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In this study, (Na,K,Li)(Nb,Sb,Ta)O3 ceramics substituted with (Sr,Ca)ZrO3 by conventional solid state method were manufactured and their dielectric and piezoelectric properties were investigated. The (Na,K,Li)(Nb,Sb,Ta)O3 ceramics substituted with 0.01 (Sr,Ca)ZrO3 showed excellent piezoelectric properties. The density(ρ), piezoelectric constant(d33), and the piezoelectric voltage constant (g33), planar piezoelectric coupling coefficient(kp), mechanical quality factor(Qm), and dielectric constant(εr) showed the excellent values of 4.55 g/cm3, 254pC/N, 26.17(×10−3 Vm/N) 0.46, 156, and 1096, respectively. The multilayer piezoelectric energy harvester was fabricated using the above composition ceramics by tape casting methods. When driving frequency was 80 Hz under gravity acceleration 1G, the multilayer energy harvester with the size of 30 mm ×3 mm ×1 mm showed the maximum output voltage of 1.1V at no load. And the maximum output power 3.28 µW of the harvester was also shown at the 50 Hz under gravity acceleration 1G. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the treatment efficiency of UV/TiO2 and UV/TiO2/chemical oxidant processes for the removal of humic acid and hazardous heavy metals in aqueous TiO2 suspensions. The reaction rate (k) of humic acid and hazardous heavy metals by UV/TiO2 was higher than that of UV illumination alone or TiO2 alone. The removal efficiency for humic acid and Cr(VI) at acid or neutral pH values was higher than that at basic pH values. However, the removal efficiency for Cu(II) at acid pH values was smaller compared with that at neutral or basic pH values. The reaction rate (k) of humic acid and hazardous heavy metals in the TiO2 concentration range of 0.1-0.3 g l-1 increased with increasing TiO2 dosage. However, amounts higher than a TiO2 dosage of 0.3 g l-1 reduced the removal efficiency for humic acid and hazardous heavy metals because of the shielding effect on the UV light penetration in the aqueous solution caused by the presence of excessive amounts of TiO2. The addition of oxidants to the UV/TiO2 system showed an increase in degradation efficiency for the treatment of humic acid and hazardous heavy metals. The optimal concentration of oxidants was: H2O2 50 mg l-1, O3 20 g m-3 and K2S2O8 50 mg l-1, respectively. The degradation efficiency of UV/TiO2/oxidant systems for the removal of humic acid and hazardous heavy metals was much greater when H2O2 was used as the oxidant. [ABSTRACT FROM AUTHOR]

The concept of solids retention time (SRT) was used for describing the growth of biofilm in a biological aerated filter (BAF) system. The SRT profile was obtained from the change in solids accumulation, estimated from the head loss profile data before and after backwash using the Carmen-Kozeny equation. The SRT profile along the filter bed depth showed the SRT of about 2 days for the lower layer and about 6 days for the upper layer. The overall SRT was determined by the direct estimation of excess solids mass during backwash and of solids retained in the filter bed. The ideal characteristic SRT distribution was maintained by regular backwash, for organic removal and nitrification. The SRT for high organic removal and nitrification is demonstrated by the SRT distribution along the filter bed in this BAF process. [ABSTRACT FROM AUTHOR]

Nitrogen and phosphorus compounds, mainly from the households in residential areas are responsible for eutrophication occurring in lakes or estuaries. In Korea, there is a growing trend for villages in the countryside, rest areas of express ways, military unit bases, etc. to use small scale sewage treatment plants (SSTPs). However, the technological developments have mainly focused on medium or large scale sewage treatment plants, leaving a gap in the development of technologies for SSTPs without a residing operator. In this study, a soil-covered sequencing batch reactor (SBR) process for SSTPs in combination with a natural purification technology is developed to remove nitrogen and phosphorus as well as organic contamination (BOD), and the results are as follows: (1) the removal rates of BOD, total nitrogen (T-N), total phosphorus (T-P) and suspended solids (SS) are 93%, 74%, 80% and 95%, respectively, (2) the soil-covered SBR process without the decanter used for effluent discharge is similar to other SBR processes in suspended solids removal rate, and (3) the performance of the field pilot plant was monitored by remote sensing system in real time, and the results show that this system can be applied to SSTPs with no residing operators. [ABSTRACT FROM AUTHOR]

The shortcut biological nitrogen removal (SBNR) hybrid (suspended cells combined with attached cells) process is an innovative technology that nitrosofies ammonium to nitrite and then denitrifies nitrite to nitrogen gas. Theoretically, this results in a 25% savings of the oxygen needed for nitrification and a 40% of savings in carbon source needed for denitrification. In this study, the influences of free ammonia (FA) and dissolved oxygen (DO) concentrations on nitrite accumulation were investigated to find the optimal operational factors for stable nitrite accumulation over a long period. The maximum specific utilization rates for ammonium (qa) and nitrite (qn) were determined for suspended and attached cells taken from a bench-scale SBNR reactor and a pilot-scale livestock wastewater treatment plant reactor. For the ammonium and nitrite oxidations in both reactors, the attached cells were more resistant to the FA concentration, but were more significantly influenced by the DO concentration than the suspended cells. In addition, the effect of the DO concentration was more significant than that of the FA concentration for both types of cells from both reactors. In this SBNR hybrid system, a simultaneous manipulation of DO concentration (<1.5 mg l-1) and FA concentration (10-20 mg l-1) was required for maintaining high levels of nitrite accumulation. [ABSTRACT FROM AUTHOR]

The metal injection mold (MIM) process is the most cost effective, highest quality means to produce complex shaped, high performance parts. In the MIM process, debinding is a key step for successful MIM. However, the conventional debinding processes, which are thermal debinding and solvent debinding, have disadvantages that include long product development times, and harm to the environment. Therefore, the study of supercritical CO2 that can be used as solvent for debinding, a new debinding technology as substitute for a conventional technology, was considered. In this paper, we used two methods to investigate a method for reducing debinding time as well as lowering operation condition other than pure supercritical CO2 debinding: the first method was to add cosolvent in supercritical CO2, the second method was to use the mixture of propane + CO2, as the supercritical solvent. It was found that the addition of cosolvents and the use of binary mixture propane + CO2 for supercritical solvent remarkably improved the binder removal rate, in comparison with using pure supercritical CO2. [ABSTRACT FROM AUTHOR]

Though the concentration of serum lipoprotein(a) [Lp(a)] is mostly determined by genetic factors, secondary factors such as acute-phase response (APR) and end-stage renal disease (ESRD) also contribute to its increase. Lp(a) is known to be one of the acute-phase reactants and interleukin-6 (IL-6) is the key cytokine in the hepatic synthesis of acute-phase proteins. The serum concentrations of Lp(a) and IL-6 were measured in patients with APR and in patients with ESRD to investigate the relationship between Lp(a) and IL-6. A total of 180 patients were selected for the study: 60 patients were normal controls, 60 were patients with renal disease who had been on hemodialysis for more than 6 months [C-reactive protein (CRP)<4.0 mg/L], and 60 were APR patients who had a erythrocyte sedimentation rate (ESR) of over 50 mm/h. The three groups were age- and sex matched. The serum concentrations of Lp(a) and IL-6 were measured by ELISA. The serum concentrations of Lp(a) [median (interquartile range)] in normal controls, ESRD patients, and APR patients were 0.222 (0.103-0.364) g/L, 0.511 (0.308-0.755) g/L, and 0.546 (0.234-0.747) g/L, respectively; those of IL-6 were 1.0 (0.7-1.3) pg/mL, 2.1 (1.4-3.3) pg/mL, and 26.2 (15.2-35.6) pg/mL. The concentration of IL-6, which increases Lp(a) synthesis, was much lower in ESRD patients than in APR patients (p<0.001). However, there were no significant differences in Lp(a) concentration between the two groups (p=0.88). In APR patients, the increase in Lp(a) synthesis seems to play a significant role in the increase in blood Lp(a), but there might be different mechanisms that regulate the increment of serum Lp(a) concentrations in ESRD patients other than synthesis of Lp(a). [ABSTRACT FROM AUTHOR]