Search

In this paper, novel closed-form point estimators of the beta distribution are proposed and investigated. The first estimators are a modified version of Pearson's method of moments. The underlying idea is to involve the sufficient statistics, i.e., log-moments in the moment estimation equations and solve the mixed type of moment equations simultaneously. The second estimators are based on an approximation to Fisher's likelihood principle. The idea is to solve two score equations derived from the log-likelihood function of generalized beta distributions. Both two resulted estimators are in closed forms, strongly consistent and asymptotically normal. In addition, through extensive simulations, the proposed estimators are shown to perform very close to the ML estimators in both small and large samples, and they significantly outperform the moment estimators.

In recent years, over one million tons of Municipal Solid Waste (MSW) incineration fly ash has been generated annually Taiwan. Only a small percentage of the ash was used as raw material for other utilities besides landfill. Fly ash contains many harmful heavy metals, such as Cd and Cr, among others; however, fly ash also contains many valuable metals, including as Zn, Pb, and Ga.To recover Zn from fly ash, in this work, an experiment was first designed to determine the physical and chemical properties of the fly ash. Then, treatment processes, including water leaching, acid leaching, and ion exchange were conducted.Test samples were subjected to scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence spectrometer (XRF), and atomic absorption spectroscopy (AAS) to determine their physical and chemical properties. Then, water leaching was conducted under optimal experimental conditions. Thereafter, acid leaching was performed using two different acids (hydrochloric and sulfuric) to extract the target metal ions, and finally the ion exchange process was deployed to concentrate and recover the target metal ions.Ultimately, an optimal process to recover zinc from MSW incineration fly ash was developed in this work. An aqueous solution containing approximately 1 wt% zinc was obtained by leaching with sulfuric acid. Zn was then concentrated using a chelating resin IRC-747 in column mode.

The treatment and disposal of municipal solid waste incineration (MSWI) fly ash containing significant amounts of dissolvable salts and heavy metals is a seriously challenge. At present, the common treatment method for MSWI fly ash in Taiwan is the cement-based stabilization/solidification (S/S) process. In this work, an integrated hydrometallurgical process for the treatment of MSWI fly ash was evaluated. Ca was first recovered by combining water washing and ion exchange sequentially. Meanwhile, Zn in the water-washed fly ash was recovered by combining acid leaching and ion exchange sequentially. Combining the water washing efficiency of 30% on raw ash and the acid leaching efficiency of 40% on pre-washed ash, a total of 58% mass reduction rate of fly ash was achieved. In addition, an 80% Zn and 58% Ca recovery was achieved.

Reservoirs have been widely constructed all over the world in recent years to alleviate the shortage of water resources. Nevertheless, the assessment method of water quality and its trophic status needs to be developed. In this study, water quality parameters of a newly constructed shallow reservoir were regularly monitored for a period of two years, which is used as a major drinking water source of Shanghai, China. Furthermore, the trophic state indices of the reservoir were investigated based on literature and evaluated with the two-year field data. The results indicated that the studied reservoir is reaching the mesotrophic–eutrophic boundary, where further nutrient enrichment could cause water quality degradation; total phosphorus is the limiting nutrient for algal growth in the studied reservoir. Results of the study can help operators understand change and status of water quality of the reservoir and provide valuable data demonstrating variation of water quality indicators and trophic charac...

This study proposes methods for constructing tolerance limits for the gamma distribution. The gamma distribution is found to be useful in many areas and the tolerance limits are often desirable in some monitoring and control problems. Existing inference methods either assume some parameters known or do not work well for one-sided tolerance limit case. In this study, the generalized fiducial method is used for constructing the tolerance limits for the gamma distribution. The proposed methods are assessed by a simulation study. An illustrative example demonstrates the inference methods.

The stress in films of semirigid and rigid polyimides (PIs) on silicon (Si) substrate has been measured in situ during curing using a newly modified bending beam apparatus. By using the apparatus, the onset of residual stress in the initially solvent-rich films has also been investigated. The stress characteristics of the PI films are strongly ramp rate dependent. Different ramp rates result in markedly different stress patterns, thermo-mechanical properties, and film morphologies. The residual stress at room temperature after curing is scattered around 23-31 MPa for the films of pyromellitic dianhydride-4,4'-oxydianiline (PMDA-ODA). For pyromellitic dianhydride-p-phenylenediamine (PMDA-PDA), it systematically increases from -6 to 28 MPa for ramp rate increasing from 0.5 to 10°C/min. The residual stress is very low in the slowly cured PMDA-PDA films. However, these films have gone through a very high-stress transient state during curing. The maximum transient stress is comparatively higher in the films of PMDA-PDA than in PMDA-ODA. Slowly cured PMDA-PDA films exhibit high structural ordering, high in-plane anisotropy, and low coefficient of thermal expansion.

China has followed a policy of opening to the world and reinvigorating the domestic economy since the Third Plenum of the Eleventh Central Committee of the Chinese Communist Party. Guangdong province, as China's southern gateway, has adopted special policies and flexible measures. It has six of the nineteen economically open cities and zones in China, including Shenzhen, Zhuhai, Shantou, Guangzhou, Zhanjiang, and Hainan Island. Comrade Deng Xiaoping has pointed out that China's policy of opening to the world is a long-term national policy which "will not change in this century or the first five decades of the next century. It will not be easy to change in the last five decades of the next century either, as by that time China's economic and trade relations with other countries will be so close and developed that it will be hard to change even if one wanted to."

The determination of the mean degree of polymerization of polysaccharides with one reducing group by the action of 3,5-dinitrosalicylic acid has been restudied. In order to assure complete reduction the heating period of the reaction mixture has been prolonged to 4 1/2 hours, especially for starch grains and for amylopectine. In spite of the reproductibility of the results of this rapid and simple method, they are only valid to a certain extent: the resulting degrees of polymerization can only be considered as an inferior limit, and the magnitude of the error increases with the real degree of polymerization.

Die durch Addition von Chloral an Amylose gebildeten Hemiacetale werden untersucht. Ihre Loslichkeit und der Farbton ihrer Reaktion mit Jod Hangt von dem Prozentsatz der Glucosereste ab, die mit Chloral verbunden sind.