Beet tissue ensiling: An alternative for long-term storage of sugars in industrial beets for nonfood use

Industrial beets have significant potential to compete against corn grain as an important source of sugars for nonfood industrial processes including microbial bioconversions. However, dependable, long-term storage techniques are necessary to extend processing campaigns and meet increasingly-important industry requirements such as carbon footprint reductions. This work evaluated the potential of industrial-beet tissue ensiling as an alternative for long-term sugar storage. Ground industrial-beet tissue was ensiled for 8 wk at 23 °C and various combinations of pH, moisture content (MC), and sugar:solids (SSR). The pH, MC, and SSR values ranged from 2.0 to 6.8, 50%–85%, and 38%–76%, respectively, according to a central composite rotatable design. Response surface methodology was used to model and illustrate effects of parameter combinations on beet sugar retention. MC and pH had statistically significant effects on sugar retention in beet tissue silage, whereas SSR had no significant effect. Only some combinations of pH ≤ 4.0 and MC ≤ 67.5% enabled the highest sugar retentions in ensiled tissue (≥ 90%). Moreover, tissue ensiled at pH ≤ 3.0 and MC ≤ 67.5% showed increases of ≤ 7% over initial sugars after 3 d of ensiling, suggesting that highly acidic conditions may partially hydrolyze beet tissue cellulose and/or hemicellulose during storage. In contrast, tissue ensiled at some combinations of pH < 6.5 and MC > 67.5% only achieved sugar retentions of < 30% at 8 wk. Sulfuric acid cost estimates (on a dry-sugar basis) to achieve effective pH (2.0–4.0) for sugar retentions ≥ 90% range from $4.9 Mg⁻¹ to $18.6 Mg⁻¹.     

Effect of sol–gel MgO spin-coating on the performance of TiO2-based dye-sensitized solar cells

This paper is concerned with the improvement of dye-sensitized solar cell (DSSC) efficiency upon MgO post-treatment of the TiO₂ electrode. A simple sol–gel technique, involving magnesium acetate as precursor, ethanol as solvent and nitric acid as stabilizer, is applied to prepare a solution of suspended MgO nanoparticles. A single drop of MgO sol at 0.1 M precursor concentration was spin-coated at 3000 rpm for 30 s onto the TiO₂ electrode and sintered at 500 K for 1 h. Dye-loading using N3-dye was applied for 6 h. An increase in the average efficiency of the DSSC from 2.5% to 3.9% (over 50% enhancement) was recorded. Measurements of the dark I–V characteristics, the open circuit voltage decays, the SEM images and the dye absorbance spectra, for both uncoated and MgO-coated electrodes were examined. The improvement of the DSSC efficiency was attributed to an upward shift of the TiO₂ flat band energy and a reduction of the rate of back-transport and recombination.     

蒸汽转化炉对流段热效率低的原因分析

结合2500t/d甲醇装置蒸汽转化炉的工艺流程及运行状况,分析与探讨蒸汽转化炉对流段热效率低的原因,并制定出相应的改进措施。     

管壳式换热器壳程进出口流通面积调整方法

依据GB 151-1999附录K中壳程进出口流通面积的计算方法,推导出影响壳程进出口流通面积的3个因素,即壳程进出口接管内径、换热管的列数和壳体内径,并提出在壳程进出口流通面积不足时,如何调节这3个因素使流通面积满足要求。     

新型锥齿轮-滚轮平盘式无级变速器摩擦效率及温度场研究

针对摩擦式无级变速器摩擦生热和温度场的研究，以自行设计的新型锥齿轮-滚轮平盘式无级变速器为例，对传动过程中的滑移率、功率损失和摩擦效率进行理论研究，并用ANSYS软件对滚轮平盘摩擦生热温度场进行仿真分析。结果表明：随着转速的提高滚轮和平盘的温度上升，随着压紧力的增大，摩擦功率损失提高，摩擦效率降低；压紧力的提高，滑动速度会随之增大，产生更多摩擦热，同时也会增大接触面积，摩擦发热的面积更大，因此对温升影响更明显；新型锥齿轮滚轮-平盘式无级变速器具有较高的摩擦效率，其摩擦升温也较小。     

提高压气站运行效率的探索

通过对压气站室温高影响压缩机正常工作问题的分析,给出了避免压缩机吸入高温气体的设备布局、利于自然对流散热的厂房结构等的优化设计方案。实践表明,能提高压气站运行稳定性,效率提高约13%。     

日本办公建筑的绿色生态设计及其评价

介绍了日本2个绿色办公建筑实例及其获得的评价,总结了新建和改建办公建筑的主要绿色技术亮点,阐述了自然采光、可再生能源利用、室内舒适性空调设计等方面的绿色生态设计手法,供国内同行参考与借鉴。     

Synthesis of an aromatic amine derivative with novel double spirobifluorene core and its application as a hole transport material

A synthetic method to prepare a novel double spirobifluorene core structure was developed and a hole transport type exciton blocking material with the double spirobifluorene core was synthesized. A two step ring closing method was used to synthesize the double spirobifluorene core. The double spirobifluorene core based hole transport material showed high glass transition temperature due to rigid structure, and high quantum efficiency in green phosphorescent organic light emitting diodes because of efficient hole injection and triplet exciton blocking properties.     

Characteristics of turbine spacing in a wind farm using an optimal design process

The characteristics of turbine spacing for optimal wind farm efficiency were investigated using combined numerical models. The effects of wakes from upstream turbines were predicted by a model capable of determining velocity distributions on a rotor plane, based on Ainslie's approach. The performance results of a wind farm showed good agreement with measurements. The blade element momentum theory, in combination with a dynamic wake model, was applied. Wake model used the results of aerodynamic analysis as input properties. The optimal distance between wind turbines was predicted using a genetic algorithm to maximize efficiency in a wind farm. The results showed that the spacing between the first and the second turbines had the importance to the entire farm's efficiency.     

600MW机组布袋除尘器综合集成施工技术

阐述了600 MW机组布袋除尘器施工的关键技术,施工过程中把设备部件最大化地面组合后,分单元退吊、配合自制吊具解决了现场吊车站位及起重能力不够的难题,花板梁水平度控制、壳体正压密封试验、花板荧光粉检漏等综合集成技术,保证了整个工程安全、优质、高效地完成,从而提高了布袋除尘器的除尘效率,取得良好的经济效益。