Efficient implementation of pseudochaotic piecewise linear maps with high digitization accuracies

In this paper we discuss the efficient implementation of pseudochaotic piecewise linear maps with high digitization accuracies, taking the R'enyi chaotic map as a reference. The proposed digital architectures are based on a novel algorithmic approach that uses carry save adders for the nonlinear arithmetic modular calculations arising when computing piecewise linear maps with a finite precision. As a result, the system can be implemented by digital circuits obtaining high throughputs, which are not dependent on the digital resolution while involving a hardware complexity linearly proportional to the number of bits used for representing the discretized state. The proposed solutions result to be particularly suitable for the implementation of pseudorandom number generators based on pseudochaos, or for the definition of efficient digital blocks that can be integrated in most of the pseudochaotic cyphers proposed in the literature. Copyright © 2010 John Wiley & Sons, Ltd.     

Effectiveness of active and modified atmosphere packaging on shelf life extension of a cheese tart

This study evaluated the shelf life extension of a cheese cake subjected to modified atmosphere (MAP) and active packaging (AP). Cheese cakes were packaged under different N₂/CO₂ ratios (70/30 and 20/80) (MAP batches), by placing a sachet of an iron oxide-based oxygen absorber inside trays (AP batch) and with air (air batch). Changes in microbial growth, in-package gas composition, chemical–physical parameters including texture and sensory attributes were monitored for 48 days at 20 °C. AP allowed a mould-free cheese cake shelf life of 48 days, MAP extended the shelf life of samples packaged under 30% and 80% CO₂ up to 14 and 34 days, respectively, whereas tarts stored with air spoiled after 7 days. MAP resulted in a significant increase in hardness after 14 days of storage, whereas AP tarts recovered the initial texture after 48 days. Panellists judged AP tarts over the acceptability threshold during the whole shelf life of cheese tarts.     

面向永恒的建筑

每座建筑的位置一般不会改变,改变的是它所经历的沧海桑田。无论是应用一套方案复制多个建筑,还是实现建筑的多样化,只有建筑方案的存在是短暂的,而建筑本身往往会长存于世,见证着它周围社会及文化的变迁。这意味着建筑必须面对时间的流逝做出抉择——何时该随之改变,何时该保持不变,何时该果断谢幕。一些建筑（以及更多的城市开发区）往往要比它们的建筑师的寿命更长,因而对建筑而言,未来不过是另一个现在的翻版。此外,原有的（文化）基础也是建筑所必须面对的。或被动或主动,建筑总是将自己置身于艰难的位置,要面对过去的一切。而最终,使用者检验建筑要花费的正是时间,正是从建筑竣工的那一刻起,它也在以某种方式控制着自己发展的节奏。那么,我们能否设计时间呢？本文将通过横向剖析,透过与时间概念的关系,来审视新近的西班牙建筑。     

Ionic liquid-stabilized nanoparticles of charge transfer-based conductors

Well-dispersed nanoparticles of molecule-based conductors, namely TTF·TCNQ and TTF[Ni(dmit)₂]₂, have been prepared in organic solution using 1-butyl-3-metylimidazolium tetrafluoroborate as a stabilizing agent. TTF·TCNQ nanoparticles (prepared at room temperature) exhibit sizes ranging from 2 to 5.5 nm, whereas those of TTF[Ni(dmit)₂]₂ (prepared at ?80 °C) are larger (sizes in the 16–45 nm range). Nanoparticle powders have been characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and by transport measurements.     

TRISO-fuel element thermo-mechanical performance modeling for the hybrid LIFE engine with Pu fuel blanket

A TRISO-coated fuel thermo-mechanical performance study is performed for the fusion-fission hybrid Laser Inertial Fusion Engine (LIFE) to test the viability of TRISO particles to achieve ultra-high burn-up of Pu or transuranic spent nuclear fuel blankets. Our methodology includes full elastic anisotropy, time and temperature varying material properties, and multilayer capabilities. In order to achieve fast fluences up to 30 × 10²⁵ n m⁻² (E > 0.18 MeV), judicious extrapolations across several orders of magnitude of existing material databases have been carried out. The results of our study indicate that failure of the pyrolytic carbon (PyC) layers occurs within the first 2 years of operation. The particles then behave as a single-SiC-layer particle and the SiC layer maintains reasonably-low tensile stresses until the end-of-life. It is also found that the PyC creep constant, K, has a striking influence on the fuel performance of TRISO-coated particles, whose stresses scale almost inversely proportional to K. Conversely, varying the geometry of the TRISO-coated fuel particles results in little differences in terms of fuel performance.     

A CO2‐stable hollow‐fiber membrane with high hydrogen permeation flux

A Mo‐substituted lanthanum tungstate mixed proton‐electron conductor, La_5.5W_0.6Mo_0.4O_11.25?δ (LWM04), was synthesized using solid state reactions. Dense U‐shaped LWM04 hollow‐fiber membranes were successfully prepared using wet‐spinning phase‐inversion and sintering. The stability of LWM04 in a CO₂‐containing atmosphere and the permeation of hydrogen through the LWM04 hollow‐fiber membrane were investigated in detail. A high hydrogen permeation flux of 1.36 mL/min cm² was obtained for the U‐shaped LWM04 hollow‐fiber membranes at 975°C when a mixture of 80% H₂?20% He was used as the feed gas and the sweep side was humidified. Moreover, the hydrogen permeation flux did not significantly decrease over 70 h of operation when fed with a mixture containing 25% CO₂, 50% H₂, and 25% He, indicating that the LWM04 hollow‐fiber membrane has good stability under a CO₂‐containing atmosphere. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1997–2007, 2015