针织物平幅处理: 案例研究

基于案例研究,比较了现代平幅处理与绳状处理的成本优势.采用平幅处理在成本和质量上有明显的优势.当产能大于10 t/d时,成本优势进一步增长.Benninger公司的Starter Kit是理想的设备,可将生产成本优势提高到15%.     

Design options for cooperation mechanisms under the new European renewable energy directive

In June 2009, a new EU directive on the promotion of renewable energy sources (RES) entered into effect. The directive 2009/28/EC, provides for three cooperation mechanisms that will allow member states to achieve their national RES target in cooperation with other member states: statistical transfer, joint projects, and joint support schemes. This article analyses the pros and cons of the three mechanisms and explores design options for their implementation through strategic and economic questions: How to counterbalance the major drawbacks of each mechanism? How to reflect a balance of costs and benefits between the involved member states? The analysis identifies a number of design options that respond to these questions, e.g. long term contracts to ensure sufficient flexibility for statistical transfers, a coordinated, standardised joint project approach to increase transparency in the European market, and a stepwise harmonisation of joint support schemes that is based on a cost-effective accounting approach. One conclusion is that the three cooperation mechanisms are closely interlinked. One can consider their relation to be a gradual transition from member state cooperation under fully closed national support systems in case of statistical transfers, to cooperation under fully open national support systems in a joint support scheme.     

Hydrogen production by co-cultures of Clostridium butyricum and Rhodospeudomonas palustris: Optimization of yield using response surface methodology

Both dark and photo-fermentation can be used for biological hydrogen production; either performed separately, in two-stage systems, or in co-culture. A single stage process is less laborious and costly; however, the two types of microorganisms have different nutritional requirements requiring optimization of culture conditions. Here a response surface methodology (RSM) with a Box-Behnken design was used to optimize microorganism ratio and substrate and buffer concentrations, and to evaluate their interactive effects for maximization of hydrogen yield. Clostridium butyricum and Rhodopseudomonas palustris were grown on a potato starch/glucose base medium at 30 °C under continuous illumination (40 W m^?2 light intensity). The highest hydrogen yield, 6.4 ± 1.3 mol H₂/mol glucose, was obtained with a substrate concentration of 15 g/L, buffer concentration of 50 mM, and microorganism ratio of 3. The observed strong interaction between buffer and substrate concentration is most likely due to the need to optimize the pH for co-cultures.     

Ceria and zirconia modified natural clay based nickel catalysts for dry reforming of methane

Ce and Zr promoted Fe/Cu-modified natural clay based catalysts were prepared and tested in dry reforming of methane (DRM) at temperatures from 600 to 800 °C. The physicochemical properties of these catalysts were analyzed by means of N₂ adsorption, X-ray diffraction (XRD). H₂-temperature programmed reduction (H₂-TPR) and CO₂-temperature programmed desorption (TPD). Ce and Zr promotion resulted in a considerable increase of the catalytic activity. This increase can be mainly ascribed to an improved reducibility of Ni species, together with slightly higher Ni⁰ crystal size, that, on the other hand, also catalyze undesired parallel reactions resulting in carbon formation, such as direct methane decomposition. Both Ce and Zr presence also promoted the presence of weak and medium strength basic sites, which are thought to favor CO₂ adsorption and desorption on the catalyst surface, leading to enhanced catalytic activity.     

Proton-conducting ionic liquid-based Proton Exchange Membrane Fuel Cell membranes: The key role of ionomer-ionic liquid interaction

The paper deals with the synthesis and characterisation of proton-conducting ionic liquids (PCILs) and their polymer electrolytes obtained by blending modified Nafion membranes with different concentrations of PCILs. The PCILs are obtained by the neutralization of triethylamine with different organic acids. The first part of the paper studies the influence of acidity and acid structure on PCIL thermal and electrochemical performance, while the second part examines membrane conductivity and reveals it to depend more on PCIL structure than on its intrinsic conductivity. At 130 °C, conductivities exceeding 10 mS cm⁻¹ were obtained in fully anhydrous conditions.     

Synthesis by Spark Plasma Sintering: A new way to obtain electrode materials for lithium ion batteries

In the search of high-performance materials for lithium ion batteries, Li₂CoPO₄F offers many advantages like high theoretical capacity and high operating potential. The synthesis of Li₂CoPO₄F has been reinvestigated considering a conventional solid state reaction and an unconventional way. Due to the long heat-treatments required by the conventional approach, a beginning of grains coalescence is observed. Limiting particles growth has been allowed by a shorter reaction done by SPS (Spark Plasma Sintering). By this method, the synthesis of Li₂CoPO₄F was greatly shortened (from 10 h to 9 min), which favours the getting of submicrometric particles. The comparison of the electrochemical properties of the Li₂CoPO₄F obtained by the different ways confirms the advantages of SPS synthesis in performance enhancement.     

Routine instrumental procedures to characterise the mineralogy of modern and ancient silica sinters

Tightly constrained determinative methods can be used to characterise the silica minerals (opal-A, opal-CT, opal-C, quartz, moganite) and physical properties of silica sinters. Optimal X-ray powder diffraction operating parameters indicate silica lattice order/disorder using untreated, dry, <106 μm powders scanned at 0.6° 2θ/min with a step size of 0.01° from 10–40° 2θ and an internal Si standard. Simultaneous differential thermal and thermogravimetric analysis of 15.0±0.1 mg sinter samples of <106 μm grain size, at a heating rate of 20°C/min in dry air, identify thermal events associated with dehydration, organic combustion, and changes of state. Where abundant organic matter is present, nitrogen is the preferred atmosphere for thermal analysis. Thermogravimetric-determined water contents of sinters differ from Penfield determinations reflecting the differing nature of the two techniques. Laser Raman microprobe techniques can be used to explore the mineralogy of particular sinter morphologies and habits down to 10 μm diameter. The nature of the silica species present can assist in characterising individual sinter deposits and, combined with textural, density and/or porosity determinations, can lead to a better understanding of the hydrology and paleohydrology of a geothermal prospect.     

Hydrogen microscopy – Distribution of hydrogen in buckled niobium hydrogen thin films

Hydrogen absorption in thin metal films clamped to rigid substrates results in mechanical stress that changes the hydrogen's chemical potential by Δμ_H(σ) = −1.124σ kJ/mol_H for σ measured in [GPa]. In this paper we show that local stress relaxation by the detachment of niobium hydrogen thin films from the substrate affects the chemical potential on the local scale: using coincident proton–proton scattering at a proton microprobe, the hydrogen concentration is determined with μm resolution, revealing that hydrogen is not homogenously distributed in the film. The local hydrogen solubility of the film changes with its local stress state, mapping the buckled film fraction. In niobium hydrogen thin films loaded up to nominal concentrations in the two-phase coexistence region, the clamped film fraction remains in the solid solution phase, while the buckles represent the hydride phase. These results are compared to a simple model taking the stress impact on the chemical potential into account.     

Carbon nanotube thermal interfaces on gadolinium foil

We report the thermal behavior of gadolinium foils to be used in magneto thermoelectric generator cells. Magneto thermoelectric generator cell technology exploits the ferromagnetic phase transition of gadolinium to drive the movement of a diaphragm ‘shuttle’ whose mechanical energy is converted to electrical form and which enhances heat transfer through both conduction and convection. Efficient heat transfer at mechanical interfaces is critical to increase shuttle speed and the commensurate rate of heat transfer. The synthesis and characterization of carbon nanotube thermal interfaces for the gadolinium foils are described. The total thermal interface resistance of the carbon nanotube coated gadolinium was measured using a one-dimensional reference calorimeter technique. Improvement of carbon nanotube growth based on parametric process variations is described, and the effect of hydrogen embrittlement on the magnetic properties of the gadolinium foils during carbon nanotube growth is quantified. The samples generated in this study were consistently measured with total thermal interface resistances in the range of 65–105 mm² K/W, a reduction of 55–70% compared to bare gadolinium (R_int ≈ 230 mm² K/W). The addition of carbon nanotube arrays did not alter the magnetic properties of the gadolinium foils and only a slight decrease in the magnetic moment of the gadolinium samples (8–13%) was measured after growth.     

炼厂烷基化技术的未来:安全与辛烷值之间的平衡

因汽油池中的乙醇用量越来越多,为了平衡乙醇较高的RVP值,生产商必须寻找低RVP值的调和组分。持续的页岩热潮带来了充足且廉价的丁烷,同时由于致密油中含大量链烷烃,通常会使FCC汽油的辛烷值平均降低8~10个单位,这就造成了对高辛烷值汽油调和组分的需求。这些因素为烷基化运营商带来了巨大的机遇。世界已建的烷基化产能和商业技术中,液体酸(H2SO4和HF)烷基化技术一直占主导地位,因该技术有安全隐患,北美和欧洲的新建装置基本上已停止使用这种工艺技术。技术许可商已致力于开发烷基化技术的替代方案。UOP的间接烷基化工艺(InALKTM)既适用于新建装置,也适合于对现有MTBE装置改造后应用。有的炼厂对现有HF装置进行改造,再用固体酸替代HF。离子液体(ILS)在烷基化反应体系中既可作为溶剂也可作为催化剂,而且催化性能更好。Uhde公司将STAR工艺与齐聚技术整合为完整的丁烷转化为烷基化油的工艺方案。预计固体酸烷基化和离子液体烷基化技术未来的研发工作将集中于如何更长期地保持催化剂的活性和选择性,同时提高催化剂的再生能力。利用烷基化装置生产中间馏分油是最具吸引力的选择。