Pressure fluctuation properties in combustion of mixture of anthracite and bituminous coal in a fluidized bed

The combustion characteristics of a mixture of anthracite and bituminous coal were studied in a 0.155 m i.d. fluidized bed combustor (FBC). The properties of the pressure fluctuation for the bed such as the standard deviation, cross-correlation function, dominant frequency and the power spectral density function were obtained through statistical analysis. To interpret the combustion characteristics in the FBC with uniform or multi-sized particles of anthracitebituminous coal mixture, the properties of pressure fluctuation were determined as a function of the particle size distribution and anthracite mixing fraction. In the present work, it is known that the combustion region could be obtained from the analysis of pressure fluctuation properties, and the mixed-firing of anthracite-bituminous coal is related to the reaction models of both coals and particle size distribution. Moreover, the relation between coal size distribution and static mean pressure, and the ignition region could be obtained from the mean pressure profile.     

Inhibiting Invasion into Human Bladder Carcinoma 5637 Cells with Diallyl Trisulfide by Inhibiting Matrix Metalloproteinase Activities and Tightening Tight Junctions

Diallyl trisulfide (DATS), an organosulfur compound in garlic, possesses pronounced anti-cancer potential. However, the anti-invasive mechanism of this compound in human bladder carcinoma is not fully understood. In this study, we evaluated the anti-invasive effects of DATS on a human bladder carcinoma (5637) cell line and investigated the underlying mechanism. The results indicated that DATS suppressed migration and invasion of 5637 cells by reducing the activities and expression of matrix metalloproteinase (MMP)-2 and MMP-9 at both the protein and mRNA levels. DATS treatment up-regulated expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in 5637 cells. The inhibitory effects of DATS on invasiveness were associated with an increase in transepithelial electrical resistance and repression of the levels of claudin family members. Although further studies are needed, our data demonstrate that DATS exhibits anti-invasive effects in 5637 cells by down-regulating the activity of tight junctions and MMPs. DATS may have future utility in clinical applications for treating bladder cancer.     

Multi-physics analysis on a unimorphic piezoelectric diaphragm according to its shape and boundary conditions for the performance enhancement

A micro-viscometer for measuring viscosity change in small amount of liquid in real time has been proposed recently. The advantages of the device are the use of minimal liquid and maximized sensitivity for measuring viscosity. However, in previous research, even though the multi-physical simulation including electrical, mechanical, and acoustical phenomenon is necessary for design of micro-viscometer, only acoustical aspects have been considered. Thus, combined physical phenomena could not be reflected for an optimum design process. In this research, a multi-physical approach is developed for designing a micro-viscometer, and an optimized micro-viscometer design is proposed. The proposed method is able to capture multi-physical phenomena such as near field effect and added mass effect. It also has the advantage of flexible design of various shape and materials, leading to savings of cost and time.     

Identification and Field Evaluation of Grape Shoot Volatiles Attractive to Female Grape Berry Moth (<Emphasis Type="Italic">Paralobesia viteana</Emphasis>)

Solid-phase microextraction (SPME) and gas chromatography coupled with electroantennographic detection (GC-EAD) were used to identify volatile compounds from shoots of riverbank grape (Vitis riparia) that attract the female grape berry moth (GBM, Paralobesia viteana). Consistent EAD activity was obtained for 11 chemicals: (Z)-3-hexen-1-yl acetate, (E)-linalool oxide, (Z)-linalool oxide, nonanal, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene, methyl salicylate, decanal, beta-caryophyllene, germacrene-D, and alpha-farnesene. In flight-tunnel tests that involved female GBM and rubber septa loaded with subsets of these 11 compounds, we found that both the 11-component blend and a seven-component blend, composed of (E)-linalool oxide, (Z)-linalool oxide, nonanal, (E)-4,8-dimethyl-1,3,7-nonatriene, decanal, beta-caryophyllene and germacrene-D, elicited equivalent levels of upwind flight as freshly cut grape shoots. The removal of any of the seven compounds from the seven-component blend resulted in a significant decrease in female upwind flight responses. In a field trial with these two synthetic blends, traps equipped with either blend captured more female GBM compared to traps baited with hexane only (control), although the number of females caught was generally low. There were no differences in the number of males captured among treatments. Although in flight-tunnel trials, moths readily flew upwind to both grape shoots and rubber septa loaded with the best lures, they landed on shoots but not on rubber septa. Coupled with relatively low field catches, this suggests that additional host finding cues need to be identified to improve trap efficacy.     

Continuous photo-fermentative hydrogen production from lactate and lactate-rich acidified food waste

In the present work, a continuous photo-fermentative hydrogen (H₂) production from lactate was attempted at various hydraulic retention times (HRTs) (48–120 h). Electron balance was made at each operating conditions to elucidate different performances. At 120 h HRT, H₂ production was negligible, while 42% and 52% of substrate electrons diverted towards cell growth and soluble microbial products (SMPs), respectively. After changing HRT to 96 h, H₂ yield jumped to 2.3 mol-H₂/mol-lactate_added with less SMPs production and minimal cell growth. The highest H₂ production rate of 260 mL-H₂/L-fermenter/d was also achieved at 96 h HRT. When HRT was further shortened to 72 and 48 h, H₂ yield dropped to 1.4 and 0.2 mol-H₂/mol-lactate_added, respectively. While almost all of the lactate was degraded at <72 h HRT, only 65% of the lactate was consumed at 48 h HRT. From 200th day, the feedstock was changed to lactate-rich acidified food waste, which was obtained via one-day fermentation of food waste and subsequent centrifugation. At 2 g chemical oxygen demand/L, substrate conversion efficiency reached 35%, which was slightly lower than that of feeding pure lactate. SMPs were found to be mainly consisted of low molecular weight compounds (<500 Da), and the majority of organic matters were aromatic proteins at 120 h HRT and it was shifted to humic-like region in 96 h HRT.     

A three-phase current-fed dc/dc converter with a three-leg high frequency transformer for fuel cells

In this paper, a three-phase current-fed dc/dc converter with an active clamp is introduced, and a new three-phase three-leg high frequency transformer is proposed for the converter. The three-phase dc/dc converter transfers power through transformer leakage inductances in the discontinuous current mode; a single common active clamp branch is employed for zero-voltage switching (ZVS) in all active switches. Further, the converter's three-phase power configuration increases power transfer, and it reduces the rms current per phase, thus reduces conduction losses. Moreover, a delta–delta connection on the three-phase transformer provides parallel current paths and reduces conduction losses in the transformer windings. A three-phase transformer can be constructed by connecting three discrete single-phase transformers, but this process results in a higher volume and higher material costs. Therefore, a new three-phase three-leg high frequency transformer is designed with three discrete cores integrated into a single transformer core. The proposed transformer is analyzed according to the several operating modes of the converter, and its design rules are determined. Experimental results are obtained on a 500-W prototype unit; the design is fully verified and analyzed.     

Mixing–segregation phenomena of binary system in a fluidized bed

A study on mixing–segregation phenomena in a gas fluidized bed of binary density system was performed by analysis of the residence time distribution and mixing degree. The effect of particle mixing on the residence time distribution and solid mixing was studied in a binary particle system with different densities. Residence time distribution curve and mean residence time of each particle were measured according to the flotsam particle size, mixing ratio and gas velocity in a gas fluidized bed (0.109 m I.D., 1.8 m height). The characteristics of residence time distribution and the deviation of mean residence time of each particle are consistent with previous mixing index based on the axial concentration of jetsam. From this study, mixing index of binary particle system with different densities should be considered by not only axial concentration distribution of jetsam particle but also characteristics of residence time distribution. This result suggests that the solid movement by fluidization gas is more important than solid axial dispersion.