Cooling of multichip light emitting diode with ultra-high power—An application of bypass cooling from an air-conditioning system

This study focuses on the use of indium gallium nitride multichip for ultra-high power light emitting diode (LED) heat transfer and thermal cooling analysis. This research approach is based on the multichip LED experimental study of aluminum extrusion heat sink and air-conditioning system-forced cooling approach. An investigation of heat transfer characteristics of the phenomenon of variation is conducted to improve performance and develop an LED system that can become a reference guideline for thermal design and assembly. This study’s package structure can use silicon substrate material and fill copper material to increase thermal conduction. An air-conditioning system bypass cooling approach is also used. This study aims to help to increase LED thermal cooling, long life, reliability, and reduce the optic lumen decay phenomenon in the future. Results are based on different power ratings that can be used to redefine LED classifications.     

Partitioning of arsenic in soil-crop systems irrigated using groundwater: a case study of rice paddy soils in southwestern Taiwan

The accumulation of As in rice due to groundwater irrigation in paddy fields represents a serious health hazard in South and Southeast Asia. In Taiwan, the fate of As in long-term irrigated paddy fields is poorly understood. Groundwater, surface soil, and rice samples were collected from a paddy field that was irrigated with As-containing groundwater in southwestern Taiwan. The purpose of this study is to elucidate the source and sink of As in the paddy field by comparing the As fractions in the soils that were obtained by a sequential extraction procedure (SEP) with the As uptake of rice. The risks associated with eating rice from the field can thus be better understood. The concentration of As in groundwater varied with time throughout the growing seasons of rice, but always exceeded the permitted maximum (10 μg L⁻¹) for drinking water by the WHO. The As concentration increased with the concentration of Fe in the groundwater, supporting the claim that a large amount of As was concentrated in the Fe flocs collected from the internal wall of the groundwater pump. The results of the SEP revealed that As bound with amorphous and crystalline hydrous oxides exhibited high availability in the soils. The root of rice accumulated the largest amount of As, followed by the straw, husk, and grain. Although the As concentration in the rice grain was less than 1.0 mg kg⁻¹, the estimated intake level was close to the maximum tolerable daily intake of As, as specified by the WHO.     

Effects of various ions on the dechlorination kinetics of hexachlorobenzene by nanoscale zero-valent iron

The effect of several anions and cations normally co-present in soil and groundwater contamination sites on the degradation kinetics and removal efficiency of hexachlorobenzene (HCB) by nanoscale zero-valent iron (NZVI) particles was examined. The degradation kinetics was not influenced by the HCO(3)(-), Mg(2+), and Na(+) ions. It was enhanced in the presence of the Cl(-) and SO(4)(2-) ions due to their corrosion promotion. The NO(3)(-) competes with HCB so it inhibits the degradation reaction. The Fe(2+) ions would inhibit the degradation reaction due to passivation layer formed, while it was enhanced in the presence of Cu(2+) ions resulted from the reduced form of copper on NZVI surfaces. These observations lead to a better understanding of HCB dechlorination with NZVI particles and can facilitate the remediation design and prediction of treatment efficiency of HCB at remediation sites.     

Determination of volatile organic profiles and photochemical potentials from chemical manufacture process vents

The main objective of this study was to monitor the volatile organic compounds (VOCs) in the stack gas released from organic chemical industrial plants to determine emission factors. Samples from 52 stacks, with or without air pollution control devices (APCDs), from seven industrial processes were taken and VOCs measured using U.S. Environmental Protection Agency (EPA) Method 18. These 7 processes, including 26 plants, were the manufacturers of acrylonitrile-butadiene-styrene (ABS), polyvinyl chloride (PVC), polystyrene (PS), acrylic resin (ACR), vinyl chloride (VC), para-terephthalic acid (PTA), and synthetic fiber (SYF). The results clearly indicate significant variations of emission factors among the various industrial processes, particularly emission factors for those without APCDs. As expected, those with APCDs yield much less emission factors. Regardless of those with or without APCDs, the order of manufacturing processes with regard to VOC emission factors is SYF > ABS > PS >ACR > PTA > PVC > VC. The emission factors for some processes also differ from those in EPA-42 data file. The VOC profiles further indicate that some VOCs are not listed in the U.S. VOC/Particulate Matter Speciation Data System (SPECIATE). The potential O3 formation is determined from the total amount of VOC emitted for each of seven processes. The resultant O3 yield varied from 0.22 (ACR) to 2.33 g O3 g(-1) VOC (PTA). The significance of this O3 yield is discussed.     

Black and Smelly Waters: how citizen-generated transparency is addressing gaps in China’s environmental management

ABSTRACT

Information communication technologies (ICTs) generate new forums for transparency via governance-by-disclosure initiatives designed to improve environmental management and policy. Data generated by these programs are a means to empower citizens, narrowing the accountability gap between governments and people and enhancing public service. There is little empirical evidence, however, that supports the theory that citizen-generated data can be used to improve the accountability of local government officials. Citizen-led transparency efforts are emerging in China, as the country undergoes an information revolution that has brought ICTs to near ubiquity. We evaluate the transformative potential of a new ICT initiative, the ‘Black and Smelly Waters’ program, which China’s government launched to help enforce local government water remediation efforts. Many examples of citizen-generated transparency are grassroots initiatives, yet the Black and Smelly Waters program is distinct in its top-down structure. An empirical evaluation of preliminary data illuminates Black and Smelly Waters’s early successes and challenges as a means to generate transparency and accountability. We discuss these findings and propose a broad application of this new type of disclosure to reshape environmental management in China.     

A study on recovery of SiC from silicon wafer cutting slurry

Journal of Material Cycles and Waste Management - The objective of this study is to recover SiC from silicon wafer cutting slurry using physical separation and acid/alkali purification processes....     

Preparation and Application of PEG/PVP Copolymers

In this study, we produced a series of environmentally friendly multifunctional additives by polymerization of biodegradable polyethylene glycol (PEG) and N-Vinyl-2-pyrrolidone in different proportions. The copolymer molecular structure was confirmed by Fourier transform infrared spectroscopy, and the impact of the copolymers on dye absorption and dye interaction was investigated. The results showed that the series of copolymers produced displayed enhanced dye decolorization with increasing copolymer dose and time. Additionally, the PEG/polyvinylpyrrolidone (PVP) copolymers and dye molecules interacted; addition of copolymer enabled shifts of the dye λ_max toward shorter wavelengths and decreased the UV absorbance. The addition of copolymers reduced the overall Zeta potential of the dye and increased the particle sizes, facilitating dye decolorization. In particular, the dye decolorization effect was the best when the PEG/PVP molar ratio was 8:1.     

Mixed Integer Linear Programming Models for Selecting Ground-Level Ozone Control Strategies

The traditional strategy for ground-level ozone control is to apply emission reductions across the board throughout certain time periods and locations. In this paper, we study various mixed integer linear programming (MILP) models that seek to select targeted control strategies for the Dallas Fort-Worth (DFW) region to reduce emissions, in order to achieve the State Implementation Plan (SIP) requirements with minimum cost. Statistics and optimization methods are used to determine a potential set of cost-effective control strategies for reducing ozone. These targeted control strategies are specified for different types of emission sources in various time periods and locations. Three MILP models, a static model, a sequential model, and a dynamic model, are studied in this research. These different MILP models allow decision makers to study how the targeted control strategies change under different circumstances. Meanwhile, two types of auxiliary variables are considered as supplemental control strategies in the optimization if the current set of control strategies is unable to reduce ozone to comply with the 8-h ozone standard. Results from the different models can provide decision makers with information concerning how the effectiveness of the control strategies varies with daily emission patterns and meteorology.     

Advanced superhydrophobic electroactive fluorinated polyimide and its application in anticorrosion coating

A novel superhydrophobicelectroactive fluorinated polyimide (HEFPI) was first synthesized from aniline trimer and 4,4′-(Hexafluoroisopropylidene) diphthalic anhydride. The HEFPI could be fabricated as superhydrophobicfilm by replicated the surface of the Xanthosomasagittifolium leaves. The water contact angle of HEFPI film reaches as high as 157 ° and the superhydrophobic property of HEFPI could coat on cold-rolled steel (CRS) to prevent the metal corrosion. Electroactivity of EFPI was evaluated by performing electrochemical cyclic voltammetry study. Besides, redox catalytic capabilities of aniline trimer units existed in HEFPI main chain may induce the formation of passive metal oxide layers on the CRS electrode. The synergistic effects (hydrophobic property and passive metal oxide layers) make the HEFPI coating has great potential for advanced anticorrosion material.     

Prenatal diagnosis of a fetus harboring an intermediate load of the A3243G mtDNA mutation in a maternal carrier diagnosed with MELAS syndrome

We prenatally diagnosed MELAS syndrome in a fetus whose mother and older brother had the MELAS-specific A3243G mutation. The mutant mtDNA level of the amniotic fluid cells was not significantly different from that of the postnatal peripheral blood and hair follicle samples. The obstetrical course was uncomplicated except for transient exacerbation of the mother's diabetes, which required insulin control. At term, the infant was macrosomic, and the delivery was complicated by shoulder dystocia. MELAS syndrome in itself does not influence either the prenatal course of the mother or the fetal outcome. In contrast to the fulminating clinical course of this mother's first child, MELAS symptoms did not develop in her second child until age four, despite similar high tissue levels of mutant mtDNA. The phenotypic diversity in two offspring with similar higher levels of mutant mtDNA suggests that prenatal genetic diagnosis of cultured amniotic cells may yield results that are poor prognosticators of fetal outcome. Copyright © 2004 John Wiley & Sons, Ltd.