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https://www.readbyqxmd.com/read/28103551/ultrasound-flow-mapping-for-the-investigation-of-crystal-growth
#1
Norman Thieme, Paul Bonisch, Dagmar Meier, Richard Nauber, Lars Buttner, Kaspars Dadzis, Olf Patzold, Lamine Sylla, Jurgen Czarske
A high energy conversion and cost efficiency are keys for the transition to renewable energy sources, e.g. solar cells. The efficiency of multi-crystalline solar cells can be improved by enhancing the understanding of its crystallization process, especially the directional solidification. In this paper, a novel measurement system for the characterization of flow phenomena and solidification processes in low-temperature model experiments on the basis of ultrasound Doppler velocimetry is described. It captures turbulent flow phenomena in two planes with a frame rate of 3...
January 16, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28059359/fundamental-and-practical-limits-of-planar-tracking-solar-concentrators
#2
Alex J Grede, Jared S Price, Noel C Giebink
Planar microtracking provides an alternate paradigm for solar concentration that offers the possibility of realizing high-efficiency embedded concentrating photovoltaic systems in the form factor of standard photovoltaic panels. Here, we investigate the thermodynamic limit of planar tracking optical concentrators and establish that they can, in principal, achieve the sine limit of their orientationally-tracked counterparts provided that the receiver translates a minimum distance set by the field of view half-angle...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28001034/the-o2-evolving-complex-of-photosystem-ii-recent-insights-from-quantum-mechanics-molecular-mechanics-qm-mm-extended-x-ray-absorption-fine-structure-exafs-and-femtosecond-x-ray-crystallography-data
#3
Mikhail Askerka, Gary W Brudvig, Victor S Batista
Efficient photoelectrochemical water oxidation may open a way to produce energy from renewable solar power. In biology, generation of fuel due to water oxidation happens efficiently on an immense scale during the light reactions of photosynthesis. To oxidize water, photosynthetic organisms have evolved a highly conserved protein complex, Photosystem II. Within that complex, water oxidation happens at the CaMn4O5 inorganic catalytic cluster, the so-called oxygen-evolving complex (OEC), which cycles through storage "S" states as it accumulates oxidizing equivalents and produces molecular oxygen...
December 21, 2016: Accounts of Chemical Research
https://www.readbyqxmd.com/read/27997553/solar-aligned-pictographs-at-the-paleoindian-site-of-painel-do-pil%C3%A3-o-along-the-lower-amazon-river-at-monte-alegre-brazil
#4
Christopher Sean Davis
The archaeological sites near Monte Alegre, along Brazil's lower Amazon River, provide new information on the little-known activities and symbolism of South American Paleoindians toward the end of the Ice Age. While paleoindian sites like Monte Verde in Chile, or Guitarrero Cave in Peru, are located near the pacific coast, Monte Alegre lies much further inland, 680 km upriver from the mouth of the Amazon River and the Atlantic Coast. With excavated wood charcoal radiocarbon dated as early as 13,200 calibrated years ago, the hill-as a source of sandstone and quartz lithics-supplied early pioneers with adequate tools needed for colonizing the interior of the continent...
2016: PloS One
https://www.readbyqxmd.com/read/27976474/chlorophyll-fluorescence-tracks-seasonal-variations-of-photosynthesis-from-leaf-to-canopy-in-a-temperate-forest
#5
Hualei Yang, Xi Yang, Yongguang Zhang, Mary A Heskel, Xiaoliang Lu, J William Munger, Shucun Sun, Jianwu Tang
Accurate estimation of terrestrial gross primary productivity (GPP) remains a challenge despite its importance in the global carbon cycle. Chlorophyll fluorescence (ChlF) has been recently adopted to understand photosynthesis and its response to the environment, particularly with remote sensing data. However, it remains unclear how ChlF and photosynthesis are linked at different spatial scales across the growing season. We examined seasonal relationships between ChlF and photosynthesis at the leaf, canopy, and ecosystem scales and explored how leaf-level ChlF was linked with canopy-scale solar-induced chlorophyll fluorescence (SIF) in a temperate deciduous forest at Harvard Forest, Massachusetts, USA...
December 14, 2016: Global Change Biology
https://www.readbyqxmd.com/read/27898002/design-of-a-solar-tracking-system-using-the-brightest-region-in-the-sky-image-sensor
#6
Ching-Chuan Wei, Yu-Chang Song, Chia-Chi Chang, Chuan-Bi Lin
Solar energy is certainly an energy source worth exploring and utilizing because of the environmental protection it offers. However, the conversion efficiency of solar energy is still low. If the photovoltaic panel perpendicularly tracks the sun, the solar energy conversion efficiency will be improved. In this article, we propose an innovative method to track the sun using an image sensor. In our method, it is logical to assume the points of the brightest region in the sky image representing the location of the sun...
November 25, 2016: Sensors
https://www.readbyqxmd.com/read/27891228/a-probabilistic-algorithm-to-process-geolocation-data
#7
Benjamin Merkel, Richard A Phillips, Sébastien Descamps, Nigel G Yoccoz, Børge Moe, Hallvard Strøm
BACKGROUND: The use of light level loggers (geolocators) to understand movements and distributions in terrestrial and marine vertebrates, particularly during the non-breeding period, has increased dramatically in recent years. However, inferring positions from light data is not straightforward, often relies on assumptions that are difficult to test, or includes an element of subjectivity. RESULTS: We present an intuitive framework to compute locations from twilight events collected by geolocators from different manufacturers...
2016: Movement Ecology
https://www.readbyqxmd.com/read/27889810/rhodamine-bound-maghemite-as-a-long-term-dual-imaging-nanoprobe-of-adipose-tissue-derived-mesenchymal-stromal-cells
#8
Vratislav Cmiel, Josef Skopalik, Katerina Polakova, Jan Solar, Marketa Havrdova, David Milde, Ivan Justan, Massimiliano Magro, Zenon Starcuk, Ivo Provaznik
In the last few years, magnetically labeled cells have been intensively explored, and non-invasive cell tracking and magnetic manipulation methods have been tested in preclinical studies focused on cell transplantation. For clinical applications, it is desirable to know the intracellular pathway of nanoparticles, which can predict their biocompatibility with cells and the long-term imaging properties of labeled cells. Here, we quantified labeling efficiency, localization, and fluorescence properties of Rhodamine derivatized superparamagnetic maghemite nanoparticles (SAMN-R) in mesenchymal stromal cells (MSC)...
November 26, 2016: European Biophysics Journal: EBJ
https://www.readbyqxmd.com/read/27855952/decay-of-sewage-sourced-microbial-source-tracking-markers-and-fecal-indicator-bacteria-in-marine-waters
#9
Mia Catharine Mattioli, Lauren M Sassoubre, Todd L Russell, Alexandria B Boehm
The decay of sewage-sourced enterococci, Escherichia coli, three human-associated microbial source tracking (MST) markers, Salmonella, Campylobacter, and norovirus GII was measured in situ in coastal, marine waters. Experiments examined the effects of sunlight intensity and season on decay. Seawater was seeded with untreated sewage, placed into permeable dialysis bags, and deployed in the coastal ocean near the water surface, and at 18 cm, and 99 cm depths, to vary solar intensity, during winter and summer seasons...
January 1, 2017: Water Research
https://www.readbyqxmd.com/read/27824085/bulk-heterojunction-morphology-of-polymer-fullerene-blends-revealed-by-ultrafast-spectroscopy
#10
Almis Serbenta, Oleg V Kozlov, Giuseppe Portale, Paul H M van Loosdrecht, Maxim S Pshenichnikov
Morphology of organic photovoltaic bulk heterojunctions (BHJs) - a nanoscale texture of the donor and acceptor phases - is one of the key factors influencing efficiency of organic solar cells. Detailed knowledge of the morphology is hampered by the fact that it is notoriously difficult to investigate by microscopic methods. Here we all-optically track the exciton harvesting dynamics in the fullerene acceptor phase from which subdivision of the fullerene domain sizes into the mixed phase (2-15 nm) and large (>50 nm) domains is readily obtained via the Monte-Carlo simulations...
November 8, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27818888/dish-layouts-analysis-method-for-concentrative-solar-power-plant
#11
Jinshan Xu, Shaocong Gan, Song Li, Zhongyuan Ruan, Shengyong Chen, Yong Wang, Changgui Gui, Bin Wan
Designs leading to maximize the use of sun radiation of a given reflective area without increasing the expense on investment are important to solar power plants construction. We here provide a method that allows one to compute shade area at any given time as well as the total shading effect of a day. By establishing a local coordinate system with the origin at the apex of a parabolic dish and z-axis pointing to the sun, neighboring dishes only with [Formula: see text] would shade onto the dish when in tracking mode...
2016: SpringerPlus
https://www.readbyqxmd.com/read/27714661/the-role-of-visible-light-active-tio2-specimens-on-the-solar-photocatalytic-disinfection-of-e-coli
#12
Nazmiye Cemre Birben, Ayse Tomruk, Miray Bekbolet
Solar photocatalytic disinfection efficiency of novel visible light activated (VLA) photocatalysts was evaluated with the aim of assessing inactivation of Escherichia coli as the pathogen indicator organism present in drinking water. Influence of humic acid (HA) on the photocatalytic disinfection efficiency of the specified VLA TiO2 specimens i.e., N-doped, Se-doped, and Se-N co-doped TiO2 was also investigated. Photocatalytic disinfection efficiency was assessed by the enumeration of bacteria following selected irradiation periods...
October 6, 2016: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/27708053/incorporation-of-rubidium-cations-into-perovskite-solar-cells-improves-photovoltaic-performance
#13
Michael Saliba, Taisuke Matsui, Konrad Domanski, Ji-Youn Seo, Amita Ummadisingu, Shaik M Zakeeruddin, Juan-Pablo Correa-Baena, Wolfgang R Tress, Antonio Abate, Anders Hagfeldt, Michael Grätzel
All of the cations currently used in perovskite solar cells abide by the tolerance factor for incorporation into the lattice. We show that the small and oxidation-stable rubidium cation (Rb(+)) can be embedded into a "cation cascade" to create perovskite materials with excellent material properties. We achieved stabilized efficiencies of up to 21.6% (average value, 20.2%) on small areas (and a stabilized 19.0% on a cell 0.5 square centimeters in area) as well as an electroluminescence of 3.8%. The open-circuit voltage of 1...
October 14, 2016: Science
https://www.readbyqxmd.com/read/27670748/tracking-the-fate-of-surface-plasmon-resonance-generated-hot-electrons-by-in-situ-sers-surveying-of-catalyzed-reaction
#14
Rui Liu, Zuoliang He, Jiefang Sun, Jingfu Liu, Guibin Jiang
Plasmonic catalysis is an emerging process that utilizes surface plasmon resonance (SPR) process to harnesses solar energy for the promotion of catalyzed reactions. In most cases, SPR generated hot electrons (HEs) play an indispensable role in this solar-chemical energy shift process. Therefore, understanding the effectiveness of the HEs in promoting chemical reactions, and identifying the key factors that contribute to this utilization efficiency is of profound importance. Herein, the authors outline an in situ surface enhanced Raman spectroscopy protocol to track the fate of HEs...
December 2016: Small
https://www.readbyqxmd.com/read/27661602/25%C3%A2-%C3%A2-w-m-sup-2-sup-collection-efficiency-solar-pumped-nd-yag-laser-by-a-heliostat-parabolic-mirror-system
#15
D Liang, J Almeida, C R Vistas
A large aspheric fused silica lens was used to couple efficiently the concentrated solar radiation from the focal zone of a 1.5-m-diameter primary concentrator into a 4-mm-diameter, 35-mm-long Nd:YAG single-crystal rod within a conical pump cavity. Continuous-wave laser power of 29.3 W was measured, attaining 25.0  W/m<sup>2</sup> solar laser collection efficiency, corresponding to a 19% increase over the previous record. Its laser beam figure of merit-the ratio between laser power and the product of Mx2, My2 beam quality factors-of 0...
September 20, 2016: Applied Optics
https://www.readbyqxmd.com/read/27661362/traceability-of-solar-uv-measurements-using-the-qasume-reference-spectroradiometer
#16
Gregor Hülsen, Julian Gröbner, Saulius Nevas, Peter Sperfeld, Luca Egli, Geiland Porrovecchio, Marek Smid
One major objective of the European Joint Research Project "Traceability for surface spectral solar ultraviolet (UV) radiation" was to reduce the uncertainty of spectral UV measurements. The measurement instrument used for this work was the portable UV European reference spectroradiometer Qasume. The calibration uncertainty of this instrument was decreased and validated by a comparison of direct calibrations against a primary standard for spectral irradiance, a high temperature blackbody radiator, and against a reference detector using a spectrally tunable laser as a monochromatic source...
September 10, 2016: Applied Optics
https://www.readbyqxmd.com/read/27575549/inhibition-of-tafel-kinetics-for-electrolytic-hydrogen-evolution-on-isolated-micron-scale-electrocatalysts-on-semiconductor-interfaces
#17
Robert H Coridan, Zebulon G Schichtl, Tao Sun, Kamel Fezzaa
Semiconductor-liquid junctions are ubiquitous in photoelectrochemical approaches to artificial photosynthesis. By analogy with the antennae and reaction centers in natural photosynthetic complexes, separating the light-absorbing semiconductor and electrocatalysts can improve catalytic efficiency. A catalytic layer can also impair the photovoltage-generating energetics of the electrode without appropriate microscopic organization of catalytically active area on the surface. Here, we have developed a method using high-speed X-ray phase contrast imaging to study in situ electrolytic bubble growth on semiconductor electrodes fabricated with isolated, micron-scale platinum electrocatalysts...
September 21, 2016: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/27553381/additive-free-transparent-triarylamine-based-polymeric-hole-transport-materials-for-stable-perovskite-solar-cells
#18
Taisuke Matsui, Ieva Petrikyte, Tadas Malinauskas, Konrad Domanski, Maryte Daskeviciene, Matas Steponaitis, Paul Gratia, Wolfgang Tress, Juan-Pablo Correa-Baena, Antonio Abate, Anders Hagfeldt, Michael Grätzel, Mohammad Khaja Nazeeruddin, Vytautas Getautis, Michael Saliba
Triarylamine-based polymers with different functional groups were synthetized as hole-transport materials (HTMs) for perovskite solar cells (PSCs). The novel materials enabled efficient PSCs without the use of chemical doping (or additives) to enhance charge transport. Devices employing poly(triarylamine) with methylphenylethenyl functional groups (V873) showed a power conversion efficiency of 12.3 %, whereas widely used additive-free poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) demonstrated 10...
September 22, 2016: ChemSusChem
https://www.readbyqxmd.com/read/27518595/halogen-bonding-promotes-higher-dye-sensitized-solar-cell-photovoltages
#19
Sarah J C Simon, Fraser G L Parlane, Wesley B Swords, Cameron W Kellett, Chuan Du, Brian Lam, Rebecca K Dean, Ke Hu, Gerald J Meyer, Curtis P Berlinguette
We report here an enhancement in photovoltage for dye-sensitized solar cells (DSSCs) where halogen-bonding interactions exist between a nucleophilic electrolyte species (I(-)) and a photo-oxidized dye immobilized on a TiO2 surface. The triarylamine-based dyes under investigation showed larger rate constants for dye regeneration (kreg) by the nucleophilic electrolyte species when heavier halogen substituents were positioned on the dye. The open-circuit voltages (VOC) tracked these kreg values. This analysis of a homologous series of dyes that differ only in the identity of two halogen substituents provides compelling evidence that the DSSC photovoltage is sensitive to kreg...
August 24, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27505130/use-of-surface-photovoltage-spectroscopy-to-measure-built-in-voltage-space-charge-layer-width-and-effective-band-gap-in-cdse-quantum-dot-films
#20
Jing Zhao, Benjamin A Nail, Michael A Holmes, Frank E Osterloh
Surface photovoltage spectroscopy (SPS) was used to study the photochemistry of mercaptoethanol-ligated CdSe quantum dot (2.0-4.2 nm diameter) films on indium doped tin oxide (ITO) in the absence of an external bias or electrolyte. The n-type films generate negative voltages under super band gap illumination (0.1-0.5 mW cm(-2)) by majority carrier injection into the ITO substrate. The photovoltage onset energies track the optical band gaps of the samples and are assigned as effective band gaps of the films...
September 1, 2016: Journal of Physical Chemistry Letters
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