Influence of sintering temperature on ion dynamics of Na0.5Bi0.5TiO3-δ: Suitability as an electrolyte material for SOFC

Sodium bismuth titanate samples with different morphology were synthesized via varying the sintering temperature from 1000 to 1150 °C. The conductivity was significantly affected with the morphology of the system. The dynamics of ions was understood from the conductivity spectra. The dc conductivity, hopping frequency and exponent values were extracted from the conductivity spectra analysis. The impedance and modulus spectroscopy along with exponent behaviour suggested short range hopping for the sample sintered at 1000 °C and followed Ghosh scaling instead of Summerfield scaling. While long-range hopping was observed for the samples sintered at 1150 °C and it followed both the Summerfield scaling and Ghosh scaling. Moreover, the stability of the sample is checked in reducing atmosphere.     

两个大型住宅项目设计配套消防备供电源供电方案分析及优劣对比

通过对两个大型住宅项目配置消防备供电源供电方案进行对比,分析由此产生的建设安装造价成本高低,以及后期物业管理程序的难易程度,总结出适宜于大型住宅项目的消防备供电源供电方案,既能降低建设投资成本,又可以简化后期物业管理程序,更好地保障消防系统供电安全,值得推广。     

The long-run price elasticity of residential demand for electricity: Results from a natural experiment

In one of two otherwise similar adjacent regions in a Canadian province, the price of electricity changed abruptly, substantially, and permanently. That natural experiment allows for a simple differences-in-differences calculation of the long-run price elasticity of residential demand for electricity. This analysis is of interest for two reasons. First, it is a rare circumstance when such a methodology can be used. Secondly, the magnitude of the elasticity estimate has substantial implications for utilities, regulators, and policymakers.     

Simulation and prediction of hydrological processes based on firefly algorithm with deep learning and support vector for regression

ABSTRACT

Hydrological processes are hard to accurately simulate and predict because of various natural and human influences. In order to improve the simulation and prediction accuracy of the hydrological process, the firefly algorithm with deep learning (DLFA) was used in this study to optimise the parameters of support vector for regression (SVR) automatically, and a prediction model was established based on DLFA and SVR. The hydrological process of Huangfuchuan in Fugu County, Shanxi Province was taken as the research object to verify the performance of the prediction model, and the results were compared with those by the other six prediction models. The experimental results showed that the proposed prediction model achieved improved prediction performance compared with the other six models.     

循环荷载作用下钢桥面铺装疲劳损伤失效行为研究

针对钢桥面铺装工程中普遍采用的改性沥青(Stone Matrix Asphalt,SMA)、浇筑式沥青(Guss asphalt,GA)、环氧沥青(Epoxy asphalt,EP)混合料双层铺装结构,进行了循环车载作用下钢桥面与沥青混凝土铺装疲劳损伤特性理论分析与试验研究。基于疲劳损伤度,研究了钢桥面铺装疲劳损伤失效行为和疲劳开裂过程中损伤场、应力和应变场动态演变机制,推导出疲劳失效时的损伤场、应力和应变场计算表达式,并给出钢桥面铺装疲劳寿命理论公式。以三座钢箱梁桥桥面铺装(润扬长江大桥2005,南京长江三桥2005,苏通大桥2008)为例,对不同铺装结构组合方案下的复合梁进行疲劳试验分析和使用寿命理论预测。实例研究结果表明,钢桥面铺装疲劳损伤失效行为预估模型合理可行;相较于改性沥青、浇筑式沥青,环氧沥青混合料具有较强高的强度低变形能力,更适合于大跨径钢桥面铺装抗疲劳的设计要求;由环氧沥青混合料组合而成的“双层环氧沥青混凝土”和“浇注式沥青混凝土(下层)+环氧沥青混凝土(上层)”的抗疲劳性能优于其它沥青混合料铺装结构组合方案,同等厚度组合情况下疲劳使用寿命可延长1倍~2倍以上;“双层环氧沥青混凝土”已应用于润扬长江大桥、南京长江三桥和苏通长江大桥钢桥面工程,并已成功运行10年以上,其跟踪观测结果良好。     

地下水渗流场可视化方法与应用研究

渗流场是反映地下水位与运移时空动态特征的有效形式,水位红线是对地下水开采严格管控的重要指标。从地下水渗流的流线绘制、流速计算、流场种子点与终止点选择、流线追踪4个方面论述了孔隙地下水渗流场可视化算法,设计了一种新的种子点布局方法表征地下水渗流场,采用改进的EULER方法实现流线的可视化表达。并将地下水渗流场空间分异性和水位红线进行融合与叠加分析,基于地下水渗流场从2D的视角揭示地下水的开采强度与超采程度的空间分布特征,自动圈定地下水超限采的区域范围。可为地下水的合理开采方案与地质管理保护措施的制定提供空间辅助决策支持。     

Identification of factors that accelerate hydrogen production by Clostridium butyricum RAK25832 using casamino acids as a nitrogen source

The ability of Clostridium butyricum RAK25832 to use casamino acids as a nitrogen source was investigated. Strain RAK25832 showed the capacity to utilize different types of carbon sources. With glucose as a carbon source (10 g/L), the preferred final concentration of casamino acids was 26.67 g/L, with a cumulative hydrogen production, production rate, and yield of 2505 mL H₂/L, 160 mL/h, and 1.81 mol H₂/mol glucose, respectively. Eighteen metal elements were screened to identify the most important metals for biohydrogen production, and four elements were optimized. The optimal medium composition was MgCl₂·6H₂O (0.1 g/L), K₂HPO₄·3H₂O (6.67 g/L), NaHCO₃ (2.6 g/L), and FeCl₂·4H₂O (0.002 g/L). Vitamin supplementation of the medium showed no significant effect on hydrogen production. Under the optimized conditions, cumulative hydrogen production reached 3074 mL H₂/L. This is the first study to demonstrate the use of casamino acids as a nitrogen source by C. butyricum.     

Should medium-sized contractors still implement home-made information technologies on construction sites?

Despite the increasing dissemination of the Building Information Modeling (BIM) approach, many firms are still far from BIM and are only starting to adopt information technologies. We conducted an ethnographic action research with an industrial partner that implements information technologies on its construction sites, with a strong preference for home-made applications. Results show that the development of such applications faces difficulties and that multiple iterations and versions are necessary before achieving the expected goals because the required competencies are lacking among internal development teams. Moreover, initial needs evolve considerably throughout the application’s development and evaluation process. However, notwithstanding the difficulties encountered during the different application development phases, the industrial partner believes the decision to be worthwhile because of the desire to have internal control over the project data and the need to consider certain specificities related to business processes.     

Microscopic investigation of the formation of a thermoset wheat gluten network in a model system relevant for bread making

Although the impact of heat on molecular properties of wheat gluten is well understood, changes in its microstructure have rarely been studied. Here, formation of the thermoset gluten network in a model system relevant for bread baking was studied with confocal laser scanning microscopy and protein network analysis. From 65 °C onwards, gluten converts from thick aligned protein strands in a highly branched and homogeneous network of small thin protein threads. Neither gliadin incorporation in the network nor application of aqualysin 1, the thermo-active serine peptidase from Thermus aquaticus which recently has been reported to hydrolyse gluten proteins in dough only at temperatures exceeding 80 °C, impacts on the gluten microstructure. As starch causes structure setting itself and thereby decreases protein mobility, molecular scale changes in the gluten network at temperatures exceeding 80 °C brought about by aqualysin 1 do not impact its microstructure.     

Enumeration of stereo,position and chiral isomers of polysubstituted giant fullerenes: applications to C180 and C240

Abstract

We have developed combinatorial generation function methods that combine M?bius inversion and character cycle indices for the enumeration of stereo, position and chiral isomers of icosahedral giant fullerenes C₁₈₀ and C₂₄₀. Techniques are also developed for the machine perception of symmetries of especially giant fullerenes. The techniques yield, symmetries, position, stereo and chiral isomers of giant fullerenes which we illustrate with applications to icosahedral C₁₈₀(I_h), and C₂₄₀(I_h). We have obtained combinatorial tables for the isomers of C₁₈₀X_k and C₂₄₀X_k. Our results point to errors in previous computations on C₂₄₀ permutations. We have also outlined applications to NMR and ESR spectroscopy.