Search results for "conversion"
showing 10 items of 707 documents
Boosting Long-Term Stability of Pure Formamidinium Perovskite Solar Cells by Ambient Air Additive Assisted Fabrication
2021
Due to the high industrial interest for perovskite-based photovoltaic devices, there is an urgent need to fabricate them under ambient atmosphere, not limited to low relative humidity (RH) conditions. The formamidinium lead iodide (FAPI) perovskite α-black phase is not stable at room temperature and is challenging to stabilize in an ambient environment. In this work, we show that pure FAPI perovskite solar cells (PSCs) have a dramatic increase of device long-term stability when prepared under ambient air compared to FAPI PSCs made under nitrogen, both fabricated with N-methylpyrrolidone (NMP). The T80 parameter, the time in which the efficiency drops to 80% of the initial value, increases f…
Energy conversion efficiency in betavoltaic cells based on the diamond Schottky diode with a thin drift layer
2020
The HPHT diamond Schottky diode was assembled as a Metal/Intrinsic/p-doped structure betavoltaic cell (BC) with a very thin (1 μm) drift layer and tested under 5–30 keV electron beam irradiation using a scanning electron microscope (SEM). The effect of the β-radiation energy and the backscattering of electrons on the energy conversion was studied. From the results obtained, it is shown that, the efficiency of the investigated BC increases from 1.01 to 3.75% with the decrease of β-particle energy from 30 to 5 keV due to an increase of the electron beam absorption in a thin drift layer. Maximum efficiency is achieved when the electron beam energy is close to the average β-decay energy of 3H. …
Effects of soybean meal based diet on growth performance, gut histopathology and intestinal microbiota of juvenile rainbow trout (Oncorhynchus mykiss)
2006
Abstract Effects of soybean meal (SBM) based diet on growth performance, histology of the intestinal epithelium and on the gut microbiota of juvenile rainbow trout (Oncorhynchus mykiss) were investigated on two trials lasting for 8 weeks (Trial I) and 18 weeks (Trial II). The microbiological characterization was done both with conventional plating techniques, biochemical profiling and length heterogeneity analysis of PCR amplified 16S rDNA (LH-PCR). Typical histological changes were found after 18 weeks of SBM feeding (Trial II). Mean height of simple foldings were significantly higher within the group fed with fish meal (FM) based diet. These changes were not, however, reflected in the app…
Bacterial Bioconversion of Primary Aliphatic and Aromatic Alcohols into Acids: Effects of Molecular Structure and Physico-chemical Conditions
1997
The biotransformation of four alcohol substrates (butanol, 2-methylbutanol, 3-methylbutanol and 2-phenylethanol) into their acids was studied using a strain of Acetobacter aceti. Bioconversion yields depended on the molecular structure of the alcohol. Biotransformation of high concentrations of alcohols was possible until the precursor reached an inhibiting concentration (3.8 g dm -3 for butanol and 3-methylbutanol, 4.2 g dm -3 for 2-methylbutanol). In contrast, biotransformation of 2-phenylethanol decreased when alcohol concentration was higher than 0.3 g dm -3 . Dissolved oxygen concentrations and pH conditions of the medium were important factors in improving bioconversion. Transformatio…
The effect of the length of repeated feed deprivation between single meals on compensatory growth of pikeperch Sander lucioperca
2009
Abstract Juvenile pikeperch ( Sander lucioperca ) were reared for 58 days according to one of the following feeding regimes: control (fed once every day); 1 + 1 (fed every other day); 1 + 3 (one-day feeding followed by a three-day feed deprivation); and 1 + 6 (fed once a week). Control fish had significantly higher growth rate than the 1 + 3 and 1 + 6 fish, and consequently the final weight of the controls (125.2 ± SD 30.0 g, n = 4) was higher than that of the 1 + 3 (84.0 ± 17.9 g) and 1 + 6 fish (64.7 ± 7.2 g). Fish in the treatment groups were capable to compensate for the reduced number of feedings by increasing intake relative to the controls when feed was available. This hyperphagic r…
Imidazolium-Functionalized Carbon Nanohorns for the Conversion of CO2 Unprecedented Increase of Catalytic Activity after Recycling
2017
Carbon nanohorns (CNHs) were selected as a novel catalytic platform for the design of imidazolium based hybrid materials able to promote the conversion of carbon dioxide into cyclic carbonates. Several heterogeneous catalysts were prepared using a one-step procedure based on the radical polymerization of various bis-vinylimidazolium salts in the presence of pristine CNHs. The as-synthesized materials were tested for the fixation of CO2 into epoxides. The excellent catalytic performances were evaluated in terms of turnover number and productivity. The versatility of the above hybrids was proved using several epoxides as substrate. Catalysts recyclability was successfully verified for several…
Design of POSS-Imidazolium Supported Hybrids for the Conversion of Carbon Dioxide into Cyclic Carbonates
2018
Nowadays, the design of heterogeneous catalysts for the conversion of CO2 into useful chemical products is attracting the attention of the scientific community. The catalytic processes involving carbon dioxide as C1 feedstock are of growing interest for the sustainable development.1 The synthesis of cyclic carbonates by coupling CO2 with epoxides is one of the most interesting pathways for the conversion of carbon dioxide in terms of both atom economy and final products applications. Moreover, ionic liquids emerged as one of the most active catalysts for the production of cyclic carbonates starting from CO2 and epoxides.2 Herein, a series of heterogeneous catalytic systems bearing imidazoli…
Imidazolium Based Cross-Linked Nanostructures from POSS molecular bricks for the Efficient Conversion of Carbon Dioxide
2019
Polyhedral oligomeric silsesquioxanes (POSS) have been employed as molecular bricks for the synthesis of imidazolium cross-linked networks as heterogeneous catalyst for the conversion of carbon dioxide into cyclic carbonates via reaction with epoxides. Two hybrid materials with different nucleophilic species (bromide and iodide) have been prepared and characterized by means of elemental analysis, 13C and 29Si solid state NMR, thermogravimetric analysis and IR spectroscopy. The solids were tested as the sole catalyst under metal- and solvent-free reaction conditions showing full selectivity toward the formation of cyclic carbonates and outstanding productivity values. Several epoxides were r…
Materiali ibridi a base di POSS-Imidazolio per la conversione della CO2 in carbonati ciclici
2018
Lo sviluppo di catalizzatori per i processi di conversione della CO2 è una tematica che sta rivestendo un ruolo di rilevante importanza in ambito non soltanto accademico ma anche industriale grazie alla possibilità di trasformare un rifiuto, quale il diossido di carbonio, in una vasta gamma di prodotti. Nel presente lavoro, nuovi materiali ibridi costituiti da silsesquiossani poliedrici oligomerici (POSS) supportati su silice e funzionalizzati con sali di imidazolio sono stati progettati per la fissazione della CO2. 1 Tutti i solidi sono stati ampiamente caratterizzati e testati per la sintesi di carbonati ciclici tramite reazione tra CO2 ed epossidi in condizioni di reazione solvent-free (…
Color Conversion Light-Emitting Diodes Based on Carbon Dots: A Review
2022
This paper reviews the state-of-the-art technologies, characterizations, materials (precursors and encapsulants), and challenges concerning multicolor and white light-emitting diodes (LEDs) based on carbon dots (CDs) as color converters. Herein, CDs are exploited to achieve emission in LEDs at wavelengths longer than the pump wavelength. White LEDs are typically obtained by pumping broad band visible-emitting CDs by an UV LED, or yellow–green-emitting CDs by a blue LED. The most important methods used to produce CDs, top-down and bottom-up, are described in detail, together with the process that allows one to embed the synthetized CDs on the surface of the pumping LEDs. Experimental results…