On manifestation & physics of the Kurdjumov and spillover effects in carbon nanostructures,under intercalation of high density hydrogen

Abstract

Some experimental evidences and the physics (thermodynamics) of the nanoscale self-intercalation of high-density gaseous molecular hydrogen (ρ?≈?0.045?g/cm³, T?≈?300?K) into surface nanoclusters in highly oriented pyrolytic graphite and epitaxial graphene, as well as the nanoscale self-intercalation of high density solid molecular hydrogen (ρ?≈?0.5?g/cm³, T?≈?300?K, the compressed pressure ～ 0.5 Mbar) into graphite nanofibers are considered, with regard to the problem of compact and efficient hydrogen on-board storage and other clean energy applications. Perspectives of further developments of these results are considered, as well.     

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.     

Comparative analysis of energy absorption behavior of tapered and grooved thin-walled tubes with the various geometry of the cross section

ABSTRACT

In this paper, Crush force efficiency (CFE), Specific Energy Absorption (SEA), Energy Absorption per Crush Length (E_cl), Maximum and average crush forces of straight and grooved tapered thin-walled tubes with various cross-section shapes (circle, ellipse, square, rectangle, hexagon, and octagon) have been studied. The effects of taper, the groove (as initiator) and their interaction have been presented in the current study using Finite Element Method as a numerical method. The tubes have the same volume, height, average cross-section area, thickness and material and have been subjected to axial and oblique dynamic loading. The results of simulations show that the section's geometry, taper and groove addition have a significant effect on energy absorption behavior and the hexagon cross section have better energy absorption behavior compared with other considered geometries. On the other hand, it was found that the behavior of these structures could improve against dynamic axial and oblique impact loading with the cost-effective geometry modifications. These results could help to improve and choose appropriate energy absorber structure based on desirable crush force and energy absorbing characteristics.     

预制构件厂精益设计方案评价研究

作为新兴产业，预制构件厂的设计和运营是实现装配式建筑构件高效率、高质量生产和配送的关键前提要素。而精益设计可以帮助预制构件厂从源头消除浪费、提高生产效率，所以对预制构件厂构建精益设计方案并且评价实施后的效果无疑是一个重点问题。针对以上问题，本文从节约资金能力、生产能力、交付能力、持续改进能力等4个视角构建出了预制构件厂精益设计评价指标体系，采用了AHP-DEMATEL法确定了指标的权重，并用改进TOPSIS法得到最终结果，最后以某预制构件厂为例验证了精益设计评价指标体系的合理性和可行性。     

Design of an aeronautic pitot probe with a redundant heating system incorporating phase change materials

The aim of this work is the design of a pitot probe (PP) prototype in order to retard the cool down of the tip, in case of a heating element failure. The viability of operation in flight conditions is evaluated. The design consists of a redundant heating system incorporating phase change materials (PCM). Combining experimental observations of ice formation with the implementation of the conjugate heat transfer (CHT) model, with the addition of the heat release due to the phase change of the PCM, the numerical evaluation is developed. The modelling assumptions and numerical implementation of the phase change process are presented. Then, the selection an appropriate PCM is based on the low flammability and volume dilation and the quantitative effects of the material properties on the heat transfer. A commercial PCM solution based on salt hydrates was chosen as the most adequate for the design. The parametric design of the prototype, based on the design of experiment method and fractional factorial testing, is established. A multiple linear regression model was obtained in order to maximize the cooling retardation. The numerical simulations demonstrate that the prototype PP tip temperature remains 194 s longer above 0 °C than that of the conventional model analyzed.     

南阳盆地北缘更新世以来的构造演化特征

南阳盆地是白垩纪晚期以来持续发育的断陷盆地，通过对南阳盆地钻孔及河流阶地的研究，并结合ESR测年方法，对南阳盆地北缘更新世以来的构造演化特征进行了分析。结果表明：研究区冲洪积层主要由全新统、上更新统、中更新统组成，分别构成了湍河的Ⅰ级、Ⅱ级、Ⅲ级阶地；中更新统以来，研究区垂直升降运动较为明显，湍河下蚀作用十分强烈，多级阶地的结构体现了更新世中晚期以来的总体持续下蚀过程，且时间和空间上表现出不均衡性，其下蚀速率由慢至快又逐渐减缓。     

基于设备改造的选煤厂介质消耗控制研究

同忻选煤厂采用重介质选煤技术,磁性介质的消耗较大,为此,相关技术人员针对介质回收系统设备进行了改造设计。改造后,设备运行稳定,介质消耗降低,提高了原煤的分选效率,创造了较好的安全经济效益。     

Comparison of modeling methods for wind power prediction: a critical study

Prediction of power generation of a wind turbine is crucial, which calls for accurate and reliable models. In this work, six different models have been developed based on wind power equation, concept of power curve, response surface methodology (RSM) and artificial neural network (ANN), and the results have been compared. To develop the models based on the concept of power curve, the manufacturer’s power curve, and to develop RSM as well as ANN models, the data collected from supervisory control and data acquisition (SCADA) of a 1.5 MW turbine have been used. In addition to wind speed, the air density, blade pitch angle, rotor speed and wind direction have been considered as input variables for RSM and ANN models. Proper selection of input variables and capability of ANN to map input-output relationships have resulted in an accurate model for wind power prediction in comparison to other methods.