Estimate of Landfill Settlements Due to Mechanical and Decompositional Processes

Approximate closed form solutions are developed for estimating the mechanical and decomposition settlement of landfills. The mechanical settlements are the immediate (primary) settlement and long term creep. The decomposition settlements are generated by mass loss and gas generation. Based on the approximate solution, the decomposition settlement can constitute a significant portion of the total settlement and can be in the same order as the mechanical settlements. Settlement remaining after landfill closure depends on the decomposition environment during filling. For an average decomposition environment, postoperation settlement can still be significant 20?years after completion of filling.     

Lactic acid production from dining‐hall food waste by Lactobacillus plantarum using response surface methodology

BACKGROUND: Food waste generally has a high starch content and is rich in nutritional compounds, including lipids and proteins. It therefore represents a potential renewable resource. In this study, dining‐hall food waste was used as a substrate for lactic acid production, and response surface methodology was employed to optimise the fermentation conditions. RESULTS: Lactic acid biosynthesis was significantly affected by the interaction of protease and temperature. Protease, temperature and CaCO₃ had significant linear effects on lactic acid production, while α‐amylase and yeast extract had insignificant effects. The optimal conditions were found to be an α‐amylase activity of 13.86 U g^?1 dried food waste, a protease activity of 2.12 U g^?1 dried food waste, a temperature of 29.31 °C and a CaCO₃ concentration of 62.67 g L^?1, which resulted in a maximum lactic acid concentration of 98.51 g L^?1 (88.75% yield). An increase in inoculum size would be appropriate for accelerating the depletion of initial soluble carbohydrate to enhance the efficiency of α‐amylase in dining‐hall food waste fermentation. CONCLUSION: A suitable regression model for lactic acid production was developed based on the experimental results. Dining‐hall food waste was found to be a good substrate for lactic acid fermentation with high product yield and without nutrient supplementation. Copyright © 2008 Society of Chemical Industry     

Efficient modeling of panel-like structures in perforation simulations

This paper presents results of numerical simulations for impact effects in panel-like structures using solid and shell element modeling techniques. Three examples from experiments in literature have been numerically analyzed. The nonlinear transient dynamic analysis code, LS-DYNA is used in the simulations to model projectiles and panel-like targets. It is found that models established for panel-like targets using solid shell elements cannot only save significant computational effort, but also produce good results as long as the panel-like targets satisfy certain conditions. A criterion that governs the validity of modeling panel-like targets with shell elements is proposed in the paper.     

FEM model of the ohmic resistance of IP-SOFCs

In the present work, the ohmic resistance of an integrated planar-SOFC (IP-SOFC) has been evaluated by developing a model whose equations have been solved numerically through an FEM method. The model allows to estimate the distribution of voltage and current density in the cell. A comparison between simulated and experimental data of area specific resistance is reported, which shows satisfactory agreement. The mathematical model has also been used to carry out some parametric studies for optimisation purposes. Indeed, a reduction in cell pitch length and an increase in electrode thickness are predicted to lead to a reduction in ohmic losses in IP-SOFCs.     

Fabrication of damascene Cu wirings using solid acidic catalyst

The copper damascene process is one of the most promising technologies for fabricating Cu wirings for electronic devices such as LSIs. In this research, the fabrication of damascene Cu wirings was conducted using solid acidic catalyst. When a Cu-plated wafer, whose oxide is a basic oxide is dipped into a mixture of oxidizing solution and acidic solution, surface atoms are ionized and etched off into the solution. However, because conventional nonelectrolytic etching does not have a reference surface, it is difficult to utilize for planarization. Therefore, a new nonelectrolytic machining method using a cation-exchange fabric instead of an acidic solution was developed. To be more precise, the planarization of a Cu-plated wafer was carried out by rubbing with the cation-exchange fabric in ozone water. Basically, this method exploits chemical reactions so that the physical properties of the workpiece surface are not deteriorated. Furthermore, this method uses no chemicals except for ozone water, which easily dissociates into water and oxygen molecules; thus, this method is a low-cost, environmentally friendly process. In this paper, as a preliminary experiment, the nonelectrolytic etching of a Cu sample using solutions of O₃ and CO₂ was carried out to inspect the dependence of the etching rate on [O₃] and [H⁺]. The results indicate that the etching rate increased as [O₃] and [H⁺] increased. When [H⁺] was high relative to [O₃], a smooth etch-pit-free surface was achieved. Next, nonelectrolytic etching using a cation-exchange fabric was carried out, and properties similar to those in the case of etching using solutions were obtained. Finally, damascene Cu wirings were fabricated using ozone water and a cation-exchange catalyst.     

ESW激波吹灰器在余热锅炉的应用

介绍了ESW激波吹灰器的工作原理及其在茂名分公司Ⅲ套催化裂化装置余热锅炉的应用情况。应用结果表明，使用ESW激波吹灰器吹灰效果明显，吹灰后余热锅炉排烟温度可下降29℃，过热蒸汽产量增加7t/h，锅炉自产饱和蒸汽产量增加2t/h，有效提高了余热锅炉的传热效率和过热能力，节能效果显著。对应用中出现的一些问题提出了改进建议。     

Use of zeolite-rich rocks and waste materials for the production of structural lightweight concretes

This paper aims at testing the use of mixtures constituted by natural zeolitized products and SiC-bearing industrial wastes (sludge deriving from polishing of porcelain stoneware tiles, hereafter DPM) for the production of lightweight expanded aggregates as constituents of structural and/or thermo-insulating lightweight concretes. Two commercial products have been used as zeolite natural source: Cab70 (Yellow facies of Campanian Ignimbrite) and IZclino (Turkish clinoptilolite-rich epiclastite). Different amounts of a calcareous material (Pozzano limestones — hereafter CP) from the Sorrento peninsula (Naples — Italy) were also added to a Cab70–DPM mixture. All raw materials were characterized by means of mineralogical (XRPD) and chemical (XRF) analyses. All the products and mixtures were tested from a technological point of view by means of fusibility and firing tests in order to evaluate the expanding properties. It was evidenced that the expansion of the mixture was deeply depending on the occurrence of SiC in the industrial waste. The addition of CP (10 wt.%) to the mixtures accounts for an even increased expansion, though this is accompanied by a worsening of the mechanical features of the material.These results along with literature data allowed to select 3 mixtures (70% Cab70–30% DPM, 70% IZclino–30% DPM, 60% Cab70–30% DPM–10% CP) and each of them was used for the preparation of 5 l of lightweight aggregates afterward employed for the manufacture of lightweight concretes. It was remarked that natural zeolitized materials mixed with DPM (30 wt.%) can provide lightweight aggregates with densities ranging between 0.8 and 1.0 g/cm³ suitable for the preparation of structural lightweight concretes. The addition to the mixture of CP (10 wt.%) produces less dense aggregates (0.6–0.7 g/cm³) potentially useful for the manufacture of thermo insulating lightweight concretes.     

利用废硅胶生产五水偏硅酸钠的研究

概述了五水偏硅酸钠的市场现状,介绍了以废硅胶为原料生产五水偏硅酸钠的实验方法。通过实验,得出了优化实验条件为:模数采用0.5~0.8,波美度在35~50°,加热废硅胶及浓缩结晶的温度为90~100℃,时间为持续沸腾5min以上,采用自然降温法,时间在10h左右。最终制得良好的晶体,其中氧化钠含量为28.5%,氧化硅含量27.3%,产品质量达到国内同类产品的一级品标准。     

水吸收-催化燃烧技术处理PET聚酯废气的中试研究

应用水吸收—催化燃烧技术处理PET聚酯生产中排放的含乙二醇、2—甲基—1，3—二氧戊环、乙醛等废气。水吸收可以有效脱除高沸点的乙二醇，通过对乙醛的吸收、解吸作用使废气的总烃浓度得到均匀化处理；采用Pt／Pd／CeO2蜂窝状催化剂，在反应器床层空速40000h^-1，人口温度250℃，人口总烃浓度3522—5666μL/L的条件下，反应器出口总烃浓度54—84μL/L，乙醛浓度3—11μL/L，总烃去除率达到97．6％一98．9％，净化后气体符合国家排放标准。     

Eight mole percent yttria stabilized zirconia powders by organic precursor route

An organic precursor-mixing route has been developed for preparation of 8 mol% yttria stabilized zirconia (8YSZ) ceramics. Polymeric salt of succinic acid with yttrium and zirconium has been prepared separately by treating sodium succinate with yttrium chloride and zirconyl chloride followed by washing with water and drying at 120 °C. Thorough mixing of the two salts in stoichiometric proportions by planetary ball milling followed by calcination at 850 °C resulted in a precursor powder containing nanocrystalline (∼40 nm) monoclinic zirconia, tetragonal YSZ, cubic YSZ and yttria. Compacts prepared after deagglomeration of powder by planetary ball milling produce 8YSZ ceramics having density 99.3% TD on sintering at 1550 °C for 2 h.