Thermochemical recuperation of exhaust gases heat can be a promising way to save energy when it comes to high-temperature plants heated by natural gas, for example glass melting furnaces. This ...technology can help to save up to 10–25% of energy without affecting other parameters of the process.
Schemes of glass melting furnaces with various options for thermochemical recuperation were simulated using Mathcad code and Aspen Plus code. It is shown that the dependence of specific primary energy consumption on the volume fraction of recirculated exhaust gases used as an oxidant for the reforming process is non-monotonic and has a minimum at the range of values 0.19–0.22 of mentioned volume fraction.
Determination of the oxidant flow coefficient for the reforming process for all considered options of thermochemical recuperation were suggested, as well as method of that calculation. In the industrial plant with reforming based on the recirculated exhaust gases transition to the optimal value of this coefficient (close to 1.00) is considered to be energy-saving, which reduces fuel consumption by 16% and reduces environmental pollution.
Use of economic evaluation of environmental pollution will allow to choose the scheme of thermochemical recuperation more efficiently.
•Study of glass furnaces with options of thermochemical recuperation was performed.•The method of calculation the oxidant flow coefficient for the reforming process.•A technique of ensuring minimum of the primary energy consumption.
We synthesised a new type of photochromic tungsten oxide nanoparticles, analysed their photocatalytic activity and carried out a thorough analysis of their effect on prokaryotic and eukaryotic ...organisms. Ultrasmall hydrated tungsten oxide nanoparticles were prepared by means of hydrothermal treatment of tungstic acid in the presence of polyvinylpyrrolidone as a template, stabiliser and growth regulator. Tungstic acid was synthesised through an ion-exchange method using sodium tungstate solution and a strongly acidic cation exchange resin.
Upon illumination, photochromic nanoparticles of WO3 were shown to increase greatly their toxicity against both bacterial (both gram-positive and gram-negative – P. aeruginosa, E. coli and S. aureus) and mammalian cells (primary mouse embryonic fibroblasts); under the same conditions, fungi (C. albicans) were less sensitive to the action of tungsten oxide nanoparticles. UV irradiation of primary mouse fibroblasts in the presence of WO3 nanoparticles demonstrated a time- and dose-dependent toxic effect, the latter leading to a significant decrease in dehydrogenase activity and an increase in the number of dead cells. WO3 nanoparticles were photocatalytically active under both UV light and even diffused daylight filtered through a window glass, leading to indigo carmine organic dye discolouration.
The obtained experimental data not only show good prospects for biomedical applications of tungsten trioxide, but also demonstrate the need for clear control of biosafety when it is used in various household materials and appliances.
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•Photochromic WO3 nanoparticles were synthesised using ion-exchange method.•UV increased toxicity of WO3 nanoparticles against bacterial and mammalian cells.•WO3 nanoparticles were photocatalytically active under UV-illumination.
Bismuth-based compounds are considered to be the best candidates for computed tomography (CT) imaging of gastrointestinal (GI) tract due to high X-ray absorption. Here, we report the introduction of ...polymer-coated bismuth oxychloride (BiOCl) nanosheets for highly efficient CT imaging in healthy mice and animal with colitis. We demonstrate simple, low cost and fast aqueous synthesis protocol which provides gram-quantity yield of chemically stable BiOCl nanosheets. The developed contrast gives 2.55-fold better CT enhancement compared to conventional contrast with negligible in vivo toxicity. As a major finding we report a regioselective CT imaging of GI tract by using nanoparticles coated with differentially charged polymers. Coating of nanoparticles with a positively charged polymer leads to their fast accumulation in small intestine, while the coating with negatively charged polymers stimulates prolonged stomach retention. We propose that this effect may be explained by a pH-controlled aggregation of nanoparticles in stomach. This feature may become the basis for advancement in clinical diagnosis of entire GI tract.
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We demonstrate continuous wave supercontinuum generation extending to the visible spectral region by pumping photonic crystal fibers at 1.07 microm with a 400 W single mode, continuous wave, ...ytterbium fiber laser. The continuum spans over 1300 nm with average powers up to 50 W and spectral power densities over 50 mW/nm. Numerical modeling and understanding of the physical mechanisms has led us to identify the dominant contribution to the short wavelength extension to be trapping and scattering of dispersive waves by high energy solitons.
We present a measurement of R_{K^{*}}, the branching fraction ratio B(B→K^{*}μ^{+}μ^{-})/B(B→K^{*}e^{+}e^{-}), for both charged and neutral B mesons. The ratio for the charged case R_{K^{*+}} is the ...first measurement ever performed. In addition, we report absolute branching fractions for the individual modes in bins of the squared dilepton invariant mass q^{2}. The analysis is based on a data sample of 711 fb^{-1}, containing 772×10^{6} BBover ¯ events, recorded at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. The obtained results are consistent with standard model expectations.
We report the fabrication of photonic crystal fibers with a continuously-decreasing zero-dispersion wavelength along their length. These tapered fibers are designed to extend the generation of ...supercontinuum spectra from the visible into the ultraviolet. We report on their performance when pumped with both nanosecond and picosecond sources at 1.064 microm. The supercontinuum spectra have a spectral width (measured at the 10 dB points) extending from 0.372 microm to beyond 1.75 microm. In an optimal configuration a flat (3 dB) spectrum from 395 to 850 nm, with a minimum spectral power density of 2 mW/nm was achieved, with a total continuum output power of 3.5 W. We believe that the shortest wavelengths were generated by cascaded four-wave mixing: the continuous decrease of the zero dispersion wavelength along the fiber length enables the phase-matching condition to be satisfied for a wide range of wavelengths into the ultraviolet, while simultaneously increasing the nonlinear coefficient of the fiber.
In this study, we experimentally determined the local drag coefficient (LDC) of a round exhaust hood that was improved with different shaped inlet sections along the boundaries of the vortex zones ...occurring in the flow at the inlet of an exhaust hood. The LDC measurements were performed using two methods. The first method used a micromanometer and pneumometric tube to determine the LDC with and without considering frictional losses. Meanwhile, the second method determined the LDCs using the pressure and velocity distributions in the boundary layer with specially designed pressure miniprobes. The experimental and numerical results show that it is possible to achieve a drag reduction of more than 90% by shaping the inlet edges of the exhaust hood. This increases the range of contaminant capture, reduces noise, and prevents contaminants from escaping from the exhaust hood by eliminating the vortex zones and reducing the fan power.
•Two designs of shaped exhaust hoods have been set up.•Local drag coefficients have been determined experimentally for exhaust hoods.•Numerical computations are compared with experimental measurements.•We show that shaping increases the capture range of an exhaust hood.•Shaped exhaust hoods reduce fan power consumption.
Semiconductors are considered as promising materials for the criating of new photo-sensors. The photons generated by a KrF laser source (λ = 248 nm, τ
FWHM
≤ 25 ns) at a fluency of 3.5 and 4.5 J/cm
...2
were used for the synthesis of hybrid Fe/Cr 2D structures via the reaction of ablated iron and chromium atoms from combined target Fe/Cr with oxygen molecules (O
2
) by reactive pulsed laser deposition (RPLD) process. Hybrid Fe/Cr 2D structures of (50–100) nm thickness were deposited on 293 or 800 K on < 100 > Si substrates in O
2
atmosphere of 0.1, 0.5 Pa. GIXD (grazing incident X-ray diffraction) analysis evidenced amorphous structures of the deposits. Element analysis was carried out by energy dispersive X-ray spectroscopy (EDXS). Semiconductor temperature trend was detected with variable energy band gap (
E
g
) in the range of (0.38–0.86) eV depending on the substrate temperature, O
2
pressure, hybrid Fe/Cr 2D structure thickness, and laser fluencies for atoms’ ablation. The highest photosensitivity of these hybrid Fe/Cr 2D structures was high as 300 V/W in the range of (293–800) K. The influence of hybrid Fe/Cr parameters structures’ synthesised with laser radiation on their photosensitivity was investigated. An interpretation for such high photosensitivity was provided. Thus synthesised 2D structures are exceptionally advanced materials for creation of photo-sensors operating at moderate temperatures.
29 W High power CW supercontinuum source Cumberland, B A; Travers, J C; Popov, S V ...
Optics express,
2008-Apr-14, 2008-04-14, 20080414, Letnik:
16, Številka:
8
Journal Article
Recenzirano
Odprti dostop
A 29 W CW supercontinuum spanning from 1.06 to 1.67 microm is generated in a short length of PCF with two zero dispersion wavelengths. The continuum has the highest spectral power density, greater ...than 50 mW/nm up to 1.4 microm, reported to date. The use of a short length of PCF enables the continuum to expand beyond the water loss at 1.4 microm. The dynamics of the continuum evolution are studied experimentally and numerically with close attention given to the effects of the water loss and the second zero dispersion wavelength.
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