Separation dynamics of hydrogen isotope gas in mesoporous and microporous adsorbent beds at 77 K: SBA-15 and zeolites 5A,Y, 10X

The separation of a hydrogen isotope mixture on porous materials was studied using equilibrium and breakthrough experiments. The adsorption equilibria of H₂ and D₂ on SBA-15 with mesopores and molecular sieves 5A, Y, and 10X with micropores were measured at 77 K using the volumetric method. The breakthrough experiments of a H₂ and D₂ mixture in each adsorbent bed were carried out at various conditions of flow rate and pressure. The equilibrium ratio of D₂ to H₂ on mesoporous molecular sieves was larger than the ratio on microporous molecular sieves (SBA-15 > 10X > Y > 5A), but the difference among the adsorbents decreased with increases in pressure. On the other hand, the order of breakthrough separation factor showed the opposite result (SBA-15 < 10X < Y < 5A). The breakthrough separation factors for zeolite 10X was approximately equal to the equilibrium ratio of D₂ to H₂ at the corresponding partial pressures, whereas zeolites 5A and Y showed higher breakthrough separation factors than their equilibrium ratios. In SBA-15, the separation factors from breakthrough results were even smaller than the corresponding equilibrium ratio. In the microporous adsorbent with a limited pore size (zeolite 5A in the study), the diffusion mechanism contributed to the separation of hydrogen isotope gases as one of key factors.     

“生活里充满了惊奇!”时尚鞋子品牌Mary Ching设计师的家

第一次见到Mary Ching品牌的时尚高跟鞋,是在博雅珊画廊主人的家庭派对上。优雅的女主人一袭黑色天鹅绒的礼服,配上那双水蛇皮高跟鞋,高贵和性感便不露声色地显现,魅力更是华光四射。就在那个派对上,我认识了Mary Ching的女设计师和创始者,华裔英籍的     

The indirect synthesized method induced relaxor state to ferroelectric characteristics for Pb0.95La0.05(Fe2/3W1/3)0.65Ti0.35O3 ceramics

Pb_0.95La_0.05(Fe_2/3W_1/3)_0.65Ti_0.35O₃ ceramics are synthesized by using the conventional direct oxide synthesized (DS) method and the indirect synthesized (IS) method. The low-field dielectric response is investigated by using the empirical law, two ordering models and the space charge polarization. The temperature-dependent dielectric peak of the samples prepared using the IS synthesized method is obviously increased; the temperature-dielectric constant is changed to sharp and the diffused phase characteristic is decreased. It is concluded that the IS synthesized method can change the dielectric natures from a relaxor like behavior to a sharp ferroelectric state. The space charge polarization is also changed by using the IS synthesized method. According to these results, it is suggested that the 1:1 ordered domain is enhanced based on the random-site type by using the IS synthesized method for Pb_0.95La_0.05(Fe_2/3W_1/3)_0.65Ti_0.35O₃ ceramics. However, if the sintering temperature is not high enough for some calcined powders, the random-site type can be changed to the space charge type.     

Properties of radiation stable, low viscosity impregnating resin for cryogenic insulation system

Impregnating resins in fusion magnet technology are required to be radiation stable, low viscosity, long usable life and high toughness. To meet these objectives, we developed a new epoxy based composite which consists of triglycidyl-p-aminophenol (TGPAP) epoxy resin and isopropylidenebisphenol bis[(2-glycidyloxy-3-n-butoxy)-1-propylether] (IPBE). The ratio of TGPAP to IPBE can be varied to achieve desired viscosity and working time. The boron-free glass fiber reinforced composites were prepared by vacuum pressure impregnation. The radiation resistance was evaluated by ⁶⁰Co γ-ray irradiation of 1 MGy at ambient temperature. The mechanical properties of the composites have been measured at room temperature and at 77 K.     

Developing the index for product design communication and evaluation from emotional perspectives

Often customers make their purchase decision based on price, quality and functionality of the product. Sometimes the decision is influenced by the perceived value, which is always subjective and emotion-driven. In order to ensure successful launch of a product, it is extremely important to predict the perceived value of design alternatives systematically based on the common language understood by both target users and designers. However, the index for communicating and evaluating such value from emotional perspective is not available in the literature. Therefore, the objective of this research is to extract key indexes of perceived value from emotional perspectives and develop an effective algorithm to evaluate products. First, through literature review and the interview of participants, many scenarios of purchase decision were collected. A focus group was invited to identify the essential elements that influence the perceived value of products. Followed by a large scale questionnaire survey and factor analysis, four indexes were extracted. These indexes, named as FASE Index in brief, included features, association, social-esteem, and engagement. Second, by combining the fuzzy mathematics and the pairwise comparison method, an evaluation model was developed. Third, the perception differences of sample products were conducted to verify the validity of FASE index. The findings of this study demonstrated that FASE index was effective for decision making in product design.     

Using Statistical Regressions to Identify Factors Influencing PM2.5 Concentrations: The Pittsburgh Supersite as a Case Study

Using data from the Pittsburgh Air Quality Study, we find that temperature, relative humidity, their squared terms, and their interactions explain much of the variation in airborne concentrations of PM _2.5 in the city. Factors that do not appreciably influence the concentrations over a full year include wind direction, inverse mixing height, UV radiation, SO ₂ , O ₃ , and season of the year. Comparison with similar studies of PM _2.5 in other cities suggests that the relative importance of different factors can vary greatly. Temperature and relative humidity are important factors in both Pittsburgh and New York City, and synoptic scale meteorology influencing these two sites can explain much of the pattern in PM _2.5 concentrations which peak in the summer. However, PM _2.5 levels in other cities have different seasonal patterns and are affected by a number of other factors, and thus the results presented here cannot be generalized to other locations without additional study.     

Second‐Law Based Thermodynamic Analysis of a Novel Heat Exchanger

In the present investigation, second‐law based thermodynamics analysis was applied to a new heat exchanger with helical baffles. The helical baffles are designed as quadrant ellipses and each baffle occupies one quadrant of the cross‐section of the shell side. Experimental tests were carried out with cold water in the tube side with a constant flow rate, and hot oil on the shell side with flow rate range from 4–24 m³/h. The temperatures and pressures for the inlet and outlet of both sides were measured. The heat transfer, pressure drop, entropy generation, and exergy loss of the new heat exchanger were investigated and compared with the results for a conventional shell‐and‐tube heat exchanger with segmental baffles. The computed results indicated that both the entropy generation number and exergy losses of the new heat exchanger design are lower than those of the heat exchanger with segmental baffles, which means that the novel heat exchanger has a higher efficiency than the heat exchanger with segmental baffles, from the second‐law based thermodynamics viewpoint.     

A new comprehensive model for nucleate pool boiling heat transfer of pure liquid at low to high heat fluxes including CHF

Based on the fractal distribution of nucleation sites present on heating surfaces, a new comprehensive model is developed for the nucleate pool boiling of pure liquid at low to high heat fluxes including the critical heat flux (CHF). The proposed model is expressed as a function of total number, minimum and maximum sizes of active nucleation sites, fractal dimension, superheat temperature, and properties of fluids. No additional empirical constant is introduced in the proposed model. This fractal model contains less empirical constants than the conventional models. The model predictions are in good agreement with the available experimental data.     

Modular generic software system for cellular FMS

The development of complex, flexible manufacturing systems (FMS) is very much dependent on the development of the associated control software. Because of the complexity involved, reliable and quality FMS software with comprehensive functionality and sophistication is difficult to design, implement and maintain. This paper proposes a modular, generic software system. Using the software developed, a range of cellular FMS (CFMS) control software can be generated from a library of well-defined software building blocks. This paper also describes the design of a generic software architecture, covering specifications for the control architecture, controller structure and software platform. Application of the building block concept has addressed the CFMS software problem effectively and the resulting software possesses a high degree of modularity and flexibility.