The effect of OPWF filler on impact strength of glass-fiber reinforced epoxy composite

In the present study, oil palm wood flour (OPWF) particles with less than 250 μm sizes have been used as filler materials in the woven-glass-fiber reinforced epoxy composite. The hybrid composites were fabricated using a hand lay-up method and cured at room temperature under a compressive load of 196 N (20 kg). The OPWF of 2.5 to 10 parts per hundred (pph) by weight was used to evaluate its effect on impact strength of the hybrid composites at a range of temperature from −50 to 50 °C. The impact strength, evaluated using V-notch Charpy method, showed reduction with increasing filler content up to 5 pph and then the strength increment in those composites containing more than 5 pph OPWF. More severe damages were found in specimens with higher filler contents resulting higher energy absorption during impact. The composites with a large amount of OPWF particles deflected crack propagation paths or created obstacles at the crack tips and increased toughness of the composites. The impact strength was found to decrease when the samples fractured at subzero temperatures and this happened because of the reduction of the matrix ductility at lower temperatures.     

煤粉粒度对高炉风口前燃烧性能的影响

安钢炼铁厂在喷吹瘦煤后，将小于0．074mm的比例由70％放宽到30％，使磨煤能力提高了21％。采用自行设计的风口取样器，研究了风口前气体成分和煤粉燃烧率的变化。当煤粉粒度变粗后，风口前循环区变长，放宽煤粉粒度与高富氧、高风温配合，能使高炉得到较好的经济效益。     

Design aspects of planar and conventional SMPS transformer: a cost benefit analysis

The intent of this paper is to design a high-frequency transformer that is to be incorporated into the DC/DC pulsewidth-modulated switch-mode power supplies by two different technical approaches: a conventional wound-coil magnetic using copper wires, and a planar magnetic with layered copper tracks on laminated printed circuit board. Comparisons will be made between the two approaches in terms of profile: mounting height and surface area, and performance: power losses and efficiency. Other indicators like temperature rise and leakage inductance that causes electromagnetic interference, and cost, materials, and process fluency are also to be looked into. A sandwiched configuration for primary and secondary windings is proposed for the planar type. Issues arising and typical phenomena encountered will be discussed in detail. Primarily, the dominating factor in performance, cost effectiveness, or circuit compactness that restrains the choice of a particular type is to be evaluated.     

Forecasting Canadian nuclear power station construction costs

Because of the huge volume of capital required to construct a modern electric power generating station, investment decisions have to be made with as complete an understanding of the consequences of the decision as possible. This understanding must be provided by the evaluation of future situations. A key consideration in an evaluation is the financial component. This paper attempts to use an econometric method to forecast the construction costs escalation of a standard Canadian nuclear generating station (NGS). A brief review of the history of Canadian nuclear electric power is provided. The major components of the construction costs of a Canadian NGS are studied and summarized. A database is built and indexes are prepared. Based on these indexes, an econometric forecasting model is constructed using an apparently new econometric methodology of forecasting modelling. Forecasts for a period of 40 years are generated and applications (such as alternative scenario forecasts and range forecasts) to uncertainty assessment and/or decision-making are demonstrated. The indexes, the model, and the forecasts and their applications, to the best of the author's knowledge, are the first for Canadian NGS constructions.     

Preparation and properties of water‐soluble polyester surfactants. II. Preparation and surface activity of silicone‐modified polyester surfactants

We prepared a novel series of water‐soluble silicone‐modified polyesters [poly(ethylene glycol) (PEG)–silicone polyesters] by reacting organopolysiloxane with a hydroxy‐terminated polyester. The polyesters were obtained by the polymerization of maleic anhydride and PEGs (molecular weights = 2000, 4000, 6000, 8000, and 10000). These water‐soluble PEG–silicone polyesters can be used as auxiliaries in dyeing process because they exhibit good surface activities such as surface tension, low foaming, and wetting power. The presence of these surfactants also retarded the rate of nylon dyeing with acid dyes. The retarding effect and low‐foaming property of these novel PEG–silicone polyesters make it possible for these surfactants to be used as leveling agents for modern nylon dyeing with acid dyes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3005–3012, 2002     

Preparation and surface activity of modified soy protein

A series of novel surfactants have been prepared by the reaction of hydrolyzed soy protein with alkyl succinic anhydride. These novel surfactants exhibit excellent surface active properties including surface tension, foaming, emulsifying, wetting power, and buffer ability. The hydrophobic modified protein exhibit more surface activity than original protein because of the enhanced hydrophobicity in structure. The increase in hydrophobic chain length leads to an increase in the surface activity. The surface tension reduction is correlated to the hydrophobicity of the modified molecule, which was determined by a fluorescent probe. In application on cotton bleaching procedures, these surfactants increase the whiteness of fabrics. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3498–3503, 2006     

Adsorption and desorption kinetics of hydrocarbons in FCC catalysts studied using a tapered element oscillating microbalance (TEOM). Part 2: numerical simulations

The factors affecting the adsorption and desorption kinetics in a TEOM are reviewed in detail with particular attention given to the assumptions required to obtain physical transport parameters from the data. Two models are presented to simulate TEOM adsorption data in the case that concentration differences down the catalyst bed can be neglected, as is appropriate when the amount of catalyst used is small, the carrier gas flowrate is large, and/or the adsorbate partial pressure is low. In the first model, the effective diffusion coefficient, D_e, is taken to be constant. In the second model, the effective diffusion coefficient is assumed to obey the Darken equation, D_e=D₀/(1−θ). The TEOM results obtained on n-hexane, n heptane, n-octane, toluene and p-xylene on a commercial FCC catalyst and on pure rare-earth exchanged zeolite Y under non-reacting conditions (373-) are analysed in detail. It is found that intracrystalline diffusion is not the limiting factor affecting the overall rates of adsorption and desorption for the systems studied. Instead, it is the transport of molecules between the adsorbed and vapour phases at the edge of zeolite crystallites that is the limiting transport step affecting the overall kinetics. For the FCC catalyst, the limiting step is the transport of molecules at the zeolite-matrix interface rather than, say, the matrix-vapour interface. Local rate constants for the desorption of the hydrocarbons at the rate-controlling interface have been obtained.     

A novel synthesis method for the preparation of aromatic poly(imide benzoxazole) from trimellitic anhydride chloride and bis(o‐aminophenol)

A poly(imide benzoxazole) was prepared directly from trimellitic anhydride chloride and 2,2‐bis(3‐amino‐4‐hydroxyphenyl)hexafluoropropane (BisAPAF) monomers in a two‐step method. In the first step, a poly(hydroxyamide amic acid) precursor was synthesized by the low‐temperature solution polymerization in an organic solvent. Subsequently, thermal cyclodehydration of the poly(hydroxyamide amic acid) precursor at 350°C produced the corresponding poly(imide benzoxazole). The inherent viscosity of the precursor polymer was 0.22 dL/g. The cyclized poly(imide benzoxazole) showed a glass transition temperature (T_g) at 329°C and a 5% weight loss temperature at 530°C in nitrogen and at 525°C in air. The poly(imide benzoxazole) is amorphous as evidenced by the wide‐angle X‐ray diffraction measurement. The structures of the precursor polymer and the fully cyclized polymer were characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance spectroscopy (¹H NMR). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2388–2391, 2003     

先进的搅拌摩擦焊

搅拌摩擦焊是利用一种特殊形式的搅拌头边旋转边前进，通过搅拌头与工件的摩擦产生热量，摩擦热使该部位金属处于热塑性状态，并在搅拌头的压力作用下从其前端向后部塑性流动，从而使待焊件压焊为一个整体。它可以焊接所有牌号的铝合金以及用熔焊方法难以焊接的材料，并突破了普通摩擦焊对轴类零件的限制。由于搅拌摩擦焊是固态焊接，所以没有熔化焊时的气孔、裂纹等缺陷。搅拌摩擦焊的接头性能普遍优于熔化焊的。