Scanned images resolution improvement using neural networks

A novel method of improving the spatial resolution of scanned images, by means of neural networks, is presented in this paper. Images of different resolution, originating from scanner, successively train a neural network, which learns to improve resolution from 25 to 50 pixels-per-inch (ppi), then from 100 to 200 ppi and finally, from 50 to 100 ppi. Thus, the network is provided with consistent knowledge regarding the point spread function (PSF) of the scanner, whilst it gains the generalization ability to reconstruct finer resolution images unfamiliar to it. The novelty of the proposed image-resolution-enhancement technique lies in the successive training of the neural structure with images of increasing resolution. Comparisons with the image scanned at 400 ppi demonstrate the superiority of our method to conventional interpolation techniques.     

The synthesis of symmetrical and unsymmetrical alkylaminonaphthalic‐1,8‐N‐alkylimides

Symmetrical 4‐n‐alkylamino and 2‐(n‐alkylamino)naphthalic‐1,8‐N‐alkylimides are prepared with primary amines from 4‐ and 2‐halogenonaphthalic‐1,8‐anhydrides in N‐methylpyrrolidinone. 3‐Halogenonaphthalic‐1,8‐anhydrides only react at the anhydride. Unsymmetrical 4‐compounds result by reaction of primary amines with the anhydride in ethanol and then the 4‐halogeno‐N‐alkyl product in N‐methylpyrrolidinone with primary or secondary amines © 2000 Society of Chemical Industry     

Multirate SPAMM tagging

Many magnetic resonance tagging sequences rely on periodicity in order to produce a uniform tagging grid that covers the whole image plane. This, however, is not always desirable, since motion may be restricted to specific parts of the image, and also different motion characteristics may call for different tagging grid densities. In this paper, we present a combination of the spatial modulation of magnetization 1-1 method with selective excitation pulses that can be used in order to restrict the tagging grid only to regions of interest and produce tagging grid of different density in each region. The method is fast and easy to implement even on older or less expensive systems, since it does not require extensive gradient switching.     

What makes an accurate and reliable subject-specific finite element model? A case study of an elephant femur

Finite element modelling is well entrenched in comparative vertebrate biomechanics as a tool to assess the mechanical design of skeletal structures and to better comprehend the complex interaction of their form–function relationships. But what makes a reliable subject-specific finite element model? To approach this question, we here present a set of convergence and sensitivity analyses and a validation study as an example, for finite element analysis (FEA) in general, of ways to ensure a reliable model. We detail how choices of element size, type and material properties in FEA influence the results of simulations. We also present an empirical model for estimating heterogeneous material properties throughout an elephant femur (but of broad applicability to FEA). We then use an ex vivo experimental validation test of a cadaveric femur to check our FEA results and find that the heterogeneous model matches the experimental results extremely well, and far better than the homogeneous model. We emphasize how considering heterogeneous material properties in FEA may be critical, so this should become standard practice in comparative FEA studies along with convergence analyses, consideration of element size, type and experimental validation. These steps may be required to obtain accurate models and derive reliable conclusions from them.     

Effect of microstructure on electrical and mechanical properties of La5.4WO12-δ proton conductor

The relationships between microstructural characteristics and electrical as well as mechanical properties of La_5.4WO_12-δ (LWO54) materials were studied. Polycrystalline LWO54 samples revealed identical transport mechanisms regardless of the sample microstructure. The studied samples show predominately proton conductor behaviour below 800?°C and become predominant n-type and oxygen ion conductors above this temperature. The magnitude of the total conductivity is enhanced with larger grain size and lower porosity. Young’s modulus decreased by 20% with increasing temperature up to 1000?°C regardless of grain size and atmosphere. Fracture strength was determined via ring-on-ring bending tests, yielding values that strongly depended on microstructural characteristics and homogeneity of the microstructure. Elevated temperature deformation studies revealed that creep is governed by cation diffusion mechanism.     

一等奖:时间的层级

该竞赛方案是我们在国立雅典科技大学建筑工程学院的毕业论文项目的一部分.学校开展的大多数研究是关于雅典的城市环境问题处理,研究与干预的对象主要集中在城市特定区域.风景园林设计学科整合在建筑学院中.在过去3年的学习中,我们选择了大尺度的项目进行研究.然而,我们发现要对自然风景进行干预是极其困难的,甚至很小的一个举动就会在自然里留下痕迹.竞赛方案是有关于对柯蒂齐泻湖的干预.柯蒂齐泻湖位于希腊伯罗奔尼撒半岛西部,有温和的冬季和温暖的夏季,是希腊最重要的泻湖之一,也是往来非洲的候鸟栖息和中转的地方.     

Cone Calorimeter and Thermogravimetric Analysis of Glass Phenolic Composites Used in Aircraft Applications

The increasing use of composite materials in aircraft cabins and structures poses significant challenges in order to maintain and improve the fire safety of aviation. In this work, the flammability characteristics of a commercial glass-fibre reinforced phenolic composite (GFRP) used for aircraft cabin partitions and furnishing are investigated experimentally. Thermogravimetric analysis under inert atmosphere at several heating rates provided information on the thermal decomposition process. The degradation process is modelled with one and two-step mechanisms using the Ozawa–Flynn–Wall iso-conversional method and the GPYRO numerical code which utilizes a genetic algorithm optimization scheme. The estimated activation energy and pre-exponential factor values, especially in the two-step case (77.18 and 104.69 kJ/mol and 2.60 × 106 and 3.19 × 106 min−1 for the first and the second step respectively), recover reasonably well the conversion degree and its derivative. Tests with a cone calorimeter (CC), performed at different incident heat fluxes, provided information on the reaction to fire characteristics of the material and the influence of the heat flux on the combustion process. In general, combustion proceeds in two stages, flaming and smoldering combustion. The CC results assisted by scanning electron microscopy photos provide information on the charring characteristics of the material. The critical heat flux for ignition and the corresponding ignition temperature are estimated, correlating heat fluxes with time to ignition. Thermally thin and thick models are considered, as well as a modified technique bridging the gap between these limit cases and therefore valid for thermally thin and thick but also intermediate conditions (more pertinent in the present case). The results for this latter approach are $$\dot{q}^{\prime\prime}_{ig,cr}$$ ~ 20 kW/m2 and Tig = 469°C, providing also complementing information on thermophysical properties, such as thermal diffusivity, α = 1.23 × 10−7 m2/s, thermal conductivity, k = 0.325 W/(m K) and specific heat capacity, c = 1.330 kJ/(kg K). This work provides information on the reaction to fire characteristics of GFRP, but also on physical and flammability properties in a form suitable to be used in numerical codes, for the prediction of fire and evacuation scenarios. The influence of the reinforcement structure on the fire behaviour of the composite is also illustrated and discussed.     

Freestanding foils of nanotube arrays fused with metals

Novel freestanding foils of vertically aligned carbon nanotube arrays (VANTAs) fused with metals are fabricated in a scalable four-step process of (1) VANTA synthesis, (2) deposition of partially infused metal film, (3) removal from growth substrate, and (4) optional deposition of a second metal film on the back side. Mechanical and electrical testing demonstrates excellent contact between the VANTA and the interface-infused metal layers.