Novel application of an optical inspection system to determine the freshness of Scomber japonicus (mackerel) stored at a low temperature

Food Science and Biotechnology - This study evaluated the use of an optical inspection system (OIS) to determine the freshness of mackerel (Scomber japonicus). The correlations between the light...     

A nanoforest structure for practical surface-enhanced Raman scattering substrates

A nanoforest structure for surface-enhanced Raman scattering (SERS) active substrates is fabricated and analyzed. The detailed morphology of the resulting structure can be easily controlled by modifying the process parameters such as initial gold layer thickness and etching time. The applicability of the nanoforest substrate as a label-free SERS immunosensor is demonstrated using influenza A virus subtype H1N1. Selective binding of the H1N1 surface antigen and the anti-H1 antibody is directly detected by the SERS signal differences. Simple fabrication and high throughput with strong in-plane hot-spots imply that the nanoforest structure can be a practical sensing component of a chip-based SERS sensing system.     

Decomposition of 2-chlorophenol by supercritical water oxidation with zirconium corrosion

The 2-chlorophenol (2-CP) was oxidized in a continuous anti-corrosive supercritical water system. The variation of decomposition efficiency by the corrosion of zirconium 702 was also studied at the variation of feed concentration and reaction time. According to AES depth profile, the oxygen penetration depth to zirconium was not proportional to the exposure time. It might stem from the formation of zirconium oxide layer on the surface delaying the corrosion. However, the increase in feed concentration accelerated the corrosion of zirconium. The corrosion of zirconium at low feed concentration led to the improvement of decomposition efficiency due to the catalytic effect of formed zirconium oxides, while that at high feed concentration deteriorated the decomposition efficiency owing to large consumption of oxidant in corrosion.     

Development of a numerical analysis methodology for the multi-dimensional and multi-phase phenomena of a sodium–water reaction in an SFR steam generator

A numerical approach on the exothermic sodium–water reaction (SWR) in a SFR steam generator is carried out by using a commercial computational fluid dynamics (CFD) code. The applicability of the analysis models and the physical limitations of some codes was investigated to select the most powerful CFD code to simulate a chemically reacting flow with various phases and components. In order to model the phenomena, among the several chemical reaction models studied, the eddy dissipation model (EDM) was employed because the EDM is the proper one when the reaction rate is sufficiently high when compared to the flow transport time. Based on the basic understandings for the characteristics of the SWR phenomena and the capabilities of the CFD codes, the numerical analysis methodology for a SWR was developed and transient analyses up to 0.05 s and 0.1 s with a time step of 0.0001–0.0005 s were carried out with a consideration of the geometric effect. The vapor mass flow rate and the corresponding hydrogen production rate were also calculated and compared with the conventional one-dimensional analysis results. As a result, it was found that the multi-dimensional approach underestimates the hydrogen production rate by 17% when compared to the theoretical values, and the difference is mainly caused by a multi-dimensional effect of the chemical reaction. The analysis performed in this study presents detailed information on each phase and the components of the SWR process and it also reflects the realistic SWR phenomena well. In order to confirm the applicability of the methodology, a multi-dimensional analysis was also carried out for the 49 tube bundle condition, and it was found that the results of the analysis were satisfactory.     

Fabrication and scanning-angle temperature dependence of metal-based, optical resonant scanners with PZT actuation

Metal-based, optical scanning devices with a large mirror size of 1 mm(2) and a wide scanning angle of over 90 degrees were fabricated. A high optical scanning angle (90 degrees ) was achieved at a resonance frequency of 7.33 kHz and a driving voltage of 80 V (peak-to-peak) in ambient air without vacuum packaging. We compared the performance of metal-based, optical scanners driven by PZT bulk ceramic and aerosol-deposited PZT thick films over the temperature range from -20 degrees C to 80 degrees C in an environmental chamber.     

Melt complex viscosity and molecular weights for homo-polypropylene modified by grafting bifunctional monomers under electron beam irradiation

High melt viscosity polypropylene was manufactured by grafting bifunctional monomers, HDDA (1,6-hexanediol diacrylate) and TPGDA (tripropyleneglycol diacrylate), onto homo-polypropylene under an electron beam irradiation. Melt complex viscosity (η^∗) of modified polypropylene was sensitive to irradiation dose and monomer content. The melt viscosity of the polypropylene modified with TPGDA increased to 132,290 Pa s (at 190 °C and 0.1 rad/s of frequency) from 5039 Pa s for virgin homo-polypropylene. TPGDA monomer could give higher melt viscosity at low dosages than HDDA monomer, probably due to the structural feature of TPGDA with three numbers of methyl groups.Modified polypropylene with high melt complex viscosity had a broad molecular weight distribution with remarkable shift to higher molecular weight leading to high values of both and . Melt viscosity of modified polypropylene could be properly correlated by the equation , where the term gave a dominant effect for the estimation of η^∗.     

Verification and refinement of the one-dimensional analysis code for the integrated steam generators in an SFR

The thermal-hydraulic performance analysis code, ISGA (Integrated Steam Generator Analyzer) for the design of the integrated steam generator concept of double tube bundle steam generator (DTBSG), which is considered to eliminate a SWR possibility fundamentally in a sodium-cooled fast reactor, was developed for three candidate configurations of tube bundles; the integrated double region, integrated single region and radially separated bundle types. To verify the ISGA code and to confirm the viability of the concept, comparisons to experimental data have been carried out. The effects of properties deviation to total heat transfer rate are negligible through the sensitivity studies. General tendency of the temperature profiles seems to be reasonable for integrated type of the DTBSG. The multidimensional effects of the helical tube bundle which includes the entrance effect result in slight discrepancy. The calculated heat transfer rate curve shows a good agreement with the experimental data for the three types of DTBSGs. In the integrated type DTBSG, the convection heat transfer is less dominant for the heat transfer mechanism of the medium flow than in the radially separated type DTBSG. The feasibility of the three candidate DTBSG concepts was demonstrated and the validity of the 1-dimensional thermal-hydraulic analysis code ISGA was shown with comparisons to experimental data.     

Killing Effect of Ozone on House Dust Mites,the Major Indoor Allergen of Allergic Disease

This study examined whether ozone could kill house dust mites (HDMs), one of the most common causes of allergic diseases, and if an ozone application might be helpful in the environmental control of allergic patients. The experiments were performed in a small chamber (50 cm³), in which the continuous contact between the gaseous ozone and 40–60 live HDMs could be maintained during the reaction time (temperature=25°C and relative humidity=75%). Within the ozone range of 0.19–10.62% (v/v), the higher concentration dose resulted in a more rapid inactivation of the live HDMs. The CT value of ozone showed a linear relationship with the inactivation efficiency (%) of the live HDMs. From our results, it was found that a CT value 400 mg-min/L was required to obtain an almost 100% removal efficiency of the 40–60 live HDMs.     

Characterization of carbonaceous particulate matter emitted from marine diesel engine

In an effort to aid the Korean ship-building industry to effectively respond to the upcoming environmental regulations, a series of experimental campaigns to characterize carbonaceous Particulate matters (PMs) emitted from a cruising marine ship have been carried out. To this end, the carbonaceous PMs emitted from two-stroke marine-diesel engines burning Bunker B (Low residual fuel oil, LRFO 3%) were sampled on-board at various locations: 1) After the turbo charger (TC), 2) before the economizer (ECO), 3) after the economizer, and 4) in the funnel of the chimney. Sampled carbonaceous PM particles were then analyzed using a High-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. Results obtained from the analysis of HRTEM images and Raman spectra indicate that carbonaceous PMs are mainly fractionated into Black carbon (BC) and Organic carbon (OC), respectively and the each fraction of sampled carbonaceous PMs varies with engine operation conditions and exhaust gas temperatures at the sampling location. The present work is anticipated to provide a useful set of information for characterizing carbonaceous PMs emitted from marine diesel engines.