基于模拟退火的混合遗传算法研究

针对常规遗传算法会出现早熟现象、局部寻优能力较差等不足,在遗传算法运行中融入模拟退火算法算子,实现了模拟退火的良好局部搜索能力与遗传算法的全局搜索能力的结合。经验证,该混合算法可以显著提高遗传算法的运行效率和优化性能。     

In-situ X-ray and visual observation of foam morphology and behavior at the batch-melt interface during melting of simulated waste glass

To attain a basic understanding of the primary foam structure and behavior, which affects the heat and mass transfer and the efficiency of the glass melting process, we investigated the primary foam layer under the glass batch floating on molten glass. The primary foam affects mass transfer during batch melting, in turn affecting the melting process. The recently performed direct in-situ three-dimensional X-ray computed tomography of the batch melting in a laboratory-scale melter vessel allowed us to visualize the features of the reacting batch layer and the foam that develops at its bottom, though with an insufficient resolution of images. In this study, we obtained better temporal and spatial resolution using the two-dimensional X-ray radiography and visual observation of the structure and behavior of transient primary foam as it formed and decayed. As soon as the batch was charged onto the melt surface, foam bubbles began to evolve, grow, and coalesce, forming a primary foam layer, 5–10 mm thick, within tens of seconds. This foam layer was sustained by ongoing gas evolving reactions counterbalanced by bubble coalescence into cavities that moved sideways and escaped to the atmosphere. Eventually, the entire remaining batch turned into foam that gradually decayed at the melt surface. The decay rate agreed with literature observations of surface foam produced by secondary foaming.     

Effects of annealing temperature and atmosphere on performances of Zn0.9Mg0.1O buffer layers for CIGS solar cell

Zn_0.9Mg_0.1O (ZMO) thin films were fabricated by magnetron co-sputtering without substrates heating. Annealing process was introduced to reduce the defect density and improve the photoelectric performances. The effects of annealing temperature and atmosphere on the crystallization, defect density, and photoelectric performances of ZMO films were investigated. The variation mechanisms for intrinsic point defects in ZMO films during the annealing process were discussed. The results show that annealing reduces the defect-bound emission and improves the crystallization. And annealing promotes the desorption of adsorbed oxygen and the diffusion of oxygen in air. Besides, the near-band-edge emission peak shifts to shorter wavelengths and the band gap (Eg) increases, which should be attributed to the changes in the position of Mg atoms. And the common increase of the Hall mobility and carrier concentration of the ZMO films, which leads to a decrease in the resistivity. Finally, after annealing in air and Ar atmosphere, the resistivity of ZMO films is 63.8 and 2.2 Ω.cm, and the value of Eg is 3.42 and 3.39 eV, respectively. And based on the performance optimization of ZMO films, the efficiency of CIGS solar cells with ZMO buffer layers reaches up to 12.9%. These results are helpful for the application of ZMO buffer layers on CIGS solar cells to improve cell efficiency.     

Alternative cost-effective electrodes for hydrogen production in saline water condition

For the sustainable clean and green energy, hydrogen is considered as one of the prominent renewable energy source which attracted increasing interests in recent years. To produce this, one of the cheapest method is water electrolysis. But several challenges in water electrolysis are, to reduce the maintenance cost, energy consumption and high cost of platinum electrode material. So, in search of an alternative low cost and efficient electrode material, researchers are modifying various metals electrodes to replace the noble metal electrodes. Stainless steel (SS 304) is one of the types of carbon steel material commonly used for various applications. The aim of the work is to explore the stainless steel (SS 304), annealed at high temperature, with and without “hydrogen and argon” environment and tested the samples for hydrogen production in sea water condition (3.5% NaCl). Cr₂O₃ and MnCr₂O₄ spinel oxide formation was observed over the surface of the electrodes after annealing process. From Raman, X-ray Photoelectron Spectroscopy (XPS) and electrochemical measurements it was observed that, the sample prepared under hydrogen and argon environment is stable when compared with the rest of the samples. Decrease in relative amount of chromium oxide was observed for the sample annealed in air environment. The rate of production of hydrogen prepared under “hydrogen and argon” environment is higher and the results are discussed.     

Effect of annealing on the functionality of Bambara groundnut (Vigna subterranea) starch–palmitic acid complex

Bambara groundnut is an underutilised African leguminous crop. This study investigated the effect of annealing on the complexing ability and functionality of Bambara groundnut starch with palmitic acid. Corn starch was included as the reference. Annealing created cracks and pores on the surface of Bambara groundnut and corn starches, respectively. Bambara groundnut starch had significantly higher amylose content, higher peak and final viscosities than corn starch. The peak viscosities of native Bambara groundnut and corn starches significantly reduced with palmitic acid addition. Greater reduction in peak viscosities was observed when the annealed starches were complexed with palmitic acid, suggesting that more palmitic acid was complexed after annealing. This was confirmed by XRD peaks and melting enthalpies. Pasting of native Bambara groundnut and corn starches with palmitic acid resulted in the formation of type I V‐amylose complexes, while type II complexes were formed from annealed starches pasted with palmitic acid.     

Study of an industrially oriented Mg content control technology during annealing process for the LaMg(NiAl)3.5 hydrogen storage alloy

In this paper, we propose a novel and industrial feasible method for the high temperature annealing process of Mg-contained hydrogen storage alloys. To keep the Mg content in the alloy constant during manufacturing at high temperatures, the annealing process is carried out in a sealed container together with an external Mg vapor-producing source. The closed environment reduces the volume for the forming of Mg vapor pressure during the annealing process and excludes the influence from the “Cold Zone” areas of the furnace. External Mg metal, which is also loaded in the container with the alloy, plays an important role in providing the Mg source for the forming of the Mg vapor. This reduces the required Mg amounts from the alloy to produce saturated Mg vapor pressure during the annealing process. Our experimental results show that alloys annealed by this novel method have better electrical discharge properties and cyclic stability compared to alloys prepared by traditional annealing method used by most of hydrogen storage alloy manufacturers. This method could help to reduce the alloy production costs by making the phases' ratio and performance change of the alloy more controllable during the production of this kind of hydrogen storage alloys.     

Lipid accumulation in the new oleaginous yeast Debaryomyces etchellsii correlates with ascosporogenesis

The growth characteristics, lipid accumulation and composition during the life cycle of a newly isolated strain of Debaryomyces etchellsii were studied under nitrogen limiting conditions. This yeast, grown in batch flask or bioreactor cultures, reproduced asexually by buds when nitrogen was available in the growth medium, or sexually by ascospores after nitrogen exhaustion, producing more than 7 g L⁻¹ biomass. During ascosporogenesis, an important increase in the cellular lipid content in dry cell mass occurred, i.e. from a mass fraction of 11.9% in the vegetative phase to 22.4%, in the ascosporogenic phase. During transition of D. etchellsii from batch to continuous cultures using dilution rates 0.026 and 0.019 h⁻¹, a shift from sexual to asexual reproduction was observed. At 0.019 h⁻¹, few pseudomycelia were also formed. The yeast synthesized lipids containing long chain fatty acids (mainly C16 and C18). Budded cells at steady-states contained only 8.6–9.3 % of lipids mass fraction per dry cell mass that were composed of oleic and linoleic acids and, to a lesser extent, of palmitic and palmitoleic acids. Neutral lipids were the major fraction represented 61.8–66.1%, of total lipids followed by phospholipids, which was the only fraction in which linoleic acid predominated over oleic acid.     

X-ray absorptiometry for non-destructive monitoring of the salt uptake in bone-in raw hams during salting

Salt uptake variability in dry-cured ham batches is a problem for the dry-cured ham industry because part of the hams have either an excess or a lack of salt and therefore are more prone to sensory defects. The aim of this study was to evaluate the feasibility of an X-ray inspector for a non-destructive, on line determination of the salt uptake in entire bone-in hams during the salting procedure. Moreover, its usefulness in combination with a modified salting procedure to reduce the salt content and within batch variability was evaluated in an industrial case study. Predictive models for salt content, accurate enough for classification purposes (RMSEV = 0.210−0.257%), were developed using only one X-ray energy (50 kV). The use of an X-ray inspector in combination with slight modifications of the process allowed the reduction of the average salt content a 13.75% and 26.67% and a within-batch standard deviation from 0.45% to 0.21% or 0.26% depending on the reduced target salt content.     

退火温度对DLC膜热稳定性及摩擦学性能的影响

采用非平衡磁控溅射技术分别在氮化硅陶瓷球和高速工具钢圆盘表面制备了类金刚石(DLC)膜。使用箱式电阻炉对DLC膜在大气环境中进行高温退火处理以研究环境温度对DLC膜摩擦学性能的影响;并分别采用激光拉曼光谱仪和球-盘式摩擦磨损试验机对退火处理前后DLC膜的结构和摩擦学性能进行了研究。采用金相显微镜观察了摩擦副磨损表面的形貌。研究发现,随着退火温度的升高,DLC膜中sp3杂化键向sp2杂化键的转化加快,当退火温度为600℃时,DLC膜发生严重的石墨化。而当退火温度为400℃时,DLC膜的摩擦系数及磨损率最小。拉曼测试表明400℃退火处理后DLC膜表层含有Si及SiO2,在摩擦过程中形成了含SiC的转移膜,使得DLC膜的摩擦系数明显降低,磨损减小。研究结果表明,退火处理对DLC膜的热稳定性和摩擦学性能有重要的影响。     

A new object model of batch equipment and procedural control for better recipe reuse

Application of the ISA-88 standard in industrial batch-process control often leads to repetition of information in recipes and to a low level of their reuse. This problem stems from the deficiencies of the standard batch-process control object model. A solution to the problem is proposed that is based on a more sophisticated object model of equipment and procedural control, with dynamically defined and potentially overlapping unit classes. The new concept, together with its elements, is described, and its use is illustrated and validated by means of a real batch control project. The validation is carried out as a comparison of the number of master recipes and unit procedures created under the new object model with the number of master recipes and unit procedures needed to perform the same functionality using the standard object model. The comparison demonstrates that the proposed approach has a significant advantage.