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Carbonaceous catalysts from orange pulp for limonene oxidation
Wróblewska Agnieszka,Serafin Jarosław,Gawarecka Alicja,Miądlicki Piotr,Urbaś Karolina,Koren Zvi C.,Llorca Jordi,Michalkiewicz Beata 한국탄소학회 2020 Carbon Letters Vol.30 No.2
The possibility of orange pulp utilization for nanoporous carbons production was investigated. Moreover, processing the obtained materials as limonene oxidation catalysts was studied as well. Limonene was separated from orange pulp obtained from fragmented orange peels—the waste from industrial fruits processing—by means of simple distillation. After the sepa�ration of limonene from the biomass, the dried orange pulp was converted to three types of nanoporous carbon catalysts: without activating agent, with NaOH, and with KOH. The catalysts were characterized by XRD, SEM, EDX, AFM, and sorption of N2 methods. The activities of the obtained catalysts were tested in the oxidation of limonene to perillyl alcohol (the main product), carveol, carvone, and 1,2-epoxylimonene and its diol. In the oxidation processes, hydrogen peroxide was used as the oxidizing agent. This work has shown for the frst time that nanoporous carbons obtained from orange pulp waste, after separation of limonene, are active catalysts for limonene oxidation to industrially important value-added products.
Kopytko, Marta,Nikolchuk, Yulia,Urba, Svitlana,Darmits, Rostyslav International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.10
The main purpose of the study is to analyze the features of innovation and project management in the system of improving the performance of personnel as a factor in ensuring competitiveness and investment security. For the successful operation of enterprises, regardless of their form of ownership and field of activity, in order to carry out effective activities, they turn to innovative methods related to the formation of the potential of the workforce, and increasing the level of education and qualifications of staff and establishing their potential ability to make independent decisions. Based on the results of the study, the key features of innovation and project management in the system of improving the performance of personnel as a factor in ensuring competitiveness and investment security are characterized.
Material-Versatile Ultrabroadband Light Absorber with Self-Aggregated Multiscale Funnel Structures
Ryu, Yunha,Kim, Changwook,Ahn, Junmo,Urbas, Augustine M.,Park, Wounjhang,Kim, Kyoungsik American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.35
<P>Broadband light absorbers are essential components for a variety of applications, including energy harvesting and optoelectronic devices. Thus, the development of a versatile absorbing structure that is applicable in various operating environments is required. In this study, a material-versatile ultrabroadband absorber consisting of metal-coated self-aggregated Al<SUB>2</SUB>O<SUB>3</SUB> nanowire bundles with multiscale funnel structures is fabricated. A high absorptance of ∼0.9 over the AM 1.5G spectrum (300-2500 nm) is realized for absorbers with a range of metal coatings, including Al, W, and titanium nitride (TiN). We demonstrate that the plasmonic nanofocusing and index-matching effects of the funnel structure result in strong ultrabroadband absorption for the various metal coatings, even though the coating materials have different optical properties. As an example of applicability in an operating environment, in the evaluation of the thermal-oxidation resistance, the Al-coated solar absorber exhibits superior performance to those coated with refractory materials such as W and TiN because of the protective alumina layer formed on the Al surface.</P> [FIG OMISSION]</BR>
Hu, Dehua,Liu, Qing,Tisdale, Jeremy,Nam, Haerim,Park, Soo Young,Wang, Hsin,Urbas, Augustine,Hu, Bin Elsevier 2015 ORGANIC ELECTRONICS Vol.26 No.-
<P><B>Abstract</B></P> <P>This paper reports Seebeck effects from optically-induced intramolecular proton-transfer HPI-Cbz molecules based on vertical electrode/organic film/electrode thin-film devices. We observed large Seebeck coefficients of 428μV/K and 390μV/K from HPI-Cbz based thin-film devices at 60°C when proton-transfer was induced by the photoexcitation of a 325nm laser with an intensity of 12mW/cm<SUP>2</SUP> and 6mW/cm<SUP>2</SUP> respectively. Under dark condition without proton transfer occurring, the Seebeck coefficient was measured to be 342μV/K at 60°C. The Seebeck coefficient enhancement by the induced intramolecular charge transfer can be attributed to the enhanced polarization difference between high- and low-temperature surface due to the stronger electron–phonon coupling followed with the proton-transfer in HPI-Cbz under photoexcitation, and the strength of electron–phonon coupling is proportional to the photoexcitation intensity. The enhanced temperature-dependent electrical polarization between the high and low-temperature surfaces acts as an additional driving force to diffuse the majority charge carriers for the development of a large Seebeck effect. Therefore, using intramolecular proton-transfer presents an effective approach of enhancing Seebeck effect in organic materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Photoinduced proton-transfer states lead to enhancement on Seebeck coefficients. </LI> <LI> Photoinduced proton-transfer states lead to enhancement on electrical conductivity. </LI> <LI> Temperature-dependent polarization acts as a new driving force for Seebeck effect. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Oh Kim, Jun,Ku, Zahyun,Krishna, Sanjay,Kang, Sang-Woo,Jun Lee, Sang,Chul Jun, Young,Urbas, Augustine American Institute of Physics 2014 Journal of Applied Physics Vol.115 No.16
<P>We propose and analyze a novel detector structure for pixel-level multispectral infrared imaging. More specifically, we investigate the device performance of a grating-integrated quantum dots-in-a-well photodetector under backside illumination. Our design uses 1-dimensional grating patterns fabricated directly on a semiconductor contact layer and, thus, adds a minimal amount of additional effort to conventional detector fabrication flows. We show that we can gain wide-range control of spectral response as well as large overall detection enhancement by adjusting grating parameters. For small grating periods, the spectral responsivity gradually changes with parameters. We explain this spectral tuning using the Fabry-Perot resonance and effective medium theory. For larger grating periods, the responsivity spectra get complicated due to increased diffraction into the active region, but we find that we can obtain large enhancement of the overall detector performance. In our design, the spectral tuning range can be larger than 1 mu m, and, compared to the unpatterned detector, the detection enhancement can be greater than 92% and 148% for parallel and perpendicular polarizations. Our work can pave the way for practical, easy-to-fabricate detectors, which are highly useful for many infrared imaging applications. (C) 2014 AIP Publishing LLC.</P>