Improving cost-effectiveness for the furnace in a full-scale refinery plant with reuse of waste tail gas fuel

The waste tail gas fuel emitted from refinery plant in Taiwan e.g. catalytic reforming unit, catalytic cracking unit and residue desulfurization unit, was recovered and reused as a replacement fuel. In this study, it was slowly added to the fuel stream of a heater furnace to replace natural gas for powering a full-scale distillation process. The waste tail gas fuel contained on average 60 mol% of hydrogen. On-site experimental results show that both the flame length and orange-yellowish brightness decrease with increasing proportion of waste gas fuel in the original natural gas fuel. Moreover, the adiabatic flame temperature increases as the content of waste gas fuel is increased in the fuel mixture since waste gas fuel has a higher adiabatic flame temperature than that of natural gas. The complete replacement of natural gas by waste gas fuel for a heater furnace operating at 70% loading (i.e. 3.6 × 10⁷ kcal/h of combustion capacity) will save 5.8 × 10⁶ m³ of natural gas consumption, and 3.5 × 10⁴ tons (or 53.4%) of CO₂ emission annually. Recovering and reusing the waste tail gas fuel as natural gas replacement will achieve tremendous savings of natural gas usage and effectively lower the emission of carbon dioxide.     

Development of low‐fat mayonnaise containing polysaccharide gums as functional ingredients

BACKGROUND: The objective of this study was to develop a low‐fat (LF) mayonnaise containing polysaccharide gums as functional ingredients. Xanthan gum (XG, 15 g kg^?1), citrus fiber (CF, 100 g kg^?1) and variable concentration of guar gum (GG) were used to formulate the optimum ratios of polysaccharide gums as fat replacers. The fat content in LF mayonnaise was reduced to 50% if compared with full‐fat (FF) mayonnaise, and the products still maintained ideal rheological properties. RESULTS: The rheological parameters showed that there were no (P > 0.05) differences in yield stress, viscosity and flow behavior index between XG + 10 g kg^?1 GG, CF + 5 g kg^?1 GG and FF control. LF mayonnaises had lower caloric values and higher dietary fiber content than the FF counterpart. Scanning electron microscopy (SEM) micrographs illustrated that the network of aggregated droplets in LF treatments contained a large number of interspaced voids of varying dimensions. Furthermore, in a comparison of sensory evaluation of LF treatments with commercial and our FF mayonnaises, there were no (P > 0.05) differences in any sensory scores among XG + 10 g kg^?1 GG control. CONCLUSION: This study shows that XG + 10 g kg^?1 GG and CF + 5 g kg^?1 GG could be used in LF mayonnaise formulations based on its multiple functions on processing properties. Copyright © 2010 Society of Chemical Industry     

A Bibliometric Study of Semiconductor Literature, 1978–1997

Semiconductor is the key element for information industry. The present study investigated the growth of semiconductor literature based on the database of INSPEC. Well-established bibliometric techniques, such as Bradford-Zipf's plot and Lotka's law have been employed to further explore the characteristics of semiconductor literature. Quantitative results on the literature growth, form of publication, research treatment, publishing country and language, author productivity and affiliate are reported. Moreover, from the Bradford-Zipf's plot, 25 core journals in semiconductor were identified and analyzed.     

Soil dioxins levels at agriculture sites and natural preserve areas of Taiwan

In this study, agriculture soil in Taiwan has been sampled and analyzed to determine the background level of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DF) in the agricultural and nature preserve areas. Another objective is to investigate relationship between soil characteristics and air deposition in Taiwan. The results indicate that in nature preserve areas the topsoil shows an extraordinary profile of PCDD/DF compared to that in the air deposition. The PCDD/DF levels of the low-contaminated agricultural soils are compatible with those of the nature preserves soils. However, in the highly-contaminated agricultural soils, there is an abrupt jump in their concentrations, 10-100 times higher. The overall I-TEQ values of the background topsoils range from 0.101 to 15.2 ng I-TEQ/kg. Near industrial/urban areas in Taiwan the PCDD/DF are slightly higher compared to those in the low concentration group. Typically, the PCDD/DF background values found in this survey fall in the 90% confidence interval and can thus, be deemed the background levels in Taiwan. Ninety-five percent of these data are below the European and American soil standard of 10 ng I-TEQ/kg d.w. The PCDD/DF profile with one neighborhood soil sample was shown no significant difference.     

Memory representation of alphabetic position and interval information.

The authors conducted 3 sets of experiments. In the 1st set of experiments, participants made alphabetic position estimations. In the 2nd set, participants made interletter distance estimations. In the 3rd set, they made comparative judgments of the alphabetic order of a pair of letters. The results showed that participants had highly accurate ordinal level information about the alphabet in memory but that interval level information was systematically distorted. In addition, alphabetic serial information was found to be used in 2 distinct modes in memory, depending on whether the representation could be contained within the span of immediate memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

(Al/sub 0.5/Ga/sub 0.5/)/sub 0.65/In/sub 0.35/P/Ga/sub 0.65/In/sub 0.35/P double-heterostructure orange light-emitting diodes

Visible light-emitting diodes (LEDs) emitting at 615 nm and employing the AlGaInP/GaInP double heterostructure (DH) grown on a lattice-matched GaAs/sub 0.7/P/sub 0.3/ substrate have been fabricated for the first. The external quantum efficiency of 0.156% for the orange LEDs can be achieved by introducing the GaP material as the current spreader and window layer for the DH LEDs.<>     

Enhancing the output power of GaN-based LEDs grown on wet-etched patterned sapphire substrates

GaN-based light-emitting diodes (LEDs) with emitting wavelength of 450 nm were grown on patterned sapphire substrates (PSSs) fabricated by chemical wet etching. The crystallography-etched facet was {1-102} R-plane with a 57/spl deg/ against {0001} C-axis and had superior capability for enhancing light extraction efficiency. The light output power of the PSS LED was 1.15 times higher than that of the conventional LED at an injection current of 20 mA. The output power and external quantum efficiency were estimated to be 9 mW and 16.4%, respectively. The improvement was attributed not only to geometrical shapes of {1-102} crystallography-etched facets that efficiently scatter the guided light to find escape cones, but also to dislocation density reduction by adopting the PSS growth scheme.     

Organic light-emitting diode-based plausibly physiologically-friendly low color-temperature night light

Light sources with lower color temperature (CT) show markedly less suppression effect on the secretion of melatonin, an oncostatic hormone. Light sources with higher color rendering index (CRI) provide better visual comfort. In this report, we demonstrate the design and fabrication of low CT, high CRI fluorescent organic light-emitting diode (OLED) with five-band emitting from a single emissive layer. The best performed device exhibits a CT of 1773 K, much lower than that of candles (1800–2000 K) or incandescent bulbs (2000–2500 K), 87 CRI, a beyond theoretical limit external quantum efficiency (EQE) 6.4%, and 11.9 lm/W at 100 cd/m². One major reason for having the ultra-low CT and relative high CRI may be attributed to the significantly intensive deep red emission. The comparatively high efficacy and EQE may be attributed to the employment of a smooth stepwise energy-level structure, enabling low injection barriers and balance carrier injection.     

Two-dimensional scanning leaky-wave antenna by utilizing the phased array

An aperture-fed patch antenna array is connected to the open end of a short leaky-wave antenna (LWA) to demonstrate the two-dimensional beam-scanning capability in this paper. This design not only offers another radiation path of the reflected wave, but also creates another scanning radiation pattern on the back plane of the substrate. The reflected wave of the LWA is equally separated by a power divider, modulated by each varactor-tuned phase shifter, and injected into two radiating aperture-coupled antennas. The operated frequencies are tuned to control the LWA main position in the elevation plane; meanwhile, by tuning the phase difference between two phase shifters, the main beam of the aperture-coupled antenna array can be scanned in the backside E plane. Experimental result shows that the suppression of the reflected wave can be 7 dB at 10.0 GHz with a short LWA length of 6 cm (two wavelengths). The H-plane and backside E-plane scanning radiation patterns have great potential in many applications and provide more flexibility to traditional designs.