohamed Gadalla. "Energy Harvesting Using Small Renewable Energy Sources: UAV Application." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51650.
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A renewable energy harvesting system is designed and tested for micro power generation. Such systems have applications ranging from mobile use to off-grid remote applications. This study analyzed the use of micro power generation for small unmanned aerial vehicle (UAV) flight operations. The renewable energy harvesting system consisted of a small wind turbine, flexible type PV panels and a small fuel cell. Fuel cell is considered the stable source while PV and wind turbine produced varying power output. The load of around 250 W is simulated by a small motor. The micro wind turbine with the total length of 4.5 m and the disk diameter of 1.8 m is tested. The micro wind turbine dimensions make it big enough to be used to charge batteries yet small enough to be installed on rooftops or easily transportable. The wind turbine blades are installed at an angle of 22°, with respect to the disk plane, as it gives the highest rotation. The voltage and current output for the corresponding RPM and wind speeds are recorded for the wind turbine. Two 2 m and a single 1 m long WaveSol Light PV panels are tested. The PV tests are conducted to get the current and voltage output with respect to the solar flux. The variation in solar flux represented the time of day and seasons. A 250 W PEM fuel cell is tested to run the desired load. Fuel cell’s hydrogen pressure drop is recorded against the output electrical power and the run time is recorded. System performance is evaluated under different operating and environmental conditions. Data is collected for a wide range of conditions to analyze the usability of renewable energy harvesting system. This energy harvesting method significantly improves the usability and output of the renewable energy sources. It also shows that small renewable energy systems have existing applications.
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Olympio, Raul B., John Donahue, and Adam M. Wickenheiser. "Theoretical and Experimental Analysis of Frequency Up-Conversion Energy Harvesters Under Human-Generated Vibrations." In ASME 2014 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/smasis2014-7674.
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Piezoelectric energy harvesters are devices capable of converting the kinetic energy present in vibration-based motion into electrical energy using piezoelectric transducers. This kind of device has its maximum efficiency when the exciting frequency matches its natural frequency. In the past years, some authors have explored the use of human motion as a vibration source, and harvesting energy in this situation is not trivial because the low-frequency characteristics of the motion are not compatible with small, light-weight transducers, which have relatively high natural frequencies. To overcome this problem, a method known as frequency up-conversion is used; it consists of a nonlinear vibration-based, magnetically excited harvester that exhibits frequency-independent performance, allowing the device to be efficient in a wide band of frequencies. In this work, the power output of a piezoelectric energy harvesting with frequency up-conversion submitted to walking and running vibrations is analyzed. Data are collected using an accelerometer located on the front pocket of each subject and then used in simulations. The model used consists of a cantilever beam with a permanent magnetic tip at the free end; this tip interacts with a magnetized structure that adds a nonlinear interaction to the model. A pure resistance matching the device’s impedance at its fundamental frequency is used to account for the output power. To verify the advantages of using the frequency up-conversion method for vibration-based energy harvesters regarding the power output and frequency band, a comparison with the linear cantilever model is analyzed. Also, in order to confirm the simulation results, a prototype of the device is built and submitted to vibration tests using a horizontally oriented motor-driven cart that recreates the motions recorded by the accelerometer; it is tested with and without the magnetic force in order to experimentally determine the nonlinearity’s effects on the power harvesting performance.
Reports on the topic "Light harvesting methods"
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Burks, Thomas F., Victor Alchanatis, and Warren Dixon. Enhancement of Sensing Technologies for Selective Tree Fruit Identification and Targeting in Robotic Harvesting Systems. United States Department of Agriculture, October 2009. http://dx.doi.org/10.32747/2009.7591739.bard.
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The proposed project aims to enhance tree fruit identification and targeting for robotic harvesting through the selection of appropriate sensor technology, sensor fusion, and visual servo-control approaches. These technologies will be applicable for apple, orange and grapefruit harvest, although specific sensor wavelengths may vary. The primary challenges are fruit occlusion, light variability, peel color variation with maturity, range to target, and computational requirements of image processing algorithms. There are four major development tasks in original three-year proposed study. First, spectral characteristics in the VIS/NIR (0.4-1.0 micron) will be used in conjunction with thermal data to provide accurate and robust detection of fruit in the tree canopy. Hyper-spectral image pairs will be combined to provide automatic stereo matching for accurate 3D position. Secondly, VIS/NIR/FIR (0.4-15.0 micron) spectral sensor technology will be evaluated for potential in-field on-the-tree grading of surface defect, maturity and size for selective fruit harvest. Thirdly, new adaptive Lyapunov-basedHBVS (homography-based visual servo) methods to compensate for camera uncertainty, distortion effects, and provide range to target from a single camera will be developed, simulated, and implemented on a camera testbed to prove concept. HBVS methods coupled with imagespace navigation will be implemented to provide robust target tracking. And finally, harvesting test will be conducted on the developed technologies using the University of Florida harvesting manipulator test bed. During the course of the project it was determined that the second objective was overly ambitious for the project period and effort was directed toward the other objectives. The results reflect the synergistic efforts of the three principals. The USA team has focused on citrus based approaches while the Israeli counterpart has focused on apples. The USA team has improved visual servo control through the use of a statistical-based range estimate and homography. The results have been promising as long as the target is visible. In addition, the USA team has developed improved fruit detection algorithms that are robust under light variation and can localize fruit centers for partially occluded fruit. Additionally, algorithms have been developed to fuse thermal and visible spectrum image prior to segmentation in order to evaluate the potential improvements in fruit detection. Lastly, the USA team has developed a multispectral detection approach which demonstrated fruit detection levels above 90% of non-occluded fruit. The Israel team has focused on image registration and statistical based fruit detection with post-segmentation fusion. The results of all programs have shown significant progress with increased levels of fruit detection over prior art.