Structured data on customer feedback is becoming more costly and timely to collect and organize. On the other hand, unstructured opinionated data, e.g., in the form of free-text comments, is ...proliferating and available on public websites, such as social media websites, blogs, forums, and websites that provide recommendations. This research proposes a novel method to develop a knowledge-based recommender system from unstructured (text) data. The method is based on applying an opinion mining algorithm, extracting aspect-based sentiment score per text item, and transforming text into a structured form. An action rule mining algorithm is applied to the data table constructed from sentiment mining. The proposed application of the method is the problem of improving customer satisfaction ratings. The results obtained from the dataset of customer comments related to the repair services were evaluated with accuracy and coverage. Further, the results were incorporated into the framework of a web-based user-friendly recommender system to advise the business on how to maximally increase their profits by introducing minimal sets of changes in their service. Experiments and evaluation results from comparing the structured data-based version of the system CLIRS (Customer Loyalty Improvement Recommender System) with the unstructured data-based version of the system (CLIRS2) are provided.
Self-assembled supramolecular organization of nano-structured biomimetic light-harvesting modules inside solid-state nano-templates can be exploited to develop excellent light-harvesting materials ...for artificial photosynthetic devices. We present here a hybrid light-harvesting system mimicking the chlorosomal structures of the natural photosynthetic system using synthetic zinc chlorin units (ZnChl-C6, ZnChl-C12 and ZnChl-C18) that are self-aggregated inside the anodic aluminum oxide (AAO) nano-channel membranes. AAO nano-templates were modified with a TiO2 matrix and functionalized with long hydrophobic chains to facilitate the formation of supramolecular Zn-chlorin aggregates. The transparent Zn-chlorin nano-aggregates inside the alkyl-TiO2 modified AAO nano-channels have a diameter of ∼120 nm in a 60 μm length channel. UV-Vis studies and fluorescence emission spectra further confirm the formation of the supramolecular ZnChl aggregates from monomer molecules inside the alkyl-functionalized nano-channels. Our results prove that the novel and unique method can be used to produce efficient and stable light-harvesting assemblies for effective solar energy capture through transparent and stable nano-channel ceramic materials modified with bio-mimetic molecular self-assembled nano-aggregates.
Democratic politics creates a specific ‘chain of representation’. According to Article 104 of the Polish Constitution, the MPs are the representatives of the entire Nation. The understanding of the ...“entire Nation” allows to determine whether national identity is open and inclusive, or closed and exclusive. One can distinguish two ideal types of a nation: heterogeneous and homogeneous. The first type is connected to the universalist understanding of “constitutional essentials”, the second to the particularistic one. In the paper, we pointed out the elements of heterogeneity in the text of Polish constitutions as well as the elements of homogeneity in the constitutional practice. Religion becomes an important factor influencing the interpretation and application of the constitution. The heterogeneous concept of the nation and the universalist “constitutional essentials” can be narrowed down in the political practice.
In this study, we investigated the influence of long carbon chains in ester group of the zinc chlorophyll derivatives, zinc hexyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-C6), zinc ...octadecyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-C18), zinc dodecyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-C12) and zinc methyl 3-devinyl-3-methylhydroxymethylpyropheophorbide-a (ZnChl-OH), on the DSSC performance. Photovoltaic performances were determined in the order of ZnChlC12 > ZnChlC18 > ZnChlC6 > ZnChlOH from J–V curves. The higher Jsc obtained from the ZnChl-C12 sensitizer could result from the presence of long alkyl chain which reduce the charge recombination rate and facilitate electron injection. However, it was observed to decrease in the DSSC performance with the presence of longer alkyl chains (>C12). It was understood from the obtained results, the length of the alkyl chains is directly affect the DSSC performance.
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•Zinc chlorophyll materials have been synthesized.•Zinc chlorophyll materials have been fully characterized.•Performances of the materials were evaluated in DSSC.
Chlorophyll dyes for dye sensitized solar cell.
•Zinc chlorophyll materials have been synthesized.•Zinc chlorophyll materials have been characterized.•Dye sensitized solar cells were fabricated and ...characterized.
To design sensitizers for dye sensitized solar cells (DSSCs), a series of zinc chlorins with different substituents were synthesized. Novel zinc methyl 3-devinyl-3-hydroxymethyl-20-phenylacetylenylpyropheophorbide-a (ZnChl-1), zinc methyl 20-bromo-3-devinyl-3-hydroxymethylpyropheophorbide-a (ZnChl-2), zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-3), zinc propyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-4) were synthesized and their photovoltaic performances were evaluated in dye-sensitized solar cells. Photoelectrodes with a 7μm thick nanoporous layer and a 5μm thick light-scattering layer were used to fabricate dye sensitized solar cells. The best efficiency was obtained with ZnChl-2 sensitizer. ZnChl-2 gave a Jsc of 3.5mA/cm2, Voc of 412mV, FF of 0.56 and an overall conversion efficiency of 0.81 at full sun (1000Wm−2).
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